Predictive Variables for Postoperative Opioid Requirements Following Hysterectomy

Abstract

Study Objective To identify predictive factors for opioid consumption following hysterectomy by determining the relationship between perioperative opioid requirements, preoperative pelvic pain scores and patient variables. Design A prospective cohort study. Setting Canadian tertiary care academic center. Patients or Participants The study included 191 women undergoing hysterectomy. Interventions Preoperatively, all patients completed the Pain Sensitivity Questionnaire (PSQ), Pain Catastrophizing Scale and the Numeric Rating Scale (NRS). Cumulative opioid consumption (COC), calculated in oral morphine equivalents (OME), was the sum of opioid consumption recorded during three time periods; (i) intraoperatively, (ii) recovery room, and (iii) first 24 hours postoperatively. Measurements and Main Results 191 women underwent hysterectomy, 68 vaginal (36%), 91 laparoscopic assisted (48%), and 32 open (17%). The mean age and body mass index were 50 (27–77) and 27 (17-64) kg/m2, respectively. Most hysterectomies (138, 73%) were performed in premenopausal women. The majority of all hysterectomies were for benign indications (166, 87%), and 40 (21%) were pain-related. Median COC for all hysterectomies was 75 mg OME, and median 24h postoperative COC was 16 mg OME. In multivariate analysis, preoperative NRS scores, PSQ minor scores, preoperative use of pain medication and an open approach were found to be significant predictors of increased COC. Each additional point on the PSQ minor mean score and preoperative NRS score was found to be associated with an increase of 4 and 2.5 mg OME, respectively. Patients with open hysterectomy consumed 59.75 mg OME more than minimally invasive surgery patients, when all other factors were equal. Each additional preoperative pain medication was associated with a 9 mg OME increase. Conclusion Predictors of cumulative postoperative opioid requirements for hysterectomy include preoperative NRS scores, PSQ minor scores, number of preoperative pain medications, and surgical approach. This information can be used to create a predictive calculator to individualize perioperative interventions, optimize postoperative pain management, and tailor opioid use.