WO1997029789B1

WO1997029789B1 - System and method for real-time monitoring and control of load sterilization and parametric release

Info

Publication number: WO1997029789B1
Application number: PCT/US1997/003271
Authority: WO
Filing date: 1997-02-11
Publication date: 1997-10-23

Abstract

The invention is a system and method for real-time monitoring and control of sterilization cycle parameters within a load-simulation device that simulates the same conditions as those within an acceptable standard challenge load to be sterilized. Integration of the device into the sterilizer control system allows critical sterilization parameter levels to be achieved and maintained within the simulated load throughout a sterilization cycle, thus resulting in a significant reduction in the number of unsuccessful cycles. A redundant parameter-monitoring system within the device is included. When acceptable sterilization parameter levels are shown to have been met, the sterile loads are automatically released for use immediately upon completion of the cycle, thus eliminating the need for biological indicators and chemical integrators.

Claims

AMENDED CLAIMS[received by the International Bureau on 12 September 1997 (12 09.97); original claims 1-11 replaced by amended claims 1-10 (3 pages)]

1. A challenge load-simulating device including a housing (10, 25, 54, 84) with a sterilant or disinfectant receiving opening (14, 34, 68, 86) characterized by: a baffle (11, 32, 34, 70, 82) resistant to penetration by a sterilant or disinfectant, the baffle disposed adjacent the sterilant or disinfectant receiving opening; a receiving area (12, 30) for receiving the sterilant or disinfectant that penetrates past the baffle; a sensor probe (13, 22, 23, 24) positioned adjacent the receiving area for real-time sensing during a sterilization or disinfection cycle of physical conditions at the receiving area to determine a sterilization or disinfection parameter value, wherein the probe senses at least one of temperature, pressure, relative humidity, concentration of sterilant or disinfectant, time and multiples, and combinations thereof; and a means (16) for electronically transmitting the parameter value from the device for use by a control system (Figs. 6, 7, 8) to provide real-time monitoring and control of (i) the sterilization or disinfection cycle and (ii) the physical conditions at the receiving area in accordance with the transmitted parameter value.

2. The device of claim 1, further characterized by: a second sensor probe (22, 23, 24) positioned adjacent the receiving area (12, 30) for real-time sensing of the physical conditions at the receiving area and generating a second parameter value; and a means (16) for transmitting the second parameter value from the device.

3. The device of either of preceding claims 1 and 2 further characterized by the baffle being selected from the group consisting essentially of a tortuous path for entrance of the sterilant into the device, a tortuous path for the sterilant within the device, and multiples and combinations thereof.

4. The device of either of preceding claims 1 and 2 further characterized by the baffle being constructed of a material selected from the group consisting essentially of cellusocis, teflon, silicon, polypropylene, polyethylene, polycarbonate, and combinations thereof.

5. The device of any of the preceding claims further characterized by the sterilant being selected from the group consisting essentially of steam, ethylene oxide gas, liquid hydrogen peroxide, vaporized hydrogen peroxide, liquid formaldehyde, vaporized formaldehyde, liquid peroxy compounds, vaporized peroxy compounds, ozone, ionized gases, plasmas, and combinations thereof .

6. A sterilization or disinfection system including a chamber (1) for receiving items to be sterilized or disinfected, a means (3) for controlling movement of a sterilant into the chamber, and a control means (100) for controlling in real time the entrance of the sterilant into the chamber and other sterilization parameters, further characterized by: a challenge load-simulating device in accordance with any of the preceding claims .

7. A method of monitoring and controlling a sterilization or disinfection process in a sterilization or disinfection chamber, the method characterized by: placing in the chamber a challenge load-simulating device that has a baffle that is resistant to penetration by a sterilant or disinfectant and a receiving area for receiving sterilant or disinfectant that penetrates the baffle; conducting a sterilization or disinfection cycle in the chamber; during the sterilization or disinfection cycle, sensing a physical condition in the receiving area and generating an electronic sterilization or disinfection parameter value in response thereto, wherein the physical condition is at least one of temperature, pressure, relative humidity, concentration of sterilant or disinfectant, time and multiples, and combinations thereof; transmitting the sensed parameter value to a control system; and, controlling the sterilization or disinfection cycle and the monitored physical conditions at the receiving area in real¬ time in response to the transmitted, sensed parameter value.

8. The method as set forth in claim 7 further characterized by: comparing the transmitted, sensed parameter value with a stored acceptable parameter value range; signalling an unacceptable sterilization or disinfection cycle when the transmitted, sensed parameter value fails to fall in the acceptable range during a sterilization cycle.

9. The method of either of preceding claims 7 and 8 further characterized by the parameter value being selected from the group consisting essentially of temperature, pressure, relative humidity, sterilant concentration, time, and multiples and combinations thereof.

10. The method of any one of preceding claims 7-9, further characterized by the sterilant or disinfectant being selected from the group consisting essentially of steam, ethylene oxide gas, liquid hydrogen peroxide, vaporized hydrogen peroxide, liquid formaldehyde, vaporized formaldehyde, liquid peroxy compounds, vaporized peroxy compounds, ozone, ionized gases, plasmas, and combinations thereof. STATEMENT UNDER ARTICLE 19

In response to the International Search Report of 16 July 1997, the Applicant requests amendment of claims 1, 7 and 8 as shown on substitute pages 22, 23, and 24.

If this amendment is delayed in transit and fails to arrive within the time period required for an Article 19 amendment, or fails to meet any other requirement for an Article 19 amendment ', it is requested that the amendment be considered as an amendment under Article 34.

The Searcher has cited two references in the "X" category. These references are: German Patent DE 24 27 834

⁽corresponds to US 3,861,875 of Joslyn) ; and International Application WO 95/32742.

The '875 patent to Joslyn discloses an electronic sensor with a challenge load 14A, 14B, 14C which is disposed in a sterilization chamber. Information from the electronic challenge load is fed to a circuit 30 which develops the sensed information into usable form (column 3, lines 51, 52) . The Joslyn patent suggests in column 1, lines 52-57 that the output can be used to determine when the sterilization cycle is completed.

The International Application WO 95/32742 sets forth an electronic monitor which records temperatures at numerous times during a steam sterilization cycle. This reference does not suggest controlling the sterilization cycle as a result of the parameters that are monitored. Rather, this application merely discloses a monitor from which a pass/fail determination can be made after the cycle is completed.

Second, the Searcher cited two references in the "Y" category. These references are: German Patent DE 93 19 369; and European Application 0 604 387A (corresponds to US 5,426,428 to Binder, et al. ) .

U.S. Patent No. 5,426,428 shows an electronic challenge load which is capable of sending the monitored information out of the sterilization chamber in real time. The '428 patent fails to teach using this monitored information to control the sterilization cycle.

German Patent DE 93 19 369 is directed to a monitor for a sterilizer. Although the monitor is said to be used for controlling sterilization conditions in a sterilization chamber, all that is disclosed is a monitor (see page 6, line 27 - page 7, line 13) . Indeed, claim 1, line 14, calls for the transmission of sterilization conditions from the measuring instrument 2 to be delayed ("lδsbar") . The Searcher also cited International Application WO 93/21964 as in the "A" category. That reference is not particularly relevant, and merely describes the general state of the art .

None of these references disclose or suggest a load simulated device for monitoring and controlling sterilization chamber conditions in real time and controlling the sterilization cycle in real time in accordance with the monitored conditions.

Claim 1 has been amended to recite expressly that the sensor probe senses at least one of temperature, pressure, relative humidity, concentration of sterilant or disinfectant, time and multiples, and combinations thereof. Claim 1 has also been amended to recite that the parameter value transmitted by the means (16) is used by the control system to provide real-time monitoring and control of both (i) the sterilization or disinfection cycle and (ii) the physical conditions at the receiving area, in accordance with the transmitted parameter value.

Claim 7 has been amended to recite a sterilization or disinfection system that is characterized, at least in part, by a challenge load-simulating device, such as recited in claim 1, and which includes a control means for controlling in real time, the entrance of the sterilant into the chamber and other parameters.

Claim 8 has also been amended. Specifically, claim 8 now recites the controlling operation as controlling both the sterilization or disinfection cycle and the physical conditions at the receiving area in real-time in response to a transmitted, sensed parameter value. Claim 8 has been further amended to recite that the physical conditions are at least one of temperature, pressure, relative humidity, concentration of sterilant or disinfectant, time and multiples, and combinations thereof.

These aspects are not disclosed or suggested in the cited references. Joslyn describes terminating sterilization in response to monitored conditions, and not controlling the sterilization or disinfection cycle and the physical conditions at the receiving area in real-time and in response to a transmitted, sensed parameter value. The '742 International Application merely discloses a monitor from which a pass/fail determination can be made after the cycle is completed. The German '369 patent and '387 European Application are even less relevant.

Claim 5 has been canceled since the subject matter of that claim has been incorporated into independent claim 1. Original claims 6-11 have been renumbered as claims 5-10.

An early indication of the allowability of all claims is earnestly solicited.