Acid-Base Balance in Cerebrospinal Fluid

Introduction  ALTHOUGH delirium, reduced consciousness, and abnormal motor function frequently accompany systemic acid-base disorders, the mechanisms producing these symptoms are unknown. Blood pH and other serum acid-base variables usually correlate poorly with the neurological symptoms. Therefore, several laboratories, including our own, have recently investigated the cerebrospinal fluid (CSF) acidbase balance in systemic disorders. Since these data have not previously been discussed in the neurological literature and since no previous report has attempted to correlate CSF acid-base balance with neurological function, the entire field is reviewed here in some detail. Preliminary reports of some of our material have appeared in abstract form.^1,2The CSF pH depends almost entirely on its carbon dioxide-bicarbonate ratio (CO₂/HCO-₃) and contains so little protein that its buffering capacity resembles a 20 millimolar (mM) bicarbonate solution. Foa,³ in 1906, first measured the CSF pH electrometrically and obtained in dog a value of