Thiopental Loading During Controlled Hypotension for Intracranial Aneurysm Surgery

In this study we report our clinical experience with supplementary thiopental loading, based on 30 patients undergoing surgery for intracranial aneurysm after a recent episode of subarachnoid haemorrhage. As standard procedure we used pentobarbitone induction, pancuronium relaxation, endotracheal intubation, maintenance with halothane 0.5%, N₂O 66% in oxygen, fentanyl, and moderate hypocapnia. A thiopental load of up to 20 mg.kg^-1 was supplied while the aneurysm was approached. Satisfactory and well-controlled hypotension was obtained in five cases after thiopental alone, and after thiopental and sodium nitroprusside (SNP) ( ± s.d.) 1.3 ± 0.9 μg-kg^-1-min^-1 in the remaining 25 patients. No ECG sign of myocardial ischaemia was observed. One disadvantage was a prolonged recovery period, which in some cases necessitated controlled ventilation for some hours. We conclude that thiopental loading can be used safely as a supplement to neuroanaesthesia for aneurysm surgery.