Cause of Device-Related Incident
*Not stated

Clinical Specialty or Hospital Department

Device Factors
*Not stated

Document Type
Checklists/Emergency Procedures

External Factors
*Not stated

Mechanism of Injury or Death
Barotrauma; Exposure to hazardous gas; Failure to deliver therapy; Overdose; Underdose; Wrong drug

Support System Failures
*Not stated

Tampering and/or Sabotage
*Not stated

User Errors
*Not stated

Pre-Use Checklist for Anesthesia Units (Machines and Accessories)


To be performed daily.

Items marked with an asterisk (*) should also be performed before each case.

* ¨ 1. Controls off

Has anything been left on? If gas has been leaking through a vaporizer all night, there may be significant initial concentration (i.e., a distinctive odor) of vapor due to condensed liquid anesthetic in the piping manifold.

* 2. Cylinder contents sufficient

Turn on each cylinder and check its contents gauge for adequate pressure. Is there sufficient O2 to operate the ventilator in an emergency? Turn all cylinders off, or pipeline fluctuations may gradually use up reserve supplies.

3. O2 supply failure

Turn on the O2 analyzer in STANDBY or ON mode for later test. Turn on flows of both O2 and N2O. Then disconnect the O2 hose. Confirm N2O flow decrease or cessation and alarm (if so equipped) indicating proper operation of the O2 supply failure device (failsafe).

4. Pipeline supplies

When reattaching the O2 hose, check that all fittings hold firmly, that no leaking gases can be heard, and that the hoses are arranged properly to prevent occlusion.

Check pipeline pressure gauges (if so equipped) for proper pressure (50 to 55 psig). (Test O2 flow during the ventilator test, Item 13.)

5. Controls, gas flow

Confirm that all gas flow rates are easy to adjust accurately and that floats do not stick. Press the flush control and confirm that the reservoir bag fills quickly.

* 6. Vaporizers filled

Examine fluid levels in vaporizers that might be used, fill carefully with the correct agent to the proper level, and record the amount. Since it may be necessary to change anesthetics during the course of a procedure, the reserve vaporizer should also be filled and ready.

Be sure all vaporizers are tightly capped and off before leak testing (Item 7). If the patient may be sensitive to the agent in an unused vaporizer, do not include it in the following leak test.

7. Leak test, machine (if no manufacturer-specified test)

Attach a pressure gauge to the common outlet in place of the fresh gas hose and set the O2 flow so that it indicates a steady 30 cm H2O. Less than 30 mL/min inflow should be required to compensate for leakage. If such a low flow cannot be set, use the manufacturer's recommended leak test. Turn on vaporizers individually with O2 flowing through them if they are to be included in the leak test. Remove gauge, replace fresh gas hose, and verify that all vaporizers are off.

8. O2 and vaporizer check

Confirm O2 analyzer battery condition (if so equipped). Calibrate the sensor with air, then install in the fresh gas flow line and check at 100% O2.

With the O2 analyzer set at 100%, turn on the vaporizer and check for decreases in the O2 concentration while increasing the vaporizer control in 1% steps. Turn off the vaporizer, set the gas flow for 50% O2, and check for that reading (this also checks flowmeters). Note how rapidly the indication changes. Compare these observations with the manufacturer's recommendations on need for maintenance. Adjust, in turn, the high- and low-O2 alarms to the indicated concentration to confirm proper alarm actuation. Leave the low-O2 alarm at 20% or higher.

* 9. CO2 Absorber

Be sure the absorbent has been changed at least weekly for machines used daily and during the pre-use check for machines that have remained idle for ³ 48 hr. Also be sure that its color indicates adequate capacity for the next procedure. Confirm that the bypass valve (if so equipped) is shut.

* 10. Patient circuit assembly

Confirm that the patient circuit is properly assembled and that hoses are wrung on tightly.

* 11. Patient circuit leak test (if no manufacturer-specified test)

Occlude the reservoir bag fitting (or roll up bag and hold it to prevent inflation), shut off the pressure-limiting (pop-off) valve, and measure the O2 flow rate that will sustain a pressure of 30 cm H2O. It should not exceed 150 mL/min. Tighten the absorber seals, drain plug, and other possible sources, or replace the bag and hoses to reduce leakage. Continue until within specification.

* 12. Patient circuit flow

Attach a simple lung simulator to simulate patient ventilation. Fill and compress the reservoir bag while checking for proper operation of one-way valves. Confirm that the lung is insufflated and empties with both forcible and gentle compression.

Confirm that the pressure-limiting (pop-off) valve can be adjusted for various pressure levels in the patient circuit during simulated ventilation.

* 13. Ventilator and alarm

Turn on the ventilator (with appropriate fresh gas flow and settings) and the ventilation (disconnect) alarm, and confirm that the simulated lung is ventilated as intended. Also confirm that the O2 flow rate does not fall more than 10% on inspiration. Disconnect the lung, and note if the alarm is activated after proper delay. Confirm battery condition, if so equipped. Perform a leak test per manufacturer's method. Turn off the ventilator and open the pressure-limiting valve.

14. Scavenging system

Confirm proper connection of the scavenging system and that an active system has the manufacturer-specified suction flow rate. Alternatively, with a gas flow of 8 L/min O2, put the O2 sensor at the overflow release point of the scavenging system and check that the O2 analyzer does not indicate over 21%. Replace the O2 sensor.

* 15. Controls off

Note completion of tests on the Anesthesia Record.

Completion of this safety check ensures that more common equipment items have been tested for the most important types of failures. However, equivalent safety checks should be performed on drugs to ensure that they are properly marked and mixed and on any other equipment that may be used.

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