[Comparative study of decompression-induced formation of gas bubbles using ultrasonic equipment and the development...

442 altitude experiments on 40 volunteers were performed. Gas bubbles in venous blood were detected using an ultrasonic Doppler system functioning in a continuous mode at a frequency of 5 MHz. The threshold of bubble formation was identified in 31 test subjects and that of emergency of altitude-decompression disorders, in 28 test subjects. Individual resistance to decompression-induced bubbles was revealed. It was shown that the thresholds may vary with time, in the head-down position and in the head-down position combined with exercises. A correlation was established between the rate of intravascular bubble formation and the frequency of altitude-decompression disorders.