A SIMPLE EMERGENCY UNDERWATER BREATHING AID FOR HELICOPTER ESCAPE

Experiments were undertaken to determine whether ct simple rebreathing system, termed ''Air Pocket'' (AP), could, when integrated into an im mersion dry suit, extend the underwater survival time of individuals w hen compared with their maximum breath hold time (BHTmax), Eight naive healthy merle subjects undertook ct series of resting submersions and simulated simple helicopter underwater escapes in water 25 degrees C and 10 degrees C, During the submersions the subjects breath-held maxi mally and then rebreathed using an otherwise empty AP. The BHTmax time s of subjects and the total time they could remain underwater (RBT) we re recorded, The results showed that the ability to rebreathe followin g a BHTmax extended the time all subjects could remain submerged, rest ing or exercising, in cold water by ct factor of at least two, The ave rage BHTmax during simulated helicopter underwater escapes in the cold water was 17.2 s., It is concluded that the ability of subjects to re breathe immediately following maximum breath holding extends the time they can remain submerged in cold water to as much as 60 s, Further, i f used unprimed, a simple rebreathing system will not introduce any ad ditional dangers such as a pulmonary over-pressure accident.