Volume 5, Issue 5 (May 2008)
Fainting Passengers: The Role of Cabin Environment
Reported percentages of in-flight medical incidents caused by syncope, the medical term for fainting, vary between 15 % and 22 %. Syncope is usually a benign medical event, but it may cause fear and distress among passengers and the individual involved. Incorrectly diagnosed benign syncope may lead to unnecessary flight diversions. In this context, the incidence of in-flight syncope and possible relationships with cabin environmental and passenger factors were studied. In September 2005, questionnaires were handed out to the senior purser on all KLM long haul flights. Pursers were asked to record all cases of in-flight syncope and to answer questions concerning cabin climate. Literature data were analyzed concerning in-flight and passenger factors that may cause or elicit syncope. With a response rate of 79 %, 1625 forms were analyzed. The in-flight syncope risk was 3–9 per 1000 passenger flight hours, depending on type of aircraft. The frequency of syncopal events was weakly correlated with cabin climate conditions. Literature analysis provides evidence that hypoxia is a sufficient cause for syncope in a sub-set of healthy airline passengers. There is evidence that cabin pressure and temperature may contribute to the occurrence of syncope. The syncope risk appears to be higher aboard an aircraft than on the ground. Hypoxia is a sufficient cause for syncope in a sub-set of healthy airline passengers. Airline passengers may become considerably hypoxic due to reduced pulmonary ventilation caused by immobility, drowsiness, and gastro-intestinal distension. In-flight hypoxia may reach levels sufficient to cause syncope. High cabin temperature may further trigger this reaction.