Decrease in platelet count during saturation diving.
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.


CONCLUSIONS
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.
Domoto
H
H
Japan Maritime Self-Defense Force Undersea Medical Center,  Yokosuka, Kanagawa. hdomoto@biochem.swmed.edu
Nakabayashi
K
K
Hashimoto
A
A
Suzuki
S
S
Kitamura
T
T
D000328:Adult; D000704:Analysis of Variance; D002470:Cell Survival / Q000502:physiology; D003665:Decompression Sickness / Q000097:blood / Q000175:diagnosis*; D004242:Diving / Q000502:physiology*; D004562:Electrocardiography; D006801:Humans; D010976:Platelet Count