Abstract ID: A20
Abstract Title: The use of dexmedetomidine for hemodynamic stability during awake carotid endarterectomy
Poster Type: Poster
ABSTRACT BODY
Introduction:Carotid endarterectomy for the prevention of stroke is performed in awake patients under regional anesthesia to enable the surgeon and the anesthetist to use the patient as monitor of cerebral ischemia. Current sedatives such as fentanyl and midazolam have side-effects which include respiratory depression, drowsiness and nausea. Dexmedetomidine, an intravenously titratable, selective a2-agonist, does not have these side-effects, and also has potentially beneficial analgesic and hemodynamic stabilizing properties.
Materials and Methods: Following institutional ethics committee approval, we performed a randomized, double blinded, controlled trial assessing the hemodynamic profiles of patients undergoing awake carotid endarterectomies using dexmedetomidine or a fentanyl/midazolam combination for sedation. 56 patients scheduled for carotid-endarterectomy under deep and superficial cervical plexus blocks were randomized to sedation using either a dexmedetomidine infusion, or a combination of fentanyl and midazolam given as intermittent bolus injections. Sedation was titrated to a Ramsay Sedation Score (RSS) of 2 to 4. Hemodynamic stability was assessed by the number of pharmacological interventions required to treat heart rates and/or blood pressures outside of a predetermined range. Secondary outcomes included quality of operating conditions, pain and sedation scores during surgery, recovery room hemodynamics and analgesic requirements, patient satisfaction surveys and perioperative cardiac and neurological events
Results:There was no difference between groups in terms of the total number of hemodynamic interventions. However, fewer patients in the dexmedetomidine group required treatment for intra-operative tachycardia or hypertension (p = 0.03). There was a trend toward patients in the dexmedetomidine group requiring more interventions for treatment of hypotension and bradycardia however this was not statistically significant. In recovery, patients in the dexmedetomidine group had significantly lower heart rates and blood pressures for up to 50 min post procedure, and fewer patients in the dexmedetomidine group required morphine for analgesia. There was no difference in the rate of carotid artery shunting, and there were no differences in overall patient satisfaction, cardiac or neurological outcomes.
Discussion: This study shows that dexmedetomidine used as an infusion during awake carotid endarterectomy reduces the incidence of perioperative hypertension and tachycardia whilst maintaining similar levels of sedation to a conventional sedation regime using fentanyl and midazolam. Previous studies using dexmedetomidine for awake carotid endarterectomy have reported trends toward higher rates of carotid artery shunting during surgery raising concern that the potential for dexmedetomidine to reduce cerebral blood flow may have influenced this outcome. Whilst underpowered to detect a difference, this trend was not apparent in our study.
ATTACHED FILES
Reg Anesth Pain Med 2004; 29(2):A20