(112) Preoperative Cerebral Spinal Fluid β-Endorphin Levels and Opioid Use after Cesarean

Thursday, February 9, 2023

10:30 AM – 12:00 PM

Objective: Prior work indicates that responsiveness to opioid analgesics is influenced by endogenous opioid system function in the lab. We evaluated whether preoperative levels of β-Endorphin (BE), an endogenous opioid agonist, in cerebrospinal fluid (CSF) and plasma are associated with opioid use after cesarean.

Study Design: We enrolled 136 pregnant patients without opioid use disorder or chronic pain undergoing scheduled cesarean with regional anesthesia. In the preoperative period, participants completed surveys with validated pain measures (Table 2) and we analyzed BE levels from plasma and CSF using ELISA assay. In the postoperative period, participants completed pain measures again at 48 hours and 2 weeks and reported total opioid use. Our primary outcome was total opioid use summed from both inpatient and outpatient periods. We studied the association between preoperative CSF BE levels and our primary outcome using linear regression and controlling for age, BMI, and race. Secondary outcomes included inpatient and outpatient opioid use examined individually. In a second analysis, we examined associations between preoperative plasma BE levels and the primary outcome, and associations between preoperative BE levels and pre and postoperative pain measures.

Results: All participants completed pre and postoperative surveys and demographics are reported (Table 1). Neither CSF nor plasma BE levels were associated with total opioid use. CSF BE levels weakly correlated with plasma BE levels (r = 0.28, p < .01). CSF BE levels were associated positively with preoperative and 48-hour postoperative pain intensity scores. Plasma BE levels were associated positively with 48-hour and 2-week postpartum pain intensity scores (Table 2).

Conclusion: Preoperative CSF levels of β-endorphin are not associated with opioid analgesic use after scheduled cesarean but are associated with higher pre and postoperative pain intensity scores. It is possible that variability in opioid receptor sensitivity modifies these associations.

Primary & Presenting Author(s)

Amelie Pham, MD (she/her/hers)
Fellow
Vanderbilt University Medical Center
Nashville, Tennessee, United States

Coauthor(s)

SO
Sarah S. Osmundson, MD,MSCR
Associate Professor
Vanderbilt University
Nashville, Tennessee, United States
AP
Alex Pedowitz, BA
University of Miami Leonard M. Miller School of Medicine
Miami, Florida, United States
NW
Nancy E. Wickersham, BS
Senior Research Analyst
Vanderbilt University
Nashville, Tennessee, United States
LS
Laura Sorabella, MD
Assistant Professor
Vanderbilt University
Nashville, Tennessee, United States
SB
Stephen Bruehl, PhD
Vanderbilt University Medical Center
Nashville, Tennessee, United States