T3

AUSTRALIAN AND NEW ZEALAND COLLEGE OF ANAESTHETISTS
ABN  82 055 042 852

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1. PURPOSE AND SCOPE

1.1 Safe anaesthetic machines are essential to the provision of safe patient care.

1.2 This document specifies minimum safety requirements for anaesthetic machines in clinical practice in Australia and New Zealand.

1.3 The general intent of this document is that all anaesthetic machines in clinical use should comply with Australian/New Zealand Standard AS/NZS 3200.2.13:2005 "Medical electrical equipment - Particular requirements for safety - Anaesthetic systems" and other relevant national standards by 1st January 2011.

1.4 It also provides guidance to anaesthetists when considering whether an anaesthetic machine is suitable for clinical use or should be replaced.

1.5 This document does not cover:

1.5.1 Anaesthetic ventilators, suction systems or anaesthetic gas scavenging systems.

1.5.2 Alternative equipment used for the delivery of anaesthesia (e.g. anaesthesia drug infusion devices).

1.5.3 Monitoring equipment, whether integral to or separate from the machine, except as required by AS/NZS 3200.2.13:2005. Monitoring recommendations are in College Professional Document PS18 - Recommendations on Monitoring During Anaesthesia.

2. ANAESTHETIC MACHINE SAFETY ASSESSMENT

2.1 Anaesthetic machines must be assessed for safety, reliability and functionality by a specialist anaesthetist or other person with appropriate technical knowledge at least once a year.

2.2 This assessment will result in a classification of each machine into one or more of the following categories, each of which defines a specific course of action for that machine:

2.2.1 Anaesthetic machines that fail to comply with one or more of the essential safety requirements specified in section 3.

Action: Anaesthetic machines in this category should be removed from clinical use. If they can be upgraded to meet the requirements of section 3, they may be returned to clinical practice only after re-assessment confirms full compliance with all essential safety requirements.

2. Anaesthetic machines that meet all of the essential safety requirements of section 3 but fail to comply with one or more of the relative safety requirements of section 4.

Action: Anaesthetic machines in this category should enter an update or replacement process for which planning should start immediately. By 1 January 2011, all anaesthetic machines in this category must either have been upgraded to comply with all the safety requirements of this document or have been removed from clinical use.

3. Anaesthetic machines that do not comply with one or more of the safety requirements of section 5 (whether or not they comply with the requirements of sections 3 and 4).

Action: Anaesthetic machines in this category must be withdrawn from clinical use no later than 6 months from the date on which their lack of compliance with section 5 was documented.

4. Anaesthetic machines that comply with all the safety requirements of this document.

Action: Anaesthetic machines in this category are not excluded from clinical use. These machines require assessment of other safety areas not covered in this document (e.g. see section 2.3) and future reassessment as per section 2.1.

2.3 An anaesthetic machine may be unsafe for clinical use for reasons other than those assessed in this document (e.g. failure to meet electrical safety requirements, lack of appropriate monitoring equipment). Unsafe anaesthetic machines, regardless of the reason, should not be used.

3. ESSENTIAL SAFETY REQUIREMENTS

3.1 Connections for medical gas cylinders (e.g. yokes or regulators) must be pin indexed.

3.2 A reserve supply of oxygen (e.g. from an attached oxygen cylinder) must be functionally attached to the anaesthetic machine in such a manner that it is easily activated should the oxygen supply failure warning device (3.5) indicate impending failure of the oxygen supply.

3.3 Non-interchangeable gas hose connectors, e.g. Diameter Index Safety System or Sleeve Index System connectors, must be present on any gas inlet socket to prevent incorrect gas hose connections.

3.4 Means to display gas supply line and cylinder pressures shall be provided. This display (or a suitable indication of the gas supply status) must be visible from the front of the machine.

3.5 An oxygen supply failure warning device must be present. This must:

3.5.1 Activate automatically when the oxygen supply pressure falls below a predetermined critical level.

3.5.2 Generate an auditory alarm to warn the operator.

3.5.3 Prevent the delivery of hypoxic gas from the fresh gas outlet (e.g. by promptly interrupting the nitrous oxide supply).

3.6 If the anaesthetic machine incorporates a gas flowmeter bank, oxygen must be the last gas to enter the common gas manifold at the top of the flowmeter tubes.

3.7 If mechanical means are provided to mix the anaesthetic gases on the anaesthetic machine, there must be only one gas flow control knob for each gas.

3.8 If a mechanical oxygen flow knob is provided, it must be fluted and larger than the other flow control knobs so that tactile identification of the oxygen control knob is possible.

3.9 If the anaesthetic machine is capable of delivering nitrous oxide, means must be provided to prevent unintentional selection of a hypoxic gas mixture, e.g. an O2/N2O proportioning system or inspired gas measurement control.

3.10 If two or more vaporisers can be simultaneously mounted on the anaesthetic machine, only one vaporiser may be "ON" at a time (ie a vaporiser interlock system must be present, functional and unable to be bypassed).

3.11 Vaporisers with mechanical rotary dials must increase the delivered anaesthetic vapour concentration when the dial is rotated in an anti-clockwise direction.

3.12 A fresh gas outlet, if provided, must be 22 mm outer diameter and 15 mm inner diameter, visible to the operator, and should be capable of being connected to the breathing system in such a way as to prevent accidental disconnection.

3.13 A breathing system high pressure relief valve or other means of automatically preventing dangerously high and/or prolonged pressures in the breathing system must be provided.

3.14 Anaesthetic gas scavenging system connections must be of a diameter that is different (e.g. 19mm or 30mm) from the other connections used in the breathing system.

3.15 When each functional sub-system of the anaesthetic machine is enabled, its associated monitors and alarms must be automatically activated.

3.16 Adequate maintenance of the anaesthetic machine must be possible. Replacement parts of suitable quality and appropriately qualified certified service personnel must be available, so that the anaesthetic machine can continue to operate to its original performance specification.

4. RELATIVE SAFETY REQUIREMENTS

4.1 An airway pressure alarm that responds to sustained positive pressure in the breathing system must be present.

4.2 The emergency oxygen flush control must be protected from accidental activation.

4.3 An “on/off” switch, if present, must be protected from unintended activation.

4.4 If an immediate return to normal operation is not possible, turning "off" an anaesthetic machine should either require a confirmatory step or the machine should display a warning (for a period of at least 10 seconds) that it is going to turn off and provide an option to cancel this action.

4.5 If the anaesthetic machine requires electrical power for normal operation, a backup power supply must be a part of the machine and permit normal operation for at least 30 minutes after a mains power supply failure. An alarm must be activated at the time of the mains failure, and the state of the reserve power supply must be indicated while it is in use.

4.6 An airway pressure alarm should be provided in response to high peak pressure and negative pressure in the breathing system because these conditions can result in patient harm.

5. OTHER SAFETY REQUIREMENTS

5.1 A maintenance record and problem log should be kept for all anaesthetic machines in clinical use. A machine should be considered for replacement if its maintenance history indicates that problems with the machine are adversely impacting clinical service to an extent that is unacceptable to the institution or which threatens patient safety.

5.2 An anaesthetic machine should be considered for replacement if it cannot meet the reasonable needs of current anaesthetic practice in the facility.

REFERENCES

• American Society of Anesthesiologists "Guidelines for Determining Anesthesia Machine Obsolescence" (2004)
• Australian/New Zealand Standard AS/NZS 3200.2.13:2005 "Medical electrical equipment - Particular requirements for safety - Anaesthetic systems".

RELEVANT PROFESSIONAL DOCUMENTS

T1 Recommendations on Minimum Facilities for Safe Administration of Anaesthesia in Operating Suites and Other Anaesthetising Locations

PS18 Recommendations on Monitoring During Anaesthesia

PS31 Recommendations on Checking Anaesthesia Delivery Systems

COLLEGE PROFESSIONAL DOCUMENTS

College Professional Documents are progressively being coded as follows:

TE Training and Educational

EX Examinations

PS Professional Standards

T Technical

POLICY - defined as 'a course of action adopted and pursued by the College'. These are matters coming within the authority and control of the College.

RECOMMENDATIONS - defined as 'advisable courses of action'.

GUIDELINES - defined as 'a document offering advice'. These may be clinical (in which case they will eventually be evidence-based), or non-clinical.

STATEMENTS - defined as 'a communication setting out information'.

This document is intended to apply wherever anaesthesia is administered.

This document has been prepared having regard to general circumstances, and it is the responsibility of the practitioner to have express regard to the particular circumstances of each case, and the application of this document in each case.

Professional documents are reviewed from time to time, and it is the responsibility of the practitioner to ensure that the practitioner has obtained the current version. Professional documents have been prepared having regard to the information available at the time of their preparation, and the practitioner should therefore have regard to any information, research or material which may have been published or become available subsequently.

Whilst the College endeavours to ensure that professional documents are as current as possible at the time of their preparation, it takes no responsibility for matters arising from changed circumstances or information or material which may have become available subsequently.

Promulgated: 2006

Date of current document: June 2008

© This document is copyright and cannot be reproduced in whole or in part without prior permission.

College Website: http://www.anzca.edu.au/