Effect of dexmedetomidine infusion on desflurane requirement and perioperative hemodynamic changes during laparoscopic gastric sleeve operations: a study based on entropy

Context Obese patients undergoing laparoscopic gastric sleeve operations are sensitive to the respiratory depressant effect of opioid analgesics. Alternative methods for analgesia may be beneficial for intraoperative management of those patients. Dexmedetomidine is a highly selective α2 agonist with anesthetic and analgesic sparing properties that makes it an adjuvant in general anesthesia. Aim The aim of this study was to assess the effect of intravenous administration of dexmedetomidine during laparoscopic gastric sleeve operations on desflurane requirements, perioperative hemodynamic changes, and also postoperative recovery. This study was based on entropy to monitor the depth of anesthesia. Patients and methods Eighty patients of American Society of Anesthesiologists II and III who were scheduled for laparoscopic gastric sleeve operations were randomly allocated to two groups of 40 patients each. Dexmedetomidine at a loading dose of 1 μg/kg was given over 10 min before anesthesia induction, followed by 0.5 μg/kg/h maintenance throughout the operation in group II, and saline (placebo) was given in group I at the same volume and rate. Routine induction with propofol, fentanyl, and cisatracurium was carried out. Anesthesia was maintained with desflurane that was adjusted to maintain adequate depth of general anesthesia with response entropy between 40 and 60 and a difference of less than 10 with the state entropy. Desflurane inspired fraction and desflurane expired fraction were monitored. Results End-tidal concentration of desflurane was significantly low at 15, 30, 45, and 60 min of operation. End-tidal concentration of desflurane decreased by 13.2–21.8% with the use of dexmedetomidine in comparison with group I. Systolic blood pressure, diastolic blood pressure, and heart rate were significantly decreased with the use of dexmedetomidine at different time intervals throughout the operation in comparison with group I and in comparison with the baseline in group II. Perioperative fentanyl consumption was significantly low with the use of dexmedetomidine in group II in comparison with group I. It was 325±55 μg in group II in comparison with 178±45 μg in group I. There was no significant difference between the two study groups as regards the extubation time. Pain score was significantly higher in group I in comparison with group II on admission to the postoperative acute care unit, and at 1 and 2 hlater. Conclusion In conclusion, the use of dexmedetomidine as preanesthetic medication followed by infusion during laparoscopic sleeve gastrectomy reduces desflurane requirement, maintains hemodynamic stability due to attenuation of stress response, and reduces the fentanyl requirement during intraoperative and early postoperative period, with decreased risk for respiratory depression in the postoperative acute care unit for morbidly obese patients who are at great risk for obstructive sleep apnea and oxygen desaturation.