WO1997032610A1

WO1997032610A1 - Method and apparatus for disinfecting medical instruments

Info

Publication number: WO1997032610A1
Application number: PCT/US1997/002977
Authority: WO
Inventors: Durward I. Faries, Jr.; Bruce R. Heymann
Original assignee: Medical Products, Inc.
Priority date: 1996-03-05
Filing date: 1997-03-05
Publication date: 1997-09-12
Also published as: AU2057297A

Abstract

A disinfection system (1) for medical instruments includes a basin (20) containing a disinfectant (glutaraldehyde) solution with a tray having preformed portions to receive instruments for disposal in the basin (20). The system may be disposed on a support structure, or be integral with a storage facility. The instruments are exposed to the solution heated to a certain temperature for a specific duration to achieve either an intermediate or high level disinfection. Ultrasonic energy may be injected into the solution for a short duration to enhance disinfection. The basin (20) is disposed within a hood (2) having a filtration system (21) including a prefilter followed by primary and secondary filters to remove noxious or toxic contaminants from vapors emitted by the heated solution. A control console (8) disposed on the hood (2) includes control switches (20, 44, 46, 48, 50, 54, 55, 58) and displays (38, 42, 52) for various control parameters of the disinfection including the temperature of the solution, the time remaining until the disinfection cycle is complete and the number of days the solution has been in use. The basin (20) includes a drainage opening for draining the solution from the basin wherein a drainage system may be employed with the disinfection system to facilitate drainage of the solution from the basin (20) to a container or common sink.

Description

Method and Apparatus for Disinfecting Medical Instruments

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from provisional U S Patent Application Serial No 60/012,831 filed March 5, 1996, entitled "Method and Apparatus for Disinfecting Medical Instruments"

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention pertains to improved methods and apparatus for disinfecting medical instruments The present invention has particular utility in the disinfection of flexible and rigid endoscopes and involves disposing the endoscope or other instrument in a heated temperature controlled solution for a measured period of

2. Discussion of the Prior Art

Arthroscopic instruments typically include various internally disposed channels for receiving different tools commonly used for numerous tasks including biopsy extraction, gas and fluid passage, circulation and other surgical procedures Several methods known for cleaning arthroscopic instruments typically include brushing and scrubbing However, in order to disinfect or sterilize the instrument, all of the instrument surfaces must be exposed to a disinfectant solution, such as an activated dialdehyde solution, for a specific length of time dependent upon the temperature of the solution Merely submerging the instrument in the solution may not be sufficient to n

guarantee that all instrument surfaces, especially the internally disposed channels, are fully exposed

Certain prior art techniques assure that all instrument surfaces are exposed to the disinfectant solution by applying ultrasonic energy to the solution and/or by flushing the solution through the instrument channels Specifically, Sierra (U S Patent No 3,697,222) discloses sterilization of laboratory, surgical and dental instruments through use of the combination of an acid aqueous solution of glutaraldehyde and ultrasonic sound energy The glutaraldehyde solution is optimally heated to temperatures exceeding 45°C, but cooling and/or heating the solution to temperatures as low as approximately 15°C or 25°C (i e , room temperature) is said to yield acceptable performance

Boucher (U S Patent No 3,708,263) discloses a sterilization method wherein contaminated objects are submerged in a tank of ultrasonically activated glutaraldehyde solution Subsequently, the objects are submerged into a second tank of ultrasonically activated sterile water to remove the glutaraldehyde, and this is followed by a final drying stage

Voit (U S Patent No 4,308,229) discloses a sterilization technique wherein materials are immersed in a heated disinfectant solution subjected to ultrasonic energy

Currently, medical instruments are typically disinfected by initially pre-cleanmg the instruments with an enzymatic detergent The detergent utilizes enzymes to dissolve and lift protein while the remaining parts of the detergent remove dissolved organic residue from the instruments The detergent is able to remove debris from inaccessible channels within the medical instruments, thereby improving the disinfection After pre-cleanmg, the instruments are typically rinsed in water or other solution to remove the detergent and other organic matter clinging to the instruments The instruments are then placed in a disinfectant solution for either ten or forty-five minutes with the solution heated to 20°C or 25°C Upon removal from the disinfectant solution, the instruments are again rinsed to remove any solution remaining on the instruments A commonly used disinfectant solution is a glutaraldehyde based solution such as the Cidex family of products sold by Johnson & Johnson Medical, Inc These solutions are typically activated by an activator applied to the solution Various levels of disinfection may be effected by immersing the instruments in the disinfectant solution heated to certain temperatures for specific durations of time For example, intermediate level disinfection may be accomplished by immersing the medical instruments in the solution for at least ten minutes with the solution heated to 20°C to 25°C The bacterial kill rate for this level of disinfection is approximately in the range of 87 9% to 99 98% depending upon the temperature and the particular Cidex product used High level disinfection, yielding a bacterial kill rate of approximately 100%, is accomplished by immersion in a Cidex glutaraldehyde solution for at least forty-five minutes with the solution heated to 25°C The level of disinfection required is typically dependent upon the intended use of the instrument For instance, intermediate disinfection is commonly required for medical instruments where a risk of cross contamination exists in non- cπtical procedures (i e , contact is only made with intact skin) On the other hand, high level disinfection is typically required for heat sensitive medical instruments used in semi-critical procedures where sterilization is not practical (i e , contact is made with mucous membranes or other bodily parts not normally considered to be sterile)

Glutaraldehyde solution typically has an effective life of up to twenty-eight days or longer depending upon the particular glutaraldehyde solution utilized However, costs generally prohibit utilization of glutaraldehyde solutions lasting longer than twenty-eight days Further, certain glutaraldehyde solutions are advantageous because they are considered to be a nonsurfactant and do not become entrapped in the cracks and crevices of rigid medical instruments, especially rigid endoscopes, which may corrode the walls surrounding apertures in the instruments Examples of such solutions are the Cidex solutions having an effective life less than twenty-eight days (e g , fourteen days) In current practice, the remaining effective life of a glutaraldehyde solution is determined by nurses observing the written date of initial use Alternatively, test strips may be disposed in the solution to check the concentration and active ingredients of the solution These tasks must be performed periodically, at least on a daily basis, to ensure an active gluteraldehyde solution and proper disinfection of the instruments Once the gluteraldehyde solution becomes inactive or surpasses its effective life, the solution is either transferred into its original container or poured down a sink drain while being diluted with water (i e water is flowing into the sink drain along with the solution) A new batch of glutaraldehyde solution must then be activated and used to disinfect further instruments Instrument disinfection is accomplished by disposing the instruments in the glutaraldehyde solution and manually keeping track of the time the instruments have been immersed or exposed to the solution After the instruments have been exposed to the solution for a sufficient duration, the instruments are removed and commonly rinsed to remove any remaining glutaraldehyde solution

The prior art and current procedures for disinfecting medical instruments suffer from significant disadvantages The continuous use of ultrasonic energy commonly breaks down the glutaraldehyde solution, thereby reducing its effective life Further, there is generally no provision to minimize the amount of time for human exposure to the glutaraldehyde solution or fumes emitted therefrom, which exposure can lead to asthma, rhinitis, and eye and skin irritation The harmful effects of the exposure are so severe that the U S Occupational Safety and Health Administration (OSHA) presently requires that corrective action be taken when exposure to glutaraldehyde solution exceeds 0 2 parts per million in the work place

The current procedure for disinfecting medical instruments through immersion of the instruments in glutaraldehyde solution is accomplished entirely by hand There are no means for indicating the age of the glutaraldehyde solution, the temperature of the glutaraldehyde solution, the particular disinfection level being performed nor the time remaining until a particular instrument disinfection cycle is complete, thereby requiring nurses to pay almost constant detailed attention to the disinfection process The absence of indicators also limits the number of personnel able to attend to the disinfection since specific information is required to complete the disinfection Further, manual recordation of each of the age of the solution, the level of disinfection being performed, the start time of the disinfection and the temperature of the solution increase the chances of human error and can lead to imprecise and/or improper disinfection of instruments, thereby causing serious injury or infection to patients Moreover, since generally there is various switching of personnel due to different work shifts, there may be gaps in communication with regard to the age of glutaraldehyde solution, or the time a disinfection cycle was initiated, thereby causing the disinfection cycle to re-start In addition, there is no process or heating control for maintaining the glutaraldehyde solution at a constant temperature, thereby varying the required immersion time without the knowledge of attending personnel and resulting in instruments being only partially disinfected

A further disadvantage of the prior art is the absence of effective ways to dispose of the glutaraldehyde solution The solution is manually poured either back into its original container or down a drain of a sink, thereby exposing personnel draining the solution to the harmful effects of exposure to the solution and emitted fumes

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to disinfect medical instruments in a heated disinfectant solution while minimizing the amount of time for human exposure to the harmful effects of the solution by capturing and filtering noxious and/or toxic vapors emitted from the disinfectant solution

It is another object of the present invention to disinfect medical instruments in a heated disinfectant solution while automatically monitoring the disinfection process by displaying the time remaining in an instrument disinfection cycle and the temperature and age of the disinfectant solution, and by sounding an alarm and flashing a light at the expiration of the cycle

Yet another object of the present invention is to disinfect medical instruments in a heated disinfectant solution while maintaining the temperature of the solution at a constant predetermined value via fuzzy logic or proportional-integral-deπvative (PID) control of a heater

Still another object of the present invention is to substantially automate the information maintenance for the disinfection of medical instruments, thereby leaving operating room personnel free to tend to other tasks during the disinfection cycle

A further object of the present invention is to disinfect medical instruments utilizing a tray having preformed portions to receive the instruments, and slots disposed about the tray wherein the tray is disposed in a heated disinfectant solution such that the heated solution infiltrates the slots to disinfect the instruments

Yet another object of the present invention is to disinfect medical instruments utilizing multiple trays simultaneously wherein each tray includes a non-planar floor to receive the instruments, and slots disposed about each tray to permit a heated O 97/32610 PC17US97/02977

6 disinfectant solution to infiltrate the slots and disinfect the instruments when the trays are disposed in the heated disinfectant solution

Still another object of the present invention is to disinfect medical instruments in a heated disinfectant solution while minimizing human exposure to the harmful effects of the solution during solution disposal

The aforesaid objects are achieved individually and in combination, and it is not intended that the present invention be construed as requiring two or more of the ob_jects to be combined unless expressly required by the claims attached hereto

According to the present invention, a method and apparatus for disinfecting medical instruments employ a basin disposed in a hood and supported on a base of the apparatus The basin contains a disinfectant solution bath and includes a heater and digital thermometer disposed underneath the basin to heat and maintain the solution at a predetermined temperature A transducer may also be disposed beneath the basin to impart ultrasonic energy into the solution A combination tray having preformed portions and slots receives medical instruments, such as large rigid endoscopes and flexible endoscopes, in the respective preformed portions and is disposed within the disinfectant solution bath The combination tray includes a peripheral ledge that engages the basin periphery to support the tray within the basin, and may further include handles and/or fasteners disposed on the peripheral ledge to securely fasten the tray to the basin and enable removal and placement of the tray within the basin, respectively The slots enable the disinfectant solution from the bath to infiltrate the combination tray and immerse and disinfect the instruments Alternatively, multiple rigid endoscope trays may be placed in the solution bath to disinfect medical instruments, such as small rigid endoscopes and other instruments that may be cold sterilized Each of the rigid endoscope trays includes a non-planar floor for receiving the medical instruments and slots for permitting the disinfectant solution from the solution bath to infiltrate the rigid endoscope trays and disinfect the instruments when the rigid endoscope trays are disposed in the solution bath Each rigid endoscope tray includes a peripheral ledge that engages the basin periphery to support that rigid endoscope tray within the basin Further, the rigid endoscope trays may include handles and fasteners disposed on their respective peripheral ledges to securely fasten the rigid endoscope trays to the basin and enable quick removal and placement of the O 97/32610 PC17US97/02977

7 rigid endoscope trays within the basin, respectively, in substantially the same manner described above The hood includes an access panel or door to enable access to the basin, and a filtration system having a prefilter, a primary filter and a secondary filter combining to capture and filter toxic and/or noxious vapors emitted from the disinfectant solution during instrument disinfection A fan or blower draws the vapors through the filters and exhaust openings disposed on opposite sides of the hood A dual speed fan may be employed wherein the two speed fan automatically operates at a higher speed when the access panel is opened to prevent the vapors from escaping the confines of the hood The apparatus may be disposed on a table or other structure, or be disposed integral with a storage facility containing a drainage system

A control panel is disposed on the top surface of the hood to enable selection of either an intermediate or high level disinfection cycle (i e , either a ten minute cycle with the solution heated to a temperature of 20°C or 25°C, or a forty-five minute cycle with the solution heated to a temperature of 25 °C, respectively) The control console monitors the disinfection cycle and displays the time remaining in the cycle and the temperature and the age of the solution on separate light emitting diode (LED) or liquid crystal (LCD) displays At the expiration of an instrument disinfection cycle, a five second audible alarm sounds, while both a light disposed on the top surface of the control console and the displayed time flash continuously until the apparatus is reset A microprocessor disposed in the control console performs the monitor and display functions and implements fuzzy logic or proportional-integral-deπvative (PID) control of the heater to maintain the solution at the predetermined temperature

The apparatus further includes a drainage system permitting removal of the disinfectant solution from the basin with minimal exposure for personnel The apparatus may be disposed integral with a cabinet or other storage facility containing the drainage system wherein the drainage system includes a storage tank for receiving spent solution, a plurality of pumps for controlling flow of the solution, and a multi¬ directional valve for controlling direction of solution flow The basin includes a drain connected via a hose to a drain valve controlled by a security switch, preferably a key switch, and a dram valve switch. Each switch is disposed on the apparatus front panel wherein the security switch is typically rotated to enable the drain valve switch to control the drain valve The storage facility further includes a miniature sink for expelling fluid from the drainage system and directing fluid received from an external source into a sink dram of the miniature sink for placement in the storage tank A basin drainage pump is controlled by a corresponding basin drainage pump switch disposed on the storage facility front panel to direct solution from the basin through the drain valve to a multi-directional valve The multi-directional valve is controlled by a valve directional switch, disposed on the storage facility front panel, to direct solution from the basin drainage pump to either the storage tank or to the miniature sink A storage container pump is disposed within the storage tank to direct solution from the tank to the miniature sink in response to actuation of a corresponding storage container pump switch disposed on the storage facility front panel A common sink interface connector is typically connected to the miniature sink to direct solution from the miniature sink to a common sink dram

An alternative drainage system may be utilized by the disinfection system wherein the basin drain may be directly connected via a hose to the drain of a common sink or a container for receiving the spent solution The hose includes a drain valve for controlling solution outflow and preventing overflow in the container The dram valve is controlled by a combination of the security switch and the drain valve switch disposed on the apparatus front panel wherein the security switch is typically rotated to enable the dram valve switch to control the drain valve The dram valve remains open while the dram valve switch is actuated to permit an operator to control the amount of solution being drained The distal end of the hose includes a seal having an interface with the common sink or collection container to prevent leakage of the solution during drainage A pump or other device may be used to initiate and maintain the flow of the solution Further, a low pressure generator or venturi section may be disposed at the collection container opening with a tube extending down into the collected drained solution Fluid is injected through the venturi to create a low pressure which draws collected solution from the container into the venturi section The aspirated solution is diluted in the venturi section by the injected fluid and transported to a common sink drain

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, particularly when taken in conjunction with the accompanying drawings wherein like reference numerals in the various figures are utilized to designate like components.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1a is a view in perspective of a disinfection system constructed in accordance with the present invention.

Fig. 1 b is a view in perspective of the disinfection system of Fig. 1a with the hood removed.

Fig. 1c is a front view in elevation of a fan control portion of the disinfection system of Fig. 1 a.

Fig. 2 is a view in perspective of the disinfection system of Fig. 1a disposed integral with a movable cabinet according to the present invention.

Fig. 3a is a sideview in elevation of the disinfection system of Fig. 2.

Fig. 3b is a side view in elevation of another side of the disinfection system of Fig. 2.

Fig. 3c is a rear view in elevation of the disinfection system of Fig. 2.

Fig. 3d is a front view in elevation of a drainage system control portion of the disinfection system of Fig. 2.

Fig. 4 is a top view in plan of a basin or pan for containing the disinfectant solution according to the present invention.

Fig. 5a is a top view in plan of a combination tray having preformed portions for receiving medical instruments according to the present invention.

Fig. 5b is a side view in elevation and partial section of the combination tray of Fig. 5a containing an endoscope in a preformed portion according to the present invention.

Fig. 5c is a view in perspective of the combination tray of Fig. 5a.

Fig. 5d is a view in perspective of the combination tray of Fig. 5a having handles for placement and removal of the combination tray from a disinfection system basin according to the present invention.

Fig. 6a is a top view in plan of a rigid endoscope tray for receiving and disinfecting medical instruments according to the present invention. Fig 6b is a view in perspective of the rigid endoscope tray of Fig 6a arranged with an additional rigid endoscope tray for disposal in a disinfection system basin according to the present invention

Fig 6c is a top view of the tray pair of Fig 6b with one rigid endoscope tray containing a plurality of endoscopes according to the present invention

Fig 6d is a side view in partial section of the tray pair of Fig 6c disposed in a disinfection system basin with one rigid endoscope tray containing a plurality of endoscopes according to the present invention

Fig 7a is a front view in elevation of a disinfection system control console according to the present invention

Fig 7b is a rear view in elevation of the control console of Fig 7a

Fig 8 is a schematic block diagram of control circuitry for the control console of Figs 7a - 7b according to the present invention

Fig 9 is a procedural flow chart for software controlling the circuitry of Fig 8

Fig 10a is a view in perspective of the disinfection system of Fig 1a with the hood removed, diagrammatically illustrating the air flow path through the system according to the present invention

Fig 10b is an exploded view in perspective of the placement of filters within the disinfection system of Fig 10a

Fig 10c is an exploded rear view in elevation of the filters and disinfection system of Fig 10b

Fig 10d is a side view in elevation and partial section of the disinfection system of Fig 10a diagrammatically illustrating the airflow path through the system according to the present invention

Fig 1 1 is a schematic diagram of a drainage system disposed within the disinfection system storage facility of Fig 2 according to the present invention

Fig 12a is a front view in elevation of a drainage system storage container for receiving used disinfectant solution from a disinfection system basin according to the present invention

Fig 12b is a top view in plan of the storage container of Fig 12a

Fig 12c is a side view in elevation of the storage container of Fig 12a Fig 13a is a side view in elevation of a common sink interface connector for draining disinfectant solution from a disinfection system to a common sink dram according to the present invention

Fig 13b is a top view in plan of an adapter for a common sink drain to enable solution to flow from the connector of Fig 13a into a common sink drain according to the present invention

Fig 14 is a diagrammatic side view in elevation and partial section of a combination tray and basin of a disinfection system showing the basin connected to a container via a hose for draining the disinfectant solution from the basin according to one embodiment of the present invention

Fig 15a is an electrical schematic block diagram of the overall circuitry of a disinfection system having a single speed fan and the drainage system of Fig 11 according to the present invention

Fig 15b is an electrical schematic block diagram of the overall circuitry of a disinfection system having a single speed fan and the drainage system of Fig 14 according to the present invention

Fig 15c is an electrical schematic block diagram of the overall circuitry of a disinfection system having a dual speed fan according to the present invention

Figs 16a - 16c are procedural flow charts illustrating the sequence of operation of a disinfection system according to the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A system or unit 1 for disinfecting medical instruments, particularly flexible and rigid endoscopes, in a heated disinfectant solution is illustrated in Figs 1a - 1c Specifically, system 1 includes base 4, a hood 2 disposed over the base, and a control console 8 disposed on a top surface of the hood Base 4 includes a pair of opposite side walls 17, 19, a rear wall 7, a front wall 71 , and a bottom wall 29 Side walls 17, 19 are substantially right trapezoids and have exhaust vents 90 defined therein toward their upper rearmost top portions (the exhaust vent on side wall 19 not being visible in Figs 1a - 1c) The forwardmost portion of bottom wall 29 is slightly elevated forming a step or rise to form an overhang at the front of the unit, while front wall 71 extends from the overhang between side walls 17, 19 to partially cover the front portion of the unit. Rear wall 7 is substantially rectangular and covers the back of the unit.

Right side wall 19 typically includes a fuse 131 (Fig. 3b) for a heating system described below, a ground fault circuit interrupter 108 and an International Electrotechnical Commission (IEC) standard outlet 133 (e.g , typically fused for ten amps) for receiving power from a wall outlet jack, preferably via a hospital grade #18 extension cord, wherein fuse 131 , ground fault circuit interrupter 108 and outlet 133 are disposed adjacent each other above vent 90. The terms "right", "left", "top", "bottom", "front" and "rear" as used herein are merely used as directional references in relation to the disinfection system and do not limit the present invention to any specific configuration or orientation The interior of the unit is subdivided into a rear air filtration compartment 21 and a forward disinfection compartment 15 by a vertical dividing wall 13 extending across the entire unit interior Compartments 21 and 15 are closed off from one another except for multiple through slots 82 defined in dividing wall 13 to enable fumes and vapors from the disinfection compartment 15 to enter the filtration compartment 21 as described below Slots 82 may be oriented in any manner permitting the fumes to be drawn into the filtration compartment. A removable access cover 3 covers a portion of the filtration compartment to permit access to filters disposed in that compartment. Cover 3 is substantially rectangular and covers an aperture defined in the rearward portion of hood 2 wherein the cover may be removably attached to the hood via fasteners 171 (Figs 3c, 10c) disposed on rear wall 7 of the system for removably securing the cover to the hood. Alternatively, cover 3 may pivot to an open and closed state via hinges (not shown) connecting the cover to the hood The hood and cover are typically made of plexiglass, glass or other suitable and preferably transparent material. Hood 2 extends horizontally forward and then down a short distance along the front of the unit where it is pivotably joined to an access panel or door 32 by virtue of a plurality of hinges 33 Access panel 32 is substantially rectangular and extends from hood 2 to the top portion of front wall 71 when in a closed position. The access panel includes a cut-out portion to permit air to enter disinfection compartment 15 The access panel cut-out portion extends for a substantial distance approximately centered between side walls 17, 19, and extends vertically from front wall 71 to _just slightly below hinges 33. Access panel 32, when closed, extends generally downward and is supported at its ends by sloped forward edges of the side walls 17, 19 Hinges 33 permit the access panel to be selectively swung upward toward the top of the hood to provide access to the interior of the disinfection compartment Base 4 is typically constructed of polyvinyl chloride (PVC) but other suitable plastics may be used

Interiorly of the disinfection compartment, base 4 includes a substantially flat rectangular recessed floor 25 A pair of substantially rectangular right and left block supports 24, 27 are disposed at opposite ends of floor 25 adjacent respective side walls 17, 19 and extend along those side walls from the front surface of dividing wall 13 to front wall 71 Further, front and rear block supports 56, 57 are disposed adjacent to front wall 71 and dividing wall 13, respectively, and extend along those walls from block support 24 to block support 27 Front wall 71 has a lighted hood power switch 31 disposed on its front facing surface coincident right block support 27 for selectively enabling application of electrical power to the unit wherein switch 31 is illuminated to indicate that power has been turned on A pressure indicator 124 is disposed adjacent switch 31 to indicate when insufficient pressure levels are present to effect filtering, by a forced air flow, of fumes emitted by the disinfectant solution A security switch 110, preferably a key switch, and a dram valve switch 112, are disposed on a front surface of front wall 71 coincident left block support 24 and are used to control drainage of the disinfectant solution as described below Block supports 24, 27, 56, 57 form a substantially rectangular perimeter about recessed floor 25 within disinfection compartment 15 for receiving a basin or pan 20 typically containing a disinfectant solution such as glutaraldehyde, the Cidex family of disinfectant solutions, or other suitable disinfectant solution (e.g , Banicide, Metracide, Sterall) A tray or plurality of trays (not shown) are utilized to receive and immerse medical instruments in the solution disposed in basin 20

Control console 8 is disposed substantially centrally between side walls 17, 19 on a top surface of hood 2, proximate dividing wall 13, for controlling and monitoring disinfection of instruments Control console 8 includes a substantially rectangular front display panel 53 with numerous displays and control switches In particular, control console 8 includes a day display 38, a day reset switch 40, a disinfection cycle timer display 42, an intermediate disinfection cycle switch 44, a high disinfection cycle switch 46, a reset switch 48, a temperature display 52, a start switch 50, temperature switches 54, 55 (for 20°C and 25°C, respectively), and console power switch 58 The start, temperature, disinfection cycle, and reset switches each include a light which illuminates the switches during the disinfection cycle at appropriate times to indicate the various selections for the cycle and the times to start or reset the system as described below Power switch 58 also includes a light that is illuminated during actuation of the power switch The housing for control console 8 includes a generally rectangular bottom wall (not shown) disposed on hood 2, and a casing 30 is disposed over the wall having a front display panel 53 The housing further includes two side panels 26, 35, a back panel 39, and a top panel 37 Top panel 37 has dimensions slightly larger than the bottom wall such that the top panel overhangs display panel 53 Back panel 39 is substantially rectangular, disposed between the rear edges of side panels 26, 35, and extends from the top panel to the bottom wall Side panels 26, 35 are generally right trapezoidal with forward edges angled slightly forward to support the longer dimension of the top panel and form the overhang In other words, the top edges of the side walls are slightly longer than their bottom edges A lamp 9 is disposed at the approximate center of the top panel 37 and flashes to indicate completion of the disinfection cycle An audible alarm 11 (Fig 7b), typically a sonalert alarm, is disposed within or on back panel 39 of the control console also for indicating completion of the disinfection cycle Flashing lamp 9 is substantially cylindrical and similar to the lights on police or fire vehicles, but significantly smaller in size Further, back panel 39 includes a series of default slide switches 59, 61 (Fig 7b) and an alarm switch 63 described below Default slide switch 59 enables setting of a default disinfection cycle temperature, while default slide switch 61 enables setting of a default disinfection cycle time These default slide switches are generally conventional switches mampulable by a pen, mechanical pencil or other pointed device Alarm switch 63 enables or disables the audible alarm and may be any conventional switch The disinfection system, in use, is typically disposed on a table, cabinet or other support surface (not shown) having conventional rollers or casters disposed at the bottom of the table legs The table enables the system to be readily transportable, and the rollers or casters include locks to stably maintain the table at desired locations Alternatively, the system may be disposed on stationary support surfaces for disposal in a particular location Further, the system may be disposed integral with a cabinet or other storage facility as illustrated in Figs 2, 3a - 3d Specifically, disinfection system 1 is substantially similar to the system described above except that the system is disposed atop or integral with a storage cabinet 65 Storage cabinet 65 typically includes capacity for storing four rigid endoscope trays described below, a storage container for receiving used disinfectant solution, a heating system for maintaining the temperature of the solution within the basin described below, and electπcal power supply and pumps for directing the solution to various destinations The system and cabinet typically have a height of approximately 58 0 inches, a width of approximately 36 0 inches and a depth of approximately 31 5 inches The disinfection system itself typically includes a working area having a height of approximately 10 5 inches, a width of approximately 35 3 inches and a depth of approximately 19 5 inches The cabinet includes cabinet side walls 67, 69, front and rear walls 94, 95, top and bottom surfaces (not shown) and wheels or casters 91 Alternatively, cabinet 65 may be stationary and not include wheels or casters 91 The top surface of storage cabinet 65 is contoured to match the bottom surface of system 1 , while the cabinet bottom surface serves as a floor for the cabinet storage facility The cabinet front, rear and side walls, and the cabinet top and bottom surfaces essentially form a compartment within cabinet 65 for storing the various peripherals described above or other suitable items Cabinet side walls 67, 69 respectively extend from side walls 17, 19 to the bottom of the cabinet, while cabinet rear wall 95 extends from rear wall 7 to the bottom of the cabinet Front wall 94 extends from the bottom of the cabinet to a ledge 96 disposed adjacent bottom wall 29 Cabinet side walls 67, 69, front and rear walls 94, 95 and the cabinet bottom surface are substantially rectangular Ledge 96 is disposed adjacent and below bottom wall 29, and is formed integral with front wall 94 and side walls 67, 69 Ledge 96 extends forward along bottom wall 29 and includes a bottom portion that slopes downward to interface the upper front portions of side walls 67, 69, and the top portion of front wall 94 The ledge further includes a dip or downward step toward the rear portion of the ledge in order to contour the overhang of system 1 described above In other words, ledge 96 is in the form of a rounded step molded to fit within the recess created by the overhang of system 1 described above Ledge 96 includes switches 114, 115 disposed adjacent each other and below dram valve switch 112 for respectively controlling individual pumps of a solution drainage system disposed within the cabinet described below Locking doors 97 are disposed adjacent each other on front wall 94 below ledge 96 via hinges 99 to permit access to a storage area within cabinet 65 Doors 97 include respective handles 98 for enabling the doors to pivot in opposite directions about their respective hinges 99 in order to open and close the doors such that a maximum amount of access space exists for the storage area Front wall 94 further includes a rotatable valve directional switch 101 for controlling drainage of spent solution to a storage tank or common sink described below Valve directional switch 101 is disposed within a substantially rectangular recess 107 defined in front wall 94 adjacent left cabinet side wall 67 and ledge 96 The valve directional switch includes a rotatable bar 103 in the shape of a crude arrow or pointer that is typically rotated one hundred eighty degrees between two directional indicators 104, 105 respectively designating the common sink or the storage tank for receiving the solution The directional indicators are disposed directly opposite each other on opposing sides of recess 107

Left side wall 67 (Fig 3a) includes a miniature sink 109 disposed toward the top portion of the side wall approximately centered between front and rear cabinet walls 94, 95 Sink 109 resides within a substantially rectangular recess in left sidewall 67 and includes a drain 111 disposed at the approximate center of the sink floor, a connector 162 (Fig 11 ) for receiving solution from a transfer hose, and a door 113 connected to the sink via hinges 117 The miniature sink floor is sloped to direct contained liquid out through drain 111 Door 113 typically includes a handle 119 disposed toward the top portion of the door to enable a user to pivot door 113 downward about hinges 117 and access the sink area. A pair of brackets 121 is disposed on each side of sink 109 to retain transfer hoses for the drainage system The brackets include a handle portion 123 attached to side wall 67 wherein a rigid strip 125, preferably made of metal, plastic or other suitably rigid material, is disposed between the handle and side wall Strip 125 is formed to provide a flat surface for the handle for connection to side wall 67 wherein the strip curves away from the handle subsequent to the handle ends forming gaps between the strip and the side wall Drainage system hoses may be wrapped around brackets 121 wherein strip 125 retains the hoses in the gaps between side wall 67 and the strip Alternatively, the hoses may be stored within the storage area of the cabinet Rear wall 95 (Fig 3c) includes a substantially rectangular access panel 127 disposed at the approximate center of the rear wall The access panel includes dimensions slightly smaller than the dimensions of rear wall 95 and is attached to the rear wall by a plurality of fasteners 128 Access panel 127 enables access to the storage area within the cabinet. Further, rear wall 95 includes a pair of brackets or hooks 129 disposed on each side of access panel 127 for retaining a combination tray described below

Right side wall 69 (Fig. 3b) includes a pair of handles 174 disposed toward the top portion of the side wall for enabling the system to be transported, via wheels 91 , to a desired location In addition, an International Electrotechnical Commission (IEC) standard outlet 135 (e g., typically fused for ten amps) is disposed toward the upper portion of wall 69 adjacent rear wall 95 to provide power to the drainage system from a wall outlet jack, preferably via a hospital grade #18 extension cord.

A basin or pan 20 for containing the disinfectant solution is illustrated in Fig. 4. Basin 20 is preferably substantially rectangular and is typically constructed of sixteen gauge stainless steel. In an exemplar embodiment, the basin has a length of approximately twenty-eight inches, a width of approximately eighteen inches, and a depth of approximately three inches Basin 20 includes a substantially flat rectangular bottom surrounded by four side walls The top edges of the walls are bent outward substantially perpendicular to the walls to form a planar ledge 23 about the entire periphery of the basin The ledge extends transversely outward from the walls for approximately three-quarters of an inch A drain 22 is disposed in the basin bottom wall, close to one side wall (i.e., the leftmost wall as viewed in the figure), for example, at the approximate front to back center of the basin approximately three-quarters of an inch from the widthwise wall. The basin is sloped to direct all contained liquid out through drain 22 during drainage of disinfectant liquid. Basin or pan 20 is disposed in hood 2 between and supported on support blocks 24, 27, 56, 57 (Fig. 1b) such that ledge 23 rests on the support blocks. In this regard, the support blocks are separated by respective distances slightly larger than the length and width of the basin (excluding ledge 23) to ensure a proper and secure fit.

A combination endoscope tray 6 for holding medical instruments, such as large rigid endoscopes and flexible endoscopes, and adapted to be inserted into the basin or pan 20 is illustrated in Figs 5a - 5d Specifically, combination tray 6 is preformed to receive medical instruments, such as rigid and flexible endoscopes The combination tray may be constructed of fiberglass, acrylonitπle-butadiene-styrene (ABS) or other types of plastic or suitably sturdy material non-reactant with the disinfectant solution Combination tray 6 is generally rectangular and has dimensions substantially similar to but slightly smaller than basin 20 such that the combination tray may snugly fit within the basin Combination tray 6 includes a tray floor surrounded by four side walls and a plurality of channels defined in the floor The channels include a substantially continuous loop channel 41 with a substantially linear channel 43 extending therefrom diagonally in the combination tray The loop and diagonal channel in combination form a configuration substantially similar to the number six or nine, depending upon the orientation of the combination tray Loop channel 41 has a width substantially larger than the diameter of a flexible endoscope to be disinfected, and diagonal channel 43 has substantially the same width as the loop channel A plurality of substantially straight linear parallel channels 16 are defined longitudinally across the combination tray floor within and surrounded by the loop channel 41 for receiving rigid endoscopes 10 in the combination tray Linear channels 16 have a width larger than the diameter of rigid endoscopes to be disinfected but usually smaller than the width of loop channel 41 Flexible endoscopes (not shown) are wound in a plurality of loops or in loop channel 41 and surround the rigid endoscopes Further, extender channels 45, 47 are disposed coincident the linear channels and extend from loop channel 41 to diagonal channel 43 The extender channels have substantially the same width as the linear channels and accommodate end sections of rigid endoscopes having a length greater than the corresponding linear channel within the looped channel Additional extender channels may be disposed within combination tray 6 coincident the linear channels, and may extend from diagonal channel 43 and/or loop 41 along a longitudinal axis of the combination tray toward respective combination tray side walls to accommodate larger or a greater quantity of large endoscopes Disposing endoscopes within combination tray 6 in this fashion conserves space and maximizes the number of endoscopes or instruments that can be disinfected at one time

Diagonal channel 43 includes a ramp in the combination tray floor having an incline extending upward from its end at loop channel 41 for approximately three- quarters the length of the diagonal channel, and a decline extending approximately the remaining one-fourth of the diagonal channel length The ramp accommodates an eyepiece portion of a flexible endoscope disposed at the proximal end of the endoscope Combination tray 6 further includes multiple through slots 12 disposed throughout the combination tray channels permitting the disinfectant solution from the basin to infiltrate the channels and disinfect the endoscopes Multiple ribs 18 project into loop channel 41 to both reinforce the combination tray and resiliently secure the flexible endoscope within the loop channel Further, combination tray 6 includes a ledge 49 disposed about the combination tray periphery substantially similar to, but slightly narrower than, ledge 23 disposed about the basin periphery Ledge 49, adjacent the left and right combination tray walls (i e , as viewed in Fig 5a), includes quick-release fasteners 14 to engage ledge 23 and secure the tray within the basin The fasteners may be any conventional quick-release fasteners and are typically made of plastic and disposed at the longitudinal centers of their respective ledge sections

Alternatively, combination tray 6 may include handles 145 (Fig 5d) disposed integral with the combination tray periphery wherein ledge 49 supports the combination tray 6 within the basin, while the handles facilitate quick placement and removal of the combination tray from the basin Handles 145 may be disposed at the approximate center of opposing side walls of combination tray 6 wherein each handle generally extends forward from a rear portion of ledge 49 sloped upwardly at an angle sufficient to provide a gap between the handle and the basin periphery for receiving an operator's hand to grip the combination tray within basin 20

Referring to Fig 5b, combination tray 6 is shown disposed in basin 20 with the channels 41 , 43, 16, etc and their received endoscopes suspended and immersed in the disinfectant solution Combination tray 6 has its horizontal periphery contoured to match the shape of basin 20 and is supported by its ledge 49 disposed on and secured to basin 23 The disinfectant solution in the basin infiltrates the combination tray through slots 12 to immerse and disinfect the endoscopes A heater 5 is disposed at the bottom of basin 20 to heat the disinfectant solution to the predetermined temperature (typically 20°C or 25°C) depending upon the desired level of disinfection to be effected A transducer (not shown) may also be disposed beneath the basin or pan for applying ultrasonic energy to the disinfectant solution at selected times for enhanced endoscope disinfection A digital thermometer 28 is also disposed beneath the basin or pan for monitoring the temperature of the disinfectant solution to be utilized by fuzzy logic or proportional-integral-deπvative (PID) control to control heater 5 as described below

Alternatively, two rigid endoscope trays may be disposed within basin 20 directly adjacent each other to immerse medical instruments, such as small rigid endoscopes or other instruments that may be cold sterilized, within the solution in substantially the same manner described above Referring to Figs 6a - 6d, a rigid endoscope tray 6 is substantially rectangular with its shorter dimension substantially similar to half the length basin 20, while its longer dimension is slightly less than the basin width The rigid endoscope tray may be constructed of fiberglass, acrylonitπle-butodiene- styrene (ABS) or other types of plastic or suitably sturdy material non-reactant with the disinfection solution Rigid endoscope tray 6 has a non-planar floor 172 surrounded by four side walls Non-planar floor 172 includes a plurality of elevated or peak sections 139 and recessed or valley sections 140 alternately disposed with each section extending along the longer dimension of the rigid endoscope tray wherein endoscopes are retained in the valley sections during disinfection Rigid endoscope tray 6 further includes three consecutive ledges 141 , 142, 143 disposed about the rigid endoscope periphery, and a multitude of slots 144 for enabling the disinfectant solution to infiltrate the rigid endoscope tray and disinfect the endoscopes when the rigid endoscope tray is immersed in the disinfectant solution Slots 144 generally include elliptical or oval shaped slots that are defined within peaks 139 and valleys 140 of the rigid endoscope tray floor A portion of slots 144 disposed in valleys 140 are oriented such that their major axes are parallel to a longitudinal axis of valleys 140 (i e , the longer dimension of the rigid endoscope tray), while smaller slots 144 are also disposed in valleys 140 oriented with their major axes substantially perpendicular to the major axes of the larger slots (i e , the major axes of the smaller slots extend along the shorter dimension of the rigid endoscope tray) The smaller slots tend to be disposed at each end of a valley 140 adjacent rigid endoscope tray walls, while the larger slots are disposed between the smaller slots Further, peaks 139 tend to only include the larger slots, however, slots 144 may be of any shape or size, and may be disposed in the rigid endoscope tray in any manner capable of permitting the disinfectant solution to infiltrate the rigid endoscope tray

Ledges 141 , 142, 143 extend transversely from and perpendicular to the edges of the rigid endoscope tray walls, and are disposed about the rigid endoscope tray periphery with each succeeding ledge disposed at an increased height In other words, ledges 141 , 142 and 143 are disposed in a step-like configuration wherein each ledge forms a next higher step Rigid endoscope tray 6 includes handles 145 disposed across ledges 141 , 142, 143 on two rigid endoscope tray side walls extending along the rigid endoscope tray longer dimension Handles 145 are disposed integral with the side walls and each handle extends from lowermost ledge 141 toward uppermost ledge 143 sloped upward at an angle sufficient to form a gap between the handle and the basin periphery for receiving an operator's hand to grip the rigid endoscope tray within basin 20 Lowermost ledge 141 includes a series of small recesses 146 disposed at each end of valleys 140 Recesses 146 are substantially rectangular and include a substantially circular opening or stop 147 defined in the approximate center of each recess Recesses 146 receive an endoscope eyepiece when the eyepiece is not to be disinfected Recesses 146 are disposed at a sufficient height to maintain an endoscope eyepiece above a solution line in the rigid endoscope tray when the rigid endoscope tray is immersed in basin 20 In other words, recesses 146 prevent the solution from contacting the eyepiece, while stop 147 restricts eyepiece movement within recess 146 during disinfection

Two rigid endoscope trays 6 are typically inserted into basin 20 with the peaks and valleys extending along the basin width (i e , the shorter dimension of the basin) The rigid endoscope trays are disposed in the basin adjacent each other with a handle 145 from each rigid endoscope tray in facing relation at the approximate basin center The rigid endoscope trays are supported by ledge 143 contacting the basin peripheral ledge and may be secured to the basin by fasteners in a similar manner as described above Handles 145 may also be disposed on the rigid endoscope trays in any manner capable of permitting placement and removal of the rigid endoscope trays from the basin Rigid endoscopes 10 are placed within valleys 140 of rigid endoscope trays 6 such that endoscopes having eyepieces disinfected are disposed in valleys 140, while endoscopes having eyepieces not being disinfected have the eyepieces placed within recesses 146 as described above Recesses 146 remain above the solution line when the rigid endoscope tray is immersed in the basin to prevent the solution from contacting the eyepiece

Control console 8 for controlling and monitoring the disinfection of medical instruments is illustrated in greater detail in Fig 7a - 7b Control console 8 displays and maintains several control parameters for the overall system and for individual disinfection cycles Specifically, day display 38, disposed toward the left side of console control panel 8, displays the age in days that the disinfectant solution has been in use Generally, glutaraldehyde based disinfectant solutions have an effective life of fourteen or twenty-eight days, depending upon the solution and operating conditions Currently, nurses monitor the age of the disinfectant solution and utilize test strips to determine the viability of the solution The solution age indication at display 38 is initialized to zero (in the manner described below) when a fresh solution is disposed in basin 20, and automatically increments each day the disinfectant solution is in use The age of the solution is numerically displayed by light emitting diodes (LEDs) or liquid crystal displays (LCDs) such that the nurses are always made aware of the age of the disinfectant solution and put on notice as to when to change the solution The day display typically includes a pair of LED or LCD digit displays to display the solution age in days with the two digits Additional LED or LCD displays corresponding to additional digits may be added to display larger numbers

Disposed directly beneath day display 38 is the day reset switch 40 actuated manually when fresh disinfectant solution is placed in basin 20 to reset the day count age of the solution to zero Disinfection cycle timer display 42 is disposed adjacent and to the right of day display 38 and indicates the amount of time remaining in an instrument disinfection cycle The timer is actuated when the disinfectant solution reaches a predetermined temperature of 20°C or 25°C (i e , plus or minus one half of one degree) and start button 50 is depressed as described below Timer display 42 displays the remaining minutes and seconds (i e , plus or minus one half of one second) in the disinfection cycle while counting down to zero The timer display typically includes four LED or LCD displays to present two digits each for minutes and seconds Additional LED or LCD displays may be added to display longer periods of time Disposed directly beneath timer display 42 from right to left are intermediate and high disinfection cycle push-button switches 44, 46, respectively These switches are illuminated when actuated and enable selection of the particular disinfection cycle being performed During the intermediate disinfection cycle, medical instruments are exposed to the disinfectant solution heated to 20°C or 25°C (i.e , plus or minus one half of one degree) for ten minutes (i e., plus or minus one half of one second), while the high disinfection cycle involves exposing the medical instruments to the disinfectant solution heated to 25°C (i e , plus or minus one half of one degree) for forty-five minutes (i e , plus or minus one half of one second) The intermediate cycle has a slightly lower bacterial kill rate than the kill rate of the high cycle Reset push-button switch 48 is disposed to the right of and adjacent the intermediate cycle button 44 and is manually actuated at the expiration of the disinfection cycle to disable alarms and indicators as described below Reset push-button 48 is illuminated at the expiration of the disinfection cycle to indicate the need for the system to be reset Adjacent and to the right of reset switch 48 is the start switch 50 which is illuminated when the system is awaiting initiation of an instrument disinfection cycle, wherein depressing the start switch activates the cycle

Temperature display 52 is disposed above the reset and start switches and displays the current temperature of the disinfectant solution within a few degrees of the desired temperatures of 20°C or 25°C The temperature display typically includes two LED or LCD displays for indicating temperature as two digits Additional LED or LCD displays may be added to display larger temperatures or indicate the sign of the temperature Directly to the left of temperature display 52 is a 25° lighted switch 54, to the right is a 20° lighted switch 55 These switches are manually actuable to select the desired temperature and are illuminated when actuated

An ultrasound switch (not shown) may be disposed adjacent switch 55 to initiate a burst of ultrasonic energy injected into the disinfectant solution via a transducer to enhance the disinfection as descπbed above The ultrasonic energy is injected only for a certain period of time, typically much shorter than the disinfection cycle, to prevent breakdown of the disinfectant solution Adjacent and to the right of start switch 50 is console power switch 58 for selectively enabling and disabling power to the console A flashing light 9 is disposed on the top surface of console 8 and continuously flashes at the completion of a disinfection cycle until reset button 48 is depressed to indicate that the disinfection cycle is complete

Referring to Fig 7b, the back of console 8 includes default slide switches 59, 61 disposed toward the right portion (as viewed in Fig 7b) of the back panel, alarm 11 disposed at the approximate center of the back panel, and an alarm switch 63 disposed adjacent alarm 11 Switches 59, 61 control parameters that set the time and temperature settings for a disinfection process depending upon the type of disinfection being performed or the type of solution utilized For example, Banicide and Sterall solutions may be utilized for only a high disinfection cycle, while Cidex and Metracide solutions may be utilized for either the intermediate or high disinfection cycles The default settings enable the disinfection system to automatically reset to the default values upon completion of a cycle until the default settings are altered, or an alternative disinfection cycle is selected by actuating switches on console 8 as described above The selection of an alternative cycle only alters the settings for the upcoming cycle wherein the disinfection system resets to its default values upon completion of that alternative cycle The default settings may initially be factory set, and changed via switches 59, 61 as described above It is to be understood that the various switches and displays of console 8 may be arranged on or within the console in any manner

Operation of the various displays, temperature, and timing functions controlled from and indicated at console 8 is accomplished by console circuit 136 illustrated in Fig 8 Specifically, console circuit 136 includes a microprocessor or CPU 60, a power supply 66, a heater controller 62, parallel port 72, and digit decoder 70 Microprocessor 60 includes a memory 68 and EPROM 64 storing the control software described below, and is connected to all of the displays and lighted switches on console 8 described above Microprocessor 60 receives a temperature signal through parallel port 72 from a digital thermometer or thermistor 28, typically disposed beneath the basin or pan as descπbed above, and processes the signal to determine the temperature of the solution and the appropriate operation of heater controller 62 to control the heater 5 (Fig 5b) disposed beneath the basin or pan The temperature signal is preferably utilized in a conventional fuzzy logic or proportional-integral- deπvative (PID) control algorithm implemented in software in the microprocessor to derive the proper controls for the heater and maintain the disinfectant solution as close as possible to the desired disinfection cycle temperature The temperature of the solution, as determined by microprocessor 60 based on the temperature signal from the digital thermometer, is sent by the microprocessor, via port 72, to digit decoder 70 Digit decoder 70 converts the temperature into a seven segment code to illuminate the appropriate segments of the LED or LCD displays of temperature display 52 such that the temperature may be displayed at temperature display 52

Microprocessor 60 keeps track in memory of the age, in days, of the disinfectant solution and increments the age each day When the day reset counter switch 40 is actuated, microprocessor 60 resets the age to zero Microprocessor 60 further includes non-volatile memory 68 such that the age is maintained in memory even though the console may be powered down The age in days is sent from microprocessor 60 via parallel port 72 to decoder 70 for display on day display 38

Parallel port 72 typically includes an internal crystal oscillator which microprocessor 60 utilizes to time the duration of the disinfection cycle The crystal oscillator is preferred because of the convenience and accuracy as compared to the effort required to utilize the microprocessor internal clock During the disinfection cycle, microprocessor 60 reads the time from port 72, determines the time remaining in the cycle in the appropriate measurement units (e g , hours and seconds), and sends the time via the port to decoder 70 for display on timer display 42 Alternatively, the microprocessor may utilize other internal or external timing devices in substantially the same manner described above

Microprocessor 60 further illuminates the various buttons and indicators on the control panel and detects actuation of the switches controlling the disinfection cycle Further, an audible alarm 11 , typically a sonalert alarm, is activated by microprocessor 60 at the expiration of an instrument disinfection cycle for approximately five seconds The alarm may be any conventional or commercially available audible alarm Moreover, the switches and indicators may be implemented by any conventional and commercially available push-buttons, switches, lights, diodes or the like, however, a membrane switch panel is preferably utilized to implement the lighted switches and buttons The components of the circuit of Fig 8 may be any conventional or commercially available integrated circuits or chips By way of example only, the circuit may be implemented by an Axom 8125B/386 microprocessor with an Axom 10424 parallel port having a built-in crystal oscillator, a Zenith ZPS-45C power supply, a Gordos GA5-2D10 heater controller, a Dallas Semiconductor DSI620 Digital Thermometer Thermostat, a Computer System Technology CST070192 digital decoder, and conventional LED displays manufactured by Canyon Memory 68 may be a conventional 256x9 70ns SIMM memory manufactured by Toshiba while the EPROM may be an Advanced Micro Devices AM27C040-150 EPROM

The console circuitry may be implemented on a single board or plurality of boards as desired Generally, a single board may contain day display 38, temperature display 52, timer display 42, digit decoder 70, microprocessor 60, and parallel port 72 Power supply 66 may be utilized on a separate board, while heater controller 62 and thermistor 28 are appropriately disposed proximate heater 5 and the basin_, respectively

The operational sequence performed by microprocessor 60 via software control is now described with reference to the above-described circuitry (Fig 8) and procedural flow chart (Fig 9) Initially, microprocessor 60 is powered on and performs a series of start-up routines to initialize the microprocessor and perform diagnostics This is commonly known as "booting" the microprocessor and is well known in the art The microprocessor reads the desired time and temperature for the particular disinfection cycle about to be performed and sets the time and temperature accordingly (i e , either ten minutes at 20°C or 25°C for an intermediate cycle, or forty-five minutes at 25°C for a high cycle) The system usually has a certain disinfection cycle (i e , either intermediate or high) set as a default either by the factory or the slide switches disposed on the rear panel of the system described above The non-default cycle may be selected by actuating the high or intermediate cycle switch The microprocessor is aware of the switch and default settings and selects the appropriate time and temperature Once the time and temperature are set, microprocessor 60 adjusts the age of the disinfectant solution by incrementing a day count when a new day begins Subsequently, upon actuation of the start switch, the microprocessor directs heater controller 62 to begin heating the disinfectant solution to a desired temperature A temperature signal is received from digital thermometer 28 and processed by the microprocessor via either fuzzy logic or proportional-integral-deπvative (PID) control to drive heater controller 62 to adjust solution heater 5 (Fig 5b) Fuzzy logic and PID control algorithms are well known in the art and can easily be implemented by one of ordinary skill After the solution has reached the desired temperature, the timer is enabled to start measuring the time remaining in the disinfection cycle Microprocessor 60 then loops to control the heater and decrement the time at timer display 42 each second until the cycle has expired When there is no time remaining in the cycle, microprocessor 60 flashes light 9 (Fig 7a) disposed at the top of the console, sounds audible alarm 11 for five seconds (i e , only once after the expiration of each cycle) unless the alarm has been disabled by an alarm switch, and causes timer display 42 to flash the time remaining (i e , flash zeroes) The flashing time and light are disabled when the reset switch is actuated The aforementioned operations, starting with the setting of the cycle time and temperature, are iteratively repeated after the reset switch has been actuated and while the system is powered on for subsequent disinfection cycles The heater element is also disabled at the completion of each cycle, however, upon actuation of the start switch for a subsequent cycle, the disinfection system heats the solution to the desired temperature as described above and automatically enables the timer for that subsequent cycle when the solution reaches the desired temperature

The microprocessor performs the above sequence via software control It is to be understood that the above operations may be performed by any processor having software written in any language substantially conforming to the above described algorithm, and that one of ordinary skill in the art could easily transform that algorithm from the flowchart into software By way of example only, the software of the present invention is implemented in the "C" programming language

In order to prevent the harmful vapors emitted by the disinfectant solution from entering the ambient environment, hood 2 includes a filtration system as illustrated in Figs 10a - 10d Specifically, the filtration system is disposed in filtration compartment 21 and includes slots 82 defined through dividing wall 13, an air channel 81 , prefilter 84, a primary filter 86, a secondary filter 88, a fan or blower 120, exhaust channels 92, 93 and exhaust vents 90 Filtration compartment 21 includes an air inflow channel 81 , a filter channel 79, a left outflow channel 92 and a right outflow channel 93 Air inlet channel 81 is defined between slotted compartment dividing wall 13 and a flow directing wall 36 located rearwardly of and spaced from the dividing wall The bottom edge of flow directing wall 36 is flush against the unit bottom wall 29, and its left and right edges are flush against respective left and right interior side walls 73 and 75. These interior side walls extend between rear wall 7 and wall 36 to seal off the sides of air inflow channel 81. The upper edge of wall 36 abuts hood 2 except for a transversely elongated recess 51 in that edge which permits air to flow from inflow channel 81 , over the recess and into filter channel 79. Alternatively, the upper edge of wall 36 may include a plurality of tabs (Fig. 10b) that abut hood 2 and are sufficiently spaced to provide recesses in that edge to permit air to flow from inflow channel 81 over those recesses into filter channel 79. By way of example, a pair of tabs are disposed adjacent each interior sidewall 73 and 75.

Air flowing downward in filter channel 79 first encounters prefilter 84 and then primary and secondary filters 86 Each of these filters is generally rectangular with prefilter 84 being substantially thinner than the primary and secondary filters wherein prefilter 84, primary filter 86 and secondary filter 88 are disposed horizontally to extend across the entire length and width of filter channel 79. Primary filter 86 and secondary filter 88 typically have a thickness of forty millimeters (mm), while prefilter 84 is substantially thinner, typically in the form of a thin strip. However, other arrangements (e.g., the prefilter may be situated adjacent the secondary filter, or only the prefilter and either the primary or secondary filter may be utilized) and combinations (e.g., the primary filter may have a thickness of sixty millimeters (mm) and the secondary filter may have a thickness of twenty millimeters (mm)) may be utilized to control filtering of the fumes and replacement frequency for the filters. Downwardly flowing air in filter channel 79 therefore encounters the broad rectangular surfaces of these filters in sequence and must flow through each of the filters in traversing the filter channel. Located below secondary filter 88 in filter channel 79 is an exhaust fan 120 arranged to draw air downwardly through that channel and then force the drawn air to the left and right outflow channels 92 and 93. These outflow channels communicate directly with the bottom of filter channel 79 by virtue of respective interior side walls 73, 75 being cut away at their bottom. Air entering the outflow channels flows upwardly, between walls 17 and 73 in the left outflow channel, and between walls 19 and 75 in the right outflow channel, to exhaust louvers 90 where the air is exhausted to the ambient environment.

It will be appreciated, therefore, that fan 120 draws ambient air into the disinfection compartment 15 through the cut-out portion of access panel 32. The entering air flows across the top surface of disinfectant solution disposed in compartment 15 and draws and carries fumes or vapors emitted from the solution through slots 82 in the compartment dividing wall 13 The fume-bearing air enters inflow channel 81 , and flows upwardly and over recess 51 at the top edge of flow directing wall 36 into filter channel 79 The filtering action of prefilter 84, primary filter 86 and secondary filter 88 removes the harmful fume components from the air which is then blown by fan 120 through the outflow channels 92, 93 and the exhaust louvers or vents 90 Fan 120 preferably has a single speed, but may be implemented by a two- speed fan that automatically operates at its faster speed when access panel 32 is open to prevent the vapors from escaping the confines of the hood

Prefilter 84 has rectangular dimensions substantially similar to those of primary and secondary filters 88, but is significantly smaller in depth or height than the primary and secondary filter Generally, in single filter systems, the initial portion or front end of the filter removes the majority of the contaminants and quickly becomes ineffective, thereby requiring replacement of the entire filter The cost of frequent filter replacement can be significant However, prefilter 84 is smaller and significantly less expensive than the large primary and secondary filters and removes a large amount of contaminants from the vapors prior to filtering by the primary and secondary filters 86, 88, thereby prolonging the effective life of those filters Since prefilter 84 is small and inexpensive, overall replacement costs are reduced Although primary and secondary filters 86, 88 eventually require replacement, the effective operating life between replacements is greatly increased Prefilter 84, primary filter 86 and secondary filter 88 may be carbon or charcoal activated filters or any other types of filters for filtering out the glutaraldehyde vapors Typically, prefilter 84 needs replacement after approximately every twenty or thirty days of use

Although the air filtering arrangement of the system removes the harmful vapors, significant exposure to the disinfectant solution can nevertheless occur when draining solution from the basin, either after the effective life of the solution has expired or the solution is otherwise no longer viable A drainage system for minimizing exposure of personnel to the solution is illustrated in Figs 11 , 12a - 12c The drainage system is typically disposed within storage cabinet 65 located below disinfection system 1 (Fig 2) Specifically, the drainage system includes a dram valve 148, a multi-directional valve 150, a basin drainage pump 149, a storage container pump 151 , a storage container 74 and a plurality of transfer hoses 159 for transporting the solution Transfer hoses 159 may be implemented by conventional rubber or plastic hoses used for medical or other applications Basin 20 includes dram 22 having a connector 158 for interfacing a transfer hose 159 to the basin drain to access solution contained within basin 20 Transfer hose 159 transports solution from connector 158 through drain valve 148 to basin drainage pump 149 Dram valve 148 enables and disables solution flow from basin 20 based on actuation of security switch 110 and dram valve switch 112 disposed on the disinfection system front wall described above, while basin drainage pump 149 is controlled by actuation of basin drainage pump switch 114 disposed on the front portion of the cabinet ledge as described above Basin drainage pump 149 causes solution to flow from drain valve 148 to multi-directional valve 150, typically a three-way valve, via a transfer hose 159 connected between multi-directional valve 150 and basin drainage pump 149 Multi-directional valve 150 directs solution from basin drainage pump 149 to either connector 162 disposed in miniature sink 109 described above or to storage container 74 via transfer hoses 159 extending from the multi¬ directional valve to miniature sink connector 162 and connector 153 of storage container 74, respectively The multi-directional valve is controlled by rotatable valve directional switch 101 disposed on the cabinet front wall that indicates the destination for the solution as described above

Storage container 74 includes storage container pump 151 , a removable cap 156 permitting access to the container contents, a dram plug 160 and a plurality of connectors 152, 153, 154 for transferring fluid between storage container 74, basin 20 and miniature sink 109 Storage container pump 151 is disposed within container 74 and receives power from a power supply (not shown) via an electrical connector 155 wherein the storage container pump is controlled by actuation of storage container pump switch 115 disposed on the cabinet front wall as descπbed above A transfer hose 159 extends between connector 162 of miniature sink 109 and connector 154 of storage container 74 to facilitate transfer of solution from the storage container to the miniature sink Storage container pump 151 is connected to connector 154 of the storage container, and upon activation, causes solution to flow from the storage container to the miniature sink via the hose and connectors Liquid residing in miniature sink 109, for example from an external source or solution spillage, may be drained into storage container 74 via a transfer hose 159 extending from sink dram connector 157 disposed in miniature sink drain 111 to connector 152 of storage container 74 In addition, storage container 74 may receive solution from basin 20 via multi-directional valve 150 and connector 153 as described above

Referring to Figs 12a - 12c, storage container 74 includes four substantially rectangular side walls, and substantially rectangular top and bottom walls, similar in configuration to a tank or box The bottom wall of storage container 74 includes a pair of substantially parallel legs 161 disposed integral with the bottom wall, with each leg disposed toward an opposite end of the container bottom wall adjacent a side wall, and extending along the shorter dimension of the bottom wall The bottom wall further includes a hump or reservoir 173 disposed toward the approximate center of the bottom wall for containing storage container pump 151, wherein reservoir 173 has a dram plug 160 for drainage of storage container 74 The top wall of storage container 74 includes connector 154 disposed at the approximate center and toward the front of the top wall for transferring solution from storage container 74 to miniature sink 109 as described above Connector 153 is disposed adjacent and to the right (i e , as viewed in Fig 12b) of connector 154 and receives solution from multi-directional valve 150 as described above, while connector 152 is disposed adjacent and to the right (i e , as viewed in Fig 12b) of connector 153 and receives liquid from miniature sink drain 111 as described above Storage container 74 further includes an opening (not shown) defined at the approximated center of the top wall covered by removable cap 156 Cap 156 is typically a domed shape cap that is removably fastened (e g , via threads on the cap and opening or any other fastening devices) to the opening to permit access to the container contents An electrical connector 155 is disposed adjacent and to the left (i e , as viewed in Fig 12b) of cap 156 for directing power from a power supply (not shown) to storage container pump 151 within the container as described above Storage container 74 may be made of plastic or other sturdy material that is preferably non-reactant with the disinfection solution

Connector 162 of miniature sink 109 receives solution from either basin 20 or storage container 74 as described above Solution received by connector 162 is typically directed toward a common sink drain for disposal of the received solution A common sink interface connector 163 for directing solution from miniature sink connector 162 to a common sink dram is illustrated in Figs 13a - 13b Specifically, common sink interface connector 163 includes a miniature sink interface connector 164, a sink drain connector 166 connected to miniature sink interface connector 164 via a hose 165, and a drain plate 167 Miniature sink interface connector 164 is configured to engage connector 162 of miniature sink 109 for receiving solution, wherein solution from miniature sink interface connector 164 travels through hose 165 to sink drain connector 166 having an output portion disposed, and extending through, the approximate center of drain plate 167 Dram plate 167 interfaces a sink dram plate 168, disposed over a common sink drain, during drainage of the solution Drain plate

168 is a substantially circular disk having a plurality of substantially circular openings

169 disposed throughout the disk to permit fluid to flow through the plate and into the sink drain The diameter of plate 168 is typically slightly larger than the diameter of common sink drains to enable dram plate 168 to be situated above the common sink drains An opening 170 is defined at the approximate center of dram plate 168 for receiving the output portion of sink drain connector 166 Opening 170 has a diameter slightly larger than the diameter of the output portion of sink drain connector 166 to enable that opening to receive the sink drain connector output portion Drain plate 168 essentially suspends the output portion of sink drain connector 166 above the sink dram in order to permit solution to flow from that output portion into the sink dram

Drain plate 167 is substantially similar to drain plate 168 except that its central opening is slightly smaller than that of dram plate 168 to ensure a secure fit about the output portion of sink dram connector 166 Dram plate 168 is disposed over a sink drain, while miniature sink interface connector 164 is connected to miniature sink connector 162 Sink drain interface connector 166 is subsequently placed into the common sink to engage drain plate 168 such that the output portion of sink dram connector 166 is disposed through opening 170, and drain plate 167 is disposed on top of drain plate 168 The sink faucet is enabled to permit water to flow through the openings in dram plates 167, 168 and into the common sink dram to dilute the solution as it drains into the sink

An alternative drainage system, generally for use when disinfection system 1 is placed on a table or other structure having limited storage capacity, is illustrated in Fig 14 Specifically, a dram hose 89 is connected between drain opening 22 of basin 20 and either a container 74 or directly to the drain of a sink A valve 34 is disposed about the hose flow path, preferably at or near the connection to basin dram opening 22, and is electrically operated by security switch 110, preferably a key switch, and a dra valve switch 112 as descπbed below to allow the disinfectant solution to drain through the hose Valve 34 is normally closed to inhibit solution flow and is switched to its open state in response to the security or key switch being enabled and the dram valve switch being actuated Valve 34 remains open while the pushbutton switch is activated to permit a close control over the rate of solution outflow and to prevent overflow from the container

Drainage container 74 is a substantially rectangular liquid receptacle and may be similar in size and shape to an attache case with a handle 87 disposed in the top surface to facilitate transporting the container Container 74 may be made of plastic or other sturdy material that is preferably non-reactant with the disinfectant solution A container opening 76 having dimensions slightly larger than the hose end is disposed in the top surface of the container for receiving the draining solution via hose 89 A conventional spillage film seal 78 is disposed about the distal end of hose 89 to engage and seal opening 76 The seal is substantially annular with an opening having a diameter slightly larger than the diameter of hose 89 to allow the hose to be inserted through the seal and opening 76 into the container The seal may be made of rubber, plastic or other suitable material in any shape accommodating the container opening A pump (not shown) may also be disposed in the hose flow path to pump the solution to either the container or sink drain The pump may be in line with the hose or a separate portable unit

Once container 74 is filled to a desired level with the disinfectant solution, the container may be earned away by the handle for proper disposal of the solution A new container may then be connected to hose 89 for further drainage Alternatively, a low pressure generator or venturi nozzle 80 may be connected to a drain tube 77 extending down from the venturi into container 74 An injection hose 83 is connected to inject a fluid stream, typically water, through the venturi nozzle to generate low pressure and aspirate the spent disinfectant solution from the container through dram tube 77 The solution flows through the dram tube to mix with, and be diluted by, the fluid injected into the venturi nozzle The diluted solution flows from venturi nozzle through a transport hose 85 to the drain of a sink The transport hose includes a seal substantially similar to the seal described above for securing the transport hose to the drain and preventing leakage of the solution The container is initially filled with the disinfectant solution from the basin via the security switch, drain valve switch and valve as described above prior to injecting fluid through the venturi nozzle to dram the container Once the container is filled and being drained via the venturi nozzle, valve 34 may be controlled to prevent solution overflow in container 74 during the drainage The fluid may be injected into the venturi from the faucet of a sink or by any conventional pumping device All of the above mentioned hoses may be conventional rubber or plastic hoses used for medical or other applications

The electrical system for the disinfection system having the drainage system of Fig 11 and a single speed fan is illustrated in Fig 15a Specifically, primary A C voltage is derived from a common wall outlet jack The voltage appears across leads 100 and 102 with lead 102 grounded to ground connection 175 A fuse 106 is connected in lead 100 and is typically a 1 5 amp fuse Ground fault circuit interrupter 108 is connected to leads 100, 102 subsequent to fuse 106 to disable the circuit in cases of improper grounding or current overload through the ground wire causing a ground imbalance Console circuitry 136, as described above with reference to Fig 8, is disposed in series with console power switch 58 between leads 100, 102 The control circuitry for the drainage system disposed within cabinet 65 is connected across leads 100, 102 and includes security switch 110 disposed in series with a parallel combination of valve dram valve switch 112, basin drainage pump switch 114, storage container pump switch 115 and rotatable valve directional switch 101 The drainage circuitry is enabled only in the closed state of both hood power switch 31 and an interlock relay 134 controlled by closure of access cover 3 for filter compartment 21 described below Drain valve switch 112 is biased off to prevent solution flow from basin 20 When the dram valve switch is closed, current flows to valve 148 to permit solution to drain from pan 20 as described above Similarly, closure of switches 114 and/or 115 enables current flow to activate pumps 149 and/or 151 as described above, while rotatable valve directional switch 101 enables current flow to manipulate multi¬ directional valve 150 as described above Multi-directional valve 150 may also be mechanically manipulated to control direction flow based on rotational movement of switch 101 The drainage of disinfection solution is accomplished in the manner described above with reference to Fig 11

A fan 120 having a single operating speed is connected in series with hood power switch 31 between leads 100, 102 Hood power switch 31 enables power to fan 120 and illuminates a lamp 138 when power is on A pressure switch 122 is disposed between hood power switch 31 and lead 102, and initially closes when hood power switch is activated to illuminate indicator 124 connected in series with the pressure switch When there is sufficient air flow (i e a low pressure center) in the disinfection system, pressure switch 122 enters an open state and ceases to illuminate indicator 124 within approximately fifteen seconds, thereby indicating proper air flow However, when there is insufficient air flow (i e , a high pressure center) in the disinfection system, pressure switch 122 maintains its closed state and does not open within approximately fifteen seconds to continue illuminating indicator 124, thereby giving notice of the condition The insufficient air flow or high pressure center reading typically indicates that the filters may be approaching saturation, thereby causing insufficient air flow and requiring an examination for possible replacement

Interlock switch 118 is provided to disable power to the system when filter compartment cover 3 (Fig 1 a) is not properly closed Specifically, interlock switch 118 is connected in series with relay coil 134 between leads 100, 102 and is closed when panel cover 3 is in place The closed interlock switch 118 activates relay 134 to connect hood power switch 31 to power lead 100 Normally, relay 134 is set to connect hood power switch 31 to an open circuit, thereby disabling the drainage and air flow circuitry when cover 3 is open or removed from the hood

The electrical system for a disinfection system having the alternative drainage system of Fig 14 and a single speed fan is illustrated in Fig 15b The electrical system illustrated in Fig 15b is substantially similar to the electrical system described above for Fig 15a except that the control circuitry for draining the disinfection solution is modified Specifically, the control circuitry for draining the disinfectant solution is connected across leads 100, 102 in series with hood power switch 31 and includes a security switch 110 connected in series with a series combination of drain valve switch 112, preferably a push button switch, and solenoid 116 Solenoid 116 operates valve 34 to control the drainage of disinfectant solution from the basin 20 as described above The drainage circuitry is enabled only in the closed state of both hood power switch 31 and interlock relay 134 controlled by closure of access cover 3 for filter compartment 21 described above Dram valve switch 112 is biased off to open the circuit When dram valve switch 112 is actuated to overcome the bias, the circuit is closed and current flows through solenoid 116 to actuate and open valve 34 and enable drainage of the solution The valve remains open as long as drain valve switch 112 is maintained actuated or depressed The amount of the disinfectant solution being drained may therefore be tightly controlled via drain valve switch 112 such that containers may be easily filled to their proper capacity The drainage of disinfectant solution is accomplished in the manner described above with reference to Fig 14

The electrical system for a disinfection system having a two-speed fan is illustrated in Fig 15c The electrical system is similar to the electrical systems described above for Figs 15a and 15b except that additional circuitry is provided to accommodate the two-speed fan Either drainage system described above may be utilized and the appropriate circuitry from Figs 15a and 15b may be inserted into the circuitry of Fig 15c in substantially the same manner as described above Specifically, fan 120 is a conventional fan having two operating speeds and is connected in series with the hood power switch and contacts of a relay 130 between leads 100, 102 A faster speed is utilized to prevent fumes from escaping the confines of the hood when the access panel 32 (Fig 1a) is open Under the control of relay 130, fan 120 may receive power either directly through hood power switch 31 or indirectly through a tπac circuit 132 Since greater voltage is applied to the fan when obviating the tπac circuit (i e , obviating resistive elements), the higher speed is attained when the tπac is out of the circuit A hood access panel interlock switch 126 is connected in series with relay 130 between power leads 100, 102 Switch 126 is closed when access panel 32 is closed, thereby activating relay 130 which connects fan 120 to the tπac circuit This results in greater resistance in the fan circuit and thus the slower operating speed when the access panel is closed Conversely, when access panel 32 is opened, access panel switch 126 is open and relay 130 is de-energized placing little or substantially no resistance in the fan circuit and hence a higher fan operating speed Hood power switch 31 enables power to fan 120 and illuminates a lamp 138 when power is on, as described above

The switches, relays, tπac, indicators, ground fault circuit interrupter, and blower are all conventional and commercially available components and may be implemented by any devices or combinations of devices yielding similar characteristics

Operation of the disinfection system is described with reference to Figs 1a, 2, 5a, 6a, 11 , 14 and 16a - 16c After use in a surgical procedure, medical instruments, particularly endoscopes, have debris disposed within their channels and on their exterior surfaces The debris is usually removed manually and the instruments are prepared for cold sterilization according to instrument manufacturer's specifications Generally, the instruments are immersed in a precleaning enzymatic detergent prior to disinfection After immersion in the enzymatic detergent, the instruments are rinsed to remove any residual detergent and then placed in an appropriate combination or rigid endoscope tray 6 depending upon the endoscope type and size Combination tray 6 is typically utilized for large rigid endoscopes and flexible endoscopes, while two rigid endoscope trays 6 may be accommodated by the basin and are typically utilized for smaller rigid endoscopes and other instruments that may be cold sterilized Basin 20 is filled with activated disinfectant solution (if the basin does not already contain the solution) in sufficient quantity to cover the endoscopes within each tray by at least one inch and the appropriate tray or trays are placed in the basin as described above, while access panel 32 is closed to prevent fumes from escaping The solution should be periodically tested as described below, preferably prior to each use, to ensure its viability The combination tray or rigid endoscope trays may rest on support blocks 24, 27, 56, 57 or be secured to the basin by quick release fasteners disposed on respective peripheral ledges of the trays as described above The hood filtration system is activated, typically prior to preparation of the instruments and disinfection solution, by actuation of the lighted hood power switch 31 which illuminates upon actuation of the switch Pressure indicator 124 is initially illuminated, and then disabled within fifteen seconds in response to a proper air flow reading as described above If the pressure indicator 124 remains illuminated beyond fifteen seconds, the system filters should be examined for possible replacement as described above Start switch 50 on console 8 is turned on and the lighted start switch illuminates while the default disinfection cycle time appears on the timer display 42 and the solution temperature appears on temperature display 52 The default cycle time and temperature may be preset at the factory or modified by a series of switches located in the rear of the unit and manipulable by a ball point pen, mechanical pencil, or other device having a point as described above Further, the lighted switches (i e , lighted switch 44 or 46 for the intermediate and high disinfection levels, respectively, and the appropriate lighted temperature switches 54, 55 for 25°C or 20°C, respectively) for the cycle corresponding to the default cycle are also illuminated The age of the disinfectant solution is displayed in days on day display 38 and should be checked daily to ensure solution viability When the age reaches typically fourteen or twenty-eight days corresponding to the effective life of the solution, the solution must be replaced (i e , drained from the basin as described below) and the age reset by actuating the day reset switch 40 Alternatively, the disinfectant solution may be tested via test strips having an activated tip which changes color to indicate the viability of the solution If the strip indicates the solution is no longer viable prior to the expiration of the effective life of the solution, the solution must also be changed (i e , drained from the basin as described below) and the age reset to properly maintain the new solution

In cases where an alternative disinfection cycle is desired, the cycle switch (i e , disinfection cycle switch) corresponding to the alternative cycle is depressed This causes the default cycle switch (i e , disinfection cycle and temperature) and time to be disabled while the switches and time associated with the alternative cycle are respectively illuminated and displayed on the timer display 42 Once the desired settings are selected, the solution is heated to the appropriate cycle temperature as described above in response to actuation of start switch 50 When the solution has achieved the desired temperature, timer display 42 automatically begins to count down and displays the time remaining in the disinfection cycle in minutes and seconds

Once the instrument disinfection cycle has expired, an audible alarm sounds for approximately five seconds, while lamp 9, timer display 42, and lighted reset switch 48 continuously flash Further, the heating element for the solution is also disabled at the completion of the cycle After the alarm sounds for five seconds, lamp 9, time display 42 and reset switch 48 continue to flash until the reset switch is actuated at which time all flashing stops The start switch 50 is illuminated and the disinfection cycle settings are reset to default settings regardless of whether or not the alternative cycle has expired The instruments are removed from the basin without powering down the system, and are processed according to normal operating procedures (e g , the instruments are rinsed thoroughly to remove any residue or excess disinfectant solution), while the disinfection system is on stand-by to process the next batch of instruments At this point, a new batch of medical instruments may be placed in the solution in the manner described above to be disinfected The new disinfection cycle commences after actuating the illuminated start button 50 as described above wherein the heater element is enabled to heat the solution to a desired temperature, and upon reaching that temperature, the subsequent cycle commences The process described above is repeated for each new cycle When console power switch 58 is turned off, the heater element is disabled along with all of the displays and lighted switches, however, the solution age is still stored even though there is no display In order to check the solution age without using the entire disinfection system, the console power switch is actuated to display the age and then turned off subsequent to ascertaining the age from the display in order to disable the disinfection system

The disinfectant solution must be drained either after the solution's effective life or when the test strips indicate the solution is no longer active Draining of the solution from the system to various locations via the drainage system disposed within cabinet 65 is accomplished by initially ensuring outlets 133, 135 are connected via the appropriate extension cords described above to a wall outlet jack and powering down console 8 via console power switch 58 The hood power switch 31 must also be enabled to effectuate draining of the solution and maintenance of power to the filtration system Further, access panel 32 should be maintained in a closed position during drainage Once these preliminary steps are performed, solution drainage may be accomplished via manipulation of various switches as described below Specifically, during disinfection, and for permitting liquid placed in miniature sink 109 (e g , from an external source or solution spillage) to be drained to storage container 74, security switch 110 and drain valve switch 112 are disabled to prevent solution flow from basin 20 Further, basin drainage pump switch 114 and storage container pump switch 115 are similarly disabled to prevent solution flow from basin 20 and storage container 74 Valve directional switch 101 is manipulated such that bar 103 points to indicator 105 indicating that the tank or storage container is designated to receive solution wherein valve directional switch 101 essentially controls multi-directional vale 150 as described above to direct solution flow to the storage container Since storage container connector 152 is directly connected via transfer hose 159 to sink drain connector 157, and storage container 74 is disposed in cabinet 65 below miniature sink 109, any liquid contained in miniature sink 109 flows into storage container 74 via gravitational forces acting on the liquid traversing transfer hose 159

In order to dram solution from basin 20 to a common sink drain, common sink interface connector 163 is attached to connector 162 of miniature sink 109, while drain plate 168 is disposed over the common sink drain and receives the output portion of sink dram connector 166 as described above Security switch 110 is actuated along with dram valve switch 112 to permit solution to be drained from basin 20 via drain valve 148 as described above Valve directional switch 101 is manipulated such that bar 103 points to indicator 104 indicating that the sink is designated to receive solution wherein valve directional switch 101 essentially controls multi-directional valve 150 to direct solution flow to miniature sink connector 162 as described above Basin drainage pump switch 114 is actuated, subsequent to actuation of switches 101 , 110, 112, to enable basin drainage pump 149 to pump solution through multi-directional valve 150 to miniature sink connector 162 as described above Miniature sink connector 162 directs the solution through common sink interface connector 163 to the common sink dram The sink faucet is enabled to permit cold tap water to dilute the solution and assist in draining the solution into the common sink dram In order to refill the basin with solution, the switches must be returned to states for disinfection operation described above

For draining the solution from basin 20 to storage container 74, security switch 110 is actuated along with drain valve switch 112 to permit solution to be drained from basin 20 via dram valve 148 as descπbed above Valve directional switch 101 is manipulated such that bar 103 points to indicator 105 indicating that the tank or storage container is designated to receive solution wherein valve directional switch 101 essentially controls multi-directional valve 150 to direct solution to connector 153 of storage container 74 as described above Basin drainage pump switch 114 is actuated, subsequent to actuation of switches 101 , 110, 112, to enable basin drainage pump 149 to pump solution through multi-directional valve 150 to storage container 74 In order to avoid spillage, the solution may be drained from the basin to the storage container as described above, and placed back into the basin by disabling security switch 110 and drain valve switch 112, and manipulating valve directional switch 101 to indicate that the sink is to receive solution Storage container pump switch 115 is actuated to to enable storage container pump 151 to pump solution from the storage container to the miniature sink The miniature sink connector should be connected to a transfer hose (or the common sink interface connector) that extends back to the basin Thus, the solution is pumped from the storage container to the miniature sink via storage container pump 151 and transported to the basin via the hose (or common sink interface connector) After drainage, the switches should be returned to states for disinfection operation as described above

Drainage of the storage container to a common sink is accomplished by initially connecting common sink interface connector 163 to connector 162 of miniature sink 109, and disposing drain plate 168 over a common sink drain as described above The storage container may be drained via pumping unless there is a regulation or Federal restriction requiring disposal of the solution in a particular manner Alternatively, the solution may be manually drained from the storage container via drain plug 160 as described above Security switch 110 and drain valve switch 112 are disabled to prevent solution flow from basin 20 Valve directional switch 101 is manipulated such that bar 103 points to indicator 104 indicating that the sink is to receive solution wherein valve directional switch 101 essentially controls multi-directional valve 150 to direct solution to miniature sink connector 162 as described above Storage container pump switch 115 is actuated, subsequent to manipulation of switches 101 , 110, 112, to enable storage container pump 151 to pump solution from storage container 74 to miniature sink connector 162 as described above Miniature sink connector 162 directs the solution through common sink interface connector 163 to the common sink drain The sink faucet is enabled to permit cold tap water to dilute the solution and assist in draining the solution into the sink dram In order to refill the basin, the switches must be returned to states for disinfection operation as described above Further, new solution may be placed in the basin during drainage from the container to the common sink Operation of the alternative drainage system is now described Initially, console 8 is powered down via console power switch 58, while hood power switch 31 is enabled as described above Specifically, security switch 110 is actuated, while hose 89, attached at one end to basin drain 22 and at its other end to container 74, conducts disinfectant solution flow under the control of drain valve switch 112 and valve 34 The valve remains open as long as dram valve switch 112 remains actuated or pressed to control drainage rate and amounts Drain valve switch 112 should be released when container 74 is approximately three-quarters full at which time the container may be removed for proper disposal of the solution It is advisable that the container not be disconnected from the hose until thirty seconds have elapsed in order to ensure minimal or no spillage If the container is to be drained using the low pressure generator or venturi nozzle 80, the fluid injection and transport hoses 83, 85 may be connected to the venturi nozzle 80 and fluid then injected to draw the spent solution from container 74 as described above

Basin 20 and combination and rigid endoscope trays 6 may be cleaned after utilization Initially, the disinfection system should be powered down to ensure that the heater element is disabled Subsequently, the combination tray or rigid endoscope trays are removed from the basin by unfastening the fasteners and/or lifting the tray or trays from the basin The basin may similarly be removed from the system subsequent to draining the solution from the basin by any of the above described procedures wherein the combination tray or rigid endoscope trays and basin are cleaned pursuant to normal operating procedures Further, the combination tray, rigid endoscope trays and basin may be cleaned separately

It will be appreciated that the embodiments described above and illustrated in the drawings represent only a few of the many ways of implementing the method and apparatus of the present invention

The basin 20 may be of any shape or dimension and may be constructed of stainless steel or other conductive material for heating the disinfectant solution The disinfectant solution may comprise a glutaraldehyde solution or other disinfectant solution and may be heated to any specified temperature for any period of time to accomplish varying degrees of disinfection The hood may be any conventional hood for capturing noxious or toxic vapors having a filtration system The primary filter, secondary filter and prefilter of the disinfection system may be carbon or charcoal activated or other types of filters for filtering toxic or noxious contaminants from the disinfectant solution vapor Any arrangement, quantity or combination of these filters may be utilized to filter the solution vapor Further, ultrasonic sound energy may be injected into the disinfectant solution for any appropriate duration of time

The control console of the disinfection system may include LED or LCD displays and be programmed to accommodate any specified temperature and time period Alternatively, the control console may include a single large display substantially similar to a display on a laptop computer for displaying all the information pertaining to the disinfection cycle The singular display may include a microprocessor or other control circuitry Further, the control console may be operated by any conventional microprocessor combinational logic or other circuitry capable of performing the functions of, and utilizing the LED or LCD displays of the control console The switches on the control console may be any conventional switch (e g , push button, toggle) or other device, such as a membrane switch panel, for controlling the disinfection procedure to be performed Moreover, the displays, indicators and lighted buttons or switches on the control console may be arranged in any ergonomic fashion to be user friendly for an operator In addition, the control console circuitry may utilize any conventional or other types of timing devices capable of timing the duration of the cycle The combination and rigid endoscope trays for holding instruments of the present invention may be made of ABS or other plastic, fiberglass or other rigid material, and may include various patterns for retaining medical instruments within the tray Further, the handles may be disposed on the trays in any manner capable of facilitating placement and removal of the trays from the basin Further, other containers may be used with the disinfection system in substantially the same manner described above to hold the instruments within the disinfectant solution For example, a surgical drape may be used having perforations within the drape such that the disinfectant solution may infiltrate the drape and be drained off when the drape is removed from the basin or pan to be rinsed after the instruments have been disinfected

The pumps of the present invention may be implemented by any conventional or commercially available electric or other type of pump The disinfection system may be disposed integral with, or placed atop, any supporting stationary or mobile structure capable of supporting the system The drainage systems may be disposed within a storage facility, or may be disposed adjacent the disinfection system to accommodate the various drainage system connections The valves of the drainage systems may be implemented by any commercially available or conventional electric or mechanical valves The circuitry for the disinfection system may be arranged in any manner, and may include any commercially available or other components that perform the circuitry functions described above The fan of the present invention may be implemented by any conventional or commercially available fan, having any number of operating speeds

It is apparent that several features may be incorporated into the present system A solution level detector may be incorporated to assure that the amount of the disinfectant solution residing in the pan or basin covers the medical instruments The level detector can be accompanied by an audible alarm or flashing indicator to indicate low solution level Further, an electπcal interlock may be employed to disable the disinfection cycle when an insufficient level is detected Moreover, a simplified solution detector can be used to disable power when no solution is detected in the basin or pan

A further feature may be the inclusion of a filter day counter and display substantially similar to the day counter and day display for the solution described above to keep track of the age of the prefilter and main filter When the counter reaches the corresponding filter effective life, the filter should be replaced Such a feature may be programmed into the microprocessor and displayed via an additional LED or LCD display on the console Further, extra cycles may be established to maintain and display information for a rinse and dram cycle in substantially the same manner as described above for the disinfection cycles Moreover, the drainage of the solution may include sensors or other control devices to control the amount of drainage of the solution such that a specified container is filled to a certain level without spillage

From the foregoing description it will be appreciated that the invention makes available a novel method and apparatus for disinfecting medical instruments wherein medical instruments are placed in a tray and disposed in a basin containing a heated disinfectant solution for a predetermined period of time while several control parameters of the disinfection (e g , level of disinfection, temperature of solution, time remaining in cycle) are maintained and displayed Having described preferred embodiments of the new and improved method and apparatus for disinfecting medical instruments, it is believed that other modifications, variations and changes will be suggested to those skilled in the art in view of the teachings set forth herein. It is therefore to be understood that all such variations, modifications and changes are believed to fall within the scope of the present invention as defined by the appended claims.

Claims

4 b What is Claimed is 1 An apparatus for disinfecting medical instruments disposed in a thermally treated disinfectant solution in response to selection of a particular disinfection cycle defined by disinfection cycle parameters, said apparatus comprising a basin for containing said disinfectant solution, a hood covering said basin for retaining vapors emitted from said disinfectant solution within an area confined by said hood, filtration means for removing contaminants from said vapors emitted from said disinfectant solution, thermal transfer means disposed in thermal transfer relation with said basin for heating said disinfectant solution, container means for immersing said medical instruments within said basin to expose said medical instruments to said disinfectant solution, and a control console for displaying said disinfection cycle parameters and controlling disinfection of said medical instruments in accordance with said disinfection cycle parameters of said particular disinfection cycle 2 The apparatus of claim 1 wherein said filtration means includes first, second and third filters wherein said first filter has smaller dimensions and a greater replacement frequency than said second and third filters, and said first, second and third filters are disposed sequentially within said filtration means such that said vapors traverse said first, second and third filters in sequential order 3 The apparatus of claim 1 wherein said container means includes a tray having preformed portions for receiving said medical instruments 4 The apparatus of claim 1 wherein said container means includes a plurality of trays with each tray having a non-planar floor for receiving said medical instruments 5 The apparatus of claim 1 wherein said control console includes temperature selection means for selecting a disinfection cycle temperature wherein said thermal transfer means includes temperature control means for maintaining said disinfectant solution at said selected disinfection cycle temperature, and time selection means for selecting a disinfection cycle time period, wherein said temperature control means maintains said disinfectant solution at said selected disinfection cycle temperature during said selected disinfection cycle time period 6 The apparatus of claim 1 wherein said basin includes a drainage opening and said apparatus further includes a container including a first opening for receiving said disinfectant solution from said basin, a hose extending between said drainage opening and said first opening for connecting said basin to said container, and a valve disposed about said hose to control solution flow from the basin to the container 7 The apparatus of claim 1 wherein said basin includes a drainage opening and said apparatus further includes a storage container for receiving said disinfectant solution and discarded liquid, a sink for receiving said disinfectant solution from said basin and said storage container, and supplying said discarded liquid to said storage container, a drain valve for enabling said disinfectant solution to flow from said basin, a directional valve for directing disinfectant solution flow to said container and said sink, a first pump for pumping said disinfectant solution from said basin through said directional valve to said container and said sink, and a second pump for pumping solution from said container to said sink 8 In an apparatus for disinfecting medical instruments disposed in a thermally treated disinfectant solution, a filtration system for filtering vapors emitted from said thermally treated disinfectant solution comprising a first replaceable filter for removing contaminants from said vapors, a second replaceable filter for removing residual contaminants from said vapors processed by said first replaceable filter, and a third replaceable filter for removing residual contaminants from said vapors processed by said second replaceable filter, wherein said first replaceable filter has smaller dimensions and a greater replacement frequency than said second and third replaceable filters 9 In an apparatus for disinfecting medical instruments disposed in a thermally treated disinfectant solution, a tray having a plurality of tray walls disposed about a tray floor for immersing the medical instruments within an apparatus basin containing the disinfectant solution comprising a plurality of channels defined in the tray floor for securing the medical instruments within the tray, and a ledge disposed about a periphery of the tray extending transversely outward from the tray walls to engage a periphery of said basin, wherein said ledge supports said tray within said basin 10 A method for disinfecting medical instruments comprising the steps of (a) immersing the medical instruments in a disinfectant solution, (b) selecting a disinfection cycle temperature and time period for a particular disinfection cycle, (c) heating the disinfectant solution to said selected disinfection cycle temperature, (d) maintaining the disinfectant solution at said selected disinfection cycle temperature during said selected disinfection cycle time period, (e) filtering vapors emitted from the heated disinfectant solution by removing contaminants from the vapors, and (f) removing the medical instruments from the disinfectant solution after the selected disinfection cycle time period expires 11 The method of claim 10 wherein step (a) further includes the steps of (a 1 ) placing the medical instruments in a tray having preformed portions and slots disposed about the tray, and (a 2) immersing the tray in the disinfectant solution such that the disinfectant solution infiltrates the tray via the slots to disinfect the medical instruments, and step (f) further includes the step of (f 1 ) removing the tray from the disinfectant solution after the selected disinfection cycle time period expires 12 The method of claim 10 wherein step (a) further includes (a 1 ) placing the medical instruments in a plurality of trays with each tray having a non-planar floor to receive the medical instruments, and a plurality of slots disposed about that tray, (a 2) placing the plurality of trays in the disinfectant solution such that the disinfectant solution infiltrates the slots to disinfect the medical instruments, and step (f) further includes (f 1 ) removing the trays from the disinfectant solution after the selected disinfection cycle time period expires 13 The method of claim 10 wherein step (e) further includes

(e 1 ) removing contaminants from said vapors via a first replaceable filter,

(e 2) removing residual contaminants from said vapors processed by said first replaceable filter via a second replaceable filter,

(e 3) removing residual contaminants from said vapors processed by said second replaceable filter via a third replaceable filter, wherein said first replaceable filter has smaller dimensions and a greater replacement frequency than said second and third replaceable filters

14 The method of claim 10 further including the step of (g) draining the disinfectant solution into a container

15 The method of claim 10 further including the step of (g) draining the disinfectant solution into a sink 16 In an apparatus for disinfecting medical instruments disposed in a thermally treated disinfectant solution, a method for filtering vapors emitted from the thermally treated disinfectant solution comprising the steps of

(a) removing contaminants from said vapors via a first replaceable filter,

(b) removing residual contaminants from said vapors processed by said first replaceable filter via a second replaceable filter, and

(c) removing residual contaminants from said vapors processed by said second replaceable filter via a third replaceable filter, wherein said first replaceable filter has smaller dimensions and a greater replacement frequency than said second and third replaceable filters

17 An apparatus for disinfecting medical instruments disposed in a thermally treated disinfectant solution in response to selection of a particular disinfection cycle defined by disinfection cycle parameters, said apparatus comprising a basin for containing said disinfectant solution, a hood covering said basin for retaining vapors emitted from said disinfectant solution within an area confined by said hood, filtration means for removing contaminants from said vapors emitted from said disinfectant solution, thermal transfer means disposed in thermal transfer relation with said basin for heating said disinfectant solution, container means for immersing said medical instruments within said basin to expose said medical instruments to said disinfectant solution, and a control console for displaying said disinfection cycle parameters and controlling disinfection of said medical instruments in accordance with said disinfection cycle parameters of said particular disinfection cycle, wherein said control console includes temperature selection means for selecting a disinfection cycle temperature wherein said thermal transfer means includes temperature control means for maintaining said disinfectant solution at said selected disinfection cycle temperature, and time selection means for selecting a disinfection cycle time period, wherein said temperature control means maintains said disinfectant solution at said selected disinfection cycle temperature during said selected disinfection cycle time period