M. H. Zaman1, O. P. Owodunni2, M. Ighani2, M. Grant3, D. Bettick4, S. Sateri3, T. Magnuson2, S. Gearhart2 1The Johns Hopkins University School Of Medicine,Urology,Baltimore, MD, USA 2The Johns Hopkins University School Of Medicine,Surgery,Baltimore, MD, USA 3The Johns Hopkins University School Of Medicine,Anesthesia,Baltimore, MD, USA 4The Johns Hopkins Bayview Medical Center,Quality,Baltimore, MD, USA
Introduction: Chronic opioid exposure can lead to a state of tolerance in patients where increasing doses of opioids are necessary to reduce pain; this can make postoperative management difficult. An Enhanced Recovery Pathway (ERP) is an evidence-based intervention that focuses on optimizing recovery and postoperative outcomes. The effectiveness of an ERP depends on the degree of compliance with the pathway. We wish to determine the effects of opioid tolerance in patients undergoing abdominal surgery on an ERP and its impact on compliance and postoperative outcomes.
Methods: From January 2013 to June 2017, patients undergoing major abdominal surgery prior to and following ERP-implementation were included. Patients <18 years and having emergency surgery were excluded. Compliance was measured to 14 perioperative pathway variables and high-compliance was defined as achieving ≥75%. Opioid tolerance was defined as any patient taking a prescribed opioid medication equivalent to 60 mg of Morphine per day for one week prior to surgery. CR-POSSUM scores were used for risk-adjusted analyses. Outcomes of interest include length of stay (LOS), major-complications (Clavien-Dindo“CD”≥2), and 30-day readmission rates.
Results: 1251 patients (605 pre-ERP and 646 ERP patients) were included. A total of 221 patients were opioid tolerant. Opioid tolerant patients were more likely to be younger (56 vs. 59 years, P=0.002), have disseminated cancer (11% vs. 5 %, P=0.003) and have an open procedure (69% vs. 60%, P=0.01) than non-tolerant patients. When comparing opioid-tolerant patients prior to (107 patients) and following EPR implementation (114 patients), there was no difference in demographic and clinical characteristics; however, more opioid-tolerant patients following ERP implementation had a laparoscopic procedure (42% vs. 19%, P<0.001). In a multivariable analysis, opioid tolerance was associated with an increase in major complications (OR 1.24, p=0.032) and in readmissions (OR 1.42, p=0.005). Among the ERP cohort, opioid-tolerant patients were less likely to be highly compliant with ERP variables than non-tolerant patients (35% vs. 54%; p<.001). Opioid tolerance was associated with a higher median LOS (5 days vs. 4 days; p<0.02) and a higher readmission rate (24% vs. 13%; p<0.01) than non-opioid tolerant ERP patients. In opioid-tolerant patients, high compliance with ERP was associated with a decreased odds of major complications (OR: 0.10, p<.001) and a reduction in the readmission rate (OR: 0.7, p=0.003). Opioid tolerance was an independent predictor of non-compliance with ERP (OR: 0.44, p<.001).
Conclusion: We provide evidence that opioid tolerance is associated with less favorable outcomes in patients undergoing major abdominal surgery and on an ERP; this is likely due to lack of pathway compliance. Minimizing opioid use prior to elective major abdominal surgery may improve compliance and postoperative outcomes.