Opioid-Sparing Cardiac Anesthesia

Secondary Analysis of an Enhanced Recovery Program for Cardiac Surgery

Michael C. Grant, MD, MSE; Tetsuro Isada, MD; Pavel Ruzankin, PhD; Allan Gottschalk, MD, PhD; Glenn Whitman, MD; Jennifer S. Lawton, MD; Jeffrey Dodd-o, MD; Viachaslau Barodka, MD

Disclosures

Anesth Analg. 2020;131(6):1852-1861. 

In This Article

Abstract and Introduction

Abstract

Background: Cardiac anesthetics rely heavily on opioids, with the standard patient receiving between 70 and 105 morphine sulfate equivalents (MSE; 10–15 μg/kg of fentanyl). A central tenet of Enhanced Recovery Programs (ERP) is the use of multimodal analgesia. This study was performed to assess the association between nonopioid interventions employed as part of an ERP for cardiac surgery and intraoperative opioid administration.

Methods: This study represents a post hoc secondary analysis of data obtained from an institutional ERP for cardiac surgery. Consecutive patients undergoing cardiac surgery received 5 nonopioid interventions, including preoperative gabapentin and acetaminophen, intraoperative dexmedetomidine and ketamine infusions, and regional analgesia via serratus anterior plane block. The primary objective, the association between intraoperative opioid administration and the number of interventions provided, was assessed via a linear mixed-effects regression model. To assess the association between intraoperative opioid administration and postoperative outcomes, patients were stratified into high (>50 MSE) and low (≤50 MSE) opioids, 1:1 propensity matched based on 15 patients and procedure covariables and assessed for associations with postoperative outcomes of interest. To investigate the impact of further opioid restriction, ultralow (≤25 MSE) opioid participants were then identified, 1:3 propensity matched to high opioid patients, and similarly compared.

Results: A total of 451 patients were included in the overall analysis. Analysis of the primary objective revealed that intraoperative opioid administration was inversely related to the number of interventions employed (estimated −7.96 MSE per intervention, 95% confidence interval [CI], −9.82 to −6.10, P < .001). No differences were detected between low (n = 136) and high (n = 136) opioid patients in postoperative complications, postoperative pain scores, time to extubation, or length of stay. No differences were found in outcomes between ultralow (n = 63) and high (n = 132) opioid participants.

Conclusions: Nonopioid interventions employed as part of an ERP for cardiac surgery were associated with a reduction of intraoperative opioid administration. Low and ultralow opioid use was not associated with significant differences in postoperative outcomes. These findings are hypothesis-generating, and future prospective studies are necessary to establish the role of opioid-sparing strategies in the setting of cardiac surgery.

Introduction

In 1969, Lowenstein et al[1] published their landmark article detailing the use of high dose morphine (1 mg/kg) as the sole anesthetic for aortic valve disease requiring open-heart surgery. The anesthetic, noteworthy for its hemodynamic stability, became increasingly popularized in the setting of cardiac surgery over the interceding decades.[2] Although a variety of adjuncts have been adopted during that time, including amnestic, maintenance, and paralytic medications,[3,4] present-day cardiac anesthesia continues to rely heavily on opioids. At the turn of the century, fast-track cardiac surgery sought to lower opioid administration,[5] and although the overall amount of opioid has been reduced since the era of Lowenstein and Stoelting, standard fentanyl use for cardiac surgery stands at 10–15 μg/kg (~70–105 morphine sulfate equivalents [MSE]) for a 70 kg patient.[5,6]

There are several reasons to reconsider the role of opioids in the setting of cardiac surgery. First, the US opioid crisis has led to the reevaluation of periprocedural anesthesia and pain management. Evidence suggests an association between intraoperative opioid administration and subsequent postoperative opioid use[7] as well as the incidence of postoperative complications, including readmission.[8] A number of procedures have been implicated as significant contributors to new persistent opioid use, defined as opioids prescribed greater than 90 days following surgery in otherwise naive patients.[9] Cardiac surgery, a potentially underappreciated contributor, likely plays a more central role than expected with a 6%–12% proportion of persistent opioid use compared to more modest estimates in general surgical populations.[10,11] These figures, coupled with ever more knowledgeable patients and expanding state opioid "opt-out" legislation,[12,13] which allows patients to refuse opioid-based analgesia as part of their inpatient hospital stay, suggest that cardiac service lines must develop strategies to markedly reduce the use of perioperative opioids. The use of multimodal analgesia and opioid reduction strategies was included in recommendations recently put forth by the Enhanced Recovery After Surgery Cardiac Society.[14]

Our group has implemented an Enhanced Recovery Program (ERP) for cardiac surgery, which employs a series of nonopioid interventions, that may reduce the reliance on and potentially eliminate the use of intraoperative opioids. Although other results of the program have been previously reported,[15] here, we hypothesized that the use of nonopioid interventions introduced as part of an ERP for cardiac surgery was associated with reduced intraoperative opioid administration. In addition, we hypothesized that intraoperative opioid administration would not be associated with differences in postoperative outcomes.

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