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FDA 1993 Anesthesia Machine Pre-Use Checkout
TEXTEquipment I · 9 min read
Every shift, every patient — a 6-step ritual that catches the failures that kill in seconds.
After this lesson you can
3 min read8 sections- Perform the FDA 1993 / ASA 2008 anesthesia machine pre-use checkout.
- Identify what each step is detecting and why.
- Distinguish high-pressure vs low-pressure leak tests.
- Recognize when a checkout failure mandates a different machine.
Why the checkout exists
Closed-claims data show machine-related events disproportionately involve providers who skipped checkout.
The checkout is 4-6 minutes; the closed claim is career-ending.
Built into every modern workstation's start-up.
Critical: even with automated self-tests, a manual verification of breathing-system integrity is mandatory.
Pipeline and cylinder check
Check E-cylinder back-ups: O₂ tank pressure ≥1500 psi (a full E-cylinder is ~1900-2200 psi / ~660 L; replace if <1000 psi).
Linear gauge — pressure proportional to volume.
N₂O cylinder reads 745 psi until liquid exhausted (then drops).
Replace anything <500 psi.
Auxiliary O₂ flowmeter operational (Bain circuit + AMBU bag scenarios).
Pipeline crossover (rare but catastrophic) detected by inspired O₂ analyzer — not by pressure gauges.
Low-pressure system leak test
- close gas outlet with test bulb (or built-in test)
- turn all vaporizers off
- then test each in turn (vaporizers can leak only when dial on)
Modern machines do this automatically — verify the pass on screen.
Failure causes hypoxic mixture + agent loss.
Most-missed step in surveys.
Vaporizer fill and dial
Agent-specific keyed fillers prevent wrong-agent loading.
Dial movement smooth + clicks through detents.
Tec 6 (desflurane) requires warm-up + electrical power; verify ready indicator before dialing.
Check exclusion mechanism — only one vaporizer dial should turn at a time (interlock prevents accidental dual-agent administration).
Breathing system integrity
- close APL valve
- plug Y-piece
- pressurize to
30 cmH₂Ovia O₂ flush — should hold without dropping
Verify unidirectional valves (inspiratory + expiratory) by squeezing bag in spontaneous mode + watching tidal flow direction.
CO₂ absorbent color check: fresh absorbent white/granular; exhausted turns purple (ethyl violet pH indicator).
Replace if any purple visible — partial exhaustion compromises function.
Scavenging + monitor + backup verification
- SpO₂
- capnograph (calibrated)
- inspired O₂ analyzer (verified 21% at room air calibration)
- NIBP
- ECG
- temperature probe available
Alarm limits appropriate.
Patient-specific verifications + final timeout
Pre-induction final verification before each patient: ETT/LMA + stylet sized correctly, suction strong + reachable, O2 cylinder pressure (in case pipeline fails mid-case), drugs drawn + labeled clearly, IV access functional, monitors connected + reading, allergy cross-check, time-out completed with surgical team (patient ID, procedure, side, antibiotic timing, special considerations).
VERBALIZE the plan to the team.
Document everything before drugs go in.
Common failures caught + missed
- leaks in low-pressure system (30% of machine surveys find)
- exhausted CO2 absorbent
- unfilled vaporizer
- AMBU missing or empty O2 cylinder
AUTOMATED self-tests miss things requiring human verification — never substitute machine self-test for the manual verification of bag/valve/circuit integrity.
⚠ Common pitfalls
- Skipping the low-pressure leak test — it catches downstream-of-flowmeter leaks that the high-pressure test misses.
- Treating a 'pass' on a leaky vaporizer cap as truly passed — a 2-min hold is the standard.
- Assuming the previous case's checkout is good — pre-use means BEFORE THIS PATIENT.
- Forgetting to verify backup ventilation (self-inflating bag) is present and works.
💎 Clinical pearls
- If the O₂ cylinder reads <1000 psi, swap it before induction — you don't want to discover it mid-case.
- The 'plus-pressure' leak test (close APL, plug Y-piece, fill to 30 cmH₂O, lose <100 mL/min) is the one most often skipped.
- Vaporizer interlock failure means agent could be delivered without selection — that's a machine-out-of-service event.
- Document the checkout in the anesthesia record; many programs require an explicit time-stamp.
Recap
- If the O₂ cylinder reads <1000 psi, swap it before induction — you don't want to discover it mid-case.
- The 'plus-pressure' leak test (close APL, plug Y-piece, fill to 30 cmH₂O, lose <100 mL/min) is the one most often skipped.
- Vaporizer interlock failure means agent could be delivered without selection — that's a machine-out-of-service event.
- Document the checkout in the anesthesia record; many programs require an explicit time-stamp.
Mark each section done to complete the module.
References
- · Dorsch + Dorsch Understanding Anesthesia Equipment 6e Ch 4
- · Miller's Anesthesia 9e Ch 25 (Anesthesia Machine)
- · Nagelhout Nurse Anesthesia 7e (Anesthesia Machine)
- · ASA 2020 Pre-Anesthesia Checkout
- · AANA Equipment Position Statement
- · ASA 2008 Pre-Anesthesia Checkout (FDA 1993 model)