Direct ascent from shallow air saturation exposures.
Thirty-four healthy human subjects were exposed to shallow air saturation for 48 h [1.77 ATA (25.5 fsw) n = 19, 1.89 ATA (29.5 fsw) n = 15] and then decompressed to 1 ATA (0 fsw) in about 2 min. Symptoms included fatigue, limb and joint pain, headache, myalgias, and pruritus. No subject of 19 was diagnosed as having decompression sickness (DCS) after the shallower exposure, but 4 of 15 were diagnosed and treated for DCS subsequent to the deeper exposure. Almost all subjects in both groups had Doppler-detectable venous gas emboli (VGE) lasting up to 12 h postdecompression. Treated subjects had a recurrence of VGE several hours after the hyperbaric oxygen treatment. Only the duration of VGE, and not the VGE score, correlated with symptoms; and only the subjects body weight and age correlated with the VGE variables. This study indicates that hyperbaric air exposures of this magnitude are not as benign as previously thought.
D000328:Adult; D001835:Body Weight; D003665:Decompression Sickness / Q000503:physiopathology / Q000628:therapy*; D004618:Embolism, Air / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D006931:Hyperbaric Oxygenation; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014463:Ultrasonography; D014680:Veins / Q000503:physiopathology