Bubble formation and decompression sickness on direct ascent from shallow air saturation diving.
To find the minimum supersaturation pressure for detectable bubble formation and for contraction of decompression sickness (DCS), three shallow air saturation dives at the depth of 6 m, 7 m, and 8 m were performed. The ultrasonic M-mode method was used for detecting bubbles. The exposure period was 3 d for all dives. Ten subjects were compressed to both 6 m and 7 m, and nine subjects were compressed to 8 m. One bubble streak was shown in the 6-m dive group. A small number of bubbles were seen in four subjects in the 7-m dive. All subjects in the 8-m dive presented various amounts of bubbles. DCS was not observed in the 6-m and 7-m dives. On the other hand, in the 8-m dive, four subjects suffered from DCS and required recompression treatment. The minimum depth for detectable bubble formation was assessed at around 6 m and the direct ascent from saturation at 8 m seems to have a high risk of DCS.
Ikeda
T
T
Maritime Self-Defense Force, Undersea Medical Center, Yokosuka, Japan.
Okamoto
Y
Y
Hashimoto
A
A
D000328:Adult; D003665:Decompression Sickness; D004242:Diving; D004618:Embolism, Air / Q000000981:diagnostic imaging / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography