Efficacy of preoperative transversus abdominis plane block with different volumes of ropivacaine for improving postoperative analgesia in patients undergoing laparoscopic radical resection of ovarian cancer

Abstract

Objective To evaluate the efficacy of preoperative transversus abdominis plane(TAP)block with different volumes of ropivacaine for improving postoperative analgesia in patients undergoing laparoscopic radical resection of ovarian cancer. Methods Sixty American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients, aged 30-60 yr, with body mass index of 18-24 kg/m2, scheduled for elective laparoscopic radical resection of ovarian cancer under general anesthesia, were divided into 3 groups(n=20 each)using a random number table: 0.375% ropivacaine 20 ml group(group R1), 0.375% ropivacaine 12 ml group(group R2)and control group(group C). In R1 and R2 groups, ultrasound-guided bilateral TAP block was performed before induction of anesthesia, and 0.375% ropivacaine 20 and 12 ml were injected, respectively.Both groups received patient-controlled intravenous analgesia(PCIA)with sufentanil after operation, and the PCIA pump was set up with a 0.5 ml bolus dose, a 15 min lockout interval and background infusion at a rate of 2 ml/h after a loading dose of 2 ml to maintain the visual analogue scale score ≤3.When the visual analogue scale score >3, tramadol 100 mg was intravenously injected as rescue analgesic.The consumption of sufentanil during PCIA, effective pressing times of PCIA, requirement for rescue analgesic and occurrence of adverse reactions were recorded within 24 h after operation.At 10 min before induction of anesthesia and 4, 8, 12 and 24 h after operation, venous blood samples were collected for measurement of the plasma concentrations of interleukin-6(IL-6)and IL-10 by enzyme-linked immunosorbent assay. Results Compared with group C, the consumption of sufentanil, effective pressing times of PCIA, requirement for rescue analgesic and incidence of nausea and vomiting and pruritus were significantly decreased, and the concentration of plasma IL-6 was decreased and the concentration of IL-10 in plasma was increased at each time point after operation in R1 and R2 groups(P<0.05). The consumption of sufentanil, effective pressing times of PCIA, requirement for rescue analgesic and incidence of nausea and vomiting and pruritus were significantly lower, and the concentration of plasma IL-6 was lower and the concentration of IL-10 in plasma was higher at each time point after operation in group R1 than in group R2(P<0.05). Hematoma and infection at the puncture site were not found in R1 and R2 groups. Conclusion Preoperative TAP block can enhance the postoperative analgesic efficacy, reduce the occurrence of adverse reactions, and 0.375% ropivacaine 20 ml provides better efficacy in patients undergoing laparoscopic radical resection of ovarian cancer. Key words: Amides; Abdominal muscles; Nerve block; Pain, postoperative; Laparoscopy