The protocol of a randomized, double-blinded, placebo controlled trial to investigate the role of intra-peritoneal ropivacaine in gastric bypass surgery

Robert Wu, Alexis Porte, Fatima Haggar, Isabelle Raiche, Husein Moloo, Jean Claude Gauthier, Amy Neville, Jean Denis Yelle, Joseph Mamazza. The Ottawa Hospital, University of Ottawa.

Introduction
Postoperative pain control remains a major challenge, even in laparoscopic surgery such as gastric bypass. Effective pain control reduces the risk of postoperative complication such as deep vein thrombosis and pulmonary emboli, pulmonary morbidity (eg. atelectasis and pneumonia), and tachycardia. Pain management is especially important in obese patients who may have a number of cardiovascular and pulmonary comorbidities that increase perioperative risk. These include a high prevalence of obstructive sleep apnea, hypoxia and respiratory depression. The objective of this study is to evaluate the efficacy of intraperitoneal local anesthetic (IPLA), in this case Ropivicaine, to reduce post-operative pain in patients undergoing laparoscopic Roux-en-Y gastric bypass surgery (LRYGB). We hypothesize that the use of IPLA will lead to a decrease in early postoperative pain and improvements in other clinically important postoperative outcomes and quality of life (QoL) in the period shortly after the surgery.

Methods and Procedures
A single-centre, double blinded, randomised controlled trial will be conducted to compare intraperitoneal ropivacaine (intervention) versus normal saline (placebo) in 120 adult patients undergoing LRYGB. After penumoperitoneum establishment, 200mg of Ropivacaine (0.2% Ropivacaine in 100 mL Normal Saline) will be instilled in the abdomen at the start of the case before surgical dissection. Under direct visualization, 50 mL will be infused over the esophageal hiatus. The remaining 50 mL will be infused throughout the abdomen. Patients in the control group will undergo the same treatment with normal saline. Standardized doses of local anesthesia will be used at the incision sites for all patients. All patients will be cared for by our standard bariatric post-operative protocol and discharged when criteria are met. Patients will be followed until their first follow-up clinic within 10 days of discharge.
Primary endpoint will be post-operative pain measured by the visual analogue scale (VAS). VAS pain score will be measured at baseline preoperatively, in recovery room, at 1, 2, and 4 hours post-operatively. Pain measurement will continue every 4 hours for a period of 24 hours and every 8 hours for up to 48 hours if the patients remain in hospital that long. Secondary endpoints will include opioid use, peak expiratory flow score, 6-minute walk distance, and quality of life assessed by the Quality of Recovery instrument (QR40) in the immediate post-operative period.

Conclusion
The study, regardless of its findings, will have an impact on use of (IPLA) in laparoscopic gastric bypass surgery.  A positive finding would confirm the effectiveness of IPLA in laparoscopic gastric bypass surgery.  Negative results may lead to changes to the current postoperative management practices and prompt further research to improve pain management following laparoscopic gastric bypass.

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