Effectiveness and safety studies on the training program of rapid decompression at low altitude for pilot

Abstract

Objective To study the effectiveness and safety of pilot's rapid decompression (RD)training at low altitude. Methods According to sequential design methods, 187 male high performance fighter pilots were selected for RD and divided as Group A (93 pilots) and B (94 pilots),that with and without oxygen supply respectively. Each traning was for 2 pilots who were respectively from Group A and B. Training started from the climb to 2500 m with the rate of 30-40 m/s and stayed there 1-3 minutes for stabilizing heart rate (HR). RD was executed to 5500 m within 0. 48 s and returned to ground level by the rate of 10-20 m/s after plateau maintained for 1-2 min. Oxygen had no longer supplied while the altitude was lower than 4000 m in descend. The saturation of blood oxygen (SaO2), electrocardiogram (ECG) and peak value of pressure in lung were recorded during training.Pilots were examined by thoracic roentgenoscopy when training finished and completed a questionnaire that concerned about subjective experience and the evaluation of the effect of rapid decompression training. Results Observed SaO2 in Group A was about 99% when oxygen applied but significantly dropped as the supply stopped and finally gradually recovered. In Group B, SaO2 was decreased with the altitude. ECG analysis showed that pilots in both groups appeared growing HR before RD applied and respectively reached peak value at RD started (87. 87 ±15. 97) beats/min in Group A and (91. 29±2.78) beats/min in Group B. Then HR was significantly dropped in descend. The amplitude of lead Ⅱ T wave was significantly reduced as maximum HR appeared (0.19±0.11) mV in Group A and (0. 20±0.12) mV in Group B. During decompression the peak value of the pressure in lung was (139±11) mm H2O (1 mm H2O=9.8 Pa). No abnormity was observed by thoracic roentgenoscopy for both groups. Questionnaire analysis showed that all pilots admitted the reality of simulated RD and the effectiveness of judging the happening of RD in time. Conclusions The RD training program for pilots at low altitude is categorically safe and effective. Key words: Decompression ; Altitude ; Decompression sickness ; Aviation ; Evaluation studies ;