(70 days)
The Amsco Evolution Medium Steam Sterilizer Models HC-900 and HC-1200 are designed for sterilization of heat and moisture-stable materials used in healthcare facilities and are available in two configurations:
- Prevacuum is equipped with Prevacuum, Gravity, Liquid, Leak Test and DART (Bowie-Dick) cycles.
- Steam Flush Pressure-Pulse (SFPP) is equipped with SFPP, Prevacuum, Gravity, Liquid, Leak Test and DART (Bowie-Dick) cycles.
The Amsco Evolution Medium Steam Sterilizer models HC-900 and HC-1200 are designed for sterilization of heat and moisture-stable materials used in healthcare facilities and are available in two configurations:
- Prevacuum is equipped with Prevacuum, Gravity, Liquid, Leak Test and DART (Bowie-Dick) cycles.
- Steam Flush Pressure-Pulse (SFPP) - is equipped with SFPP, Prevacuum, Gravity, Liquid, Leak Test and DART (Bowie-Dick) cycles.
The chamber sizes of the proposed Amsco Evolution Medium Steam Sterilizer Models are as follows: - 26" x 37½" x 42" (Model HC 900)
- 26" x 37½" x 54" (Model HC - 1200)
Here's a breakdown of the acceptance criteria and the study that proves the device meets them, based on the provided text:
Acceptance Criteria and Device Performance for STERIS Amsco Evolution Medium Steam Sterilizer (Models HC-900 and HC-1200)
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for this medical device, a steam sterilizer, are tied to its ability to achieve a sufficient sterility assurance level (SAL), specifically a probability of survival of at least 10-6, and proper functioning of its various cycles. The performance is demonstrated through validation studies against industry standards.
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Sterility Assurance Level (SAL): At least 10-6 probability of survival for all sterilization cycles. | Demonstrated: All validated cycles (Prevac, Gravity, SFPP, Liquid) achieved a sterility assurance level of at least 10-6 through complete kill of biological indicators and an appropriate safety factor (Fo value of at least 12 where applicable). |
| Empty Chamber Thermal Conditions: Capable of providing steady-state thermal conditions consistent with the predicted SAL in the load. | Demonstrated: Empty chamber testing, performed as described in ANSI/AAMI-ST8 Section 5.4.2.5, confirmed the sterilizer's capability across Prevac, Gravity, Liquid, and SFPP cycles. Meets ANSI/AAMI-ST8 Sections 4.4.2.2 and 4.4.2.5. |
| Fabric Test Pack (SFPP, Gravity, Prevac cycles): Qualification according to ANSI/AAMI-ST8 Section 5.5.2, including: |
- Fo value of at least 12.
- Moisture retention of less than 3% increase in presterilization test pack weight.
- No evidence of wet spots. | Demonstrated:
- All SFPP, Gravity, and Prevac cycles validated with fabric test packs met the Fo value of at least 12.
- Moisture retention was less than 3% increase in presterilization weight.
- No wet spots were exhibited. |
| Full Load Instrument Trays (SFPP, Gravity, Prevac cycles): Qualification according to ANSI/AAMI-ST8 Section 5.5.4, including: - SAL of at least 10-6 using half-cycle analysis.
- Moisture retention of less than 20% increase in presterilization weight of the towel.
- No evidence of wet spots on the outer wrapper. | Demonstrated:
- All SFPP, Gravity, and Prevac cycles validated with full load instrument trays achieved an SAL of at least 10-6 using half-cycle analysis.
- Moisture retention was less than 20% increase in presterilization weight of the towel.
- No wet spots were found on the outer wrapper. |
| Liquid Cycles: Qualification according to ANSI/AAMI-ST8 Section 5.5.3, including: - SAL of at least 10-6 through achievement of a time-at-temperature sufficient to produce an Fo value of at least 12.
- Water loss not exceeding 50 ml.
- Automatic sealing of the flask closure. | Demonstrated:
- All LIQUID cycles validated using three 1,000 ml flasks achieved an SAL of at least 10-6 with an Fo value of at least 12.
- Water loss did not exceed 50 ml.
- Automatic sealing of the flask closure occurred. |
| DART Cycle: Qualification according to ANSI/AAMI-ST8 Section 5.6.1, demonstrating a uniform color change throughout the test sheet using the Bowie-Dick Test Pack. | Demonstrated: The DART cycle validated with the Bowie-Dick Test Pack showed a uniform color change throughout the test sheet. |
| Software Validation: Compliance with FDA's moderate level of concern recommendations for software in medical devices. | Demonstrated: Software validation for cycle operation was performed according to "Guidance for the Content for Premarket Submissions for Software Contained in Medical Devices (05/11/05)." |
| Safety and Performance Requirements: Compliance with national safety codes and standards (e.g., UL, CSA, ASME). | Demonstrated: The device complies with UL Electrical Safety Code 61010-1, CSA Standard C22.2 No. 1010-1, and ASME Section VIII, Division 1. |
| Controller Safeguards: Ability to abort cycles and provide appropriate signals/warnings for unmet conditions or malfunctions. | Demonstrated: The built-in PC controller safeguards abort the cycle and provide appropriate signals, alerts, and warnings when required conditions are not met or a malfunction occurs. |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state the exact "sample size" in terms of specific numbers of sterilizer units tested or the total number of sterilization runs. However, the testing was conducted as part of internal validation studies by STERIS Corporation.
- Test Set Description: The test set for the validation of the sterilizer functionality involved various loads (fabric test packs, full load instrument trays, 1,000 ml liquid flasks) and cycles (Prevac, Gravity, SFPP, Liquid, DART).
- Data Provenance: The studies were performed by STERIS Corporation for regulatory submission in the USA (FDA 510(k)). The data would therefore be considered prospective in the context of validating the device's performance for this submission. The country of origin for the data is implicitly the USA, as STERIS is a US-based company submitting to the US FDA.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
The document does not specify the number of experts or their qualifications for establishing the "ground truth" for the test set. For a sterilizer, the ground truth is typically established through a combination of:
- Standardized Biological Indicators (BIs): These contain a known population of resistant spores, and their complete kill (indicated by no growth) after a sterilization cycle directly demonstrates sterility.
- Physical Monitoring: Temperature, pressure, and time data recorded by the sterilizer itself, along with calibrated sensors.
- Chemical Indicators: Devices that change color or state when exposed to specific sterilant conditions.
- Weight Measurements: For moisture retention assessments.
The "experts" in this context are likely the validation engineers and microbiologists who design, execute, and analyze these tests, ensuring they conform to recognized standards like ANSI/AAMI ST8.
4. Adjudication Method for the Test Set
The concept of "adjudication" (e.g., 2+1, 3+1) is typically relevant for studies involving human interpretation (e.g., radiologists reading images) where disagreement needs to be resolved. For objective performance testing of a sterilizer, especially against quantitative criteria like SAL, Fo values, and moisture retention, an adjudication method in this sense is not directly applicable.
The "adjudication" occurs through verification against predefined, quantitative criteria outlined in standards such as ANSI/AAMI ST8. If a test run meets all specified criteria (e.g., BI kill, correct Fo value, acceptable moisture, uniform color change for DART), it is deemed successful. No expert consensus or tie-breaking is needed for these objective measurements.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. This type of study is relevant for diagnostic devices where human operators interpret results (e.g., medical imaging AI). A steam sterilizer's performance is assessed through objective physical and biological tests, not human reader interpretation. Therefore, there is no "effect size of how much human readers improve with AI vs without AI assistance" to report.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, the studies described are essentially standalone in terms of the device's core function. The sterilizer's performance in achieving sterility is evaluated directly, independent of a human operator's real-time interaction with the sterilization process outcome. The "algorithm" here is the sterilizer's control system, and its performance is measured against objective standards. Human involvement is in setting up the tests, loading the sterilizer, and analyzing the results, but not in actively "interpreting" the sterilization event itself in a way that would alter its effectiveness.
7. The Type of Ground Truth Used
The ground truth used for these studies is a combination of:
- Biological Data (Microbiological Sterility): Complete inactivation of challenging biological indicators (e.g., spores). This provides direct evidence of killing microorganisms.
- Physical Measurements: Temperature, pressure, and time data collected by calibrated sensors within the sterilizer chamber and load, used to calculate Fo values (lethality measure).
- Gravimetric/Visual Assessments: For moisture retention (weighing test packs pre and post-sterilization) and visual inspection for wet spots and uniform color change (Bowie-Dick test).
- Standardized Test Packs/Loads: Specifically defined by ANSI/AAMI ST8, such as fabric test packs, full load instrument trays, and 1,000 ml liquid flasks, which represent challenging conditions for sterilization.
This is a robust form of empirical and standards-based ground truth.
8. The Sample Size for the Training Set
The document does not specify a "training set" in the typical machine learning sense. This is because the Amsco Evolution Medium Steam Sterilizer is a physical device with a deterministic control system, not an AI/machine learning algorithm that requires a training dataset. The "training" for such a device involves rigorous engineering design, manufacturing, and internal testing to meet specifications, which is then formally validated as described in the effectiveness studies.
9. How the Ground Truth for the Training Set Was Established
As there is no "training set" in the context of an AI/ML algorithm for this device, the concept of establishing ground truth for a training set does not apply here. The device's operational parameters and performance are based on established scientific principles of sterilization (heat, steam, time, pressure) and validated through adherence to industry standards, not through learning from data.
§ 880.6880 Steam sterilizer.
(a)
Identification. A steam sterilizer (autoclave) is a device that is intended for use by a health care provider to sterilize medical products by means of pressurized steam.(b)
Classification. Class II (performance standards).