Qi Zeng,1,* Jinjie Li,2,* Yanrong Liu,1 Yiran Zhang,1 Hang Su,1 Faping Tu1 

1Department of Anesthesiology, Affiliated Hospital of North Sichuan Medical College, Nanchong, People’s Republic of China; 2Operating Center, Affiliated Hospital of North Sichuan Medical College, Nanchong, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Faping Tu, Department of Anesthesiology, Affiliated Hospital of North Sichuan Medical College, Nanchong, 637000, People’s Republic of China, Tel +86-13808270833, Email tfpnc@163.com

Purpose: Sufentanil is a potent opioid analgesic frequently used to suppress the tracheal intubation response. The pathophysiological changes of obesity may affect opioid pharmacokinetics and increase the risk of opioid-induced adverse effects. Dexmedetomidine as an adjunct to anesthetic induction could save the dosage of sufentanil and attenuate hemodynamic response to tracheal intubation. This study was aimed at investigating the effect of intravenous dexmedetomidine premedication on the median effective concentration (EC50) of sufentanil for tracheal intubation in obese patients.
Patients and Methods: Fifty obese patients undergoing elective bariatric or non-bariatric surgery under general anesthesia with tracheal intubation were equally randomized into the dexmedetomidine group and the saline group. Depending on the group, the patients were intravenously premedicated with 1 μg/kg dexmedetomidine or saline before anesthesia induction. Anesthesia was induced with target-controlled infusion of propofol (at 3.5 μg/mL) and sufentanil. The effect-site concentration of sufentanil for the first patient in the two groups was set at 0.4 ng/mL. The concentration of sufentanil for the next patient was determined using Dixon’s up-and-down sequential method with an interval of 0.05 ng/mL, according to the responses of the previous patient. Hemodynamic variables and sufentanil dose were recorded. The EC50 and 95% confidence interval (CI) of sufentanil were determined using probit regression analysis.
Results: The EC50 of sufentanil and 95% CI were 0.25 (95% CI, 0.17– 0.31) ng/mL in the dexmedetomidine group and 0.43 (95% CI, 0.34– 0.46) ng/mL in the saline group (P < 0.05). The dosage of sufentanil was significantly lower in the former than in the latter. The hemodynamics were stable in both groups during the study.
Conclusion: Intravenous premedication with 1 μg/kg dexmedetomidine significantly decreased the EC50 of sufentanil and sufentanil requirement for tracheal intubation in obese patients.

Keywords: dexmedetomidine, median effective concentration, sufentanil, obesity