Pulmonary atelectasis formation during diving with closed-circuit oxygen breathing apparatus
Dahlbäck, G.O.; Balldin, U.I.
Undersea Biomedical Research 12(2): 129-137
1985
ISSN/ISBN: 0093-5387 PMID: 4071842 Document Number: 254372
The physiological effects of diving with 2 types of closed-circuit O2 breathing apparatus were investigated in 4 divers. In 1 apparatus the breathing bag was mounted on the dorsum and in the other on the chest, inducing -2 kPa [Pascal and +1 to +2KPa static lung load in the prone position, respectively. The back-mounted bag caused an unfavorable swimming position, with increased heart rate, breathing rate, and rating of perceived exertion (RPE) for work load. The greater internal and external work of breathing (the latter judged from the higher PRE for breathing resistance) probably contributed to a higher RPE for discomfort with the back-mounted bag. Three divers showed great reduction in vital capacity (VC) (0.8-1.9 l) and developed coughing attacks after dives with this apparatus; these results were interpreted as possible indications of altelectasis formation. The 4th diver showed slight reduction in VC with both types of bag, possibly because the changes in static lung loads did not influence the airway closure in this man.