The Use of Hypoxic and Carbon Dioxide Sensitivity Tests of Predict the Incidence and Severity of Acute Mountain Sickness in Soldiers Exposed to an Elevation of 3800 Meters

Abstract

OCT 2 2 i9 . 'ii 91-13717UNITED STATES ARMY MEDICAL RESEARCH & DEVELOPMENT COMMANDThe findings in this report are not to be construed as an official Department of the Army positi'n, unless so designated by other authorized documents. DISPOSITION INSTRUCTIONSDestroy this report when no longer needed.Do not return to the originator. THE USE OF HYPOXIC AND CARBON DIOXIDE SENSITIVITY TESTS TO PREDICT THE INCIDENCE AND SEVERITY OF ACUTE MOUNTAIN SICKNESS IN SOLDIERS EXPOSED TO AN ELEVATION OF 3800 METERS.Charles Do., 'eso.:-se -.0,-C:"i t-e to, tf ,ew~nq mst C 'C 0 sea0 at p .-0 :f-g adt 'e.edc a' nc Approved for public release; distribution unlimited. N13x,rr_;-m200wor,ià clute mountain sickness (AMS) is characterized by headache, nausea, and dizzines with individual differences occurring susceptibility. At any altitude, there will'be individuals who will show little or no symptoms while others will be severely incapacitated. Previous studies have shown that individuals with no symptoms of AMS tend to ventilate more than those who develop severe symptomis. The main objective of this study was to determine if susceptibility to AM5 can be predlicted from ventilatory responses to breathing hypoxic and carbon dioxi de ĩ as mixtures for 7-10 minutes prior to an altitude exposure. Another obJqctive was to determine 1q there was a difference between cigarette smokers and nonsmokers in susceptibility. Fortyseven soldiers (25 smokers and 22 nonsmokers) performed an isocapnic hp oxic ventilator,' response (HVR) test and a hypercapnic ventilatory response IHCVR test at F Riley, KS (450 mgrnor to being deployed to the Santa Lucia Base Camp, Potosi Bolivia (3500 to 4050 in). AM symptoms were assessed in Bolivia by the self-administered Environmental Symptoms Questionnaire during the first two days of exposure. Eighteen of 47 soldiers (38%) developec AMS. There was no relationship between either of the ventilatory tests and4 the subsequenm development of AM S regardless of smoking history. The results suggest that the use of the HVR and HCVR tests to preselect individuals who will develop AMS at moderate altitudes is no: warranted. It was also found that there was no difference in the incidence rate (40% vs 36%) or sev~ity of AMS batween smokers and nonsmokers. FC-90) of approximately 450 U.S. soldiers and marines were exposed to altitudes ranging from 3500 to 4050 m for nearly rive months on the Andean altiplano, in the vicinity of Potosi, Bolivia, South America to participate in a large construction project. The Task Force consisted principally of engineers and road builders assembled from Ft. Riley, KS and represented the largest commitment of U.S. troops ever exposed to such high altitudes during peacetime or war. The troops conducted an operational scenario comparable to one usually conducted under sea-level conditions. Therefore, a unique opportunity existed to study the incidence and severity of altituderelated illnesses, decrements in physical and mental performance, and changes in dietary habits. The 450 army and m...