Extra Antiemetics Not Better for Bypass

Author:  Naveed Saleh MD, MS

Anesthesiology News

In gastric bypass patients, the quantity of intraoperative antiemetic agents (ie, “triple” therapy vs. “dual” therapy) is not related to postoperative nausea and vomiting, according to the results of a National Health Service study in the United Kingdom.

The researchers were surprised by the results of this small pilot study, according to Nicholas Daine, MD, the lead author and an anesthesiologist in the Department of Anaesthesia at St. Richard’s Hospital, Chichester, England. “Any simple logic tells you that if you give three antiemetics, you would probably have patients [who] are less sick than if you give them two. Certainly in bariatric surgery, the thing that makes the patient sick afterward is the surgery. … They have a lot of handling of bowel.”

In total, 38.6% of patients were administered triple therapy, with 53% of these patients later receiving antiemetic rescue treatment (P=0.31). In contrast, 60.7% of patients administered two or fewer antiemetic agents required rescue therapy.

In 2016, West Sussex Hospitals, the study institution, started standardized bariatric postoperative antiemetic and analgesia protocols by means of an electronic prescribing system. Triple therapy consisted of ondansetron, dexamethasone and cyclizine. The most common dual therapy option included ondansetron and dexamethasone. Ondansetron was the most common single antiemetic agent.

“We would caution that any benefit of triple therapy may be exaggerated in this study given that patients receiving intraoperative triple therapy with cyclizine and ondansetron are likely to have further doses of these rescue antiemetics withheld until a period of time has elapsed, tending to improve the marker of nausea,” the researchers said.

Dr. Daine hopes to expand the scope of the study. “We’ve just ma naged to get ahold of a much bigger data set of about 600 patients. That will give us more power to pick out any differences that there might be. We are also looking at opioids that we use intraoperatively and whether that influences postoperative opioid requirements.”

Peter Kranke, MD, MBA, an anesthesiologist in the Department of Anaesthesia and Critical Care at University Hospitals of Wuerzburg, in Germany, said, “My first impression is that rescue medication is one side of the [coin], and it’s not a very sensitive marker; many cases of PONV may have not been spotted. The other issue is that such an investigation largely depends on the potency of the third intervention.”