The Effect of Intraoperative Lidocaine Infusion and Intraoperative Lidocaine Combined With Ketamine Infusion on Opioid Consumption After Laparoscopic Bariatric Surgery: A Randomized Controlled Trial

The prevalence of obesity and associated diseases have been increasing in recent decades. From 1980 to 2013, the number of adults with BMI more than 25 kg/m2 increased from 28.8% to 36.9% in men, and from 29.8% to 38% in women. According to World Health Organization (WHO), the prevalence of overweight among adults in Thailand in 2016 was 32.6%, markedly increased from 2011 which was 23.9%. To date, the most effective long-term treatment for obesity is bariatric surgery because of significantly reducing body fat, the development of new obesity-related conditions, and overall mortality. However, postoperative complications, particularly respiratory complication, are concerned because obesity is associated with respiratory compromise and sleep-disordered breathing. The 2016 guideline for perioperative care in bariatric surgery developed by enhanced recovery after surgery (ERAS) society state that, regarding to current evidence, there is no specific anesthetic agents or techniques for bariatric surgery, however, multimodal analgesia should be used to reduce opioid consumption and opioid-related complications such as respiratory depression, postoperative nausea and vomiting and ileus. Moreover, several studies supported opioid-sparing technique to avoid respiratory complications.

Intravenous lidocaine is widely used to reduce postoperative pain and to reduce perioperative opioid as a multimodal analgesia. From Cochrane review, perioperative lidocaine can decrease pain at rest, postoperative ileus and postoperative nausea and vomiting in elective and urgent surgery. Few trials in obese patients underwent laparoscopic bariatric surgery found that lidocaine infusion can decrease opioid consumption. However, the supported evidence is still limit. Ketamine has been used for postoperative analgesia as well, as an effective adjunct to decrease opioid consumption in various types of surgery, including open bariatric surgery. Moreover, the recent retrospective study (Tovikkai P, in press) found that there was a positive interaction between intraoperative lidocaine infusion and ketamine for decreasing opioid consumption in obese patients underwent laparoscopic bariatric surgery. However, the benefit of lidocaine and ketamine for postoperative pain in obese patients underwent laparoscopic bariatric surgery is still debated.

Therefore, we designed this study to examine the effect of intraoperative lidocaine infusion and intraoperative lidocaine infusion combined with intraoperative low-dose ketamine infusion on opioid consumption in obese patients undergoing laparoscopic bariatric surgery.