Chest
Volume 119, Issue 2, February 2001, Pages 562-564
Journal home page for Chest

Laboratory and Animal Investigations
Home Ventilator Low-Pressure Alarms Fail To Detect Accidental Decannulation With Pediatric Tracheostomy Tubes

https://doi.org/10.1378/chest.119.2.562Get rights and content

Background

Positive-pressure ventilators are equippedwith low-inspiratory-pressure alarms to protect patients fromhypoventilation. Small uncuffed tracheostomy tubes have a highresistance, and may not trigger these alarms during decannulation.

Study objective

To determine whether ventilatorlow-inspiratory-pressure alarms are effective in detecting tracheostomydecannulation.

Design

We connected tracheostomy tubesof varying inner diameters (3.0 to 6.0 mm) to a home ventilator andsimulated decannulation using low (tidal volume [Vt], 600mL; peak inspiratory pressure [PIP], 25 cm H2O), medium(Vt, 800 m, L; PIP, 30 cm H2O), and high(Vt, 1,000 m, L; PIP, 35 cm H2O) ventilatorsettings.

Results

When the ventilatorlow-inspiratory-pressure alarm was set at 4 cm H2O belowthe desired PIP, it failed to alarm for simulated decannulation oftracheostomy tubes < 4.5 mm on low and medium settings, and < 4.0mm on high settings. When the ventilator low-inspiratory-pressure alarmwas set at 10 cm H2O below the desired PIP, it failed toalarm with tracheostomy tubes < 6.0 mm.

Conclusion

We conclude that ventilator low-inspiratory-pressure alarms fail toalarm during simulated decannulation with small tracheostomy tubescommonly used in children. We speculate that low-inspiratory-pressurealarms set at 4 cm H2O below the desired PIP will detectmore decannulation than when set at 10 cm H2O below thedesired PIP.

Section snippets

Materials and Methods

Tracheostomy tube decannulation was simulated using sevendifferent tracheostomy tube (Bivona Medical Technologies; Gary, IN)sizes, ranging from an inner diameter (ID) of 3.0 to 6.0 mm. Thecircuit from a home ventilator (Aequitron LP-10; Mallinkrodt; Minneapolis, MN) was attached to the tracheostomy tubes that, in turn, were connected to a test lung (Siemens Test Lung 180; Siemens Elema AB; Solna, Sweden) using an appropriately sized endotracheal tube adapter.

Decannulation was simulated by

Results

With the LPA4, simulated decannulation with a tracheostomy tube of< 5.0-mm ID was not detected on the low and medium ventilatorsettings. The LPA4 failed to alarm on decannulation with a tracheostomytube of < 4.5-mm ID on the high ventilator settings (Table 1).

With the LPA10, simulated decannulation using the low ventilatorsettings was not detected with any of the tracheostomy tubes tested. The LPA10 failed to alarm on decannulation with all tracheostomy tubesexcept those with an ID of 6.0 mm on

Discussion

Our study shows that home ventilator low-inspiratory-pressurealarms do not sound during simulated decannulation with smalltracheostomy tubes. Although this possibility is mentioned in the, Aequitron LP-10 clinician's manual, it has not been verified and/orreported. Undetected low-pressure states place ventilator-dependentchildren at significant risk for hypoventilation and cardiopulmonaryarrest. The alarms may fail to sound because of the high resistanceinherent with small tracheostomy tubes.

Conclusion

In summary, we conclude that home ventilatorlow-inspiratory-pressure alarms frequently fail to detect simulateddecannulation with small tracheostomy tubes. This occurred regardlessof the low-inspiratory-pressure alarm setting. With the LPA10, decannulation was detected with nearly all tracheostomy tubes studied. With the LPA4, the detection of decannulation was slightlybetter. However, the LPA4 remained unable to detectdecannulation in tracheostomy tubes with an ID of < 5.0 mm. Therefore, we

References (3)

There are more references available in the full text version of this article.

Cited by (0)

View full text