The clinical assessment of acute mountain sickness.

During three expeditions to high altitude the Birmingham Medical Research Expeditionary Society has studied the effects of the ascents on its members. The severity of acute mountain sickness (AMS) produced was assessed by three methods, interview, self assessment and peer review. Physical examination was unhelpful. The results of the three methods were closely correlated. Clinical interview permitted allowances to be made for individual factors such as fatigue. There was no tendency for self assessment to indicate effects consistently more or less than the other methods. Peer review revealed a wide spread of opinions but the large number of observers allowed the derivation of plausible mean values. Correlation of AMS with arterial pH and PaCO2 showed little relationship but correlation with PaO2 was good, particularly for self assessment. As all the methods are subjective a combination of techniques is recommended for future expeditions.