Fig. 1.

The high kurtosis curve shows that most patients had a normal pH of 7.4. This is because many were suffering from disease that did not compromise the acid–base status of blood. However, the incidence of a pH of 7.5 is also important since at high altitude hyperventilation is one of the fundamental compensation mechanisms for acute hypoxia. Metabolic (or rarely respiratory) acidosis is present and a result of disease that is of the same characteristics as at sea level