Nitrogen output and bubbles formation during decompression after denitrogenation in rabbits

    WU Yanª²Hong1, SUN Xiª²Qing1, WANG Yongª²Chun1, ZHANG Shu1, NI Heª²Ying1, QUAN Haiª²Xi2

    1Department of Aerospace & Aviation Biodynamics, School of Aerospace & Aviation Medicine, Fourth Military Medical University, Xi¬ðan 710033, China, 2Institute of Diving Physiology, Shanghai Jiaotong University, Shanghai 200030, China

    ¡¾Abstract¡¿AIM: To analyse quantitatively the efficiency of nitrogen elimination at different denitrogenation time. METHODS: Twentyª²four rabbits were randomly divided into control group, denitrogenation 30, 60 and 120 min groups. The rabbits were anesthetized and ventilated by mechanical ventilator. After 0, 30, 60 and 120 min of denitrogenation, the rabbits were exposed to 11000 m for 30 min. The nitrogen output was analysed by chromatography and the gas bubbles generated in the body of rabbits were monitored by Doppler ultrasound method. RESULTS: The nitrogen concentration and nitrogen output decreased sharply (approximately 93%) in the first 5 min of denitrogenation, then decreased gradually with the prolonged denitrogenation time. Accumulative number of bubbles decreased with the elapse of denitrogenation time. Accumulative number of bubbles was negatively correlated with denitrogenation time (P<0.01). As compared with the control group, accumulative number of bubbles decreased significantly in denitrogenation 60 and 120 min groups. CONCLUSION: The nitrogen output decreases sharply at first and then gradually. Denitrogenation for 60 and 120 min may reduce gas babbles during decompression in rabbits. ......