P001: REDUCED POST-OPERATIVE OPIOID REQUIREMENT AFTER OPIOID-FREE ANESTHESIA
Enrico M Camporesi, MD1, Devanand Mangar, MD1, Abdullah Abou-Samra, BS2, Prachiti H Dalvi, MS3, David Samuels, MD3; 1University of South Florida & TEAMHealth Anesthesia, 2University of South Florida, 3TEAMHealth Anesthesia
INTRODUCTION: Opioid-free analgesia is accepted as an alternative to manage post-surgical pain. Opioid-free anesthesia (OFA) is possible by intraoperative use of agents that lead to opioid sparing effects via sodium channel blockade, G protein-coupled receptor blockade, NMDA blockade, central alpha-2 agonists and use of anti-inflammatory blockers. We conducted a retrospective chart review at an outpatient surgery center to evaluate whether patients who received no opioids intraoperatively required more opioids post-operatively when compared to patients who received standard anesthesia with opioids.
METHODS: University of South Florida’s Institutional Review Board approved this protocol and granted a waiver for informed consent. In the last two years, one of the authors (D.S.) changed his anesthesia regimen to use opioid-free anesthesia (OFA) for breast reconstructions, cochlear implants, stapedectomies, and mastoidectomies. We reviewed all patients anesthetized during two months in 2015 while he was using an opioid-free anesthesia regimen and compared them to similar patients operated on by the same group of surgeons when a substitute anesthesiologist was staffed. The substitute anesthesiologist used a standard opioid anesthesia (OA) regimen. This created a unique model to study the effects of opioid anesthesia on patient outcomes.
All patients received general anesthesia utilizing varying concentrations of Sevoflurane. The OA cases received a typical dose of intraoperative opioids (average 17mg morphine equivalent). The OFA cases did not receive opioids at all. Three preoperative oral medications (1000mg acetaminophen, 400mg gabapentin, and 400mg celecoxib) and 3 intraoperative intravenous medications (2g magnesium sulfate, 0.15mg/kg ketamine, 0.3mg/kg dexmedetomidine) were used instead of opioids. The primary endpoint was post-operative opioid consumption and secondary endpoints included postoperative Ondansetron and length of stay. We utilized t-tests with Bonferroni corrections to determine significance (p<0.05).
RESULTS: Table 1 shows that both groups had similar age, duration of surgery, and BMI. As detailed in Table 2, the OA group required twice as many opioids in the PACU as the OFA group (p<0.05). This difference persisted in the surgical post-operative unit (SPU). The OFA group also required less Ondansetron, but this difference was not significant. Most interestingly, 73% of the OFA patients required no postoperative opioids, compared to 52% of OA patients. Patients in the OFA group experienced less nausea and vomiting, as interpreted by their lower use of Ondansetron in the PACU. We also noted longer PACU times in the OA group.
DISCUSSION: This retrospective study demonstrates that giving no opioids intraoperatively reduces the need for opioids both in the PACU and post-operatively. We hypothesized that extra post-op narcotic was needed in patients receiving intra-op narcotics due to upregulation of mu opioid receptors.The availability of opioids perpetuates the problem of non-medical use of opioids since approximately 4 to 20% of all opioid pills prescribed after surgery in the United States are being used nonmedically. Only 20% of non-medical users of opioids obtained them from their own physician, with a majority of non-medical users consuming drugs intended for someone else. By reducing the need for opioid medications to manage pain post-surgically, we start to address opioid abuse at its root.