1、STP-PT-047Principles of Safety and Performance for Medical Hyperbaric Chambers: Guidelines for Regulatory SubmissionSTP-PT-047 PRINCIPLES OF SAFETY AND PERFORMANCE FOR MEDICAL HYPERBARIC CHAMBERS: GUIDELINES FOR REGULATORY SUBMISSION Prepared by: ASME PVHO Subcommittee on Medical Hyperbaric Systems
2、Date of Issuance: June 30, 2011 This report was prepared as an account of work sponsored by ASME Pressure Technology Codes and fire, with consequent pressure rise, equipment damage and potential patient/attendant injury. These hazards must be considered in the governing standards and in the design o
3、f hyperbaric chambers. Various types of chamber configurations are available in the marketplace, ranging from single occupant chambers manufactured from flexible composite materials that may also be capable of being folded and transported, to large steel chambers that can accommodate multiple patien
4、ts along with medical attendants. There are currently two basic types of monoplace chamber designs available: the all metal chamber with one or more windows and the acrylic cylinder chamber with metal ends. Monoplace chambers are in use throughout the world, primarily in hospitals and clinics. In re
5、cent years there has been considerable interest in chambers constructed of materials other than the metallic materials traditionally used. The most prevalent type of monoplace chamber is the acrylic cylinder chamber, with a significant portion of the chamber body being comprised of a single acrylic
6、cylinder, held in place by steel tie rods connecting two metallic end caps. The common element of the acrylic cylinder chamber is the patients ability to view his surroundings, which eases patient confinement anxiety and allows relatively unobstructed viewing and monitoring of the patient by attendi
7、ng medical personnel. One of the chamber end caps has a door mechanism to allow patient entry and egress. The patient entry/ egress process is handled by a variety of door closure designs, ranging from interrupted breech rotating lock to a simple cam-action lever closure. All closures must meet the
8、basic needs of safety under pressure and rapid opening capability. Patients are placed in monoplace chambers through the use of gurney/stretcher systems or chair support systems that allow patients to be transported to, and placed into, the chamber, either reclining or in a semi-seated position. Pro
9、visions are made in the chamber hull or door to allow connection of necessary HBO2qualified electrical equipment leads to connect external patient monitoring devices. Introduction of intravenous fluids to the patient during HBO2treatment is accomplished via pressure-capable pass-through devices in t
10、he door or chamber hull. Patient ventilation is also possible using a pressure capable pass-through or pass-throughs and a ventilator qualified for use in a hyperbaric chamber. Monoplace chambers are usually pressurized with 100% oxygen but may be pressurized with medical breathing air at pressures
11、up to 3 ATA. All chambers should have provisions for administering necessary gas to the patient by use of a mask or hood system, thus allowing prescribed air breaks during oxygen pressurization or inhalation of oxygen during the therapy cycle, if air pressurized. Multiplace chambers are pressurized
12、with compressed breathing air. Multiplace chambers are typically made from metal, in a cylindrical configuration. Rectangular and square configurations are Medical Hyperbaric Chambers STP-PT-047 3 also available. Occupancy can range from two persons to twenty or more. Multiplace chambers have acryli
13、c viewports and often additional pressure locks, allowing access to the chamber when pressurized. Due to the more complex nature of a multiplace chamber, equipment and devices for patient monitoring or comfort may be installed inside the chamber pressure boundary, requiring that they be designed and
14、 validated for use in a pressurized environment. Redundant air pressurization and filtration systems are necessary to support large multiplace chambers. Patients in a multiplace chamber breathe 100% oxygen through the use of a mask or hood system, with overboard exhaust of exhalation gases. Multipla
15、ce chambers have seating facilities for multiple patients and attendants, and some have provisions for stretcher systems. They are normally fixed installations, due to the more elaborate pressurization and support equipment requirements. There are smaller multiplace design chambers that are transpor
16、table, such as deck decompression chambers used in the diving industry. Fire suppression systems are required for multiplace chambers. Typically water deluge designs are used. STP-PT-047 Medical Hyperbaric Chambers 4 3 GENERAL SAFETY INFORMATION Various health hazards are generally associated with t
17、he use of hyperbaric chambers as detailed in the table below. A detailed risk analysis should be performed to identify specific risks related to the identified hazards associated with the actual chamber as designed and constructed. All hazards should be identified and addressed in the risk analysis.
18、 The regulatory submission should describe the risk analysis method(s) utilized. Table 1 - Example Hazards and Mitigation Table Identified Hazard Recommended mitigation measures 1. Pressure Related Pressure Vessel conforms to ASME B b. Maximum operating pressure; c. Pressurization/depressurization r
19、ates and conditions under which those rates are to be maintained; d. Ventilation rates and the conditions under which those rates are to be maintained; e. Requirements affecting the amount of stored gas reserves; STP-PT-047 Medical Hyperbaric Chambers 6 f. Number of breathing gas outlets and their c
20、haracteristics; g. Temperature and humidity control requirements, if applicable; h. Minimum and maximum operating and storage temperatures; i. Fire suppression requirements as they apply; j. Type(s) of breathing gas delivery systems; k. Pressurization gas (air or oxygen); l. The edition(s) of all co
21、des and/or standards used in the development of the User Design Specification. Medical Hyperbaric Chambers STP-PT-047 7 5 SUMMARY OF DESIGN VERIFICATION AND VALIDATION 5.1 Materials 5.1.1 Pressure Bearing Materials Materials to be used for pressure bearing components should be selected based on mate
22、rial properties and the intended use. The use of PVHO-l listed materials is recommended. Design calculations or the results of experimental testing should be provided with the submission to the applicable regulatory agency or entity. 5.1.2 Biocompatibility Materials that come into direct patient con
23、tact should be evaluated for biocompatibility according to recognized standards and local regulatory requirements. Test results should be supplied or referenced in the submission to the applicable regulatory agency or entity. 5.1.3 Toxicity Potentially toxic materials that could come into contact wi
24、th the patient or that have the potential to off-gas toxic fumes should be tested according to recognized standards and local regulatory requirements. Test results should be supplied or referenced in the submission to the applicable regulatory agency or entity. 5.1.4 Material Compatibility Materials
25、 should be selected for their compatibility with one another and for normal use with any fluids or gases. Special consideration should be given to compatibility with oxygen. Acrylic window and light pipe components should be restricted from intentional contact with non-approved materials by warnings
26、 in operation and instruction manuals. Material selection information should be provided with the submission to the applicable regulatory agency or entity. 5.2 Electro-Mechanical Safety Any hyperbaric chamber designed for a pressure differential of 2 psi or greater across the pressure boundary shoul
27、d meet the safety requirements of the appropriate section of the ASME B ASME Pressure Vessels for Human Occupancy PVHO-1. Pressure vessels, fixed or mobile, intended for use in health care facilities should also comply with the additional requirements of NFPA 99, Health Care Facilities, Chapter 20 H
28、yperbaric Facilities. STP-PT-047 Medical Hyperbaric Chambers 8 Evidence of compliance with the appropriate section of the ASME B Medical Hyperbaric Chambers STP-PT-047 9 b. be mechanically stable in the intended position(s) of use; and c. provide protection to the operator and patient from moving pa
29、rts. 5.2.9 Mechanical Vibration and Shock Resistance The chamber (i.e., the complete system suitable for its intended use) should withstand the mechanical shocks and vibrations expected in the environments of intended use as defined by the design criteria or relevant recognized standards, and should
30、 remain operational within its specification. The results of engineering analysis or testing to recognized standards should be supplied or referenced with the submission. 5.2.10 Fluid Spill Resistance The chamber should be so constructed that it continues to operate within its specification after be
31、nign fluids have been dripped on the electrical components of the device. Therefore, those components of the device should meet the requirements for drip-proof equipment as specified in applicable recognized standards. 5.2.11 High and Low Temperature and Humidity a. The chamber should operate within
32、 its design specification when operating in the specified environmental temperature and humidity ranges. Testing should be performed in accordance with applicable recognized standards. The results of environmental testing should be supplied or referenced in the submission. b. The chamber should not
33、be damaged and should remain operational within its design specification after storage in the maximum and minimum specified environmental temperature range. Validation test results should be supplied or referenced in the submission. 5.2.12 Surface Temperature Temperature of surfaces of a device an o
34、perator can contact during operation should not exceed 122F (50C) in an ambient of 95F (35C). The temperature of surfaces that may come in contact with the patient should not exceed 106F (41C) in an ambient of 95F (35C). Any surface temperature exceeding 106F (41C) that may come in contact with the
35、patient should be justified with a scientifically valid explanation and data should be provided which demonstrates that the safety of the patient is not compromised. Acrylic windows shall not be subjected to temperatures exceeding their design temperature. Under no circumstances shall an acrylic win
36、dow be exposed to temperatures exceeding 150F (66C) during operation; this includes localized temperatures resulting from placement of heaters or lighting. 5.2.13 Strangulation Provision should be made in routing, retention devices, or other means to minimize the risk of strangulation of the patient
37、 by wires or tubing inside the chamber. This may also be accomplished by providing instructions for routing of patient wires and tubing in the device labeling. 5.3 Electrical The chamber should meet the design and safety requirements of ASME PVHO-1 and the applicable sections of NFPA 99. The chamber
38、 should also meet the electrical safety requirements of IEC 60601-1: Medical electrical equipment part 1: General requirements for safety for Type BF equipment and IEC 60601-1 Collateral Standard: Safety requirements for medical electrical systems. In addition, the STP-PT-047 Medical Hyperbaric Cham
39、bers 10 chamber should conform to additional local regulatory requirements which extend or supplement IEC 60601-1 and IEC 60601-1-1. Electrical testing should be performed to recognized standards and local regulatory agency requirements as applicable. The following areas should be addressed in the r
40、egulatory submission. a. Auxiliary Input/Output b. AC Power Grounding and Polarity c. DC Power Sources d. Electromagnetic Compatibility e. Electrostatic Discharge f. Voltage Dips, Short Interruptions and Voltage Variations g. Fast Transient Bursts h. Conducted Electromagnetic Energy 5.4 Software Sof
41、tware should be developed according to established software development and validation procedures. An overview of software development and validation activities should be included in the submission. Software validation results should be included or referenced in the submission. 5.5 Visual and Audibl
42、e Indicators and Alarms 5.5.1 Power Indicators The device should have visual power indicators complying with applicable recognized standards to indicate that the device is energized. Pneumatically operated systems should clearly indicate that pressure is present or absent. Indicators should be consp
43、icuously located on the chamber or control panel. 5.5.2 Visual and Audible Alarms The device should have visual and audible alarm indicators, as necessary, complying with applicable recognized standards. Visual alarm indicators should be conspicuously located on the chamber or control panel. Sound l
44、evels of audible alarms should be designed to be readily heard and identified over any ambient operational background noise. A description of the visual and audible alarms should be included in the operations manual and/or instructions for use. A description of the visual and audible alarms should b
45、e included in the submission. Medical Hyperbaric Chambers STP-PT-047 11 6 CLINICAL EVIDENCE Hyperbaric chambers employing new technology or indications for use may warrant a clinical evaluation in order to ensure that the particular device design is safe and effective for its intended use. In such c
46、ases, a clinical validation plan should be developed taking into consideration the issues discussed below. Once the clinical validation study is complete, all documentation related to the study should be maintained in the technical design file in accordance with applicable regulatory requirements. T
47、he clinical validation plan should be sufficiently detailed to enable responsible regulatory authority to access the safety and efficacy of the design/treatment. The regulatory agency may request additional information about aspects of the clinical plan, if it is not clear how the plan addresses ide
48、ntified risks, or if additional information is needed to assess the adequacy of the acceptance criteria. It is recommended that clinical validation plans should be discussed with the responsible regulatory agency prior to commencement of the clinical study. The clinical validation plan should includ
49、e the following elements: a. Statistical hypothesis b. Sample size, which should be adequate to permit reasonable confidence in the measure of all safety and effectiveness parameters. c. Statistical method(s) d. Detailed description of the protocol to be followed. The protocol should be designed as a prospective, randomized clinical trial which should lead to Level 1 clinical evidence e. A sample of any case report form to be used for design validation. STP-PT-047 Medical Hyperbaric Chambers 12 7 LABELING The following items are specific to labeling of this device class
