Does the time course of bubble evolution explain decompression sickness risk?
A probabilistic model of decompression sickness (DCS) risk based on linear-exponential (LE) kinetics has given the best fit of the human air and nitrox DCS database. To test the hypothesis that its success may be due to the formation of a gas phase during decompression, we developed a physiologically based bubble evolution model using a numerical solution of a partial differential equation system. Because of the computational intensity of this method, it could not be used to fully explore our hypothesis. Consequently, we compared the solution with that of a computationally simpler approximation that was previously published by Van Liew and found the two approaches gave similar results. Using the simpler model, assuming bubble densities of 1 and 1,000 bubbles/cm3, we found a tissue time constant of at least 80 min (equivalent to perfusion of 1/80 ml.g-1.min-1) was required to achieve a delay in bubble dissolution comparable to the prolonged risk of DCS predicted by the LE model. We suggest that the persistence of single bubbles in a uniformly perfused homogeneous tissue alone is unlikely to explain persistent DCS risk.
Ball
R
R
Naval Medical Research Institute, Bethesda, Maryland 20889-5607, USA.
Himm
J
J
Homer
L D
LD
Thalmann
E D
ED
D001783:Blood Flow Velocity; D003665:Decompression Sickness / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D004058:Diffusion; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D005741:Noble Gases / Q000493:pharmacokinetics*; D018570:Risk Assessment; D013997:Time Factors
D005741:Noble Gases