Effect of ultrasound-guided quadratus lumborum block on efficacy of postoperative analgesia after caesarean section

Abstract

Objective To evaluate the effect of ultrasound-guided quadratus lumborum block (QLB) on the efficacy of postoperative analgesia after caesarean section. Methods Sixty American Society of Anesthesiologists physical status Ⅰ or Ⅱ parturients, aged 20-39 yr, weighing 50-80 kg, scheduled for elective cesarean section under subarachnoid block, were divided into 2 groups (n=30 each) using a random number table: QLB group (group Q) and control group (group C). Ultrasound-guided bilateral QLBs were performed at the end of surgery, the solution was injected into the compartment between quadratus muscle and psoas major muscles, and 0.25% ropivacaine 1.25 mg/kg was injected to each side in group Q. The parturients in both groups received patient-controlled intravenous analgesia after surgery to maintain the visual analog scale score ≤ 3, and dezocine 5 mg was intramuscularly injected as a rescue analgesic when the visual analog scale score≥4.Bruggrmann comfort scale (BCS) and Ramsay sedation scores were evaluated at 2, 4, 6, 12, 24 and 48 h after operation.The consumption of sufentanil during patient-controlled intravenous analgesia, requirement for rescue analgesia, satisfaction score of analgesia, the number of successfully delivered doses (D1) and the number of attempts (D2) were recorded within 24 h after surgery.D1/D2 was calculated.The development of respiratory depression and over-sedation was recorded.The development of QLB-related adverse reactions and postoperative nausea, vomiting, chest tightness and pruritus was also recorded. Results Compared with group C, BCS scores were significantly increased, the consumption of sufentanil was reduced, D1/D2 was increased, the requirement for rescue analgesia was decreased, and the satisfaction score of analgesia was increased (P 0.05). Adverse reactions such as respiratory depression, over-sedation, nausea, vomiting, chest tightness and pruritus were not found in two groups.Adverse reactions such as hematoma and infection at the puncture site or local anesthetic intoxication were not observed after surgery in group Q. Conclusion Ultrasound-guided QLB can enhance the efficacy of postoperative analgesia after caesarean section, reduce postoperative consumption of opioids and raise the comfort degree for parturients. Key words: Ultrasonography; Psoas muscles; Neuromuscular blockade; Cesarean section; Analgesia, patient-controlled