Intraperitoneal lidocaine for intraoperative and postoperative pain relief in postpartum tubal ligation, a randomized controlled trial

The objective of this study was to assess the intraoperative pain relief of intraperitoneal lidocaine, intramuscular morphine or both in postpartum tubal ligation. As factorial designed,80 patients were randomly allocated into 4 groups to have no medication (group I), 10 mg of intramuscular morphine (group II), 0.5% lidocaine 80 ml. Instilled into intraperitoneal cavity (group III), and both intramuscular morphine and intraperitoneal lidocaine (group IV). Every patient had 1% lidocaine 20 ml. For local sking infiltration. Numerical Rating Scale (NRS) 0-10 (0 means no pain at all, 10 means the most possible pain) was rated by the patients during the operation. Rescued drugs (fentanyl, ketamine) were used if NRS 3. The mean NRS scores were 7.30,7.60, 2.70, and 1.55 in group I, II, III and IV respectively. There were significant differences in NRS scores between Group I or II compared to group III or IV (p 0.001) but there were no significant differences between group I and group II or group III and group IV. Rescued drugs were used more in group I, II than group III, IV (16 :16 :4 :2) (P 0.001). There were no significant differences in hemodynamic changes. The mean highest lidocaine level was 2.67 gm/ml. which was low as compared to the toxic level (9-10 gm/ml.). By cost effectiveness analysis, using intraperitoneal lidocaine cost 25.50 baht more to get one patient free from severe pain during the operation as compared to intramuscular morphine. This study shows that lidocaine instillation is an effective method for pain relief in postpartum tubal ligation while intramuscular is not, and lidocaine instillation is a good canonical and safe technique for intraoperative pain relief in postpartum tubal ligation.