Phenytoin loading in chronic alcoholic patients.

Controversy exists concerning the appropriate loading dose of phenytoin in chronic alcoholic patients. Chronic alcoholics are frequently assumed to have low albumin levels secondary to malnutrition and liver disease. Phenytoin is bound to albumin, and therefore the usual loading dose of phenytoin might result in a higher percentage of unbound drug and increased toxicity in these patients. Thirty-six chronic alcoholic patients were given a 15-mg/kg loading dose of phenytoin by constant intravenous infusion. After the infusion, patients were evaluated for clinical signs of phenytoin toxicity. At 1 hour after infusion, blood was sent for determination of total phenytoin, free phenytoin, and albumin levels. Fifteen patients were hypoalbuminemic (mean, 3.4 g/dL); 21 patients had albumin levels within the normal range (mean, 4.3 g/dL). In the hypoalbuminemic group, the mean free phenytoin level was 1.1 micrograms/mL, and the mean total phenytoin level was 13.6 micrograms/mL. In patients with normal albumin levels, the mean free phenytoin level was 1.3 micrograms/mL, and the mean total phenytoin level was 15.7 micrograms/mL. There were no statistically significant differences in total phenytoin or free phenytoin levels between either groups. No patient had a postinfusion phenytoin level (either free or total) within the toxic range. Although our sample size was small, our results suggest that a 15-mg/kg loading dose of phenytoin does not produce toxic levels in chronic alcoholics.

Blood flow in the cerebral cortex during cardiac resuscitation in dogs.

Regional cerebral cortical blood flow (rCCBF) in 15 large dogs was determined using the double thermistor dilution method during standard closed-chest massage (CCM), CCM with an epinephrine infusion at 30 micrograms/kg/min (CCM + Epi), and open-chest cardiac massage (OCCM). As a percentage of prearrest flow values, the rCCBF was 9.8% with CCM, 35% with CCM + Epi, and 156% with OCCM. The rCCBF was reduced significantly with CCM (P less than .005) and CCM + Epi (P less than .01). OCCM generated flows indistinguishable from prearrest values. The use of high-dose epinephrine significantly increased the rCCBF during CCM. The implications for intact neurologic resuscitation of these reductions in rCCBF with CCM are important.