'Defasciculation' with metocurine prevents succinylcholine-induced increases in intracranial pressure

Abstract

In order to determine whether a small, 'defasciculating' dose of metocurine could prevent increases in intracranial pressure (ICP) induced by succinylcholine (Sch), the authors studied 12 patients (ages 25-79 yr) undergoing craniotomy for excision of malignant supratentorial gliomas. After insertion of a subarachnoid bolt for ICP monitoring and a radial arterial cannula for determination of blood pressure and blood gas tensions, six patients (group I) were randomly allocated to receive MTC 0.03 mg/kg 3 min before induction of general anesthesia with thiopental 4 mg/kg and nitrous oxide 70% in O2. Six other patients (group II) received saline 0.015 ml/kg instead of MTC, followed by the same induction sequence. After induction of anesthesia, ventilation was controlled by mask (Pa(CO2) = 40 mmHg ± 2 SE), and arterial and intracranial pressures were allowed to stabilize. Four minutes after thiopental administration (7 min after MTC), after a 1-min period of relatively stable arterial pressure and ICP, Sch 1 mg/kg was administered as a bolus. ICP and blood pressure were recorded continuously until normal twitch tension was restored. In group I (MTC pretreatment), ICP did not change significantly from the mean value observed before Sch, 14 mmHg ± 2 SE. In group II (saline pretreatment), ICP increased from 11 mmHg ± 2 SE to 23 mmHg ± 4 SEE (P < .05). This study not only confirms previous work showing that Sch may induce marked ICP increases in lightly anesthetized patients with intracranial mass lesions, but also indicates that pretreatment with a 'defasciculating' dose of MTC can prevent these potentially deleterious ICP increases in patients known to be at risk.