Lung function before and after oxygen diving: a randomized crossover study.
BACKGROUND
Breathing oxygen with a partial pressure of > 50 kPa can cause pulmonary oxygen toxicity (POT). Diffusing capacity for carbon monoxide (DL(CO)) is thought to be a more sensitive indicator of POT than vital capacity (VC). Because diffusing capacity can be measured more specifically using nitric oxide (DL(NO)), we hypothesized that DL(NO) is better able to monitor and exclude POT than DL(CO).


OBJECTIVE
To compare changes in lung function after oxygen and air dives which include measurement of DL(NO) and DL(CO).


METHODS
Eleven healthy male divers (mean age 27.5 +/- 3.1 years) made two immersed dives to 150 kPa for three hours on two separate days, during which they randomly breathed 100% oxygen or air. VC, DL(NO) and DL(CO) were measured six times during a 26-hour period on both days and on a third non-diving day.


RESULTS
There were no significant changes in DL(CO), DL(NO) or other diffusing capacity or spirometric parameters after either type of dive.


CONCLUSIONS
Lung function after a single three-hour oxygen dive at a pO2 of approximately 150 kPa is comparable to that after an air dive at the same depth and duration. This suggests that such an oxygen dive does not induce detectable signs of POT. Our hypothesis that DL(NO) is more sensitive than DL(CO) for detection of POT could not be tested because the oxygen exposure did not affect either parameter.
Diving Medical Centre, Royal Netherlands Navy. Pjam.v.ooij.01@mindef.nl
P J A M
PJ
van Ooij
R A
RA
van Hulst
A
A
Houtkooper
T J S
TJ
van der Weide
P J
PJ
Sterk
D000328:Adult; D000388:Air; D000704:Analysis of Variance; D002248:Carbon Monoxide / Q000378:metabolism; D002940:Circadian Rhythm / Q000502:physiology; D018592:Cross-Over Studies; D004242:Diving / Q000502:physiology*; D006801:Humans; D007101:Immersion; D008168:Lung / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009426:Netherlands; D009569:Nitric Oxide / Q000378:metabolism*; D010100:Oxygen / Q000009:adverse effects* / Q000378:metabolism; D010313:Partial Pressure; D011653:Pulmonary Diffusing Capacity / Q000502:physiology*; D018401:Sample Size; D013147:Spirometry; D013997:Time Factors; D014797:Vital Capacity / Q000502:physiology
D009569:Nitric Oxide; D002248:Carbon Monoxide; D010100:Oxygen