Proportional assist ventilation reduces the work of breathing during exercise at moderate altitude.

Kleinsasser, Axel, Achim Von Goedecke, Christoph Hoermann, Stephan Maier, Andreas Schaefer, Christian Keller, and Alex Loeckinger. Proportional assist ventilation reduces the work of breathing during exercise at moderate altitude. High Alt. Med. Biol. 5:420–428, 2004.—Reducing the work of breathing (WOB) during exercise and thus the oxygen required solely for ventilation may be an option to increase the oxygen available for nonventilatory physiological tasks at altitude. This study evaluated whether pressure support ventilation (PSV) and proportional assist ventilation (PAV) may partially reduce WOB during exercise at altitude. Seven volunteers breathing with either PSV or PAV or without support (control) were examined for WOB, inspiratory pressure time product (iPTP), and O2 before and during pedaling at 160 W for 4 min on an ergometer at an altitude of 2860 m, where barometric pressure and oxygen partial pressure are approximately 30% less than at sea level. PSV and PAV reduced WOB from 4.5 ± 0.9 J/L-1/...