Evaluation of Intensive Care Unit Ventilators at Altitude

Devices may forgo US military air worthiness and safety testing in an attempt to expedite the availability of critical assets such as mechanical ventilators with a waiver for one-time use in extenuating circumstances.

We evaluated two Intensive Care Unit (ICU) level ventilators: Drager Evita XL and Puritan Bennett (PB) 840 in an altitude chamber at sea level and altitudes of 8,000 and 16,000 feet.

Altitude affected delivered tidal volumes (VTs) in volume control mode (VCV) and Pressure Regulated Volume Controlled (PRVC) mode at altitude with the Evita XL but the differences were not considered clinically important with the PB 840. Sixty-seven percent of the V_Ts were outside the ASTM standard of ± 10% of set V_T with the Evita XL at altitude.

The PB 840 did not deliver V_Ts that were larger than the ASTM standard up to an altitude of 16,000 feet while the majority of the delivered V_Ts with the Därger XL were greater than the ASTM standard. This could present a patient safety issue. Caregivers must be aware of the capabilities and limitations of ICU ventilators when utilized in a hypobaric environment in order to provide safe care.