title: Retrospective case-control non-inferiority analysis of intravenous lidocaine in a colorectal surgery enhanced recovery program.
abstract: BACKGROUND
  Enhanced recovery after surgery (ERAS) programs typically utilizes multi-modal analgesia to reduce perioperative opioid consumption. Systemic lidocaine is used in several of these ERAS algorithms and has been shown to reduce opioid use after colorectal surgery. However it is unclear how much the other components of an ERAS protocol contribute to the final outcome. Using a noninferiority analysis we sought to assess the role of perioperative lidocaine in an ERAS program for colorectal surgery, using pain and opioid consumption as outcomes.
  
  
  METHODS
  We conducted a retrospective review of patients who had received intravenous lidocaine perioperatively during colorectal surgery. We matched them with patients who were managed using a multi-component ERAS protocol, which included perioperative lidocaine. We tested a joint hypothesis of noninferiority of lidocaine infusion to ERAS protocol in postoperative pain scores and opioid consumption. We assigned a noninferiority margin of 1 point (on an 11-point numerical rating scale) difference in pain and a ratio [mean (lidocaine) / mean (ERAS)] of 1.2 in opioid consumption, respectively.
  
  
  RESULTS
  Fifty-two patients in the lidocaine group were matched with patients in the ERAS group. With regards to opioid consumption, in the overall [1.68 (1.43-1.98)] [odds ratio (95% confidence interval)] analysis and on postoperative day (POD) 1 [2.38 (1.74-3.31)] lidocaine alone was inferior to multi-modal analgesia. On POD 2 and beyond, although the mean odds ratio for opioid consumption was 1.43 [1.43 (1.17-1.73)], the lower limit extended beyond the pre-defined cut-off of 1.2, rendering the outcome inconclusive. For pain scores lidocaine is non-inferior to ERAS [-0.17 (-1.08-0.74)] on POD 2 and beyond. Pain scores on POD 1 and in the overall cohort were inconclusive based on the noninferiority analysis.
  
  
  CONCLUSIONS
  The addition of a multi-component ERAS protocol to intravenous lidocaine incrementally reduces opioid consumption, most evident on POD 1. For pain scores the data is inconclusive on POD 1, however on POD 2 and beyond lidocaine alone is non-inferior to an ERAS program with lidocaine. Opioid-related complications, including return of bowel function, were not different between the groups despite reduced opioid use in the ERAS group.
authors.affiliation: Department of Anesthesiology, University of Virginia, Charlottesville, VA, USA. bin4n@virginia.edu.|Department of Neurosurgery, University of Virginia, Charlottesville, VA, USA. bin4n@virginia.edu.
authors.forename: Bhiken I
authors.initials: BI
authors.lastname: Naik
authors.affiliation: Department of Epidemiology, Columbia University, New York, NY, USA.
authors.forename: Siny
authors.initials: S
authors.lastname: Tsang
authors.affiliation: Department of Anesthesiology, University of Virginia, Charlottesville, VA, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Knisely
authors.affiliation: Department of Anesthesiology, University of Virginia, Charlottesville, VA, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Yerra
authors.affiliation: Department of Anesthesiology, University of Virginia, Charlottesville, VA, USA.|Department of Neurosurgery, University of Virginia, Charlottesville, VA, USA.
authors.forename: Marcel E
authors.initials: ME
authors.lastname: Durieux
mesh_terms: D016058:Analgesia, Patient-Controlled; D000701:Analgesics, Opioid / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage*; D016022:Case-Control Studies; D013505:Digestive System Surgical Procedures; D004434:Early Ambulation; D005260:Female; D006801:Humans; D004091:Hydromorphone / Q000008:administration & dosage; D007262:Infusions, Intravenous; D007432:Intraoperative Period; D007902:Length of Stay; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000517:prevention & control*; D058996:Quality Improvement; D012189:Retrospective Studies
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D008012:Lidocaine; D004091:Hydromorphone
keywords: Colorectal Surgery; Enhanced Recovery After Surgery; Lidocaine; Opioid Consumption; Pain Scores