Thiopental Treatment after Global Brain Ischemia in Pigtailed Monkeys

Abstract

The value of high-dose thiopental (TH) therapy after 16-min complete global brain ischemia (GBI) was studied in 3 groups of pigtailed monkeys, using a neck cuff model of GBI with 96 h intensive care postischemia (PI). Control group (18): Normotension was restored within 2 min PI; paralysis/controlled ventilation was maintained for 48 h PI with 50% N2O/O2. Thiopental loading group (13): Control treatment plus TH-loading with 90 mg/kg i.v. given from 5 to 65 min PI (mean peak TH plasma level 130 .mu.g/ml). Thiopental anesthesia group (14): Control treatment plus TH anesthesia with 90 mg/kg i.v. given over 12 h PI (sustained TH plasma levels of 25-35 .mu.g/ml and EEG burst suppression). Norepinephrine requirement for blood pressure control PI was greater in the TH groups than in the control group (P < 0.05). Lidocaine was needed for control of arrhythmias in the TH loading group. There was no significant difference in mortality or neurologic outcome between the groups. At 96 h PI 7 of 11 animals were awake in the control group, compared with 7 of 12 and 6 of 12 in the 2 TH groups. Neurologic deficit scores (NDS) for the survivors at 96 h PI were 23 .+-. 6% (mean) (10) in the control group, compared with 25 .+-. 9% (11) and 26 .+-. 12% (10) in the 2 TH groups (NDS 100% = brain death, 0% = normal). Seizures PI (in 1-2 of each group) were associated with worse neurologic deficits. At 96 h PI, all 3 groups had developed the same type and distribution of histologic lesions. No brain-damage-ameliorating effect of TH loading or TH anesthesia was demonstrated after 16 min GBI in pigtailed monkeys.