Author: Michael Vlessides
Despite its increasing popularity, opioid-free anesthesia for bariatric surgery may not be the optimal choice. A preliminary trial has found that the opioid-free approach did not improve patients’ recovery profile, although the population sample was small.
“Obesity is a growing epidemic in the United States, and increasing numbers of these patients are undergoing bariatric surgery to treat this condition,” said Masha Zeltsman, DO, an anesthesia resident at the Zucker School of Medicine at Hofstra/Northwell, in New Hyde Park, N.Y. “Nevertheless, these patients typically present with many comorbidities, including a high prevalence of obstructive sleep apnea, which makes them very susceptible to the respiratory depressive effects of opioids.
“So, trying to find a way to minimize the adverse effects of opioids through opioid-sparing techniques is definitely something that may enhance patient recovery,” Dr. Zeltsman added. Given the growing trend toward opioid-free anesthesia for postoperative pain in other procedures, Dr. Zeltsman and her colleagues sought to assess its viability in bariatric surgery.
Narcotic Use, Pain Scores Compared
As part of the preliminary chart review, the researchers examined the records of 22 morbidly obese patients who underwent minimally invasive vertical sleeve gastrectomy at North Shore University Hospital between May and December 2018. Patients were managed intraoperatively with an opioid-based regimen consisting of sevoflurane with fentanyl (n=12) or an opioid-free technique of propofol with ketamine or dexmedetomidine infusions (n=10).
The investigators measured several parameters over the first 24 hours after surgery, notably total narcotic use (converted to oral morphine equivalents) and numeric rating scale pain scores. “We also recorded their Aldrete scores to determine discharge readiness,” Dr. Zeltsman said.
Despite the small number of patients, the two groups were demographically similar. On average, 80% of patients were women aged in their 40s with an average ASA physical status class III. Surgical and anesthesia times also were similar in both groups.
As Dr. Zeltsman reported at the 2019 annual meeting of the International Anesthesia Research Society (abstract F122), total postoperative opioid consumption was 23.25 mg among patients in the opioid-free anesthesia group, significantly more than among those who received opioids at 9.79 mg (P=0.03). Median maximal pain scores did not differ between groups.
Similarly, the opioid-free anesthesia group also needed 255.3 minutes to reach an Aldrete score of at least 9, significantly longer than the 135.4 minutes required by patients in the opioid group (P=0.03). Finally, 70% of patients in the opioid-free anesthesia group required more antiemetic rescue medication for breakthrough postoperative nausea and vomiting (PONV), compared with 25% of those in the opioid anesthesia group (P=0.08).
Patients in the opioid-free group also stayed longer in the PACU (317.9 vs. 244.8 minutes), but this was not statistically significant (P=0.11). Critical respiratory events were similar in both groups, and all patients were discharged on postoperative day 1 regardless of technique used.
“Interestingly, although the literature is there for other operative procedures, there is very little published on this in bariatrics,” Dr. Zeltsman said in an interview with Anesthesiology News. “Most of the literature shows that these bariatric patients do better and recover faster with opioid-free anesthesia.
“Obviously, though, our opioid-free patients were in more pain postoperatively, which is why they received more narcotics after the surgery,” she said. “Furthermore, with the trend toward more PONV in the opioid-free anesthesia group, they also received more antiemetic rescue medications. Many of these agents can be sedating, which can in turn delay PACU discharge.”
Next Steps for Opioids in Bariatric Care
Despite the findings, the investigators have no plans to stop performing opioid-free anesthesia in bariatric procedures, and instead are planning larger studies to help clarify their results. “This was really just a preliminary study to see where to go from here,” Dr. Zeltsman explained.
“I think the next thing we’re going to do is a much larger retrospective chart review,” she continued. “Twenty-two patients is hard to hang your hat on, so we want to do something much bigger to get a better sense what our results are, and then we plan on taking it to a prospective trial.
“Even though opioid-free anesthesia is a growing trend, its effect on various outcomes has not been established in this patient population,” Dr. Zeltsman added. “With the state of the current opioid epidemic, everyone is looking for effective methods to reduce or eliminate narcotic administration perioperatively.”
Roman Schumann, MD, the associate chief for research and development at the VA Boston Healthcare System, appreciated the comparative case series but noted that the study is too small to allow for any firm associations. “Today’s intraoperative bariatric care almost invariably consists of an intraoperative/perioperative multimodal and opioid-sparing or opioid-free concept,” he said.
According to Dr. Schumann, three important considerations in current opioid-sparing bariatric care include the combination and dose of intraoperative analgesics; the administration method (bolus, continuous or both) for drugs such as ketamine and dexmedetomidine; and the influence of comorbidities, such as psychopathology and preexisting pain.
“My personal bias is that opioid-free anesthesia is easily possible but ultimately the wrong approach for the vast majority of patients,” Dr. Schumann said. “The opioid receptor needs to be covered, and we can start at a much lower intraoperative dose compared to past practice when we use multimodal concepts. Perhaps we will eventually see an individualized approach when opioid responsiveness can be predicted genetically, which may even allow determination of the best opioid to use and responses to other analgesics.
“It is a benefit to see even a small study that presents counterintuitive results and adds to our debate and mindfulness whenever some of our practice becomes fashionable,” Dr. Schumann added. “I am not really surprised at the outcome here, given the fairly black-and-white approach, and believe these data are important in that way.”