General Requirements
- Connections for medical gas cylinders, yokes or regulators must be pin indexed.
- A reserve supply of oxygen must be attached to the anaesthetic machine in a manner that ensures easy activation should the oxygen supply fail.
- Non-interchangeable gas hose connectors must be present on all gas inlet and outlet sockets to prevent incorrect gas supply connections.
- Colour coding for gas cylinders and pipes should be according to international standards: oxygen (black body with white shoulder), nitrous oxide (French blue) and medical air (black body with black and white shoulder).
- A display of gas supply line and cylinder pressures must be provided. The pressure displays must be visible from the front of the machine.
- Oxygen supply failure warning device/system that indicates impending failure of the external/primary oxygen supply must be present. This must:
a. Activate automatically when the oxygen supply pressure falls below a critical oxygen concentration level of 25%.
b. Generate an audible continuous alarm to warn the operator.
c. The only means to reset the alarm will be the restoration of the oxygen supply pressure to a level above that at which the device is activated
d. Prevent the delivery of a hypoxic gas mixture. - The anaesthetic machine must not be capable of delivering a hypoxic mixture of gases under any circumstances. When oxygen and nitrous oxide are used, a hypoxic guard must be fitted to ensure a minimum oxygen concentration of 25% by either;
a. Cutting off the supply of any other gases other than air or oxygen to the common fresh gas outlet or
b. Proportionally reduce the flow of other gases such as nitrous oxide to maintain the initial FiO2. - The machine should have an emergency oxygen flush that bypasses the vaporizers and delivers at least 35L/min of oxygen. The control for this function must be protected from accidental activation.
- Whenever an automatic ventilator is used, a breathing circuit pressure monitor with high – and low-limit alarms must be incorporated.
a. Alarms: Adjustable alarm limits for all parameters.(lung tidal volumes and pressures)
b. Oxygen monitor (inspired and expired), with a low-limit alarm at least. The minimum standard should be for monitoring the FiO2 of the fresh gas being delivered to the breathing circuit. - 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 60 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.
- A fresh gas outlet, must be 22 mm outer diameter and 15 mm inner diameter, visible to the operator and should be capable of being connected to the closed breathing system in such a way as to prevent accidental disconnection.
- For semi-closed breathing system, a fresh gas outlet, 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.
- Anaesthetic gas scavenging system connections must be of a diameter that is different from the other connections used for the breathing system.
- Adequate maintenance of the anaesthetic machine must be ongoing for the life of the unit.
- Switching “off” an electronic anaesthetic machine during normal operation should require a confirmatory step and the machine should display a warning of imminent shut-down.
- Switching “off” an electronic anaesthetic machine during normal operation should require a confirmatory step and the machine should display a warning of imminent shut-down.