Static PV curve and net recruitment. (A) Static PV curve during inflation and deflation. Hysteresis is shown, with the volume at inflation, Vinf, much lower than volume during deflation, Vdef, for a given pressure, Pcrit. (B) Net recruitment as a function of pressure. Pcrit indicates pressure where net recruitment is maximised. At pressures below Pcrit, the rate of de-recruitment increases, while pressures above Pcrit, the rate of recruitment decreases.