PROTOCOL
CHECKING AN ANAESTHETIC MACHINE
BEFORE USE
1.
GASES
2.
ROTAMETERS
3.
VAPORISERS
4.
PRE-CIRCUIT LEAKS
5.
EMERGENCY OXYGEN BUTTON
6.
PATIENT BREATHING SYSTEM SELECTION
7.
PATIENT BREATHING SYSTEM
8.
SCAVENGER SYSTEM
9.
MONITORS
PROTOCOL FOR CHECKING AN ANAESTHETIC MACHINE BEFORE USE
1. BULK GAS SUPPLY AND CYLINDERS
1.1 Check the bulk gas warning lights (if piped gas)
1.2 Check that all gas cylinders are turned off and that there is no pressure in the gas lines
or machine. Check gauges are all zero.
1.3 Main oxygen supply “One Gas” test
(this eliminates the possibility of crossed pressure hoses):a. Check that the high pressure gas hose for oxygen is connected to the correct wall
outlet or large oxygen cylinder regulator and to the oxygen inlet of the machine.
b. Turn on the oxygen cylinder valve (2 turns)
c. Check cylinder regulator gauge and replace the cylinder if les than one quarter full
d. Open all rotameter controls and check that only oxygen flows.
1.4 Low oxygen pressure alarm test
a. Keep the oxygen rotameter open.
b. Turn the large cylinder regulator off (or disconnect piped supply) and check the
cylinders pressure gauge.
c. When the gauge reaches zero, an audible alarm occurs and the oxygen rotameter
flow should fall to about one third of the original flow for 1-2 minutes before failing
d. Turn off all rotameters
1.5 Repeat the “One Gas” test for reserve oxygen cylinder
a. Turn on the oxygen cylinder valve (2 turns)
b. Check the cylinder regulator gauge and replace the cylinder if less than half full
c. Open all rotameter controls and check that only oxygen flows.
d. Turn off the cylinder valve off and all rotameters, then bleed the pressure.
1.6 Repeat the “One gas” for nitrous oxide
a. Check that the high pressure gas hose for nitrous oxide is connected to the correct
wall outlet or large cylinder regulator and to the nitrous oxide inlet of the machine.
b. Turn on the nitrous oxide source (2 turns)
c. Check cylinder regulator gauge & replace the cylinder if less than one quarter full
d. Open all rotameter controls and check that only nitrous oxide flows.
e. If the machine is fitted with hypoxic gas mixture protection, no flow will occur through
the nitrous oxide rotameter until the oxygen supply is turned back on (connected
and pressurised).
i, Turn off all rotameters.
ii Turn on the main oxygen source (main cylinder or piped gas)
iii Turn on the nitrous oxide rotameter and check flow is present
1.7 Turn off all rotameters. Leave main oxygen and nitrous oxide cylinders turned on.
2. ROTAMETERS
2.1 Ensure that each bobbin rises and rotates freely when its own gas is flowing.
2.2 Turn off each rotameter control and check the position of the bobbin with no gas flow
.
3. VAPORIZERS
3.1 Check each vaporizer in turn
a. That it can be turned off
b. That it is turned off.
c. That it contains a sufficient amount of the correct liquid agent
d. Check the filing and emptying ports are fully closed
e. Ensure that only one vaporiser is mounted on the anaesthetic machine
f. If the vaporiser is mounted via a Select-O-Tec fitting, check it is locked in place.
4. TEST FOR “PRE-CIRCUIT” LEAKS
4.1 Turn on oxygen rotameter to two litres/minute and occlude the common gas outlet for
10 seconds.
4.2 If the rotameter bobbin does not fall, take steps to detect the site of the leakage.
4.3 Repeat this test with each vaporizer turned “off” and “on” in turn.
5. EMERGENCY OXYGEN BUTTON
5.1 Push button to check function
6. SELECT BREATHING SYSTEM
5.1 Check that the gas supply is connected to the selected breathing system.
5.2 Remove any unused breathing systems from the anaesthetic machine.
7. PATIENT BREATHING SYSTEM
7A CIRCLE ABSORPTION SYSTEM
7A.1 Soda Lime
Check that this is not exhausted. Renew if necessary and remove dust from
soda-lime before refilling the canister.
7A.2 Breathing hoses
Check that the breathing hoses are firmly and correctly connected.
7A.3 Valve function and leaks in the breathing system
a. Close the expiratory spill valve and attach a spare breathing bag to the patient
connection end of the “Y” piece
b. Depress the emergency oxygen button to fill the breathing bag.
c. Alternately squeeze the two bags to ensure that the oxygen passes from one bag
to the other, and check visually that each unidirectional valve functions correctly.
d. Squeeze both bags simultaneously, to raise the pressure in the system.
Maintain the pressure in the system for five seconds to check for leaks.
e. Open the spill valve and check that the gas spills easily when the bag is
squeezed.
7A.4 Disconnect the spare breathing bag and replace with a mask suitable for the
patient.
7B BAIN NON REBREATHING SYSTEM
7B.1 Visual check of the integrity of the inner and outer tubes and their connections.
7B.2 Leak test the inner tube
a. Operate the emergency oxygen button and confirm that the reservoir bag
collapses slightly
b. Set the oxygen rotameter on 2 litres per minute and occlude the outlet of the
inner tube for 5-10 seconds. If the rotameter bobbin does not fall, replace the
breathing system.
c. Turn off the rotameter
7B.3 Leak test outer tube, bag and valve
a. Occlude the patient end of the Bain.
b. Operate the emergency oxygen button so that the bag fills.
Maintain the pressure in the system for 5-10 seconds to check for leaks.
c. Open the spill valve and check that the gas spills easily when the bag is
squeezed.
7B.4 Place a suitable mask on the patient connector.
8. SCAVENGER SYSTEM & MONITORS
7.1 Connect scavenger system to exhaust valve assembly.
7.2 Ensure the entire scavenger system & any tubing is unobstructed.
9. MONITORS
8.1 Connect cables and sampling tubes to monitors
8.2 Turn monitors on
8.3 Where practical, check monitors are functioning correctly.