UMMC Narkomed 2B Checkout and Troubleshooting-1994

Different machines may require modifications of the procedure. You need to think about what you are doing, why you are doing it, and how to trouble shoot problems that develop. What follows is only a guideline. The responsibility of a properly operating machine lies with the individual administering the anesthetic. The decision to proceed or not, given the equipment on hand, lies with the individual anesthetist. Anesthesia machine requirements for this checklist: ascending bellows, capnograph, pulse oximeter, oxygen analyzer, spirometer, breathing system pressure monitor with high and low pressure alarms. *Indicates steps which may be omitted in subsequent checks.

Emergency Ventilation Equipment

1. Emergency equipment is available and functioning
· Ambu-bag and mask, oral airway(s), laryngoscope, endotracheal tube (stylet), patient suction

High Pressure System

*2. Check O2 Cylinder Supply
a. Note O2 tank color, mounting. · Watch for pressure gauge to increase when cylinder opened (should be > 1000 psi.)
b. Close cylinder.
c. Watch gauge and listen for leaks.
*3. Check central pipeline supplies for all gases
a. Inspect hoses and connections.
b. Note: pipeline gauge should read 45-55 psi.
Problem with High Pressure System?

Low Pressure System

*4. Check initial status of low pressure system
a. Flowmeters and vaporizers off.
b. Check fill levels and tighten vaporizer caps, test interlock.
c. Remove O2 monitor sensor from circuit.
d. Verify that the machine master switch and flow control valves are off.
*5. Turn on master switch
a. Check diagnostics screen.
*6. Test flowmeters
a. Adjust flow of all gases through their full range, checking for smooth operation of floats and undamaged flow tubes.
b. Attempt to create a hypoxic O2/N2O mixture and verify correct changes in flow and/or alarm.

Breathing System

7. Check initial status of breathing system
a. Selector switch is in "bag" mode.
b. Breathing circuit is complete, undamaged, and unobstructed.
c. CO2 absorbent is adequate.
8. Install Accessory Equipment
To be used during the case.
*9. Calibrate O2 monitor
a. Calibrate to read 21% in room air.
b. Reinstall sensor in circuit and flush breathing system with O2.
c. Monitor should now read > 90%.
10. Perform breathing system leak check
a. Set all gas flows to zero (or minimum).
b. Close APL valve and occlude y-piece. Note zero pressure.
c. Pressurize breathing system to 30 cm H2O with O2 flush.
d. Gauge value shouldn't noticeably drop in 10 seconds.
Problem with Breathing System?

Scavenger System

11. Check APL valve and scavenger system
a. Pressurize breathing system to 50 cm H2O and insure it remains intact.
b. Open APL valve and insure that a pressure decrease occurs as the valve is opened.
c. Insure proper scavenging connections and adjust waste gas vacuum.
d. Fully open APL valve, and occlude Y-piece.
e. With minimum O2 flow, insure negligible negative pressure at the absorber pressure gauge.
f. With O2 flush activated, insure negligible positive pressure at the absorber pressure gauge.
Problem with Scavenging System?


12. Functional test of ventilator and unidirectional valves
a. Place reservoir bag on Y-piece.
b. Set appropriate ventilator parameters for next patient, check inspiratory flows dial.
c. Set O2 flow to minimum, other gas flows to zero.
d. Set selector switch to auto, turn ventilator on and pressurize system with O2 flush.
e. Insure cycling of ventilator and free movement of bellows. Check for loss of gas from circuit by failure of bellows to refill.
f. Check for proper action of unidirectional valves.
g. Exercise breathing circuit accessories to assure appropriate function-disconnect bag, verify low pressure alarms.
h. Turn ventilator off, turn alarms off and return bag to bag mount.
Problem with Ventilator?


13. Check, calibrate and set alarm limits of all monitors
· Capnograph/agent analyzer
· Oximeter
· O2 analyzer
· Spirometer
· Invasive pressure monitors
· Respiratory pressure monitor

Final Position

14. Check final status of machine
a. All flowmeters to zero or minimum.
b. Vaporizers off.
c. Selector switch to "bag" mode.
d. APL valve open.
e. Patient suction level appropriate.
f. Patient breathing system ready to use.

What this does not check (lack of a positive control): O2 pressure alarm, Nitrous tank pressures/gauges, defective vaporizer interlock. Leak in vaporizer, defective pressure gauge.

Trouble shooting:

Comment: Alarms may be silenced in three ways:

1. Temporarily silence the alarm.
2. Turn off the offending alarm or device.
3. Fix the alarm condition.

The latter is preferable.

Common Faults

Emergency Ventilation Equipment

· Omission
· Lack of patient suction
Return to Checkout

High pressure system

· Wrong tank-pin index system failure
· High pressure leak-check washer
· Gauge failure
Low pressure system
· Low pressure leak-without vaporizer-broken flowmeter, internal leak.
· Low pressure leak-with vaporizer-loose vaporizer cap, leak in vaporizer.
· Flowmeter problems-broken, stuck float, dirty flowmeter, low gas pressures.
· Hypoxic mixture problems-faulty link 25 system (Ohmeda), faulty proportioning system (Drager).
Return to Checkout

Breathing system

· CO2 absorber-if blue, needs to be replaced.
· Breathing system leak-loose connection, CO2 canister mis-mounted, excess sampling from gas monitor, valve cover loose/missing/broken, auto peep from H2O in ventilator hose.
Return to checkout

Scavenger System

· Scavenging problems-bag too full (positive pressure), insufficient scavenging for flows, no positive pressure release.
· Scavenging problems-bag too empty (negative pressure), excessive scavenging for flows, no negative pressure relief valve.
Return to checkout


· Ventilator problems-no driving gas pressure, no electrical power, improper settings (Vt=0, rr=0), leak from bellows, sticking pop-off valve (open or closed).
· If ventilator fails to refill, there is a leak in the low pressure system. Increase the flow until the ventilator bellows refills. Flow at this point equals the leak out of the circuit.
Return to Checkout

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