A study published in Military Medicine by Oxford University Press has found that trauma patients flown without cabin altitude restrictions were more likely to experience hypoxemia, though overall outcomes did not differ between groups.

Researchers reviewed records of 837 patients with non-TBI traumatic injuries evacuated by US Air Force Critical Care Air Transport Teams between 2007 and 2020. Of these, 114 patients (14 percent) were flown with cabin altitude restrictions (CAR) and 723 (86 percent) without.

Patients in the CAR group were more likely to have penetrating injuries and required more chest tube management. In the non-CAR group, hypoxemia rates rose from 10 percent before flight to 18.1 percent in-flight. Mortality across all patients was 2.4 percent.

Median time on a ventilator was five days, ICU stay was eight days, and hospitalization lasted 25 days. These measures did not differ significantly between CAR and non-CAR groups. However, non-CAR patients with in-flight hypoxemia spent longer on ventilators and in the ICU than those without.

The authors concluded that while CAR did not change overall outcomes, it may mitigate the risks of hypoxemia. They advised in-theatre medical providers to consider CAR for selected trauma patients.