Analgesic effectiveness of rectus sheath block during open gastrectomy: A prospective double-blinded randomized controlled clinical trial

Despite recent advances in gastric cancer surgery, open gastrectomy is often needed to treat gastric cancer. Due to the large incision in the abdomen, the amount of opioid required during surgery increases and postoperative pain becomes worse. It is well known that postoperative pain has a negative impact on the patient's immune system. Herein, we performed an ultrasound-guided bilateral rectus sheath block (RSB) in patients undergoing open gastrectomy under general anesthesia and analyzed the analgesic effectiveness of RSB in open gastrectomy. A total of 46 patients scheduled for open gastrectomy were randomly divided into 2 groups: Group A (n = 21) consisted of patients who received an RSB using 40 mL of 0.375% ropivacaine under ultrasound guidance and Group B (n = 20) consisted of patients who received an RSB using 40 mL of normal saline. An electronic injection pump was connected to each patient for patient-controlled analgesia (PCA) immediately after the skin closure. The amount of remifentanil required during the surgery was analyzed. After using PCA, data on the use of PCA bolus dose were extracted and analyzed using Excel. Group A used significantly less remifentanil (1021.4 ± 172.0 μg) than group B (1415.0 ± 330.6 μg; P = .03). The number of PCA bolus dose provided to the patients after surgery was significantly lower in group A (1 h: 1.14 ± 0.9, 2 h: 0.85 ± 0.7) than in group B (1 h: 1.85 ± 0.7, 2 h: 1.45 ± 1.0) until 2 hours after the surgery (1 h, P = .008; 2 h, P = .03), but after 3 hours, there were no significant differences between the 2 groups. If ultrasound-guided bilateral RSB with 40 mL of 0.35% ropivacaine is performed precisely in patients undergoing open gastrectomy, the requirement for remifentanil during surgery can be reduced. In addition, it significantly reduces the use of PCA bolus dose for acute postoperative pain within 2 hours after surgery.