Pulmonary effects of submerged oxygen breathing: 4-, 6-, and 8-hour dives at 140 kPa
Shykoff, B.E.
Undersea and Hyperbaric Medicine Journal of the Undersea and Hyperbaric Medical Society Inc 32(5): 351-361
2005
ISSN/ISBN: 1066-2936 PMID: 16457084 Document Number: 589240
Elevated inspired oxygen partial pressures (PO2) may cause pulmonary oxygen toxicity (PO2T). However, normal variability and water immersion also cause pulmonary function (PF) changes. In 21 subjects, we measured the variability of flow-volume parameters and diffusing capacity for carbon monoxide (DLCO) for six weeks without diving. In 24 divers, we compared the effects of air (P(I)O2 = 0.3 atm = 30 kPa) and oxygen (P(I)O2 = 1.4 atm = 140 kPa) during paired resting dives of 4, 6, or 8 hours in a freshwater pool 4.6 m deep. Without diving, median coefficients of variation (CV) were: vital capacity, 3.2%; FEV1, 3.5%; peak flow, 7.0%; and DLCO, 5.9%. Measurements within 2.4.CV of baseline were considered unchanged. After 4-, 6-, and 8- hour air dives, PF decreased in one, one, and four subjects, respectively, and three, one, and two, respectively, reported symptoms. After the oxygen dives, PF decreased in two, three, and four subjects, respectively, and two, four, and seven, respectively, reported symptoms. PO2T persisted for several days after 8-hour oxygen dives.