QT interval and QT dispersion during the induction of anaesthesia in patients with subarachnoid haemorrhage: a comparison of thiopental and propofol

Background and objective: Thiopental prolongs the QT interval more than propofol, and the two induction agents were compared in patients with subarachnoid haemorrhage predisposed to electrocardiographic abnormalities and cardiac dysrhythmias. Methods: Twenty-nine patients were studied randomly. Anaesthesia was induced with either thiopental or propofol and fentanyl; vecuronium was used as a neuromuscular blocking agent. The electrocardiogram and arterial blood pressure were monitored from before the induction of anaesthesia to 2 min after endotracheal intubation. Results: The median QT interval was at baseline 423 ms in the thiopental group and at 432 ms in the propofol group, and it increased in the thiopental group to 446 ms and decreased in the propofol group to 425 ms (P < 0.01 between groups). After induction and endotracheal intubation, the number of patients with increased QT dispersion was greater in the propofol group (P < 0.05). The incidence of cardiac dysrhythmias was similar in the study groups. Conclusions: Thiopental and propofol are equally suitable for the induction of anaesthesia in patients with subarachnoid haemorrhage.