PS31 2014: Anaesthesia machine check



·         Introduction

·         Disaster prevention

·         What do the levels mean?

·         Level 1 check

·         Level 2 check

·         Level 3 check



·         Anaesthesia machines are complex

·         Many ways they can malfunction

·         Frequent checks are required

·         Each hospital should assign somebody to be in charge


Need to prevent the following disasters:

·         Failure of power supply

·         Failure to supply anaesthetic

·         Failure of monitoring and alarms

·         Failure to maintain circuit pressure within acceptable limits


What do the levels mean?




Training location

Level 1

After services and repair


Manufacturer’s course

Level 2

Before each list

Nurse delegate


Level 3

Before each case




Level 1 check:

·         Electrical safety

·         Gas delivery

·         Inhaled anaesthetic delivery

·         Ventilators

·         IV and LA delivery

·         Associated equipment

·         Documentation


Level 2 check:

High pressure system

·      Wall:

o  Check screw connection

o  Check pressure

·      O2 cylinder:

o  Check yoke connection

o  Check pressure (= fullness)

o  Turn on and off

Low pressure system

·      Flowmeters:

o  Watch each bobbin move

o  Ensure 100% N2O is impossible

·      Vapourisers:

o  Check seating and interlock

o  Ensure tank full and port sealed

o  Test for leak

·      Breathing system:

o  Auto + manual – leak at 30cmH2O with 0.3L/min

o  Resistance and compliance

o  APL valve spill

·      Mechanical ventilator:

o  Test disconnection alarm

o  Test high pressure alarm

·      Scavenging system:

o  Check connections

o  Check flow rate

o  Ensure no blockage

·      Bag-mask ventilator and sucker


·      Carrier gas analysis

·      Anaesthetic vapour analysis


·      Airway stuff

·      IV anaesthetic pump: power, connections, delivery

Final check

·      Turn vaporisers off

·      Purge circuit with oxygen


·      Name

·      Date

·      Result

*Level 2 check is particularly to detect obstruction of the expiratory limb (this causes gas trapping, obstruction to preload, hypotension*


Level 3 check:

·         Vapouriser (if changed)

·         Breathing system (if changed)

·         IV anaesthetic pump

·         Suction


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