Breath-holding ability of offshore workers inadequate to ensure escape from ditched helicopters

Background Following a helicopter ditching in water, the survival rate of i ndividuals not mortally injured by the impact ranges from 50-85%. One possi ble cause for this low survival rate is that the crew and passengers cannot hold their breath underwater long enough to make the often difficult escap e from an inverted and submerged helicopter. Methods: We investigated pulmo nary function, breath-holding times in air (BHTa) and water (BHTw) of 228 s tudents enrolled in offshore survival courses required to work in either th e offshore petroleum industry or in military marine aviation. Comparisons w ere performed based on occupation, SCUBA experience, and smoking. Results: In 25 degreesC pool water, the overall BHT. ranged from 5.4 to 120 s with a median of 37 s. Of the 228 subjects, 34% had a BHTw less than the 28 s req uired for the complete evacuation of a Super Puma helicopter under ideal co nditions. No significant differences in BHTw were observed based on either smoking history (Non-Smoker, 41.5 +/- 21.6 s; Smoker, 37.2 +/- 20.2 s) or o ccupation (Novice, 37.5 +/- 21.1 s; Offshore, 40.5 +/- 21.1 s; Military, 45 .2 +/- 20.9 s). However, SCUBA-trained individuals had a significantly long er BHTw (47.4 +/- 21.6 s) than non-SCUBA (37.6 +/- 20.6 s), as well as a gr eater force vital capacity (FVC), BHTa, and subjective comfort in water. Co nclusions: It is concluded that the inability to breath-hold in emergency s ituations is a major contributor to the low survival rates of marine helico pter ditchings. Therefore, efforts must be made to both decrease escape tim es and to increase survival time underwater.