Assessing Impact of Multimodal Analgesia and Determining Incidence of Postoperative Delirium in Patients Undergoing Shoulder Arthroplasty
Several studies have demonstrated improved outcomes in arthroplasty patients treated with multimodal analgesia regimens perioperatively.
At our institution, treatment with a multimodal analgesia protocol including acetaminophen, gabapentin, and celecoxib, has become our standard for managing postoperative pain in hip and knee arthroplasty patients. We extended this multimodal analgesia protocol to patients undergoing shoulder arthroplasty to assess the impact of multimodal analgesia in this patient population by comparing postoperative pain scores and opioid consumption in patients treated with a standard versus a multimodal analgesia regimen. In addition, we examined the incidence of postoperative delirium in patients undergoing shoulder arthroplasty who were treated with a multimodal analgesia regimen.
Prior to November 2015, all patients undergoing elective shoulder arthroplasty at our institution were treated with an interscalene regional nerve block preoperatively, followed by a standard opioid-based regimen postoperatively (Table 1). Starting in November 2015, a multimodal protocol including acetaminophen, gabapentin, and celecoxib was implemented for these patients (Table 2). After obtaining IRB approval, we performed a retrospective chart review from February 2015 to June 2016, comparing 75 patients treated with the multimodal approach to 75 patients treated with the standard approach. Patient metrics including inpatient pain scores, opioid use, length of stay, and 30- and 90- day readmission rates were collected retrospectively and compared between the two groups.
Since November 2015, Nu-DESC scores have been routinely collected on all postoperative arthroplasty patients to screen for postoperative delirium (Fig. 1). Following the cohort analysis, Nu-DESC scores were gathered from charts retrospectively for patients treated with the multimodal analgesia regimen from November 2015 to November 2017 to determine the incidence of delirium in this patient population.
The demographic characteristics of the cohorts were similar (Table 3).
Patients treated with the multimodal analgesia protocol had significantly lower postoperative day 0 pain scores (mean 1.5 vs 2.2, p=0.03). Postoperative day 1 and day 2 pain scores averaged 4.1 and 3.4, respectively, and were not significantly different between the 2 cohorts (Fig. 2). Opioid consumption in multimodal regimen patients was significantly lower on postoperative days 0, 1, and 2 (Fig. 3).
Opioid use in the multimodal cohort was lower by 47% on postoperative day 0, 37% on postoperative day 1, and 44% on postoperative day 2. The mean length of hospital stay for patients treated with multimodal pain protocol was significantly shorter than for patients treated with the standard pain protocol (average 1.44 days vs. 1.91 days, p=<0.001). There was no significant difference in 30- or 90- day readmission rates.
Out of 256 patients treated with the multimodal analgesia regimen, 221 patients had Nu-DESC scores reported in the chart. Using Nu-DESC score greater than 0 as a cutoff for determining delirium risk, 3 out of 221 patients screened positive for delirium. Therefore, the calculated incidence for delirium in this patient population is 1.36%.
In patients undergoing shoulder arthroplasty, multimodal analgesia was associated with decreased opioid consumption and shorter hospital stay. Therefore, implementation of a multimodal pain pathway is a safe and effective means to control postoperative pain with improved outcomes after shoulder arthroplasty. To the authors’ knowledge, the incidence of delirium in patients undergoing shoulder arthroplasty has not yet been reported. We found it is much lower than the incidence of delirium reported in patients undergoing other joint arthroplasty procedures. Further studies are needed to assess whether implementation of multimodal analgesia pathways has an effect on the incidence of postoperative delirium in these patients.