Anesthesia Machine Preventive Maintenance Checklist
Free anesthesia machine PM checklist for biomedical engineers. Breathing circuit leak test, hypoxic guard, vaporiser calibration steps.
Applicable Standards & Compliance
Pro Tips for Anesthesia Machine PM
Test the guard at every PM by slowly reducing O2 flow while observing N2O — document the exact flow ratio at which shutoff occurs; this must prevent FiO2 falling below 21%
Do not rely solely on colour change — a hardened, moisture-saturated absorbent can appear normal in colour yet have reduced capacity. Change on a time-based schedule regardless of colour
For paediatric circuits use 20 cmH2O, not 30 cmH2O — higher pressures can damage small paediatric breathing circuit components
Halogenated vaporisers show higher apparent concentration than delivered if the wick is partially saturated then drained. Always check output with a fresh wick at annual PM
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Anesthesia Machine Preventive Maintenance Checklist — Inspection Checklist
Common Failure Signs to Watch For
| Warning Sign | Likely Cause | Action Required |
|---|---|---|
| Breathing circuit pressure drop >300 mL/min at 30 cmH2O | APL valve seal leak, O-ring damage or reservoir bag perforation | Systematically isolate circuit sections to locate leak; replace leaking component |
| N2O does not shut off when O2 fails | Hypoxic guard mechanism failure | Remove from service immediately — no N2O until repaired; contact OEM |
| Vaporiser output consistently above or below set concentration | Wick saturation, temperature sensor drift or agent contamination | Service vaporiser; recalibrate; check desflurane heater element if applicable |
| CO2 rebreathing indicated on capnograph (elevated baseline) | Exhausted CO2 absorbent or inspiratory/expiratory valve failure | Replace absorbent; inspect unidirectional valves |
| O2 flush delivers low flow | O2 flush valve contamination or spring fatigue | Clean or replace O2 flush valve; verify O2 supply pressure |
Maintenance Notes & Sign-Off
Anesthesia Machine Maintenance Schedule
Daily
5 tasks- Pre-list machine check per AAGBI/departmental checklist before first case
- Breathing circuit leak test (30 cmH2O, <300 mL/min)
- Verify O2 supply pressure and cylinder backup pressure
- Test hypoxic guard function
- Check CO2 absorbent colour and vaporiser agent level
Weekly
4 tasks- Change CO2 absorbent if colour change observed or >1 week in use
- Check and clean all breathing circuit components
- Inspect vaporiser seals and agent level
- Clean flowmeter tubes and verify float mobility
Monthly
4 tasks- Vaporiser output check with calibrated agent analyser
- Full flowmeter calibration check
- Breathing circuit pressure decay test
- Electrical safety spot-check
Quarterly
4 tasks- Full IEC 62353 electrical safety test
- Capnography calibration if integrated
- APL valve pressure range test
- Complete alarm system test
Half-Yearly
3 tasks- Vaporiser service per OEM requirement (decontamination and calibration)
- Performance certification to ISO 80601-2-13
- Review of OEM service bulletins
Annual
4 tasks- Full PM certification — issue signed report
- Vaporiser annual service including wick and seal replacement
- Complete IEC 62353 electrical safety report
- NABH equipment maintenance documentation update
Frequently Asked Questions
An anesthesia machine PM covers gas supply verification, breathing circuit leak test (<300 mL/min at 30 cmH2O), hypoxic guard function, flowmeter and vaporiser calibration, CO2 absorber condition, ventilator accuracy (if integrated), alarm tests, and IEC 62353 electrical safety testing.
Daily pre-list checks by anaesthesia staff, monthly flowmeter and vaporiser calibration by biomedical engineer, and annual PM certification per ISO 80601-2-13, NABH and TJC EC.02.04.01.
Pressurize the breathing circuit to 30 cmH2O with patient end occluded. Pressure drop must be less than 300 mL/min. For paediatric circuits use 20 cmH2O. Any leakage above threshold requires repair before clinical use.
Gradually reduce O2 flow while observing the N2O flowmeter. The hypoxic guard must shut off N2O before the O2:N2O ratio would allow FiO2 to drop below 21%. Document the exact flow ratio at shutoff.