Ascent rate, post-dive exercise, and decompression sickness in the rat.
The effects of ascent rate and post-dive exercise on the incidence of decompression sickness (DCS) were investigated in six groups of 20 rats exposed for 2 h at a pressure equivalent to 240 feet of sea water (fsw; 735 kPa). Ascent rates were 30, 45, and 60 fsw/min (92, 138, 184 kPa/min), and the rats either rested after the exposure or exercised by walking for 30 min on a treadmill at 1.6 m/min. Post-dive signs included respiratory distress, difficulty walking, paralysis, and death. DCS was scored as non-fatal at 30-min post-dive or fatal at any time. Analysis by ordinal logistic regression indicated more DCS with post-dive exercise (P = 0.0112) and at 45 (P = 0.0011) and 60 fsw/min (P = 0.0001) compared to 30 fsw/min. Survival analysis suggested earlier death at 60 fsw/min compared to 30 fsw/min (P = 0.0006). Similar effects have been reported for the less severe DCS that occurs in humans.
Pollard
G W
GW
Department of Physical Education, North Carolina State University, Raleigh, USA.
Marsh
P L
PL
Fife
C E
CE
Smith
L R
LR
Vann
R D
RD
D000818:Animals; D003664:Decompression; D003665:Decompression Sickness / Q000453:epidemiology* / Q000503:physiopathology; D004242:Diving / Q000502:physiology*; D015994:Incidence; D008297:Male; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011446:Prospective Studies; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis; D012120:Respiration Disorders / Q000503:physiopathology; D016019:Survival Analysis; D013997:Time Factors