Transcranial Doppler ultrasonography with induction of anesthesia and neuromuscular blockade in surgical patients

Study Objectives: To evaluate the cerebral vascular effects of cis-atracurium and rocuronium given after thiopental induction of anesthesia. Design: Randomized, single-blinded study. Setting: University-affiliated hospital Patients: 39 adult ASA physical status I and II patients undergoing nonintracranial procedures. Interventions: Patients received intravenously (IV), either saline placebo, cis-atracurium, or rocuronium after induction of general anesthesia with thiopental sodium. Measurements: The right middle cerebral artery was insonated using a pulsed-wave range-gated transcranial Doppler, and data were recorded at preinduction, immediately postinduction, at injection of the study drug, and at 15-second intervals for 3 minutes thereafter. The variables recorded for each subject included the systolic, diastolic, and mean flow velocity, as well as pulsality index, systolic, diastolic, and mean arterial blood pressure (MAP), and end-tidal carbon dioxide concentration. Main Results: No significant differences between the groups were present in the postanesthetic induction maximal or minimal mean flow velocity. Conclusions: cis-Atracurium and rocuronium, administered after thiopental, do not produce clinically relevant changes in cerebral blood flow velocity.