Are home ventilators able to guarantee a minimal tidal volume?

OBJECTIVE

The aim of the study was to evaluate the ability of home ventilators to maintain a minimal tidal volume during different conditions associated with alveolar hypoventilation.

DESIGN

Bench evaluation coupled with an in vivo study on two healthy subjects.

SETTING

Tertiary university hospital and research unit.

INTERVENTIONS

Six ventilators having a "volume guarantee" module (Synchrony II, Philips Respironics; Vivo 40, Breas; Legendair, Airox; Elisee 150, Philips Respironics; Ventimotion, Weinmann; and VS III, Resmed) were tested on a lung bench in a baseline condition and in three conditions associated with alveolar hypoventilation: increase in airway resistance, decrease in lung compliance, and non-intentional leaks. An in vivo study completed the bench study for the non-intentional leak condition.

MEASUREMENTS AND RESULTS

The six ventilators were able to maintain a minimal tidal volume during an increase in airway resistance and a decrease in lung compliance. The maintenance of a minimal tidal volume during a non-intentional leak was more difficult and was associated with large variations in tidal volume, a default of pressure support delivery for some devices, and patient-ventilator dyssynchrony, both during the bench and the in vivo study.

CONCLUSIONS

The six home ventilators tested in the study were able to maintain a minimal tidal volume during an increase in airway resistance and a decrease in lung compliance, but not during a non-intentional leak.