Pre-Use Verification of Breathing Circuits
The following checks should be performed by caregivers
and clinicians whenever disposable breathing circuits are changed.
Inspect the breathing circuit package and
labeling as follows:
- Confirm that the breathing circuit package has not been previously
opened. Previously opened packages may lack components or include contents
that are contaminated with dirt or debris.
- Verify from the package label that the breathing circuit is the correct
model for the type of ventilator that will be used.
- Verify that the package contains all of the
components that are listed on the package insert, that no excess debris is
contained in the package, and, if you switch to a new brand of circuit, that
all of the required components are enclosed. Components such as humidifier
tubing and patient connection adapters are not a standard part of some
manufacturers' circuits and may have to be specifically requested or
purchased separately from a different manufacturer.
After removing the breathing circuit from its
package, inspect the breathing circuit as follows:
- Verify that the breathing circuit tubing length is sufficient. The
inspiratory limb is typically 5 ft or longer; pediatric patients may require
substantially longer lengths.
- Verify that there are no obstructions in the breathing circuit tubing
and connectors. (Note: This should be done by looking through the
translucent components, rather than by disassembling the breathing
- Verify that the proximal pressure line and exhalation drive line tubing
are clear of debris.
- Ensure that the connections are tight by pressing the fittings together,
then tugging moderately to verify that they do not loosen
- Verify that the tubing at the ventilator end of the proximal pressure
line and exhalation drive line is compatible with the portable ventilator's
While connecting the breathing circuit to the ventilator and the patient's artificial airway, verify that the end fittings connect securely. Immediately after the breathing circuit is attached to the patient, verify proper functioning of the breathing circuit as follows:*
- Observe the patient for rhythmic rise of the chest.
- Listen for the sound of the exhalation valve venting during exhalation,
and verify that the ventilator's pressure gauge indicates that the pressure
returns to baseline (i.e., ambient pressure or the PEEP level). Immediately
disconnect the inspiratory tubing before delivery of the next breath if
pressure does not return to baseline, and if necessary, manually ventilate
- Verify that the peak inspiratory pressure does not change significantly
after the breathing circuit is replaced. A significant drop in pressure
could be caused by leaks in the circuit or by an exhalation valve that does
not seal properly during inspiration.
- For patients using the assist or synchronized intermittent mandatory
ventilation (SIMV) modes, verify that the patient's inspiratory efforts
continue to initiate machine breaths with the new breathing circuit. The
exhalation valve diaphragm may vary between circuits, and it may not close
on one circuit in response to the same breathing effort that was sufficient
to close it on another.
- If the breathing circuit does not function properly in any of these
checks, replace it.
- After 15 minutes, reinspect the breathing circuit
to verify that connections are still secure after being warmed by the heated
* When changing the breathing circuit, perform
step 10 with a test lung if one is available and if an alternate means of
ventilating the patient (i.e., a backup ventilator or a manual resuscitator) is
available or if the patient can breathe spontaneously for this time. Then
connect the breathing circuit to the patient, and resume the procedure at step