CARDIOVASCULAR STABILITY DURING CAROTID ENDARTERECTOMY - ENDOTRACHEALINTUBATION VERSUS LARYNGEAL MASK AIRWAY

Study Objective: To compare cardiovascular stability during carotid en darterectomy in groups managed wither with laryngeal mask airway (LMA) or endotracheal intubation. Design: Randomized, retrospective, blinde d study. Setting: Teaching hospital. Patients: 61 ASA physical status II, III, and IV unpremedicated adults males scheduled for carotid enda rterectomy. Interventions: Following standardized anaesthetic techniqu e, including intravenous (IV) induction with thiopental sodium 3 to 4 mg/kg, fentanyl 2 to 3 mu g/kg), and isoflurane, standard intraoperati ve cardiovascular monitoring plus direct arterial blood pressure measu rements were instituted. Patients were randomly assigned to an endotra cheal intubation or LMA group. Measurements and Main Results: Distinct intraoperative episodes of +/-25% increase or decrease of mean arteri al blood pressure (MABP) and heart rate (HR) when compared with preind uction baseline values, and the number of such episodes requiring inte rventional therapy were recorded from a blinded anesthesia record retr ospectively. Mean end-tidal isoflurane determination and total case du ration enabled calculation of minimum alveolar concentration (MAC) hou rs of isoflurane administered. The LMA group had a significantly (p < 0.05) lower incidence of increased MABP and HR episodes and such episo des requiring drug therapy than did the endotracheal intubation group. No difference was found in the length of surgery, mean end-tidal isof lurane concentration, or the total number of MAC hours of isoflurane a dministered. Conclusions: During carotid endarterectomy, a reduced inc idence of hypertensive and tachycardiac episodes, as well as such epis odes requiring interventional drug therapy, was found in the group who se airway is managed by LMA when compared with endotracheal intubation . (C) 1998 by Elsevier Science Inc.