Abstract

Lumbar cerebrospinal fluid and arterial blood acid-base state were assessed in 19 patients within 24 hours of an acute cerebrovascular accident. Those with haemorrhage into the C.S.F. showed a lower C.S.F. pH and higher C.S.F. lactate than those without haemorrhage but the Pco₂, was similar in the two groups, suggesting that this greater C.S.F. acidity was not responsible for a greater degree of hyperventilation. In those without haemorrhage an inverse relation was found between C.S.F. pH and arterial Pco₂, suggesting that a non-chemical ventilatory drive—for example, due to central neurological damage—was responsible for the acid-base changes observed.