English summary: ASSESSMENT OF FITNESS TO FLY IN PEOPLE WITH RESPIRATORY DISEASE PLANNING AIR TRAVEL

There is concern that air flight may exacerbate hypoxaemia in patients with lung disease. The hypoxia challenge test is a pre-flight clinical procedure used to assess whether patients are fit to fly. It assumes that breathing hypoxic gas mixtures at sea level (normobaric hypoxia) equates to the hypobaric hypoxia of altitude. The maximum cabin altitude of 2438 m can be simulated at sea level with a gas mixture containing 15% oxygen in nitrogen. A subject is asked to breathe the hypoxic gas mixture for 20 minutes. Saturation is monitored throughout, and blood gas tensions measured before and on completion. In the years 2003-2007 we used this method to assess the fitness to fly of 35 patients suffering from lung disease. 9 patients were regarded as fit to fly while 24 patients and 2 ventilator dependent patients were recommended to use in-flight oxygen or their ventilator on board, respectively. From medical records we investigated retrospectively whether patients' planned air travel was completed and the given recommendations were followed. We conclude that in patients with lung diseases normal oxygen saturation measured at sea level frequently does not correlate to safe arterial oxygen saturation during air flight as assessed using the hypoxia challenge test. To enhance safety for passengers with pulmonary disorders travelling by air and to reduce the number of in-flight medical incidents due to respiratory disease, we recommend the hypoxia challenge test as a part of routine management of patients with serious lung and neuromuscular diseases planning air travel.