Medical support to 120 m heliox saturation 150 m excursion diving at sea

Objective To investigate the changes in the function of the vital organs of the body,their adaptability and performance in the saturation diving environment at sea,and test the medical support profile for saturation excursion diving.Methods According to the predetermined medical support profile,8 divers performed deep saturation excursion dives at sea using home made deep saturation diving systems and Heliox 18b diving equipment.The experiment was divided into 3 stages:(1) diver selection training and material preparation;(2) air and heliox bell bounce diving in waters from shallow to deep;and (3) real 120 m heliox saturation 150 m excursion diving.The saturation compression speed was 1 m/min,the stop time for each 10 m increment was 2 min,and that at 60 m was 20 min.The main environmental parameters at saturation depth were as follows:chamber pressure 1.3 MPa,PO\-2 40 kPa,PCO\-21 kPa,PN\-2140 kPa,and PHe 1.12 MPa;chamber temperature:(30±1) ℃ and relative humidity:50%~70%.The breathing gas was 7%O\-2 and 93% He mixture in excursion diving.For saturation decompression,each 5 m was a stop and with the decrease of depth the stop time was increased.Bubble sound in the precardiac region was monitored with Doppler monitor on decompression.During different stages of diving,EEG,ECG,EGG,pulmonary function,neuromotor function,and the biochemical and immunological indices of blood and urine were monitored and clinical observations were made.Results The divers stayed in the 120 m heliox environment for 64 hours and performed 9 (20 men times)excursions using a diving bell at depths from 144 to 149 m.They were decompressed for 131 hours and exposed to pressure for a total of 198 hours.There occurred 3 cases of hyperbaric arthralgia,1 case of upper respiratory infection and constipation,and a number of cases of mild skin inflammation and external auditory meatus infection.Index measurement and clinical observation showed the environment as in this study had produced no significant effects on the body.It presented a good adaptability and performance.Conclusions The medical support profile was feasible and safe.