Figure 4
Example flow versus time curves measured over two breathing cycles by the pressure support ventilator for a) medical air and b) helium/oxygen 78/22 supplied with zero pressure support. Curves were obtained for a breathing chamber compliance of 0.05 L/cm H2O, a resistive loss coefficient of 43.0, a respiratory rate of 25 breaths per minute, and a tidal volume of 700 ml.