Effects of Dexmedetomidine on Minimum Alveolar Concentration of Sevoflurane for Blunting Sympathetic Response to Pneumoperitoneum: A Randomized Trial

Abstract

Yan Yuan,1,&ast; Guanlin Zheng,2,&ast; Jinsheng Guan,2,&ast; Chenye Zhou,3 Weitao Gao,3 Junyu Li,3 Dongsheng Dai,3 Yusheng Yao3 1Department of Pharmacy, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, People’s Republic of China; 2Department of Anesthesiology, Fujian Maternity and Child Health Hospital, College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou, People’s Republic of China; 3Department of Anesthesiology, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Dongsheng Dai, Email [email protected] Yusheng Yao, Email [email protected]: Laparoscopic procedures require abdominal inflation (pneumoperitoneum), which triggers strong stress responses that typically need high concentrations of sevoflurane to manage. Despite dexmedetomidine’s known anesthetic-sparing properties, its specific effects on sevoflurane minimum alveolar concentration for blunting sympathetic response (MACBAR) during pneumoperitoneum remain incompletely characterized. This study evaluates dexmedetomidine’s impact on sevoflurane requirements for blocking sympathetic responses during laparoscopic pneumoperitoneum.Patients and Methods: This prospective, randomized, double-blind, placebo-controlled trial enrolled 90 adults (aged 18– 45 years) classified as American Society of Anesthesiologists physical status I–II scheduled for elective laparoscopic cholecystectomy. Participants received either saline, low-dose dexmedetomidine (target 0.3 ng/mL), or high-dose dexmedetomidine (target 0.6 ng/mL). We determined sevoflurane MACBAR using Dixon’s up-and-down method, defined as the concentration preventing ≥ 20% increase in heart rate or mean arterial pressure following pneumoperitoneum. Secondary outcomes included hemodynamic responses, emergence time, adverse events, and plasma catecholamine levels.Results: Dexmedetomidine significantly reduced sevoflurane MACBAR compared to control (4.70% ± 0.18%; 95% confidence interval [CI], 4.61– 4.80): to 2.90% ± 0.19% (95% CI, 2.80– 3.00) in the low-dose group and to 1.90% ± 0.16% (95% CI, 1.82– 1.98) in the high-dose group (both p < 0.001). Patients receiving dexmedetomidine had significantly lower plasma epinephrine and norepinephrine levels following pneumoperitoneum compared to control (p < 0.001), with better hemodynamic stability. Emergence times and adverse event rates remained comparable between groups.Conclusion: Dexmedetomidine produces dose-dependent reductions in sevoflurane requirements for controlling sympathetic responses during pneumoperitoneum while maintaining hemodynamic stability, making it a valuable adjunct for anesthesia in laparoscopic surgery.Registration: The Chinese Clinical Trials Registry, ChiCTR2300071257. Keywords: dexmedetomidine, sevoflurane, minimum alveolar concentration, pneumoperitoneum, laparoscopic cholecystectomy

Keywords

• Dexmedetomidine
• Sevoflurane
• Minimum alveolar concentration
• Pneumoperitoneum
• Laparoscopic cholecystectomy.