BR102018001672A2 - APPLIANCE AND METHOD FOR DETECTION OF MOISTURE IN A VACUUM CHAMBER - Google Patents

Description

(54) Title: APPARATUS AND METHOD FOR THE DETECTION OF HUMIDITY IN A VACUUM CHAMBER (51) Int. Cl .: A61L 12/04 (30) Unionist Priority: 02/02/2017 US 15 / 423,387 (73) Holder ( es): ETHICON, INC (72) Inventor (s): DOUG VO TRUONG; TODD MORRISON (85) National Phase Start Date:

01/26/2018 (57) Abstract: The present invention reveals a method of using a vacuum chamber to assist in the detection, removal and confirmation of the dryness of instrument moisture. The method may include the steps of opening a vacuum chamber; place an instrument inside the chamber, close the chamber, draw the first volume of air from the chamber; change volume of liquid water to steam, repeat for second and third volumes of air, open the chamber, and remove the instrument from the chamber in a dry state. This method can also include the steps of collecting pressure data that correspond to the pressure inside the chamber, while extracting the second volume of air from the chamber, calculating (for various values in subsequent times) the value of the second pressure derivative with respect to the time corresponding to the pressure greater than approximately the triple point of water pressure, determine whether the fourth value of the second derivative is less than or equal to the third value of the second derivative and determine that the second value of the second derivative is less or equal to the first value of the second derivative. The vacuum chamber can include a rack for hanging instruments with a lumen (...)

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Invention Patent Descriptive Report for APPARATUS AND METHOD FOR THE DETECTION OF HUMIDITY IN A VACUUM CHAMBER.

FIELD [001] The subject presented here refers to the detection of moisture in a chamber in which a vacuum is being formed. It is particularly useful in chemical steam sterilization techniques. BACKGROUND [002] Medical instruments can be decontaminated before use in order to minimize the likelihood that a device contaminated, for example, by microorganisms, will be used on an individual, which could cause an infection in the individual. Decontamination procedures include sterilization and disinfection. In various sterilization procedures that include introducing a sterilizer at low pressure into a vacuum chamber, residual moisture must be eliminated from the instrument and the vacuum chamber before the sterilizer is introduced into the instrument to maximize sterilization effectiveness. In various disinfection procedures, residual moisture must be removed from the instrument after the instruments are soaked in a chemical bath to prevent the growth of new microorganisms in the instrument.

[003] A typical chemical sterilization process for medical devices begins with medical facility personnel preparing the devices for sterilization by washing the instruments with water and / or washing solution to remove solids and liquids from the instrument. The team then dries the instruments (for example, using heat, medical-grade compressed air and / or towels) and perhaps wraps them in a blanket suitable for sterilization, which acts as a barrier for microorganisms, but allows passage sterilizer through it. Instruments wrapped in a blanket

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2/42 are sometimes called a sterilization package or charge. The load is then placed inside the sterilization system vacuum chamber and the chamber is closed (sealed), typically by closing the chamber door. The chamber can be heated, which can help to vaporize the water that may be inside the chamber. Then, the atmosphere in the chamber, which may include water vapor, is evacuated. In some sterilization procedures, the air inside the vacuum chamber can be excited to form air plasma, which can further assist in vaporizing the water to remove the chamber. After obtaining a low pressure, sometimes called a vacuum or coarse vacuum, a sterilizer is introduced into the chamber, both in gaseous form and in the form of mist that vaporizes in the low pressure environment of the chamber. The gas added to the chamber slightly increases the pressure in it. The sterilizer spreads quickly throughout the chamber, entering small or confined spaces, such as cracks, cracks and lumens in the medical devices it contains. The sterilizer bathes medical devices, which kills bacteria, viruses and spores arranged on and within the devices with which it comes into contact. In some sterilization procedures, particularly low temperature procedures that use hydrogen peroxide, the hydrogen peroxide gas can be excited through an electric field to transform the gas into plasma. Finally, the sterilizer is evacuated from the chamber and the chamber returns to ambient pressure. After the sterilization process is finished, the instruments can be removed from the chamber.

[004] Commercially available sterilization systems that use, for example, hydrogen peroxide, are designed to preferably operate without water in their sterilization chambers. If healthcare personnel mistakenly introduce water into the chamber, the water will begin to evaporate as the pressure

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3/42 inside the chamber is decreased to maintain a surface pressure balance between water and its environment. This pressure balance, which is also a function of temperature, is typically called water vapor pressure. At 100Ό, the water vapor pressure is 101 kPa (one atmosphere, or 760 torr), which is why the water is said to boil at 100Ό. However, when the local pressure around the water is less than 101 kPa (760 torr), the liquid water can change from phase to water vapor at lower temperatures.

[005] Latent heat is necessary for the water to change the phase to steam. Evaporation of water can remove at least some of this energy from the remaining water, which lowers the temperature of the remaining water. As the pressure in the chamber continues to drop and as evaporating water continues to decrease the temperature of the remaining water, the pressure and temperature approach what is often called the triple point of water, that is, the combination of temperature and pressure at which ice, water and water vapor exist in equilibrium. The triple point water temperature is 0.01 “C and the triple point water pressure is 0.616 kPa (4.58 torr). As the temperature and pressure approach the triple point, the likelihood of ice crystals forming in the remaining water increases.

[006] Ice can inhibit contact of a sterilizer with at least a portion of a medical device or instrument, potentially including blocking the lumens of the device. Consequently, ice can render a sterilization process ineffective, which can lead to the use of a non-sterile device on an individual or compel the hospital to pass the device through another sterilization cycle, which requires valuable additional time. In addition, the sterilizer may condense or become trapped inside the ice, which would lead to chemical burns on the skin of medical personnel.

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4/42 [007] In addition to sterility itself, the time and efficiency associated with decontamination processes for medical devices are important considerations for healthcare facilities. For example, hospitals often prefer to maximize the number of times that a device can be used within a certain period of time, for example, weekly. Subjecting a wet medical device to a sterilization process not only increases the likelihood that the sterilization process will not be effective, but it is also time consuming and can decrease the number of times a week that a device can be reused. Consequently, medical personnel should remove all water from the medical device after they have been cleaned, but before being placed in the sterilization chamber or at least before the sterilizing gas is introduced into the vacuum chamber.

[008] Some sterilization systems check the presence of water in the sterilization chamber before the sterilizing gas is introduced into it by checking for small increases in pressure inside the chamber while the vacuum is being drawn. If water is present in the chamber while the vacuum is being drawn, the pressure decreases asymptotically without any increase in it. However, if there is water in the chamber while the vacuum is being extracted, at least some water can be vaporized, which can cause slight local increases in pressure. Consequently, the detection of a small pressure increase while the vacuum is being drawn indicates the presence of water in the vacuum chamber. When water is detected, the sterilization process can be stopped so that excess water can be removed from medical devices before attempting to perform sterilization again. Interrupting the sterilization process as soon as water is detected can help not waste time and resources compared to continuing a

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5/42 sterilization process that may not be effective and may help to avoid using a non-sterile device.

[009] In some cases, instead of interrupting the sterilization process, it may be preferable to try to remove the water from the vacuum chamber through a process called load conditioning. Load conditioning is generally accomplished by first, a combination of heating and / or introducing plasma into the sterilization chamber and repressurizing the sterilization chamber to transfer energy to water (or ice) and, second, by extracting the vacuum again to convert water to steam. The charge conditioning can take place before, after or before and after the vacuum is extracted in the chamber. In some cases, load conditioning cannot remove water from the chamber. In other cases, load conditioning may remove some, but not all, of the water. In such cases, additional load conditioning can be attempted, but doing so requires additional time and resources. Consequently, when load conditioning fails to remove water from the chamber or when several attempts may be required to remove water, it may be desirable to give up load conditioning in favor of interrupting the process, so that excess water can be removed. removed from medical devices before attempting a new sterilization process.

[0010] Some medical instruments that include a lumen, such as endoscopes, are decontaminated by disinfection instead of sterilization. Disinfection procedures typically include immersion of the instrument in a chemical bath that includes, for example, glutaraldehyde or ortho-phthalaldehyde. After submersion, the instruments need to be washed with drinking or sterile water to remove chemicals and avoid recontamination of the instrument. These instruments are then dried by applying, for example, 870180006881, of 26/01/2018, p. 12/103

6/42 peep, towels, heat, and / or compressed air. The instruments can also be placed in a drying cabinet. Some commercially available drying cabinets circulate air inside the cabinet to further assist in the removal of moisture. Removing residual moisture helps prevent new microorganisms from re-contaminating the instrument.

SUMMARY [0011] The subject presented refers to methods of operating a vacuum chamber to dry a medical instrument and / or confirm that the medical instrument is dry. A first example method includes the steps of opening a vacuum chamber; place the instrument inside the chamber, close the chamber, draw a first volume of air from the chamber; change a volume of liquid water to steam, introduce a second volume of air into the chamber, remove the second volume of air from the chamber, change a second volume of liquid water to steam, introduce a third volume of air into the chamber, open the chamber, and remove the instrument from the chamber in a dry state. This method can also include the steps of collecting the pressure data that correspond to the pressure inside the chamber, while extracting the air from the chamber, calculating a first value of the second pressure derivative with respect to the time that corresponds to a pressure greater than approximately the triple point of water pressure, calculate a second value of the second pressure derivative with respect to the time corresponding to a pressure greater than approximately the triple point of water pressure and a time subsequent to the time corresponding to the first value of the second derivative, calculate a third value of the second pressure derivative with respect to the time corresponding to a pressure less than approximately the triple point of water pressure and a time subsequent to the time corresponding to the second value

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7/42 of the second derivative, calculate a fourth value of the second pressure derivative with respect to the time corresponding to a pressure less than approximately the triple point of water pressure and a time subsequent to the time corresponding to the third value of the second derivative, determine that the fourth value of the second derivative is less than or equal to the third value of the second derivative and determine that the second value of the second derivative is less than or equal to the first value of the second derivative. This first example method can be performed on an instrument that includes a lumen, for example, an endoscope. As such, a rack or shelf can be included in the vacuum chamber from which the endoscopes can be hung.

[0012] A second example method for drying a medical instrument in a vacuum chamber includes the steps of connecting a timer to a digital computer, extracting a first volume of air from the chamber, repeatedly determining the pressure inside the chamber at the same time as if the first volume of air is extracted from the chamber, calculate with the digital computer a first value of the second pressure derivative with respect to time, calculate with the digital computer a second value of the second pressure derivative with respect to time, the second value of the second derivative corresponding to a time subsequent to the time corresponding to the first value of the second derivative, determine, with the digital computer, that the second value of the second derivative is greater than the first value of the second derivative and automatically enter a second volume of air in the chamber. The step of repeatedly determining the pressure may include repeatedly obtaining pressure measurement data and storing it in a non-transitory digital computer storage medium. The method may also include the step of determining, with the digital computer, that the second value

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8/42 of the second derivative occurs at a pressure less than approximately the triple point of water pressure. The step of automatically introducing air into the chamber may include automatically opening a valve. In addition, the chamber can be opened automatically. The method may also comprise removing the instrument from the chamber and drying the instrument by blowing air on the instrument or applying heat to the instrument. In addition, the step of extracting the first volume of air from the chamber can begin after the step of turning on the timer. The example method can also include the step of determining that a difference between the second value of the second derivative and the first value of the second derivative is greater than the noise floor. This second example method can be performed on an instrument that includes a lumen, for example, an endoscope. As such, a rack or shelf can be included in the vacuum chamber from which the endoscopes can be hung.

[0013] A third exemplary method for drying a medical instrument in a vacuum chamber includes the steps of connecting a timer to a digital computer, removing a first volume of air from the chamber, repeatedly determining the pressure inside the chamber repeatedly while removing the first volume of air in the chamber, calculate, with the digital computer, a first group of values of the second pressure derivative in relation to time, calculate, with the digital computer, a first sum of positive differences between consecutive values of the second derivative of first group of values of the second derivative, compare the sum with a limit value, the sum indicating that the addition of residual moisture is or could be placed on the instrument when the sum is greater than the limit value and indicating that the instrument is dry when the sum is less than the limit value, determine that the first sum is greater than the limit value, open the valve to introduce a second volume of air into the inland

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9/42 of the chamber, remove the second volume of air from the chamber, repeatedly determine the pressure inside the chamber while removing the second volume of air from the chamber, calculate, with the digital computer, a second group of values of the second pressure derivative in relation to time, calculate, with the digital computer, a second sum of positive differences between consecutive values of the second derivative of the second group of values of the second derivative, determine that the second sum is less than the limit value, open the valve to enter a third volume of air in the chamber, and open the chamber. The step of opening the valve to introduce the third volume of air can be done after determining that the second sum is less than the limit value. The chamber opening step can be done after opening the valve to introduce the third volume of air. In addition, after the chamber opening step, the instrument can be removed from the chamber in a dry state. In addition, the first sum can be terminated when a first difference between the consecutive values of the second derivative is negative, and the second sum can be started after the first sum is completed and when a second difference between the consecutive second derivative values is positive. . This third example method can be performed on an instrument that includes a lumen, for example, an endoscope. As such, a rack or shelf can be included in the vacuum chamber from which the endoscopes can be hung.

[0014] For use in the present invention, the term noise floor refers to a graph of pressure data in relation to time, in which the pressure data was produced from a pressure transducer connected to a vacuum chamber. The term noise floor refers to the peak-to-peak amplitude between the largest local maximum in the graph caused by the noise inherent in the pressure transducer and the smallest local minimum in the graph caused by the noise inherent in the pressure transducer.

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10/42 pressure when the vacuum chamber is maintained at or near the lowest pressure that the vacuum chamber can maintain at or near the desired final pressure for a certain sterilization process. The noise floor can be determined empirically for a certain vacuum chamber or a certain sterilization process.

BRIEF DESCRIPTION OF THE DRAWINGS [0015] Although the specification ends with claims that specifically indicate and distinctly claim the subject described here, it is believed that the subject will be better understood from the following description of specific examples taken in conjunction with the drawings in annex, where:

[0016] Figure 1 represents, in the form of a block diagram, a sterilization system with a vacuum chamber that can be used to practice the methods presented in the present invention; [0017] Figure 2 is a graph plotting pressure in relation to time, a first derivative of pressure in relation to time, and a second derivative of pressure in relation to time, in the vacuum chamber represented in Figure 1, when water does not it is present in the chamber;

[0018] Figure 3 is a graph plotting pressure in relation to time, a first derivative of pressure in relation to time, and a second derivative of pressure in relation to time, in the vacuum chamber represented in Figure 1, when water is present in the chamber on a non-metallic surface;

[0019] Figure 4 is a graph plotting pressure in relation to time, a first derivative of pressure in relation to time, and a second derivative of pressure in relation to time, in the vacuum chamber represented in Figure 1, when water is present in the chamber on a metallic surface;

[0020] Figure 5 is a flow diagram of the procedure 870180006881, from 01/26/2018, p. 12/153

11/42 terilization that includes an exemplary method for detecting moisture, removing moisture, and confirming dryness;

[0021] Figure 6 is a flow diagram of a sterilization procedure that includes another exemplary method for detecting moisture, removing moisture, and confirming dryness;

[0022] Figure 7 is a flow diagram of a method for detecting moisture, removing moisture, and confirming dryness that can be incorporated into a disinfection process; and [0023] Figure 8 is a flow diagram of another method for detecting moisture, removing moisture, and confirming dryness that can be incorporated into a disinfection process.

DETAILED DESCRIPTION [0024] The following description presents certain illustrative examples of the claimed matter. Other examples, resources, aspects, modalities, and advantages of the technology should be evident to those skilled in the art from the description below. Consequently, drawings and descriptions should be considered as illustrative in nature.

I. Vacuum chamber [0025] A vacuum chamber can be included in a disinfection procedure or system. For example, Figure 1 reflects a sterilization system 10, represented schematically in the form of a block diagram. It comprises a vacuum chamber 12 having a load (package) 14 of instruments in it to be sterilized. Chamber 12 can be formed of any material that is strong enough to withstand pressures as low as approximately between 0.04 kPa and 0.4 kPa (approximately between 0.3 torr and 3 torr), and sufficiently inert to avoid reacting with or absorb any sterilizers introduced in it. Such materials can include aluminum and stainless steel. Chamber 12 can also InPetition 870180006881, from 01/26/2018, p. 12/163

12/42 include a barrier 16 that can be opened and sealed, such as a door, that can be opened to allow the load 14 to be placed and removed in chamber 12. The barrier must be strong enough and include a seal strong enough to withstand the low pressures extracted inside the chamber 12 and avoid leaks between the chamber 12 and the environment. A vacuum pump 18, capable of reaching the desired operating pressure, evacuates air and other gases, such as water vapor, from chamber 12. The vacuum pump 18 may include a hose or tube 20 that connects to chamber 12. The vacuum pump 18 can also include a valve 22, which can be opened or closed to assist or prevent pressure changes in chamber 12. For example, when the valve is opened and the vacuum pump is operating, the pressure in the chamber 12 can be lowered. Alternatively, when the valve is opened and the vacuum pump is not in operation, the pressure inside the chamber can be equalized to the ambient pressure. In other embodiments, a valve that is not part of the vacuum pump 18 can be used to control whether the chamber 12 has a pressure equal to the ambient pressure. A pressure monitor 24 monitors the pressure in chamber 12. Particularly suitable pressure monitors are capacitance gauges available from MKS Instruments. A heating element 26 can be used to heat the chamber 12. It can comprise separate elements connected to the outside of the chamber 12 in places sufficient to uniformly heat the chamber 12. A tank or reservoir 28 containing sterilizer, which includes a hose or tube 30, is connected to chamber 12. In some embodiments, tank 28 may also include a valve 32, which can be arranged between chamber 12 and tank 28 to control the sterilizing flow from tank 28 through hose 30 and inwardly from chamber 12. A power source and / or signal generator 33 and an electrode 34 disposed inside chamber 12 can be provided 870180006881, from 26/01/2018, p. 12/173

13/42 to create an electric field within chamber 12 between electrode 34 and the inner surface of chamber 12 to create a plasma in it. A signal, such as an RF signal, can be supplied to electrode 34 from generator 33 via a feed passage 35, such as a wire-type feed passage. Plasma creation is useful for low temperature sterilization processes that use hydrogen peroxide gas. In these processes, hydrogen peroxide gas can be excited to form a hydrogen peroxide plasma. Alternatively, another gas can be used to form the plasma, such as air, which can help decrease the hydrogen peroxide residues in the charge, in order to facilitate the removal of hydrogen peroxide from chamber 12. The sterilization system 10 it can also include a user interface 36, which can include output devices, such as a printer or display, and user input devices, such as a keyboard or touchscreen.

[0026] A control system 38, such as a digital computer, controls the operation of system 10 and its various components. The control system 38 can employ one or more microprocessors 40. One can also employ a non-transitory storage medium 42, such as random access memory (RAM), a hard disk drive or flash memory, which can store data, such as pressure values and time values. An analog to digital converter (A2D) 44 can be used to convert analog data to digital data if analog data, such as pressure data, is collected. A timer or clock circuit 45 keeps time. The control system 38 may also include software and / or logic by which the microprocessor can numerically compute the values for the first pressure derivatives with respect to time and values for the second pressure derivatives with respect to time. Such numerical calculations can be performed according to 870180006881, of 01/26/2018, p. 12/183

14/42 of the difference forward, difference backward, central difference or some combination of them, as is known in the art. These first derivative values and second derivative values can also be stored in the storage medium 42. The control system 38 may also include software and / or logic by which the microprocessor can compare the first derivative values at different pressures and different times. The control system 38 may also include software and / or logic by which the microprocessor can compare the values of the second derivative at different pressures and different times. For example, the control system is capable of storing pressure values P ,, which are measured in various increments of time i. The time period between neighboring time increments, designated as At, can be equal to approximately 0.1 second, approximately 1 second, approximately 2 seconds, approximately 5 seconds or approximately 10 seconds. Pressure values can also be expressed as a function of time, so that P, can be expressed as P (t _n ), where t _n = t _n -i + At. Pressure values can be measured throughout sterilization process and stored in the storage medium 42. Pressure values can also be measured and stored at least while the system is extracting the vacuum in the vacuum chamber. The pressure values can also be measured and stored at least while the pressure in the vacuum chamber is below approximately 4 kPa (approximately 30 torr).

[0027] A vacuum chamber can also be incorporated in a disinfection process. For example, an instrument drying rack or shelf that includes lumens, such as endoscopes, can also be arranged inside the vacuum chamber 12. The endoscopes can be hung on the drying rack, which can

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15/42 keep the endoscopes in a vertical orientation, in order to further assist in the removal of moisture. When vacuum chamber 12 is used in a disinfection process, it does not need to be connected to a sterilization tank, such as tank 28, and does not need to include components associated with plasma generation, such as electrode 34. In this configuration, the vacuum chamber can only be used to assist in drying instruments or in confirming that they are dry.

II. Residual water detection [0028] The values of the first pressure derivative with respect to time (dP (t _n ) / dt) and the values of the second pressure derivative with respect to time (d ² P (tn) / dt ² ) they can be computed for all or most of the pressure values, P, or P (tn), by the microprocessor and stored in the storage medium 42. The first and second derivatives can be calculated numerically, as is known in the art. The first and second derivatives can be calculated continuously, for example, while the vacuum is being extracted or after a predetermined pressure is reached in the chamber. Due to the nature of the numerical calculations of the first derivative and the second derivative, there may be a time lag between pressure, its first derivative with respect to time and its second derivative with respect to time. In other words, for example, a local maximum in a plot of the second pressure derivative compared to time can be observed approximately one tenth of a second, approximately half a second, approximately one second, approximately two seconds, approximately five seconds or some other time after the pressure to which it corresponds. The delay time period is a function of the technique used to calculate the derivative.

[0029] Where there is no water or other possible sources of gas (exPetition 870180006881, of 26/01/2018, page 20/123

16/42 air clusters) inside the vacuum chamber at the beginning of a vacuum extraction, the pressure in the vacuum chamber during vacuum extraction can be theoretically described by the equation

--yy for pressures between approximately atmospheric pressure and approximately 100 Pa (approximately 750 mTorr), where P is pressure, S is the speed of the vacuum pump, t is time and V is the volume of the vacuum chamber.

[0030] Figure 2 reflects a graph on which the approximate pressure is plotted compared to time data 50 for pressures under 667 Pascal (5,000 millitorr) between 30 seconds and 80 seconds in a vacuum extraction in which no residual water ( or other gas sources) were inside the gas chamber. Also included in this graph are the first derivatives of pressure values 52, which can be calculated from pressure data compared to time data 50 and the second derivative of pressure values 54, which can be calculated from data pressure data compared to time data 50 and first derivatives compared to time values 52. Pressure data 50 is the dashed line, the values of the first derivative 52 are the dotted line and the values of the second derivative 54 are the continuous line. The pressure data 50 decreases asymptotically until a minimum desired pressure is reached. The values of the first derivative 52, reflected in units of Pascal per second (millitorr per second), and the values of the second derivative 54, reflected in units of 0.01 Pascal / second squared (0.1 millitorr / second squared) , also decrease asymptotically. Although the noise in the pressure data 50 is not apparent in this graph and the noise in the values of the first derivative 52 is minimally apparent, a noise floor is apparent in the values of the second derivative 54. There is a noise floor

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17/42 of about 0.8 Pascals per second squared (about 6 millitorr per second squared) for the values of the second derivative 54. [0031] In some cases, particularly when the instruments to be sterilized are not sufficiently dry by healthcare personnel, residual water can be introduced into the vacuum chamber. In such cases, the water may be in the vacuum chamber when the vacuum extraction from the sterilization process begins. As the pressure inside the chamber decreases, at least part of the volume of waste water can change the phase to gas. At pressures equal to or less than approximately 0.611 kPa (4.58 torr) (the pressure of the triple point of water), the change from phase to gaseous state can also be caused by a corresponding phase change to ice. That is, as the ice crystallizes as waste water, latent heat is released, which heats the surrounding portions of the water. Since the three phases of water - gaseous, liquid and solid states - exist in equilibrium at the triple point and in almost equilibrium at pressures and temperatures close to the triple point, the latent heat of the phase-to-ice change of some residual water molecules can provide energy to other wastewater molecules that cause them to change from phase to gaseous state. When liquid water changes the phase to a gaseous state, regardless of whether ice is also formed, a new volume of gas is suddenly present in the vacuum chamber, which can cause an increase in the rate of pressure change, which can even sufficient to cause a local increase in pressure.

[0032] Figure 3 reflects a graph on which approximate pressure data are plotted compared to time 56 for pressures less than 667 Pascal (5,000 millitorr) between 30 seconds and 80 seconds in a vacuum extraction. Pressure data 56, reflected in Pascal units (millitorr), corresponds to an exPetition 870180006881, of 26/01/2018, p. 12/22

18/42 vacuum traction during which approximately 0.1 milliliter of residual water was inside the vacuum chamber, arranged in a plastic rack. Figure 3 also reflects the values of the first pressure derivative 58, which can be calculated from pressure data compared to time 56, and the values of the second pressure derivative 60, which can be calculated from pressure data compared to time 56 and values of the first derivative compared to time 58. The pressure data 56 is the dashed line, the values of the first derivative 58 are the dotted line and the values of the second derivative 60 are the continuous line. The values of the first derivative 58 are reflected in units of Pascal per second (millitorr per second) and the values of the second derivative 60 are reflected in units of 0.01 Pascal / second squared (0.1 millitorr / second squared). As shown in Figure 3, between approximately t = 65 seconds and approximately t = 70 seconds, at pressures equaling approximately 160 Pascal and approximately 133 Pascal (1,200 millitorr and approximately 1,000 millitorr), the curvature of the pressure data 56 changes as indicated by the circles 62 and 64, which corresponds to a decrease in the rate of pressure change, so that, momentarily, there is little or no decrease in pressure. The data suggest that the rate of pressure change within the vacuum chamber decreased when the water changed from phase to gas. These changes are reflected in the local minimum of the plotted first derivative values, as indicated by circles 66 and 68. The related changes in the curvature of the plotted second derivative values are indicated by the local maximum 70 and 72. The local maximum 70 and 72 are more readily apparent and easier to detect than changes in curvature for the pressure data and values of the first derivative indicated by circles 62, 64, 66 and 68. Consequently, the second deposition 870180006881, of 26/01/2018, p. 12/23

19/42 pressure with respect to time can assist in determining whether moisture may be in the chamber during vacuum extraction.

[0033] Figure 4 reflects a graph on which approximate pressure values are plotted compared to time 74 for pressures less than 4,000 Pascal (30,000 millitorr) between 30 seconds and 80 seconds in a vacuum extraction. The pressure data 74, reflected in Pascal units (millitorr), corresponds to a vacuum extraction during which approximately 1.5 milliliter of residual water was inside the vacuum chamber, arranged in an aluminum rack. Figure 4 also reflects the values of the first pressure derivative 76, which can be calculated from pressure data compared to time 74, and the values of the second pressure derivative 78, which can be calculated from pressure data compared to time 74 and values of the first derivative compared to time 76. The pressure data 74 is the dashed line, the values of the first derivative 76 are the dotted line and the values of the second derivative 78 are the continuous line. The values of the first derivative 76 are reflected in units of Pascal per second (millitorr per second) and the values of the second derivative 78 are reflected in units of 0.01 Pascal / second squared (0.1 millitorr / second squared). As shown in Figure 4, at approximately t = 32 seconds and a pressure of approximately 2,000 Pascals (approximately 15,000 millitorrs), indicated by reference numeral 80, the curvature of the pressure data 74 begins to change, indicating that the rate of change of pressure decreases. The greatest degree of change in curvature appears at approximately t = 33 seconds and a pressure of approximately 1,867 Pascals (approximately 14,000 millitorr), as indicated by reference number 82. The data suggests that the pressure change rate of 870180006881, 26 / 01/2018, p. 12/24

20/42 of the vacuum chamber decreased when the water changed from phase to gas. The local maximum 84 of plotting the values of the second derivative 78 corresponds to the time and pressure at which the change in the rate of pressure change was the greatest. In addition, local maximum 84 is more readily apparent and easier to detect than changes in curvature for the pressure data and values of the first derivative. Consequently, the second pressure derivative with respect to time can assist in determining whether moisture may be in the chamber during vacuum extraction.

[0034] Sterilization processes, including those that may include load conditioning (that is, a process to remove waste water from a load in a vacuum chamber), are sometimes canceled when waste water is in the vacuum chamber . Some commercially available sterilizers are designed to try to determine when there is excess water vapor or another gas in the chamber for sterilization to be effective and / or for the system's load conditioning cycle to be effective, so that it could be more efficient for health care personnel to remove the load from the system and try to dry it again. For example, some systems experience increases in pressure under conditions where the pressure must remain constant, while others simply interrupt the sterilization cycle if the vacuum extraction requires more time than it should. However, these checks may be insufficient for smaller amounts of water, which the technology described here solves. In addition, the inventors determined that the likelihood of successful sterilization and / or conditioning of the load depends on whether the water is arranged on a metallic or non-metallic surface because metallic surfaces can conduct heat into the water while non-metallic surfaces no, increasing the likelihood of formation

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21/42 ice. Consequently, the probability of avoiding failure of sterilization and / or load conditioning can be increased by determining whether waste water is disposed on metallic or non-metallic surfaces and, correspondingly, whether ice can form during vacuum extraction. . Since load conditioning may not be suitable for efficiently removing ice as soon as it is formed, in some sterilization processes it may be desirable to perform a load conditioning operation before the vacuum is removed. This can be done by heating the vacuum chamber, in order to vaporize at least a little water that can be disposed inside the chamber. In some embodiments, the chamber can be heated to pressures below atmospheric pressure.

[0035] Using the techniques described in the present invention, detectable phase changes from liquid water to steam water during vacuum extraction can occur at vacuum chamber temperatures below approximately 60 ° C and above pressure from the triple point of water, for example, between approximately 0.7 kPa and approximately 4.0 kPa (approximately 5 torr and approximately 30 torr), when residual water in the chamber is disposed on a metallic surface. As metallic objects typically have a high thermal conductivity, particularly in comparison to non-metallic objects, metallic objects are able to transfer energy to the water arranged on their surfaces, which increases the water temperature, and allows for changes in state water phase. liquid to gaseous state. Phase changes from liquid to steam during vacuum extraction are less likely in this temperature and pressure regime when liquid water is disposed on non-metallic surfaces. Non-metallic objects generally do not transfer enough energy to the water in accordance with 870180006881, from 26/01/2018, pg. 12/26

22/42 liquid to allow it to change from phase to gaseous state.

[0036] Detectable phase changes from liquid water to water vapor can also occur at vacuum chamber temperatures below approximately 60Ό and below approximately the triple point of water pressure (0.611 kPa (4.58 torr )) when residual water in the chamber is disposed on a non-metallic surface. As the pressure drops in the direction and beyond the triple point of pressure, the water can change phase to water vapor and the temperature of the waste water can fall correspondingly, which can cause the formation of ice crystals in the water residual. When ice forms, latent heat is released. Due to the fact that the water is at or near the triple point, this latent heat may be sufficient to activate neighboring water molecules to change the phase to a gaseous state as the pressure continues to drop.

[0037] Based on the previously mentioned arguments, the phase changes that occur at pressures above the triple point of water pressure indicate that at least some residual water was disposed on a metallic surface and that the phase change to steam can do not include a corresponding phase change to ice. However, the phase changes that occur at pressures near or below the triple point of water pressure indicate that at least some residual water could be disposed on a non-metallic surface and that the phase change to steam may include a corresponding change phase for ice. Consequently, when a local maximum for the curve of the second pressure derivative in relation to time occurs at a pressure greater than the triple pressure point, water is likely to be disposed on a metallic surface, indicating that ice formation has not followed vaporization. However, when a local maximum for the SePetition curve 870180006881, of 26/01/2018, p. 12/27

23/42 pressure derived from pressure in relation to time occurs at or below the triple pressure point, water is likely to be disposed on a non-metallic surface, indicating that the formation of ice accompanied vaporization.

[0038] The inventors believe that they were the first to discover and reveal what is described in the previous paragraph. They determined a new, useful and inventive application of this, described below, that improves the sterilization processes and charge conditioning techniques known in the art. This application involves evaluating whether it is advisable to carry out a load conditioning process, whether a load must be dried again manually, for example, with compressed air and / or heating, and whether a load is sufficiently dry to receive a sterilizer. This determination can be made by determining the pressure at which a local maximum of the second pressure derivative with respect to time occurs. If at least one maximum location occurs below the triple point of water pressure, it may be preferable to interrupt the sterilization process instead of trying to condition the load due to the possibility that ice crystals may be formed in the water and the load. However, if the local maximum is detected above the triple point of water pressure and no local maximum is detected below the triple point of water pressure, charge conditioning can be attempted because the water that can remain in the charge can be readily vaporized. and evacuated from the vacuum chamber without creating ice crystals in the load.

[0039] Due to measurement error associated with pressure values, such as errors caused by the resolution of a pressure transducer and conversions from analog to digital, noise may be present in the data, calculations and pressure curves compared to time, first derivative of pressure compared to time and second derivative of pressure compared to time. In order to prevent

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24/42 mistake the determination that a maximum location on the curve of the second derivative exists that does not correspond to an increase in pressure, but that is caused by the measurement error, the value of the maximum location must be sufficiently larger than the noise floor .

[0040] It may be preferable to base a determination to condition a load or interrupt a cycle at the relative size of a local maximum compared to, for example, an inflection point, a local minimum or noise floor. Alternatively, it may be preferable to base this decision on a sum of positive differences between consecutive second derivative values, which is referred to as δ +. δ + can be calculated according to the following steps. After or during vacuum extraction, the second time pressure derivative can be calculated and stored for each time increment. Differences between the values of the neighboring second derivative, that is, consecutive, can be calculated by subtracting the value of the second derivative calculated for a time increment from the value of the second derivative calculated for the next time increment. If the value of this difference is positive (that is, if the value of the second derivative has increased), the value of the difference is added up. If the value of this difference is negative (that is, if the value of the second derivative has decreased), the value of the difference is disregarded. This sum procedure for δ +. can be expressed by the following formula:

s · _ vrri (C ^ n) 1) A z 4 ² P (t _rt _i) ° + d ² dG) ^{lJ dti} > dt * [0041] In the aforementioned formula, m corresponds to the number of time increments within the period given or chosen time over which δ + is calculated. Also, in the previous formula, t _n = t _n -i + At. As noted above, At is the length of time between time increments, and can be equal to approximately 0.1 second, approximately 1 second, approximately 2 seconds , approximately 5 seconds or approximately 10 seconds. When δ + is

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25/42 calculated in this way, a single õ + can be calculated for a desired range of pressures. For example, a single õ + can be calculated for the pressure range of, for example, between approximately the triple point of water pressure (ie approximately 0.61 kPa (approximately 4.6 torr)) and the lowest pressure low obtained in a vacuum chamber during a sterilization process (eg 0.04 kPa (approximately 0.3 torr). d + can be calculated for any pressure range other than a healthcare facility or a manufacturer of sterilization system you may prefer. For example, it may be desirable to calculate multiple õ + for sub-pressure ranges within a larger pressure range.

[0042] Alternatively, the calculation of õ +, according to the sum formula set out above, can be limited to only consecutive increases in the value of the differences between the second consecutive pressure derivatives with respect to time that are not separated by any decreases in the value of those differences. For example, assuming that five consecutive values for d ² P (tn) / dt ² are calculated respectively to have magnitudes of 10, 9, 11, 12 and 9 - each having units of Pa / s ² (mtorr / s ² ) . Changes from 10 to 9 and 12 to 9 are disregarded since the differences between neighboring values are negative. The changes from 9 to 11 and from 11 to 12 are added together because the differences between neighboring values are positive. Consequently, õ + = (11-9) + (12-11) = 0.4 Pa / s ² (3 mtorr / s ² ). When õ + is calculated in this way, multiple õ + can be calculated during a vacuum extraction and each can be individually compared to a threshold. For example, assuming that ten consecutive values for d ² P (tn) / dt ² are calculated respectively to have magnitudes of 10, 9, 11, 12, 9, 13, 14, 9, 12 and 9, three different õ + could be calculated as 3, 5 and 3.

[0043] õ + can be determined through color experimentsPetition 870180006881, from 26/01/2018, p. 12/30

26/42 respond to an amount of water that may be present in a vacuum chamber when the calculation of a δ + started. Consequently, δ + can be used as a threshold condition from which it can be determined that a load conditioning routine can be performed, a sterilization cycle canceled and / or that the load can be sufficiently dry for sterilization. As noted above, when a phase change from water to liquid occurs and is detected in a vacuum chamber at a pressure less than the triple point of water pressure (0.611 kPa (4.58 torr)), techniques charge conditioning systems may be unable to remove water from the chamber, for example, when there is more than approximately 5 ml of water in the chamber. However, for smaller amounts of water, for example, between about 1 ml and 5 ml, it may be desirable to try to condition a load. In addition, it is useful to know if the vacuum chamber is dry, for example, with less than approximately 1 ml of water in it, so that the sterilization system can start sterilizing the load.

[0044] Experiments were carried out to establish a threshold against which δ + can be compared to determine whether moisture may be present in a load. In these experiments, δ + was calculated according to the example above, where the calculation is limited to consecutive increases in the value of the second pressure derivative with respect to time. The data from these experiments suggest that, for pressures less than approximately 0.61 kPa (than approximately 4.6 torr), an õ + less than approximately 1.3 Pa / s ² (approximately 10 mTorr / s ² ) indicates that a change of water phase in liquid state to water vapor did not occur in the period of time for which a õ + was calculated, while an õ + of 15 Pa / s ² (110 mTorr / s ² ) or more corresponds to a load that contains excessive moisture to be conditioned efficiently and / or quickly enough 870180006881, of 26/01/2018, pg. 12/31

27/42 aware. Consequently, for a δ + between approximately 1.3 Pa / s ² and 15 Pa / s ² (approximately 10 mTorr / s ² and 110 mTorr / s ² ), it may be desirable to try load conditioning or interrupt a sterilization cycle , depending on the preferences and / or requirements of a manufacturer, healthcare facility and / or healthcare professionals. It should be understood, however, by those skilled in the art, that these values for δ + are also a function of the sterilization system used, the load contained therein and environmental factors. The general outline of the experiment that produced the results mentioned above for δ + are thus described in the present invention purely for information purposes.

[0045] The loading configuration for this experiment included an instrument tray containing a rack for placing small medical bottles in an unsealed Tyvek® wrapper. The load was placed in a STERRAD®100NX® sterilization system. Several experimental processes were carried out with environmental conditions ranging between 18Ό and 85% relative humidity (RH), 25Ό and 50% RH and 35Ό and 50% RH. In addition, these processes were performed without adding water to the load, 1 ml added to the load or 5 ml added to the load. Pressures were measured every second as the pressure dropped from approximately 0.61 kPa to approximately 107 Pa (approximately 4.6 Torr to approximately 800 mTorr). From these measured pressures, ó + was calculated. Several processes were carried out in each environmental condition for each amount of water. The values calculated for ó +, in units of Pa / s ² (mTorr / s ² ) are given in Table 1. Although water was deposited in the test samples as drops, a threshold based on ó + can also be used to take taking into account the total humidity in or inside the load that exists in other forms besides drops, such as puddles, pipe blocks or a leaf (for example, formed

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28/42 by condensation). Table 1

Quantity of 18C, 85% 25C, 50% 35C, 50% Water UR UR UR 0 ml 9.5 9.5 8.0 0.1 ml 39.4 40.5 38.0 0.5 ml 106.9 109.5 48.0

Ό046] δ + can also be used as a threshold to determine whether load conditioning should be performed or a sterilization cycle canceled when calculated from pressures measured inside a vacuum chamber while the pressure is being decreased by approximately 4 kPa to approximately 0.61 kPa (30 torr to approximately 4.6 torr). Remember that in this pressure range, increases in pressure indicate the presence of water and that the water was placed on a metallic surface. The õ + values were determined experimentally, using techniques similar to those described above for pressures between approximately 0.61 kPa and approximately 107 Pa (approximately 4.6 torr and approximately 800 mtorr). For õ + greater than 5 Pa / s ² (40 mTorr / s ² ), it can be

1.5 ml of water disposed on a metallic surface in the vacuum chamber. Consequently for õ + greater than 5 Pa / s ² (40 mTorr / s ² ), it may be advisable to interrupt the sterilization cycle so that healthcare personnel can dry the load manually. Alternatively, as the water is arranged on a metallic surface, one can try to condition the load. However, õ + less than 5 Pa / s ² (40 mTorr / s ² ), õ + may not be a reliable indicator of whether or how much water was in the vacuum chamber because the water may be disposed on non-metallic surfaces and therefore , can be readily vaporized. Consequently, when õ + is less than 5 Pa / s ² (40 mTorr / s ² ) for pressures between approximately 4 kPa to approximately 0.61 kPa (between approximately 30 torr and approxiPetition 870180006881, from 26/01/2018, pg. 12/33

29/42 in excess of 4.6 torr), it may be preferable to allow the sterilization system to determine δ + values for pressures less than approximately 0.61 kPa (approximately 4.6 torr) and base a determination on them as to sterilize, condition load or interrupt the cycle.

IV. Exemplary methods [0047] A low temperature chemical sterilization system, such as sterilization system 10, can be designed to perform various routines to determine whether there is water in the vacuum chamber 12 and whether the sterilization system may be able to remove water of the vacuum chamber. Exemplifying sterilization processes, which include steps that a sterilization system can perform, such as a routine to determine whether load conditioning should be performed, a load conditioning routine and a sterilization routine, as well as other steps that a health care can provide, are set out in Figures 5 and 6. These processes are set up only as examples to further illustrate the revealed subject and explain its usefulness. Many of the steps included in these processes can be performed alternatively or even before or after other steps. The steps established in these examples can be performed in combinations and variable permutations, without departing from the scope of the subject presented. For example, load conditioning routines can be performed and / or air plasma can be introduced into the vacuum chamber before any sterilizers are introduced into it. In addition, in non-segment sterilization warranty applications, the steps associated with placing the instruments in a sterilization package, and the introduction and removal of a sterilizer from the vacuum chamber do not need to be performed. For these applications, some or all of the steps associated with drying the instruments / or verifying that they are

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Dry 30/42 can be performed without the steps associated with sterilization.

[0048] As detailed in Figure 5, an example of a sterilization process begins with healthcare personnel cleaning up dirty instruments from previous use, using water, washing solution or a water-soluble instrument lubricant. The instruments are then dried using any one or a combination of various methods known in the art, such as heating the instruments or blowing compressed air into the instruments, particularly the lumens of the instruments. Dry instruments can be placed inside a sterilization box or rack made of, for example, a metal, such as aluminum or a plastic, such as polycarbonate. The instruments and / or the rack are wrapped in a sterilization blanket to form the sterilization package or charge 14. The blanket acts as a barrier against microorganisms, but allows a sterilizer to pass through it. Once wrapped, the package is ready to be introduced into the vacuum chamber 12 of the sterilization system 10.

[0049] The barrier 16 that can be opened and sealed from the chamber 12 is opened and the load 14 is placed on it. A biological indicator can also be placed in the chamber. Then, barrier 16 is closed and sealed. The closing and sealing of the chamber by means of barrier 16 can be carried out simultaneously or as two separate steps which are carried out in rapid succession. The sterilization system begins to evacuate the air inside the chamber 12 by removing (pumping) air from it for a period of time established in the sterilization system by the health care personnel or the manufacturer of the sterilization system. For example, the time interval, At, can be approximately 0.1 second, approximately 1 second, approximately 2 seconds, approximately 5 seconds. Petition 870180006881, 01/26/2018, p. 12/35

31/42 seconds or approximately 10 seconds. At the end of the interval, the pressure monitor 24 determines the pressure in chamber 12. Control system 38 stores this pressure value P (t _n ) in storage medium 42. Then, control system 38 calculates and stores the first and second pressure derivatives with respect to time. However, depending on the way in which derivatives are numerically calculated, it may be preferable to skip the calculation step of the first and second derivatives until the pressures for at least two intervals, that is, P (t _n ) = {P (to) , P (ti)}, three intervals, that is, P (t _n ) = {P (t ₀ ), P (ti), P (t ₂ )} or more intervals, that is, P (t _n ) = {P (ti), P (t ₂ ), P (t ₃ ), ... P (t _m )} have been determined.

[0050] Then, the control system 38 checks if the pressure in the chamber has been extracted until the desired terminal or final pressure P _f . That is, the system checks whether P (t _n ) is less than or equal to P _f . To ensure adequate coverage of sterilizing gases, it is generally desirable to achieve a P _f less than or equal to approximately 0.4 kPa, approximately 0.1 kPa, approximately 0.09 kPa, approximately 0.07 kPa, or approximately 0.04 kPa (approximately 3 torr, approximately 1 torr, approximately 0.7 torr, approximately 0.5 torr, or approximately 0.3 torr). If the control system 38 determines that P (t _n ) is greater than P _f , the control system 38 directs the system to repeat the steps of removing the air from the vacuum chamber 12, determining P (t _n ), storing P (t _n ), calculating and storing the first and second pressure derivatives with respect to time and determining whether P (t _n ) is less than or equal to P _f .

[0051] Once control system 38 determines that P (t _n ) is less than or equal to P _f , control system 38 determines whether, for any P (t _n ) less than or equal to any threshold pressure, P _o , there is a value of the corresponding second derivative that is a local maximum among the other values of the second derivative corresponding to another P (t _n )

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32/42 less than or equal to P _o . If the control system 38 determines that there is a local maximum in this regime, the control system 38 can interrupt the process. That is, the vacuum chamber 12 returns to ambient pressure and is open. Then, health care personnel can remove the load from chamber 12 and, essentially, restart the sterilization process, starting with drying the instruments. If control system 38 determines that a local maximum does not exist in this scheme, the control system 38 determines whether there is a P (T _n) is greater than P _o which has a value of the corresponding second derivative that is a local maximum of the other values of the second derivative corresponding to another P (t _n ) greater than P _o .

[0052] If the control system 38 determines that a local maximum exists, where P (t _n ) is greater than P _o , the sterilization system can perform load conditioning. Various load conditioning procedures can be performed. Whatever the procedure, energy is transferred to the waste water due to the fact that the energy increases the temperature of the water, which helps to vaporize it for subsequent evacuation. Some charge conditioning operations begin before any sterilizing gas, for example, hydrogen peroxide, is evacuated from the chamber. In these operations, the sterilizing gas can be converted into a plasma. After evacuation of chamber 12, chamber 12 can be heated by heating element 26. Alternatively, chamber 12 can be pressurized using heated or hot air having low relative humidity. In addition, another vacuum can be extracted in chamber 12 and plasma from another gas, such as air plasma, can be introduced into it. Air plasmas can also be used to condition a load before any sterilizers are introduced in another attempt to vaporize any water that may be in the load. Likewise, a load conditioning cycle can be performed before

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33/42 that the sterilizer is introduced into the chamber, for example, by decreasing the pressure in the vacuum chamber 12 to P _f , pressurizing the chamber with ambient air and, again, decreasing the pressure to P _f .

[0053] Figure 5 includes a load conditioning operation that includes the following steps. Chamber 12 is pressurized at a higher pressure, which can be less than, equal to, or greater than atmospheric pressure. This pressurization can be carried out with ambient air, heated air or a gas with a low water content, such as air with low relative humidity. The chamber 12 can also be heated by heating elements 26. Energy from ambient air, heated air and / or heating elements 26 can heat any portion of waste water. Then, the control system 38 directs the system to repeat the steps of removing air from the vacuum chamber 12, determining P (t _n ), storing P (t _n ), calculating and storing the first and second pressure derivatives with time and determining whether P (t _n ) is less than or equal to P _f . The combination of supplying energy to the waste water in combination with decreasing the pressure in the chamber 12 by removing air and / or other gas can totally or partially remove the waste water that remained on the load. Again, the second derivatives for pressures above and below P _o are checked for local maximum to determine if the load is sufficiently dry to introduce the sterilizer into the chamber or if another load conditioning cycle may be preferred. Load conditioning can be repeated until no local maximum is calculated or the control system timeout 38 expires.

[0054] As it is desirable to determine whether ice crystals can be formed before attempting to condition a load, an exemplary value of P _o may be the triple point of water pressure, that is, 0.611 kPa (4.58 torr). However, it may be desirable to use a P _o among

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34/42 approximately 0.5 kPa and approximately 0.7 kPa (approximately 4 torr and approximately 5 torr). For example, pressures above the triple pressure point can provide greater confidence that a load conditioning attempt will be successful.

[0055] If control system 38 determines that there is no maximum location where P (t _n ) is greater than P _o , the sterilization system attempts to sterilize the device by introducing a sterilizing gas or liquid, such as hydrogen peroxide, into chamber 12 When liquid hydrogen peroxide is used, it must be introduced into chamber 12 as a vapor, or in a form, such as droplets, which vaporize readily. Hydrogen peroxide can also be converted to plasma, which can further optimize the sterilization process. Although not shown in the flow chart, hydrogen peroxide gas can be evacuated from the chamber and another form of plasma, such as air plasma, can be introduced into the chamber. The introduction of a first air plasma may first require placing the vacuum chamber at or near ambient pressure again and subsequently extracting another suitable vacuum to introduce the air plasma. After the charge has been exposed to hydrogen peroxide gas, and possibly plasma, for a period of time sufficient to kill the microorganisms that may be in the charge, chamber 12 is evacuated again and the pressure within chamber 12 is equalized. at ambient pressure. The sterilization system 10 can be opened and the instruments, which must now be sterilized, can be removed.

[0056] Another example of a sterilization process is shown in Figure 6. As the process described in conjunction with figure 5, this process begins with healthcare personnel cleaning and then drying dirty instruments from previous use placing instruments in a sterilized box or rack Petition 870180006881, of 26/01/2018, p. 12/39

35/42 tion, involving the box or rack to create a sterilization package or load 14, opening the sealable barrier 16 of the vacuum chamber 12 of the sterilization system 10, placing the load and optionally a biological indicator in it and closing the chamber. Again, the sterilization system begins to evacuate the air inside the chamber 12 by removing (pumping) air from it for a period of time established in the sterilization system by the health care personnel or the manufacturer of the sterilization system. For example, the time interval, At, can be approximately 0.1 second, approximately 1 second, approximately 2 seconds, approximately 5 seconds or approximately 10 seconds. At the end of the interval, pressure monitor 18 determines the pressure in chamber 12. Control system 38 stores this pressure value in storage medium 42. Then control system 38 calculates and stores the first and second derivatives of pressure over time. However, depending on the way in which derivatives are numerically calculated, it may be preferable to skip the calculation step of the first and second derivatives until the pressures for at least the first two intervals, that is, P (t _n ) = {P ( t ₀ ), P (ti)}, first three intervals, that is, P (t _n ) = {P (t ₀ ), P (ti), P (t ₂ )} or first other number of intervals, that is , P (t _n ) = {P (ti), P (t ₂ ), P (t ₃ ), ... P (t _m )} have been determined.

[0057] The control system 38 then determines whether the pressure inside chamber 12, P (t _n ), is above or below the threshold pressure P _o , which can be approximately equal to the triple point of water pressure. If P (t _n ) is greater than P _o , the control system 38 calculates δ +, the net positive change for the second derivative of pressure with respect to time for a duration equal to _n . In Figure 6, δ + for P (t _n )> Po θ mentioned as δι +. If δι + is greater than a predetermined threshold value determined to correspond to a load

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36/42 that is too wet to be sterilized, õ _we ti, then the sterilization process is interrupted. In this case, chamber 12 is pressurized and opened, so that healthcare personnel can remove the load and dry the instruments before restarting the process. If δι + is less than õ _we ti, air is removed from the chamber for the subsequent time interval. The previous steps of removing air, determining and storing pressure, calculating the first and second derivatives and calculating δι + are repeated until δι + is greater than õ _we ti, in which case the process is interrupted or until P (t _n ) is less than P _o .

[0058] The time when P (t _n ) becomes less than P _o can be referred to as t _P0 . At this time, the control system 38 begins to calculate δ + for pressures less than P _o , referred to in Figure 6 as δ ₂₊ . That is, δ ₂₊ is the positive change for the second derivative of pressure with respect to t _P0 at _n . If δ ₂₊ is greater than a pre-established threshold value determined to correspond to a load that is too wet to be sterilized, õ _we t2, then the sterilization process is interrupted. In this case, chamber 12 is pressurized and opened, so that healthcare personnel can remove the load and dry the instruments before restarting the process. If δ ₂₊ is less than õ _we t2, air is removed from the chamber for the subsequent time interval and δ ₂₊ is recalculated for another comparison with õ _we t2- These steps are repeated until P (t _n ) in chamber 12 it has been extracted until the desired terminal or final pressure P _f . That is, the control system 38 checks whether P (t _n ) is less than or equal to P _f . To ensure adequate coverage of sterilizing gases, it is generally desirable to achieve a P _f less than or equal to approximately 0.4 kPa, approximately 0.1 kPa, approximately 0.09 kPa, approximately 0.07 kPa, or approximately 0.04 kPa (approximately 3 torr, approximately 1 torr, approximately 0.7 torr,

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37/42 approximately 0.5 torr, or approximately 0.3 torr).

[0059] Since P (t _n ) ^ Pf, the control system 38 optionally checks whether δ ₂ + is greater or less than õ _dry , a pre-established threshold value determined to correspond to a load that is dry and therefore , ready for sterilization. Alternatively, this step can be skipped. If δ ₂₊ is less than õ _dry , or if the step is skipped, the sterilization system tries to sterilize the device by introducing sterile gas or liquid, such as hydrogen peroxide, into chamber 12. When liquid hydrogen peroxide is used, it must be introduced into chamber 12 as a vapor, or in a form, as droplets, which vaporize readily. Hydrogen peroxide can also be converted to plasma, which can further optimize the sterilization process. Although not shown in the flow chart, hydrogen peroxide gas can be evacuated from the chamber and another form of plasma, such as air plasma, can be introduced into the chamber. The introduction of a first air plasma may first require placing the vacuum chamber at or near ambient pressure again and subsequently extracting another suitable vacuum to introduce the air plasma. After the charge has been exposed to hydrogen peroxide gas, and possibly plasma, for a period of time sufficient to kill the microorganisms that may be in the charge, chamber 12 is evacuated again (for example, vented to the atmosphere) and the pressure inside the chamber 12 is equalized to the ambient pressure. The sterilization system 10 can be opened and the instruments, which must now be sterilized, can be removed.

[0060] If, however, the system checks δ ₂₊ against õ _dry and determines that δ ₂₊ is greater than õ _dry , a load conditioning routine can be performed. First, chamber 12 is pressurized. This pressurization can be carried out with ambient air, heated air or a

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38/42 gas with a low water content, such as air with low relative humidity. Chamber 12 can also be heated by heating elements 60. Energy from ambient air, heated air and / or heating elements 26 can heat any portion of waste water. Then, the system repeats the steps of removing air from the vacuum chamber 12, determining P (t _n ), storing P (t _n ), calculating and storing the first and second pressure derivatives with respect to time and determining whether P ( t _n ) is less than or equal to P _o and finally less than or equal to P _f . The combination of supplying energy to the waste water and decreasing the pressure in the chamber 12 by removing air and / or other gas can totally or partially remove the waste water that remained on the load. During load conditioning, δι + and õ ₂₊ are compared to their moisture thresholds õ _we ti θ õ _we t2 to confirm that the sterilization process should not be interrupted. Since P (t _n ) is less than or equal to P _f , õ ₂₊ is compared to õ _dry to determine if the load is sufficiently dry for sterilization. Load conditioning can be repeated until δ ₂₊ is less than õ _dry or until the control system 38 times out. [0061] The techniques described above for using a vacuum chamber to detect moisture, remove moisture, and confirm dryness are also applicable in situations where sterilization may not be the preferred method of decontamination. For example, a vacuum chamber can be used to detect moisture, remove moisture, and confirm the dryness of an instrument having a lumen, such as an endoscope, after the immersion and washing steps associated with a disinfection process. The vacuum chamber 12 of the system 10 can be equipped with a shelf to hold the endoscopes. In this configuration, the vacuum chamber 12 can be used only for purposes related to the detection of moisture, the removal of moisture, and the confirmation of dryness of endoscopes.

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Alternatively, the vacuum chamber can be incorporated into an endoscope drying cabinet so that the drying cabinet can be provided with enhanced functionality for moisture detection, moisture removal and dryness confirmation.

[0062] Figures 7 and 8 reflect routines for detecting moisture, removing moisture, and confirming the dryness of an instrument, particularly a medical instrument, such as an endoscope, which has undergone a disinfection procedure. The routines in Figures 7 and 8, which refer to disinfection, have similarities with the sterilization routines in Figures 5 and 6, respectively. A difference between the routines that refer to disinfection and the sterilization routines refers to the introduction of sterilizers and the creation of plasma. That is, in routines that refer to disinfection, the sterilizer does not need to be introduced into the vacuum chamber, and a plasma does not need to be created. However, in certain cases, it may be desirable to create a plasma in the vacuum chamber to further assist in drying instruments after a disinfection process. Another difference between the routines that refer to disinfection and the sterilization routines is the relative position of the steps that refer to the detection of moisture, the removal of moisture, and the confirmation of dryness. That is, when these steps are incorporated into a sterilization process, they must be performed before the sterilizer is introduced into the vacuum chamber. On the other hand, when these steps are added to a disinfection process, they must be performed after the instrument has been disinfected. Disinfection routines can be performed using a vacuum chamber having a rack, shelf, or any other suitable structures from which instruments, and particularly endoscopes, can be hung, preferably in a vertical orientation, which can still assist in drying the instruments.

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V. User retraining [0063] Instruments should always be completely dry when exposed to a chemical sterilizer, such as hydrogen peroxide. Also, instruments with lumens, such as endoscopes, must be completely dry after disinfection to avoid recontamination by microorganisms. Unfortunately, health care personnel sometimes fail to dry instruments sufficiently and / or properly. The steps and methods described to date to determine if there is residual water in an instrument can also be used to generate user feedback, which can assist health care facilities and personnel in drying the instruments. For example, the sterilization system may include a user retraction system, including, for example, the control system 38 and a graphical interface capable of advising healthcare personnel to remove a load of instruments and dryers. it manually because, for example, sufficiently large volumes of residual water have been detected. The feedback system can display different messages corresponding to the detected water volumes. For example, if water is not detected, the graphical interface may display a message indicating, for example, Water not detected, OK sterilization or water not detected, endoscopes can be removed from the cabinet. For example, if approximately 1 ml of water is detected, the graphical interface may display a message indicating, for example, Water detected, sterilization may be ineffective or water detected, trying to condition. For example, if more than 1.5 ml of water is detected, the graphical interface may display a message indicating, for example, Unable to condition, remove the load and dry.

[0064] The system can also compile data for health care personnel and managers, which can help to identify

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41/42 certain types of instruments that are difficult to dry or health care personnel who usually fail to dry the instruments sufficiently. The system can store the second derivative and / or the δ + calculations, as well as the user information regarding who dried the instruments. These calculations can be used to generate statistics for health care personnel. For example, the system may be able to provide information about the percentage of load that a user has dried completely, dried frequently and / or has not dried.

[0065] Consider a hospital where two nurses, nurse A and nurse B, are responsible for the sterilization and disinfection instruments, including the cleaning and drying steps of the instruments before they are placed in a vacuum chamber of a vacuum system. sterilization of a vacuum chamber or an endoscope drying cabinet. Over a desired period of time, for example, each month, the system can generate a report to the hospital management regarding the drying of each of the batches of instruments or loads that Nurse A and Nurse B have prepared. For example, the report may indicate that 95% of Nurse A's batches are dry and the other 5% are mostly dry, but that 60% of Nurse B's batches are dry, 20% are mostly dry and 20 % are too wet for sterilization. Based on this information, it may appear that Nurse A achieves better drying results than Nurse B. Consequently, management may decide to take corrective action in relation to Nurse B, such as training her on how to dry instruments properly.

[0066] It should be understood that any of the examples and / or modalities described here may include several other resources and / or steps in addition to or replacing the resources described above. The enPetição 870180006881, of 26/01/2018, p. 46/123

42/42 signs, expressions, modalities, examples etc. described here should not be seen in isolation from each other. Various suitable ways in which the teachings of the present invention can be combined should be readily apparent to those skilled in the art in view of the teachings of the present invention. [0067] Having shown and described several exemplifying modalities of the matter contained herein, further adaptations of the methods and systems described herein can be carried out by means of appropriate modifications without departing from the scope of the claims. Some other modifications will be evident to those skilled in the art. For example, the examples, modalities, geometry, materials, dimensions, proportions, steps and the like discussed above are illustrative. Furthermore, although the study material is described in the context of the field of disinfection of medical instruments, for example, a guarantee of sterilization, and although the vacuum chamber described in the present invention predominantly features a sterilization system, the material in question is applicable to other fields, including non-medical fields, where it can be useful for drying objects and / or verifying that the objects are dry. Consequently, the appended claims should not be limited to the specific details of structure and operation presented in the written description and in the drawings.

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Claims (23)

1. Method for drying a medical instrument, characterized by the fact that it comprises: (a) opening a vacuum chamber; (b) placing the instrument in the chamber; (c) close the chamber; (d) removing a first volume of air from the chamber; (e) changing a volume of liquid water to steam; (f) introducing a second volume of air into the chamber; (g) removing a second volume of air from the chamber; (h) changing a second volume of liquid water to steam; (i) introducing a third volume of air into the chamber; (j) opening the chamber; and (k) removing the instrument from the chamber in a dry state. 2. Method, according to claim 1, characterized by the fact that it also comprises: (l) collect pressure data that corresponds to the pressure inside the chamber and at the same time remove the second volume of air from the chamber; (m) from the pressure data, calculate a first value of the second pressure derivative with respect to the time corresponding to a pressure greater than approximately the pressure of the triple point of the water; (n) from the pressure data, calculate a second value of the second pressure derivative with respect to the time corresponding to a pressure greater than approximately the pressure of the triple point of the water and a time subsequent to the time corresponding to the first value of the second derivative; Petition 870180006881, of 26/01/2018, p. 48/123 2/6 (o) from the pressure data, calculate a third value of the second pressure derivative with respect to the time corresponding to a pressure less than approximately the pressure of the triple point of the water and a time subsequent to the time corresponding to the second second derivative value; (p) from the pressure data, calculate a fourth value of the second pressure derivative with respect to the time corresponding to a pressure less than approximately the pressure of the triple point of the water and a time subsequent to the time corresponding to the third value of the second derivative; (q) determine that the fourth value of the second derivative is less than or equal to the third value of the second derivative; and (r) determining that the second value of the second derivative is less than or equal to the first value of the second derivative. 3. Method according to claim 2, characterized by the fact that the instrument includes a lumen. 4. Method, according to claim 3, characterized by the fact that the instrument is an endoscope. 5. Method according to claim 4, characterized by the fact that the vacuum chamber includes a rack for hanging endoscopes. 6. Method for drying a medical instrument in a vacuum chamber, characterized by the fact that it comprises: (a) connecting a timer to a digital computer; (b) removing a first volume of air from the chamber; (c) repeatedly determining the pressure inside the chamber while withdrawing the first volume of air from the chamber; (d) calculate, with the digital computer, a first value of the second derivative of pressure with respect to time; (e) calculate, with the digital computer, a second value of the Petition 870180006881, of 26/01/2018, p. 49/123 3/6 second pressure derivative with respect to time, the second value of the second derivative corresponding to a time subsequent to the time corresponding to the first value of the second derivative; (f) determine, with the digital computer, that the second value of the second derivative is greater than the first value of the second derivative; and (g) automatically introducing a second volume of air into the chamber. 7. Method according to claim 6, characterized in that the step of repeatedly determining the pressure includes making pressure data measurements repeatedly and storing that data in a non-transitory digital computer storage medium. 8. Method, according to claim 7, characterized by the fact that it still comprises the determination, with the digital computer, that the second value of the second derivative occurs at a pressure less than approximately the triple point of water pressure. 9. Method according to claim 8, characterized in that the step of automatically introducing air into the chamber includes the opening of a valve automatically. 10. Method, according to claim 9, characterized by the fact that it still comprises opening the chamber automatically. 11. Method, according to claim 10, characterized by the fact that it still comprises removing the instrument from the chamber and drying the instrument by blowing air on the instrument or applying heat to the instrument. 12. Method according to claim 11, characterized in that the step of removing a first volume of air from the chamber begins after the step of turning on the timer. Petition 870180006881, of 26/01/2018, p. 50/123 4/6 13. Method according to claim 12, characterized by the fact that it still comprises the step of determining that a difference between the second value of the second derivative and the first value of the second derivative is greater than the noise floor. 14. Method, according to claim 13, characterized by the fact that the instrument includes a lumen. 15. Method, according to claim 14, characterized by the fact that the instrument is an endoscope. 16. Method according to claim 15, characterized by the fact that the vacuum chamber includes a rack for hanging endoscopes. 17. Method for drying a medical instrument in a vacuum chamber, characterized by the fact that it comprises: (a) connecting a timer to a digital computer; (b) removing a first volume of air from the chamber; (c) repeatedly determining the pressure inside the chamber while withdrawing the first volume of air from the chamber; (d) calculate, with the digital computer, a first group of values of the second derivative of pressure with respect to time; (e) calculate, with the digital computer, a first sum of positive differences between consecutive values of the second derivative from the first group of values of the second derivative; (f) comparing the sum to a limit value, the sum indicating that the residual humidity is or could be placed on the instrument when the sum is greater than the limit value, indicating that the instrument is dry when the sum is less than the value limit; (g) determine that the first sum is greater than the limit value; (h) opening a valve to introduce a second volume of air into the chamber; Petition 870180006881, of 26/01/2018, p. 51/123 5/6 (i) withdraw a second volume of air from the chamber; (j) repeatedly determining the pressure inside the chamber while withdrawing the second volume of air from the chamber; (k) calculate, with the digital computer, a second group of values of the second pressure derivative with respect to time; (l) calculate, with the digital computer, a second sum of positive differences between consecutive values of the second derivative from the second group of second derivative values; (m) determine that the second sum is less than the limit value; (n) opening the valve to introduce a third volume of air into the chamber; and (o) open the chamber. 18. Method, according to claim 17, characterized by the fact that the step of opening the valve to introduce the third volume of air is performed after determining that the second sum is less than the limit value, the step of opening the chamber is made after opening the valve to introduce the third volume of air, and which still comprises, after the step of opening the chamber, the removal of the instrument from the chamber in a dry state. 19. Method, according to claim 18, characterized by the fact that the first sum is completed when a first difference between the consecutive values of the second derivative is negative. 20. Method according to claim 19, characterized by the fact that the second sum is started after the first sum is completed and when a second difference between the consecutive values of the second derivative is positive. 21. Method, according to claim 20, characterized by the fact that the instrument includes a lumen. Petition 870180006881, of 26/01/2018, p. 52/123 6/6 22. Method, according to claim 21, characterized by the fact that the instrument is an endoscope. 23. Method according to claim 22, characterized by the fact that the vacuum chamber includes a rack for hanging endoscopes. Petition 870180006881, of 26/01/2018, p. 53/123 1/8