Pilot epinephrine dose-finding study to counter epidural-related blood pressure reduction

Abstract

Objective: An unwanted side effect associated with epidural analgesia is the reduction in blood pressure (BP) due to the sympathetic blockade. This study evaluated the hemodynamic effects of adding different epinephrine concentrations to epidurally injected local anesthetic solution to counteract sympathectomy. We hypothesized that epinephrine could mitigate the decrease in BP possibly caused by the local anesthetic, specifically decreasing the incidence of hypotension.

Methods: Sixty-six patients were enrolled in a randomized, controlled, quadruple-blinded prospective study into three groups: epidural ropivacaine 0.2% without epinephrine (control) or with 2 µg/mL or 5 µg/mL epinephrine. Our primary outcome was the assessment of differences in hypotension between groups, defined as a >20% decrease in hypotension from baseline to the end of the intraoperative period.

Results: Forty-seven patients completed the study, and 19 were withdrawn. Fifteen patients were in the control group, while 16 patients received 0.2% ropivacaine +2 µg/mL epinephrine, and 16 received 0.2% ropivacaine +5 µg/mL epinephrine. The overall rate of hypotension was 21.3% (10/47). There were no statistically significant differences in hypotension rates between the control group (33%) and groups receiving either +2 µg/mL (13%, p=0.165) or +5 µg/mL (19%, p=0.353) of epinephrine. In secondary analyses, respiratory rate showed greater decreases in control groups across the perioperative period compared with treatment groups (p=0.016) CONCLUSION: Adding epinephrine to the epidural local anesthetic did not significantly decrease the rate of hypotension. However, epinephrine mitigated decreases in respiratory rate across the perioperative period. Future studies will focus on increasing group size and higher epinephrine concentrations (10 µg/mL).

Trial registration number: NCT02722746.

Keywords: Autonomic Nerve Block; Nerve Block; REGIONAL ANESTHESIA; analgesia.