Intraperitoneal lidocaine decreases intraoperative Pain during postpartum tubal ligation

We conducted a randomized, double-blinded, placebo-controlled trial to evaluate the effectiveness of intraperitoneal lidocaine, IM morphine, or both drugs together for pain relief in postpartum tubal ligation. Eighty postpartum patients scheduled to have tubal sterilization were randomly divided into four groups to receive IM isotonic sodium chloride solution (1 mL) and intraperitoneal instillation of 80 mL of isotonic sodium chloride solution (Group P); IM morphine (10 mg in 1 mL) and intraperitoneal instillation of 80 mL of isotonic sodium chloride solution (Group M); IM injection of isotonic sodium chloride solution and intraperitoneal instillation of 0.5% lidocaine in 80 mL (Group L); and both IM morphine and intraperitoneal lidocaine instillation (Group ML). The minilaparotomy was performed after local infiltration with 15 mL of 1% lidocaine. A numerical rating score was used to rate pain on a 0-10 scale during the surgical procedures. The mean pain scores were 1.2 in Group L and 0.8 in Group ML. These pain scores were significantly lower than those in Groups P and M, which were 5.5 and 6.0, respectively (P < 0.001). Pain relief was inadequate in patients undergoing postpartum tubal ligation under local anesthesia, even after the administration of IM morphine. Instilling lidocaine into the abdominal cavity, however, effectively decreased intraoperative pain in these patients.