The Regularity Of Autonomic Nervous System Function Change During The Initial Phase At Acute High-altitude Exposure And Its Relationship With Acute Mountain Sickness

Background and Objectives:Acute mountain sickness (AMS) is very common during the initial phase (1-4 days) at acute high-altitude exposure. This disease is one of the crucial causes which attenuate the fighting stamina of our troops which quickly intrude into high-altitude area. Recent studies have shown autonomic nervous system (ANS) function demonstrates a nature of dynamic change during acute exposure to high altitude, and ANS dysfunction accompanies AMS. In order to elucidate the role of ANS in AMS and explore available clinic techniques to predict AMS, we investigated the dynamic change of ANS function during the initial phase at acute high-altitude exposure by advanced techniques and analyzed the relationship between ANS and AMS.Methods:1. Tibet field research99 healthy male soldiers rapidly ascended to 3675m altitude Tibet plateau by airplane from 560m chengdu plain. All subjects'ANS function were investigated at plain and 2～4 days at Tibet by heart rate variability (HRV), cold pressor test(CPT), resting heart rate (HR) and blood pressure (BP). AMS were evaluated by"principles of diagnosis and treatment of benign form of acute mountain sickness"(GJB1098-91) during the first 4 days at Tibet. According to the first day AMS symptomatic scores at Tibet, all subjects were divided into non-AMS group (55 subjects, AMS scores≤4)and AMS group(42 subjects,AMS scores>4).2. Simulated high altitude researchDuring March 2005, the hypobaric chamber provided by the high altitude military medicine department of Third Military Medical University was applied to simulate 4500 m altitude for 1 day. 43 healthy male soldiers'parameters including HRV, resting HR and BP were measured respectively before altitude and after 2h, 10h, 20h at simulated altitude. Other measurements including CPT, plasma concentration of noradrenaline (NA), adrena- line (ADR).All subjects were divided into mild AMS group (25 subjects, AMS scores≤10)...