A nasal CPAP system. Description and comparison with facemask CPAP

Nasopharyngeal pressures were compared in eight subjects breathing through either a nasal CPAP system or facemask CPAP system at a fresh gas flow of 50, 75 and 100 l.min-1. During nose breathing there was no significant difference in nasopharyngeal pressure between the two systems. During mouth breathing pressures were significantly lower with nasal CPAP. During nose breathing at 75 l.min-1 the mean inspiratory and expiratory pressures in cmH2O (SD) were 3.4 (0.68) and 5.9 (0.55) for nasal CPAP and 3.3 (0.71) and 6.3 (0.73) for facemask CPAP. The respective pressures during mouth breathing were 0.3 (0.73) and 2.9 (1.74) for nasal CPAP and 3.9 (0.73) and 5.8 (0.82) for facemask CPAP.