Minimum Requirements for Ventilator Testing
Guidance [Health Devices Sep-Oct 1998;27(9-10):363-4]
Verifying Ventilator Operation
All ventilators should be tested after
each use to verify performance before the unit is used for another patient.
Ideally, a complete operational verification procedure, established by the
facility and usually based on the manufacturer's recommendations, will be
performed each time. These procedures should be described in a facility's
policies and procedures.
There is, however, an interim solution
for instances when the staff has insufficient time to complete a full
operational verification procedure on an older unit. That is, staff can instead
test only those features that will be or that are likely to be required for the
patient about to be ventilated. This will ensure the patient's safety while
reducing testing time to under 20 minutes—or even less for ventilators
with a limited number of features. A full operational verification procedure can
then be performed at the next opportunity.
Minimum Ventilator Tests
The minimum tests that should be
performed and documented to ensure the safe use of a ventilator are listed
below. It is important to remember that this list is a stopgap measure and
should be used only when necessary, not as a routine procedure. Users can
substitute equivalent tests where appropriate and delete those tests for which a
ventilator does not have corresponding features or accessories.
- Battery test/power loss alarm. With the unit turned on, momentarily disconnect and then reconnect the
power source while the ventilator is not in use on a patient. The machine's
battery backup and its disconnection alarms should function appropriately.
- Lamp test. Test lamps according
to the manufacturer's procedures.
- Audible and visual alarms. Disconnect the oxygen supply hose and, separately, the air supply hose (if used). Appropriate alarm(s) should result. Reconnect the hoses. Using a test lung, check for the appropriate activation of all audible and visual alarms. Specifically, momentarily disconnect the circuit to test the low pressure, low exhaled volume, and apnea alarms. Occlude the circuit to test the high pressure alarm. Or, as an alternative to these steps, momentarily change the alarm setting parameter to trigger the alarm under test (e.g., FiO2 alarm). The inverse
inspiratory:expiratory (I:E) ratio alarm can be verified by momentarily
adjusting peak flow to create an inverse-ratio condition.
- Proximal airway pressure gauge and positive end- expiratory pressure (PEEP) control. Set the PEEP level required for the patient. The manometer reading should cycle and return to the appropriate baseline (±1 cm H2O) at the end of each breath delivered to the test lung. Check the manometer zero (±1 cm H2O) by momentarily
disconnecting the pressure line or inspiratory limb of the circuit.
- Leak tests. Perform either or
both of these tests as the machine allows:
--Occlude the patient
connection, set the pressure limit and tidal volume to their maximum
levels and the peak flow and rate to their minimum levels, and initiate
a breath. The manometer should reach the set maximum level, and the high
pressure alarm should activate.
--Set the inspiratory pause to
³ 2 sec, if possible, and set the PEEP level to 0. When the
ventilator cycles, observe the pressure during the pause (i.e., the
plateau pressure); the amount of drift should not exceed ±10% of
the plateau pressure.
- Modes. Set the mode to be used
for the patient. Using a test lung, verify proper operation for that mode as
the ventilator cycles.
- Ventilator rate (and rate display). Count the number of breaths delivered during a convenient interval,
timed using a clock or watch with a second hand. The measured rate should be
within ±1 breath per minute of the rate setting (and of the rate
display, if so equipped).
- Volume (and volume display)—tidal volume, sigh volume,* and minute volume. Use an
external device such as a Wright respirometer or equivalent to independently
measure exhaled volume. Connect a test lung to the circuit, cycle the
machine, and compare the measured exhaled tidal volume and minute volume to
their respective settings. Manually trigger a sigh breath, if possible, and
compare the measured value to the setting. All measurements should be within
±5% of the settings (and displays, if so equipped).
- Sensitivity. Put the ventilator
into an assist mode. Squeeze and release the test lung; an inspiration
should result when the airway pressure drops to the intended sensitivity
- Oxygen calibration. Expose the oxygen monitor (or analyzer) used with the ventilator to room air and to wall oxygen (100%), and calibrate it. Final readings should be within ±2%. Set the oxygen concentration to be delivered by the ventilator. Verify this concentration (±2% FiO2)
using the oxygen monitor (or analyzer).
- Nebulizer (if present).* Turn
the ventilator's nebulizer on, and verify that flow is produced at the
nebulizer output port during each inspiratory cycle.
- Filters. Ensure that a
high-efficiency particulate-air (HEPA) filter is present on the main
- Remote alarm operation (if present).* Set up a convenient alarm condition (e.g., power loss, high
pressure), and verify that appropriate alarm notification occurs at the
* Perform only if this feature or
accessory is to be used in the treatment of the patient about to be ventilated.