Positive pressure ventilation improves oxygen saturation at altitude during recreational aviation: A pilot study

Aim: We investigated whether a commercial bi-level positive airway pressure (BPAP) device, would improve peripheral oxygen saturation (SpO(2)) during recreational aviation up to 12,500 feet without supplemental oxygen. Ten adults with recreational flight experience (age:47 +/- 14; female = 5) completed a standardized flight profile in an unpressurised aircraft, involving randomized crossover design at 8,000 feet and 12,500 feet with BPAP or control. SpO(2), middle cerebral artery velocity (MCAv), heart rate (HR), respiratory rate (RR), and relative tidal volume (TV) index were measured continuously. Psychomotor vigilance test (3-min) assessed reaction time halfway through taxi and altitude stages. Altitude significantly (p < 0.05) decreased mean SpO(2), MCAv, and RR, and increased TV index and HR. There was no effect of altitude (p > 0.05) on reaction time. BPAP increased mean SpO(2) at 8,000 feet [Control: 92 +/- 1%; BPAP: 94 +/- 2%; mean difference (MD) = 2 +/- 2%; p = 0.002] and 12,500 feet [Control: 86 +/- 4%; BPAP: 89 +/- 4%; MD = 2 +/- 3%; p = 0.013]. BPAP lowered MCAv at 8,000 feet [Control: 53 +/- 10 cm/s; BPAP: 50 +/- 9 cm/s; MD = -3 +/- 2 cm/s; p = 0.001] and 12,500 feet [Control: 52 +/- 10 cm/s; BPAP: 50 +/- 8 cm/s; MD = -2 +/- 3 cm/s; p = 0.041]. BPAP increased TV index at 8,000 feet (Control: 6.6 +/- 1.3; BPAP:8.1 +/- 1.8; MD = 1.9 +/- 0.8; p < 0.001) but not 12,500 feet, without effect on RR or reaction time. This study provides preliminary results that BPAP may improve mean SpO(2) for recreational aviators up to 12,500 feet without supplemental oxygen.