Flow controlled expiration does not impair pedal power during physical exercise on a bicycle ergometer

Abstract

Flow Controlled Expiration (FLEX) has been demonstrated to be lungprotective in models of ARDS during controlled mechanical ventilation. However, modern ventilation strategies in critical care include spontaneous breathing. Therefore, we investigated breathing discomfort and potential performance constraints of FLEX in 24 healthy test persons under increased ventilation demand. The subjects generated 20, 50 or 100 W pedal power on a bicycle ergometer while breathing with and without FLEX and rated breathing discomfort on a scale ranging from 0 (comfortable) to 10 (not tolerable). Then the subjects were asked to indicate the power they could maintain for 30 min with and without FLEX. With FLEX, tidal volume was higher and respiratory rate lower than without. Breathing discomfort was slightly increased by FLEX (on average from 2.2 to 3.2, p = 0.002). The estimated maintainable power was similar with and without FLEX (p = 0.986). We conclude that FLEX does not intolerably increase breathing discomfort and does not impair physical performance.

Keywords: Breathing discomfort; Breathing support; Expiration; Lung stabilization; Perception; Ventilation therapy.