Effectiveness of Intraperitoneal Bupivacaine in Reducing Postoperative Morphine Used among Total Abdominal Hysterectomy Patients at Phramongkutklao Hospital.

Objective: To study the effectiveness of intraperitoneal bupivacaine in reducing 24-hour postoperative morphine used in women underwent total abdominal hysterectomy.

Material and Method: Sixty-two non-malignant gynecologic patients, aged 25 to 65 years, ASA class I-II, underwent elective total abdominal hysterectomy. On the operative day, patients were allocated simple random sampling. Blinded intraperitoneal solution was prepared and numbered for each patient. In total, 40 ml of 0.25% bupivacaine solution or normal saline was applied in the pelvic cavity after completed the operation. The abdominal muscle and subcutaneous fat were infiltrated with 0.25% bupivacaine 10 ml each layer. Intravenous morphine patient-controlled analgesia (PCA) was started in the recovery room. The assessment of total morphine used, sedative score, numerical rating score (NRS) for pain, postoperative nausea vomiting (PONV), pruritus, and the number of vomiting and antiemetic drugs used were recorded at 1, 2, 4, 8, 12, and 24 hours after intraperitoneal administration. Patients’ satisfactory NRS was evaluated after PCA cessation. Repeated measure ANOVA was used to compare means between two groups. Baseline characteristics were calculated by descriptive statistics, i.e., mean, standard deviation, median, and range. A p-value less than 0.05 was considered statistically significant. Statistical package for the social sciences (SPSS) for Windows version 23 was used.

Results: There were no significant differences were found between the two groups in general patients’ characteristics, intraoperative data, and anesthetic administration. Total morphine consumption at 24 hours after intraperitoneal administration was significantly less in the bupivacaine group than the saline group (25.03 vs. 16.13, p = 0.002). Lower pain score at 1 and 2 hours and significant difference in reduced morphine consumption were observed within the first 4 hours after intraperitoneal bupivacaine administration. Postoperative 24 hours satisfactory score, PONV, pruritic score, overall incidences of vomiting and antiemetic use were similar in both groups. Sedative scores were lower in the bupivacaine group except at 1 and 24 hours postintraperitoneal administration. No evidence of local anesthetic toxicity or operative complication was identified.

Conclusion: Administration of intraperitoneal and incisional 0.25% bupivacaine at the completion of total abdominal hysterectomy produced a significant reduction in 24-hour postoperative morphine used without adverse effect.