POSTOPERATIVE PAIN MANAGEMENT AND OPIOID REQUIREMENTS FOLLOWING TOTAL ABDOMINAL HYSTERECTOMY: COMBINED INTRAPERITONEAL AND INCISIONAL INFILTRATION VERSUS INCISIONAL INFILTRATION ONLY WITH BUPIVACAINE

Abstract

Background
Abdominal hysterectomy is associated with intense and significant postoperative pain especially in the first 24-48 hours. The benefits of adequate pain relief include better recovery from surgical procedure and early mobilization of patients to prevent respiratory and thrombo-embolic complications. The institution of non-opioid methods of pain management with the use of local anaesthetics (LAs) has been employed via different routes with varied results. The use of local infiltration plus intraperitoneal instillation of local anaesthetics in abdominal and pelvic surgery may provide good postoperative analgesia.
Study design
This was a randomized double-blinded controlled trial. Ethical approval was obtained from the University of Benin Teaching Hospital Ethics Committee. Informed consent was obtained preoperatively from patients. Eighty (80) patients were randomized; 40 to the study group (30mls of intraperitoneal bupivacaine plus 20mls of incisional bupivacaine) and 40 to the control group (30mls of intraperitoneal normal saline plus 20mls of incisional bupivacaine only). The technique of anaesthesia was subarachnoid block with 3mls of 0.5% heavy bupivacaine. After surgical removal of the uterus with or without the adnexae and securing of all bleeding vessels/structures, 30mls of the appropriate treatment solution was instilled into the peritoneum. A volume of 20mls of 0.25% plain bupivacaine was infiltrated into the abdominal wall after closure of the abdominal incision including the muscle and cutaneous layers in both groups. Postoperative analgesia was provided with pentazocine 30mg via the intramuscular route. The time to first request for analgesic drug formed the primary outcome of this study, while the total opioid consumption in 24 hours, Numerical Pain Rating Scale (NPRS) scores in the postoperative period, wound healing, duration of hospital stay and patient’s satisfaction formed the secondary outcome of this study. Statistical Package for the Social Sciences (SPSS) version 16 software was used for analysis with results being expressed as means ± S.D and percentages where necessary. Means were compared using T-test with the level of significance set at 95%.
Results
The time (minutes) to first request for analgesic was longer in the combined intraperitoneal and incisional group (167.75 ± 75.49) as compared to the incisional alone group (108.58 ± 36.07). This difference was statistically significant (P = 0.000). The NPRS at first request for analgesic drug was higher in the control group (6.11 ± 0.80) as compared to the study group (5.38 ± 0.81) and was statistically significant (p=0.000).
Statistically significant differences in the NPRS of the study versus the control group were observed in the 12th (3.85 ±1.63 vs 5.29 ± 2.58), 24th (1.90 ± 0.87 vs 3.26 ± 1.91) and 48th (1.22 ± 0.62 vs 2.13 ± 1.40) hour postoperatively (p = 0.004, 0.000 and 0.000 respectively).  Total opioid consumption over 24 hours was higher in the incisional bupivacaine alone group and was statistically significant (p = 0.00). There was no statistical difference in duration of operation, maximum sensory block height and duration of hospital stay for both groups. The level of satisfaction with postoperative pain management was observed to be better in the study group with 15% of patients reporting excellent satisfaction and 70% reporting very good satisfaction as compared to 0% and 31.6% respectively in the control group. Conclusion This study demonstrates that the use of a combination of intraperitoneal instillation and incisional infiltration of 0.25% plain bupivacaine following total abdominal hysterectomy is associated with reduced pain scores in the postoperative period, longer
duration of time to first request for analgesic and reduced opioid consumption. It also showed a low incidence of adverse effects with no detrimental effect on wound healing, making it safe.

POSTOPERATIVE PAIN MANAGEMENT AND OPIOID REQUIREMENTS FOLLOWING TOTAL ABDOMINAL HYSTERECTOMY: COMBINED INTRAPERITONEAL AND INCISIONAL INFILTRATION VERSUS INCISIONAL INFILTRATION ONLY WITH BUPIVACAINE