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

We investigated whether a commercial bi-level positive airway pressure (BPAP) device, would improve peripheral oxygen saturation (SpO₂) 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. SpO₂, 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 SpO₂, MCAv, and RR, and increased TV index and HR. There was no effect of altitude (p > 0.05) on reaction time. BPAP increased mean SpO₂ 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 SpO₂ for recreational aviators up to 12,500 feet without supplemental oxygen.