Summary

Background:

Decompression sickness (DCS) is a clinical syndrome caused by a substantial reduction in barometric pressure. DCS is more common among divers but may also occur during flight or altitude chamber (hypobaric chamber) training. DCS is classified according to symptoms as either Type 1 (musculoskeletal and skin involvement) or Type 2 (neurological and pulmonary involvement). DCS may be life threatening and often necessitates treatment with hyperbaric oxygen therapy (HBOT).

Objectives:

To examine the risk for altitude decompression sickness (ADCS) in altitude chamber training and to compare ADCS symptoms and treatment to those of DCS in divers (DDCS).

Methods:

We conducted a retrospective cohort study that included all cases of ADCS in the Israeli Air Force between 2015 to 2022. We collected demographic, flight platform, altitude chamber training, clinical manifestations, and treatment data. Data regarding DDCS was obtained via a literature review.

Results:

There were 2279 altitude chamber trainees and aviation physiology instructors. Of these, 11 presented ADCS, leading to a calculated ADCS risk of 0.5%. An additional four cases were reported following combat flights. Musculoskeletal involvement was the most common symptom in both DDCS and ADCS. A shorter HBOT protocol was used in 53% of the ADCS cases but only in 30% of the DDCS cases.

Conclusions:

Overall, ADCS is a rare event, occurring in less than 1% of altitude chamber trainees. The common manifestation is of musculoskeletal involvement, and the mainstay of treatment remains HBOT.