Effect of arterial blood pressure and serum glucose on brain intracellular pH, cerebral and cortical blood flow during status epilepticus in the white New Zealand rabbit

Generalized seizures can induce both hypertension and hyperglycemia which may aggravate preexisting cerebral or medical conditions in patients. In vivo fluorescent imaging of regional cortical blood flow and brain intracellular pH (pH_i) was performed in fasted New Zealand rabbits (n=35) in which either mean arterial blood pressure (MABP) or serum glucose was the covaried factor during pentylenetetrazole induced status epilepticus under 1.5% inspired halothane. Baseline brain pH_i and regional cortical blood flow were 7.02±0.02 and 51.1±1.7 ml/100 g/min, respectively. Following seizure induction, MABP increased to 105 mm Hg and brain pH_i fell to 6.79±0.03 within 15 min and remained at this level for 1 h (P<0.001). With normalization of MABP during ongoing seizures, there was no worsening in brain pH_i despite a significant decrease in regional cortical blood flow. Hyperglycemia decreased pH_i to 6.71±0.02 compared to 6.84±0.04 in normoglycemic animals (P<0.001). Using pH_i as a cerebral metabolic index, these data suggest that normalization of MABP does not increase metabolic injury while hyperglycemia does significantly worsen brain acidosis. Therefore, administration of glucose to patients with status epilepticus should be avoided unless there is documented hypoglycemia.