Ultrasound Guided Oblique Subcostal Transverse Abdominis Plane Block using Local Anaesthetic Versus Saline for Laparoscopic Cholecystectomies: A Randomised Controlled Trial

Abstract

Introduction: Laparoscopic cholecystectomy surgery causes patients to have postoperative discomfort due to pain caused by incisions on the anterior abdominal wall. With the introduction of peripheral nerve blocks, the dosage of systemic analgesics can be significantly reduced and thereby the side-effects that may be caused by them. Oblique Subcostal Transversus Abdominis Plane (OSTAP block) which is a variant of the TAP block provides superior analgesia for supraumbilical procedures. Aim: To compare the efficacy of ultrasound-guided OSTAP block using 0.35% ropivacaine with saline OSTAP block in patients undergoing elective Laparoscopic cholecystectomy surgery. Materials and Methods: Forty-two ASA 1 and 2 patients posted for elective laparoscopic cholecystectomies were randomly assigned into two groups. Group A received bilateral OSTAP block with 0.35% ropivacaine and Group B received bilateral OSTAP block with sterile normal saline after the induction of general anaesthesia. Intraoperatively, the dose of opioid required during surgery and postoperatively pain score, opioid consumption, Postoperative Nausea and Vomiting (PONV) and Post Anaesthesia Care Unit (PACU) length of stay were evaluated. For all statistical evaluations, a two-tailed probability p-value of <0.05 was considered significant. Results: Intraoperative opioid consumption was higher in Group B but was statistically insignificant with a p-value of 0.575. Opioid consumption during the first eight hours after surgery and within 24 hours was also lower in Group A. When considering the quality of postoperative analgesia, Group A showed a significantly lower VAS score than Group B immediately after surgery, 30 minutes, 2 hours, 4 hours, 6 hours and 24 hour postoperatively. PACU stay in Group A was significantly less (p<0.001) with nearly all patients reaching discharge criteria within 30 minutes of reaching the PACU. There was no significant difference in the incidence of postoperative nausea vomiting in the groups. Conclusion: OSTAP block with 0.35% ropivacaine provided adequate analgesia with opioid-sparing effect in the postoperative period after a laparoscopic cholecystectomy