The quality of the wake-up test in patients undergoing corrective spinal surgery ( a comparison of two different anesthetic techniques)

Abstract

Background To apply the intraoperative wake-up test, the anesthetic regimen needs to enable rapid and smooth patient recovery, an immediate neurological examination, as well as adequate postoperative amnesia. In this study, we aimed to investigate two different anesthetic regimens (sevoflurane/dexmedetomidine vs. sevoflurane/fentanyl) in patients undergoing spinal surgery with respect of the quality and the profile of the wake-up test and postoperative recall. Patients and methods Forty patients (ASA II) aged between 18 and 60 years, undergoing corrective spinal surgery, were included in this single-blind randomized study. They were divided into two groups, both which were anesthetized using sevoflurane in O 2 /N 2 O: the first group (Dex group) was administered an intraoperative infusion of dexmedetomidine (1 μg/kg/h) for 10 min as a loading dose, which was then reduced to 0.5 μg/kg/h for up to 30 min before the wake-up test and then reduced to 0.1 μg/kg/h during the test; the second group (Fent group) was administered an intraoperative fentanyl infusion (2 μg/kg/h) for up to 30 min before the wake-up test; this was stopped during the test. Time from stoppage of anesthesia to spontaneous breathing (T1), time from return of spontaneous breathing to eye opening (T2), and time from eye opening to hand and feet movement (T3) were recorded in both groups. In addition, the quality of the wake-up test was evaluated on a three-point rank scale. Recovery and extubation times were recorded for the postoperative wake-up test. On the second day, postoperative recall was evaluated by assessing the memory for a given color during the test. Results T1, T2, and T3 in the Dex group (6.2±3.1, 3.6±2.2, and 1.1±1.2 min, respectively) were significantly shorter those in the Fent group (8.9±2.1, 5.7±3.2, 1.8±0.8 min, respectively). No significant difference was observed between the two groups in terms of the quality of the wake-up test. No patient of the Dex group could recall intraoperative events, whereas four patients of the Fent group could, two of whom could recall the color presented intraoperatively. Postoperative recovery and extubation were significantly faster in the Dex group than in the Fent group. Conclusion Sevoflurane/dexmedetomidine anesthesia can result in faster recovery and a higher degree of postoperative amnesia compared with sevoflurane/fentanyl anesthesia, as shown from the wake-up test performed during corrective spinal surgery.