Exercise-induced hypoxia predicts hypobaric hypoxia during flight in patients after Fontan operation

Background: Hypobaric hypoxia (HH) during flight might be more detrimental to pulmonary circulation in Foram patients compared healthy individuals. This study was designed to clarify whether exercise-induced hypoxia could predict HH during flight in Fontan patients. Methods and results: Percutaneous oxygen saturation (SpO(2)) was analyzed during flight in 11 Fontan patients and eight volunteers. SpO(2) was measured before taking off (S1), at the initial (S2), the end of stabilization (S3), and after landing (S4). The SpO(2)-dynamics were compared with SpO(2)-dynamics during cardiopulmonary exercise testing (CPX), pulmonary function, and hemodynamics in the Fontan patients. At all measurements, SpO(2) was lower in the Fontan patients than the volunteers during flight. The total SpO(2) dedine from SI to S3 was greater in the Fontan patients than the volunteers. While SpO(2) change from S2 to S3 was negative in the Fontan patients, it was stable in the volunteers. In the Fontan patients, the median value of exercise-induced SpO(2) decline (Ex-dSpO(2)), SpO(2) at rest, and SpO(2)at peak was -6%, 93%, and 88%, respectively. In addition to exercise capacity and pulmonary function, the Ex-dSpO(2) was correlated strongly with SpO(2 )at all phases during flight (r = 0.75-0.98, p < 0.01 for all). Flight-associated adverse events occurred in two patients with SpO(2) < 80% at S3. Conclusions: Both the Fontan patients and the volunteers demonstrated similar SpO(2)-dynamics during flight with a greater HH in the Fontan patients. CPX with SpO(2) monitoring is useful in predicting SpO(2)-dynamics and adverse events during flight in these patients. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Fontan patients showed lower oxygen saturation levels during flight compared to volunteers, and exercise-induced oxygen saturation decline was strongly correlated with oxygen saturation dynamics during flight.