Decompression Bubbles in Caisson Workers

A total of 152 precordial detections of decompression bubbles was carried out in 91 caisson workers with the Doppler Ultrasonic Bubble Detector. The results were as follows: 1) Most of the bubble signals appeared and attained to their maximum grade within 60 minutes after decompression. 2) The appearance or increase of blood bubbles was accelerated by clenching the fist or raising arms above the shoulder height. Many workers, however, dislike these movements for fear of suffering from decomperession sickness. 3) Of 152 detections, bubble signals were heard in 88 (58%). They were heard in all cases of decompression sickness which requires treatment (13 bends and 3 chokes). On the other hand, 48 cases with bubble signals were asymptomatic. 4) The occurrence and grade of decompression bubble signals at successive jobs seemed to depend on the decompression schedules.