Relationship between pressure-reduction magnitude and stop time during stage decompression
Berghage, T.E.; Goehring, G.S.; Dyson, C.V.
Undersea Biomedical Research 5(2): 119-128
1978
ISSN/ISBN: 0093-5387 PMID: 675877 Document Number: 136095
Stage decompression was investigated to learn whether the amount of time spent at the 1st stop is independent of the magnitude of the initial pressure reduction. The effects of 3 different stop times (5, 40 and 120 min) and 5 different pressure reductions (3, 6, 9, 12 and 15 atm) were explored in a 3 .times. 5 factorial design using 375 female albino rats. A 2-step, single-stage decompression was initiated after a saturation exposure at 30 ATA . The 2nd step of the decompression was varied to establish a dose-response curve from which a 50% bends point could be extracted. Data analysis and subsequent inferences are based on these ED50 points. The greater the initial pressure reduction the smaller the possible subsequent pressure reduction. The decompression stop time required to reestablish equilibrium after a pressure reduction was 10 times longer than that needed to reestablish equilibrium after compression. There was an optimum decompression stop time that takes maximum advantage of the gas exchange rate. Short decompression stops were detrimental for further pressure reduction. A strong linear relationship existed between the optimum time spent at a decompression stop and the magnitude of the prior pressure reduction.