Suffocation in motor vehicle crashes.

Because death from suffocation in traffic fatalities has not been well described, we delineated the clinical, circumstantial, and autopsy findings associated with suffocation in a series of motor vehicle crashes. Medical examiner case files from a 5-year period were reviewed. Scene investigation, autopsy, toxicology, and first-responder reports were examined. Crash descriptions were reviewed, including vehicle type, mechanism of crash, response time, restraint use, occupant ejection, and victim position in cabins of vehicles. Mechanisms of suffocation, including torso compression, inversion, neck flexion, facial occlusion, and blood aspiration, were determined for each case. The files were searched for factors relevant to the diagnosis of suffocation, namely, cerebral concussion, alcohol intoxication, obesity, petechiae, lung weights as a proxy for livor, natural disease, and impact wounds. Twenty-nine traffic fatality cases were identified in which suffocation caused death. In 26, suffocation mechanisms were solely responsible for death. In 3, death was caused by suffocation in combination with other mechanisms. Twenty-five subjects were occupants of vehicles with cabins and 4 were motorcycle riders. The most common mechanism of suffocation was torso compression. Most subjects had either multiple mechanisms of suffocation or a single mechanism acting in concert with concussion or alcohol intoxication. Concussion and intoxication were common, with one or both present in 20 subjects, including all of those with blood aspiration. Petechiae were frequent but were found consistently only among those with inversion. Cutaneous chest petechiae were associated with inversion and torso compression. Lung weights were highest among those with blood aspiration and lowest among those with inversion. Body mass index was highest among those with inversion, suggesting that obesity could be a risk factor for this mechanism.