Glycerol has been used in
cerebral edema for hyperosmolar
dehydration of brain tissue, but only empirical relationships govern this use. Since the efficacy of treatment with
glycerol would likely increase with data on the relationship between
drug blood levels and intracranial pressure (ICP), we examined the clinical pharmacology of the
drug. Plasma samples were assayed for
glycerol by a new method using gas chromatography with a flame ionization detector. Data were collected from 12 children who were in Children's Hospital of Pittsburgh (CHP) and who had
cerebral edema of differing etiology that was treated with
glycerol; they were monitored by intraventricular
catheter.
Glycerol was infused according to CHP guidelines. ICP reduction correlated with
glycerol concentration and plasma concentrations of 1 to 3 mg/ml (10 to 30 mOsm/ml) were necessary to maintain an ICP below 20 torr. The relationship between osmolality and plasma
glycerol level was also examined; there was good correlation between the idiogenic osmolality and
drug concentration. Our studies support the clinical observations that relatively high doses of
glycerol (0.2 to 1.0 gm/kg/hr), leading to plasma concentrations of 10 to 30 mOsm/l, are necessary to control ICP in patients with
cerebral edema.
Glycerol blood levels may be estimated from serum osmolality.