ALFENTANIL DECREASES THE EXCITATORY PHENOMENA OF SODIUM METHOHEXITAL

Study Objective: To evaluate the effects of alfentanil or lidocaine on the excitatory phenomena (myoclonus, cough, hiccough) caused by metho hexital anesthesia and on the hemodynamic changes induced by retrobulb ar block. Design: Prospective, randomized, placebo-controlled, double- blind study. Setting: University-affiliated, tertiary-care hospital. P atients: 60 ASA physical status II and III patients who were admitted for elective cataract extractions and intraocular lens implantations. Interventions: Patients were randomly assigned to one of three groups. After adequate preoxygenation in the holding area Group 1 received al fentanil 5 mu g/kg intravenously (IV), Group 2 received lidocaine 1 mg /kg IV, and Group 3 received the placebo (saline) IV. Immediately afte r the bolus injection of the study solution, sodium methohexital 1.5 m g/kg was injected IV over 30 seconds. As soon as the eyelid reflex was lost, the retrobulbar block was placed over 5 seconds. Measurements a nd Main Results: Occurrences of excitatory phenomena were recorded by an independent observer who was blinded as to treatment allocation. Ot her side effects such as oculocardiac reflex, nausea, vomiting, itchin g or chest wall rigidity were recorded. Vital signs were recorded at b aseline and 1, 3, and 5 minutes after placement of the block. In the a lfentanil group, the incidence of myoclonus or cough was significantly less than in the lidocaine or placebo groups, Alfentanil also decreas ed systolic and diastolic blood pressure significantly at 1, 3, and 5 minutes after retrobulbar block. Changes in heart rate were not signif icantly different from baseline. Conclusion: A small dose of alfentani l (5 mu g/kg IV) decreases myoclonus and cough induced by sodium metho hexital anesthesia IV, resulting in improved quality of induction of a nesthesia. Alfentanil also attenuates the cardiovascular responses cau sed by placement of a retrobulbar bled. (C) 1998 by Elsevier Science I nc.