Cardiovascular stability during carotid endarterectomy: endotracheal intubation versus laryngeal mask airway

To compare cardiovascular stability during carotid endarterectomy in groups managed either with laryngeal mask airway (LMA) or endotracheal intubation.

Randomized, retrospective, blinded study.

Teaching hospital.

61 ASA physical status II, III, and IV unpremedicated adult males scheduled for carotid endarterectomy.

Following standardized anesthetic technique, including intravenous (i.v.) induction with thiopental sodium 3 to 4 mg/kg, fentanyl 2 to 3 microg/kg), and isoflurane, standard intraoperative cardiovascular monitoring plus direct arterial blood pressure measurements were instituted. Patients were randomly assigned to an endotracheal intubation or LMA group.

Distinct intraoperative episodes of +/- 25% increase or decrease of mean arterial blood pressure (MABP) and heart rate (HR) when compared with preinduction baseline values, and the number of such episodes requiring interventional therapy were recorded from a blinded anesthesia record retrospectively. Mean end-tidal isoflurane determination and total case duration enabled calculation of minimum alveolar concentration (MAC) hours of isoflurane administered. The LMA group had a significantly (p < 0.05) lower incidence of increased MABP and HR episodes and such episodes requiring drug therapy than did the endotracheal intubation group. No difference was found in the length of surgery, mean end-tidal isoflurane concentration, or the total number of MAC hours of isoflurane administered.

During carotid endarterectomy, a reduced incidence of hypertensive and tachycardic episodes, as well as such episodes requiring interventional drug therapy, was found in the group whose airway is managed by LMA when compared with endotracheal intubation.