Impact of Bilateral Quadratus Lumborum Block Using Different Doses of Dexmedetomidine for Postoperative Analgesia in Laparoscopic Myomectomy: A Randomized Controlled Trial.

OBJECTIVES: The optimal dosage of dexmedetomidine (DEX) for postoperative analgesia of quadratus lumborum block (QLB) after laparoscopic myomectomy is not clear. Our study evaluated the analgesic and adverse effects of different doses of locally administered DEX.

MATERIALS AND METHODS: Patients underwent laparoscopic myomectomy were enrolled in this randomized controlled trial. Transmuscular bilateral QLB was conducted postoperatively using local anesthetic plus different doses of DEX, as an adjuvant, per side. Numeric rating scales (NRS) of pain score and heart rate (HR) were assessed after performing QLB. Additional analgesics through patient-controlled analgesia pump, recovery time to first flatus, hospital stay, and other outcomes were also compared.

RESULTS: A total of 150 participants were randomly divided into 3 groups (DEX1 group: 0.1 μg/kg; DEX2 group: 0.3 μg/kg; DEX3 group: 0.5 μg/kg), 50 for each group. Compared with the DEX1 group, NRS pain scores were lower in groups DEX2 and DEX3 ( P <0.017) 20 minutes after QLB and the significance lasted for 24 hours. Patients in groups DEX2 and DEX3 needed fewer additional analgesics than the group DEX1 ( P <0.017). HR in groups DEX2 and DEX3 was lower than the group DEX1 10 minutes and 20 minutes after QLB, respectively ( P <0.017). Sixty minutes after QLB, HR in the DEX3 group was still lower than the other groups. More patients in the DEX3 group were found bradycardia. Satisfaction score of postoperative analgesia was higher in groups DEX2 and DEX3 than the DEX1 group ( P <0.017).

DISCUSSION: The results suggest that solution of DEX 0.3 μg/kg in ropivacaine 0.25% for QLB is recommended to relieve postoperative pain after laparoscopic myomectomy effectively and safely.