Jiabei Li,1,2 Wuchang Fu,3 Na Wang,1 Sisi Zeng,1 Xuechao Li,1 Jixiang Wan,1 Fangjun Wang1 

1Department of Anesthesiology, Affiliated Hospital of North Sichuan Medical College, Nanchong, People’s Republic of China; 2Department of Anesthesiology, Meishan City People’s Hospital, Meishan, People’s Republic of China; 3Department of Anesthesiology, The Second Clinical Medical College of North Sichuan Medical College (Nanchong Central Hospital), Nanchong, People’s Republic of China

Correspondence: Fangjun Wang, Department of Anesthesiology, Affiliated Hospital of North Sichuan Medical College, No. 1 Maoyuan South Road, Nanchong, Sichuan, 637000, People’s Republic of China, Tel +86 13458253172, Email wfjlxy006@126.com

Purpose: To determine the effect of dexmedetomidine on the ED50 and ED95 of sufentanil in patient-controlled intravenous analgesia (PCIA) after cesarean section.
Patients and Methods: Parturients who underwent elective cesarean section (n = 80) were randomly assigned to either the sufentanil group (S group) or the dexmedetomidine-sufentanil combination group (DS group). Patients in the S group received a combination of sufentanil, 5 mg of tropisetron, and saline, whereas patients in the DS group were administered 1.5μg/kg of dexmedetomidine in addition to sufentanil, 5 mg of tropisetron, and saline. The ED50 and ED95 of sufentanil were determined by Dixon sequential method. We used probit regression to calculate the ED50, ED95, and 95% confidence intervals for sufentanil in each group.
Results: The ED50 and ED95 for sufentanil in the S group were 1.634 (95% CI: 1.476– 1.810)μg/kg and 2.035 (95% CI: 1.841– 3.312)μg/kg, respectively. The ED50 and ED95 for sufentanil in the DS group were 1.275 (95% CI: 1.187– 1.353)μg/kg and 1.503 (95% CI: 1.406– 1.824)μg/kg. The VAS scores with rest at t5 and with movement at t4- t5 were lower in the DS group (P< 0.05). The t2-t5 Ramsay scores in the DS group were higher than those in the S group (P< 0.05). The doses of sufentanil and tramadol were markedly reduced in the DS group, while the onset of first lactation occurred significantly earlier in the DS group (P< 0.05). Compared with the S group, the DS group had a lower incidence of nausea, vomiting, and skin itching (P< 0.05), and lower frequency of patient-controlled analgesia (PCA) episodes (P< 0.05), and better postoperative pain satisfaction (P< 0.05).
Conclusion: The 1.5μg/kg dexmedetomidine can significantly decrease the ED50 and ED95 of sufentanil in patient-controlled intravenous analgesia after cesarean section, provide good postoperative analgesia and sedation, and promote the earlier occurrence of first lactation.

Keywords: dexmedetomidine, sufentanil, cesarean section, postoperative analgesia, ED50, ED95