Pulmonary Artery Pressure Response to Simulated Air Travel in a Hypobaric Chamber

BACKGROUND: Hypoxia-induced elevation in pulmonary artery pressure during air travel may contribute to the worldwide burden of in-flight medical emergencies. The pulmonary artery pressure response may be greater in older passengers, who are more likely to require flight diversion due to a medical event. Understanding these effects may ultimately improve the safety of air travel.

METHODS: We studied 16 healthy volunteers, consisting of a younger group (aged < 25 yr) and an older group (aged > 60 yr). Using a hypobaric chamber, subjects undertook a 2-h simulated flight at the maximum cabin pressure altitude for commercial airline flights (8000 ft; 2438 m). Higher and lower altitudes within the aeromedical range were also explored. Systolic pulmonary artery pressure (sPAP) was assessed by Doppler echocardiography.

RESULTS: There was a progressive increase in sPAP which appeared to be biphasic, with a small initial increase and a larger subsequent rise. Overall, sPAP increased by 5 ± 1 mmHg from baseline to 35 ± 1 mmHg at 8000 ft, an increase of 18%. The sPAP response to 8000 ft was greater in the older group than the younger group.

CONCLUSIONS: This study confirms that pulmonary artery pressure increases during simulated air travel, and provides preliminary evidence that this response is greater in older people. Advancing age may increase in-flight susceptibility to adverse pulmonary vascular responses in passengers, aircrew, and aeromedical patients.

Turner BE, Hodkinson PD, Timperley AC, Smith TG. Pulmonary artery pressure response to simulated air travel in a hypobaric chamber. Aerosp Med Hum Perform. 2015; 86(6):529–534.