Cerebrospinal fluid composition during endotoxin shock in the dog.

Cerebrospinal fluid (CSF) electrolytes, lactate, pyruvate, total proteins, and osmolality, together with arterial plasma electrolytes, total proteins, osmolarity, and systemic arterial blood pressure were monitored during 2 mg/kg and 5 mg/kg E coli endotoxin shock in spontaneously breathing dogs. During four hours of shock, Na+, K+ osmolarity, and total proteins did not change in either plasma or CSF. CSF lactate and lactate/pyruvate ratio were significantly elevated, whereas pyruvate was decreased throughout the four hours of shock. Systemic arterial blood pressure was below control during the entire shock period. Saline control experiments yielded no significant changes in all parameters monitored. These data show that during four hours of shock the brain has shifted form aerobic to anaerobic metabolism the degree of which is not sufficient to cause any detectable changes in membrane permeability or alterations in Na+/K+ active processes.