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Decrease in platelet count during saturation diving
H Domoto1, K Nakabayashi, A Hashimoto
1Japan Maritime Self-Defense Force Undersea Medical Center, Yokosuka, Kanagawa. hdomoto@biochem.swmed.edu
Background:
The change in platelet count (PC) occurring during saturation diving has rarely been discussed. We set out to clarify the details of this change in PC, and its relationship with: i) the storage depth and duration of the saturation dive, and ii) the presence of decompression bubbles.
Methods:
In a total of 42 divers, the change in PC was measured in 8 simulated saturation dives (1992-1998) using a Deep Diving Simulator with decompression procedures based on the modified DUKE-GKSS schedule. Blood samples were taken before the dive, at the bottom (twice), during decompression, on surfacing, and about 1 wk after surfacing. Decompression bubbles were examined by ultrasonic M-mode echocardiography.
Results:
PC (mean +/- SD x 10(4) x microl(-1)) was 23.9 +/- 4.85, 24.9 +/- 4.9, 24.2 +/- 4.8, 19.2 +/- 4.4*, 20.1 +/- 4.5*, 25.0 +/- 5.1 on the occasions listed above (*= p < 0.05 vs. pre-dive). The PC showed no correlation with either storage depth or dive duration. Decompression bubbles were detected during decompression in only 2 divers (4.8%), and the bubbles disappeared immediately after surfacing. In these 2 divers the decreases in PC values from baseline to the middle of decompression and on surfacing were 2 and 2.7 x 10(4) x microl(-1), and 3.4 and 1.7 x 10(4) x microl(-1) respectively. No diver complained of decompression sickness.
Conclusion:
The magnitude of the decrease in PC (< 5 x 10(4) x microl(-1)) and the time to recover to the pre-dive value (< 1 wk) suggests that changes in PC during saturation diving should not cause any clinical problems. The mechanisms underlying the decrease in PC remain unclear.