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October 21, 2008
8:00 AM - 9:30 AM
Room Room 230C
Dexmedetomidine vs. Remifentanil for Sedation in Awake Intubations-A Randomized, Double-Blind Trial
Carin A. Hagberg, M.D., Nicholas C. Lam, M.D., Steven I. Abramson, M.D., Kash Vahdat, M.D., Jack Craig, M.D.
Anesthesiology, The University of Texas Medical School, Houston, Texas
Introduction: Dexmedetomidine (DEX), a centrally acting, selective alpha-2 agonist, with analgesic and sedation properties, has been successfully used for sedation in intensive care units. Remifentanil (REM), an ultra-short acting synthetic opioid, is often used to aid awake fiberoptic intubation (AFOI). As a narcotic, REM has a potential for respiratory depression, whereas DEX does not. This study compares the use of REM and DEX as adjuncts to local anesthetic preparation of the airway for AFOI.

Methods: Thirty adult ASA I-III patients with expected difficult airways were randomized to receive REM or DEX for sedation during AFOI. Operators and assessors were blinded to the drug used. Preoperatively, all patients received 2 mg midazolam intravenously and their airways were topicalized with 4% lidocaine. Patients in the REM group received a bolus of 0.75 mcg/kg over 10 minutes followed by an infusion of 0.075 mcg/kg/min. Patients in the DEX group received a bolus of 0.4 mcg/kg over 10 minutes followed by an infusion of 0.7 mcg/kg/hr. A word and picture set was presented to each patient before any drugs were administered, after loading of either sedative, and following extubation. Heart rate, blood pressure, respiratory rate, SpO2, bispectral (BIS) index level, and Ramsay sedation level (RSS) were recorded. Recall of each 3 sets of pictures and words was assessed at 30 minute intervals for a period of 3 hours after the completion of surgery.

Results: Patient demographics were similar between the 2 groups. All patients' airways were successfully secured by fiberoptic intubation. Seventy-six percent of REM cases were intubated on the first attempt, as compared to 38% of the DEX cases (p=0.02). Intubation attempts were greater in the DEX group even after adjusting for confounders (OR unadjusted = 5.26, 95% C.I. = 1.19, 25.72; OR adjusted = 4.84, 3.43, 6.82). The DEX group had a higher mean oxygen saturation rate than REM (1.58 higher; 95% C.I. = 0.14, 3.03; p=0.03). Although the incidence of O2 saturation < 90% was greater in the REM group, it was not significant. No apneic episodes occurred and no rescue maneuvers, such as administration of reversal drugs or positive pressure ventilation, were required in either group. There was a lower Ramsey Sedation Scale (RSS) score (lower by = 0.45, 95% C.I. = 0.1142, 0.7792; p=0.008) in the DEX group compared to the REM group. A Kaplan Meier survival analysis showed that DEX patients took longer to attain a RSS of 3 despite reaching a lower RSS score. (Logrank test = 4.00 with one degree of freedom, p=0.0455) The DEX group also had 6.99 lower (95% C.I. = 1.19, 12.79; p=0.018) BIS score compared to the REM group. Generalized estimating equations (xtgee) showed no significance in the recall results with the exception of verbal recall in the DEX group after the initial bolus. Minimal hemodynamic instability was observed in both groups.

Discussion: Both Dex and REM can be safely used as sedative agents for AFOI. Despite increased sedation and lower recall after the initial bolus, the DEX group required more attempts at intubation. Nonetheless, lower oxygen saturation was observed in the REM group.

Anesthesiology 2008; 109 A14