Aeromedical evacuation of patients with pneumocephalus: Outcomes in 21 cases

Introduction: Aeromedical evacuation of patients with posttraumatic and/or post-surgical pneumocephalus has often been regarded with great concern. The expansion of intracranial air with increasing altitude can theoretically result in tension pneumocephalus, with potentially fatal results. This concern is primarily based on extremely rare case reports and theoretical models rather than any significant clinical experience. We report the outcomes of a series of 21 patients with posttraumatic and/or post-craniotomy pneumocephalus who underwent long-range air evacuation from a combat theater in military aircraft. Methods: The estimated volume for each patient was calculated with a simplified method, purposely intended to err toward overestimation, based on computerized tomography scans performed within 24 h prior to air travel. Results: The volumes of pneumocephalus ranged from 0.6 to 42.7 ml, with mean volume of 9.3 ml and median volume of 4.2 ml. No patient sustained a temporary or permanent neurologic decline as a result of air transportation. Three patients with continuous monitoring of intracranial pressure (ICP) were not observed to have any sustained pressure elevations during flight. Discussion: We conclude that pneumocephalus in the head-injured and/or craniotomy patient is not likely by itself to be an absolute contra indication to air evacuation. The mechanism causing pneumocephalus, its time course, progression, and the rate of altitude change are likely more important factors in determining its clinical significance. More clinical experience is required to better assess the safety of aeromedical evacuation of these patients, but this small series suggests that it is not as dangerous as previously thought.