低气压暴露对飞行员胃电图的影响

The effect of hypobaric pressure exposure on electrogastrogram of pilots

目的观察低气压暴露对飞行员胃电图(electrogastrogram,EGG)的影响。方法 25名参加改装体检的直升机飞行员坐于低压舱内,记录EGG 4 min,然后以20 m/s速度上升,分别在1000、2000、3000、4000 m处各停留10 min,并记录EGG 4 min,再以5 m/s速度下降返回地面,观察不同高度EGG的平均幅值、平均频率、平均节律紊乱百分比和正常慢波百分比等指标变化。结果低气压暴露对飞行员EGG的影响包括:①平均幅值总体呈现下降趋势,其中1000 m和3000 m高度EGG平均幅值为304.2μV和297.6μV,与地面EGG平均幅值357.7μV相比差异有统计学意义(t=2.69,2.42,P<0.05),但2例有轻度腹胀者表现为相反的平均幅值上升;②平均频率总体无明显变化,但2例有轻度腹胀者平均频率稍快;③平均节律紊乱百分比仅3000 m高度(24.3%)明显降低,与地面(28.2%)相比差异有统计学意义(t=3.23,P<0.01),但2例有轻度腹胀者反而增加;④正常慢波百分比总体呈现为无明显改变。结论 4000 m不同高度低气压暴露对飞行员EGG的影响差异较大,但对明显腹胀和腹痛者,EGG的平均幅值和平均节律紊乱百分比可能提供有价值的客观依据。如果在影响因素的控制方面做更深入细致的工作,有望将EGG作为高空胃肠胀气的客观评价指标。

Objective We aimed to study the effect of hypobaric pressure exposure on the electrogastrogram（EGG） of pilots. Methods A total of 25 helicopter pilots under physical examination for change to new-type of aircraft participated in this study.The examinees were seated in a hypobaric chamber and recorded with EGG for 4 minutes. They then ascended at a speed of 20 m/s,stayed at 1000,2000,3000,4000 m for 10 minutes respectively,and were recorded with EGG for 4 minutes at each stop. The pilots finally descended back to the ground at a speed of 5 m/s. Indices such as the average amplitude,frequency,percentage of dysrhythmia, percentage of normal slow waves,etc.at different heights were observed. Results The effects of hypobaric pressure exposure on pilots＇ EGG is as follows：①the average amplitude showed a overall trend of decrease with the increase of height,e.g,the average amplitudes at 1000 and 3000 m were 304.2 μV and 297.6 μV respectively,significantly lower than the average EGG on ground（357.7μV,t=2.69,2.42,P0.05）,though two pilots with mild abdominal distension showed the opposite,as average amplitudes increasing with ascent;②the average frequency generally did not change significantly,but the two cases with mild abdominal distension showed a slightly higher average frequency;③the average percentage of disrhythmia was significantly different only at 3000 m height（24.3%）,compared to that on ground（28.2%,t=3.23,P0.01）;however,the two pilots with mild abdominal distension showed increased average percentage of disrhythmia;④the average percentage of normal slow waves showed no significant changes in general. Conclusion The effect of hypobaric pressure exposure（at different heights toward 4000 m） on pilots＇ EGG varied;however,for pilots with obvious abdominal distension or pain,average amplitude and average percentage of dysrhythmia might provide valuable objective indication. With a more in-depth and meticulous work to control the inf luential factors,EGG indices might be used to objectively evaluate barometerism.