Serratus plane block versus standard of care for pain control after totally endoscopic aortic valve replacement: a double-blind, randomized controlled, superiority trial

Abstract

Introduction: Serratus anterior plane block has been proposed to reduce opioid requirements after minimally invasive cardiac surgery, but high-quality evidence is lacking.

Methods: This prospective, double-blinded, randomized controlled trial recruited patients undergoing totally endoscopic aortic valve replacement. Patients in the intervention arm received a single-injection serratus anterior plane block on arrival to the intensive care unit added to standard of care. Patients in the control group received routine standard of care, including patient-controlled intravenous analgesia. Primary outcome was piritramide consumption within the first 24 hours after serratus anterior plane block placement. We hypothesized that compared with no block, patients in the intervention arm would consume 25% less opioids.

Results: Seventy-five patients were analyzed (n=38 in intervention arm, n=37 in control arm). When comparing the serratus anterior plane group with the control group, median 24-hour cumulative opioid use was 9 (IQR 6-19.5) vs 15 (IQR 11.3-23.3) morphine milligram equivalents, respectively (p<0.01). Also, pain scores at 4, 8 and 24 hours were lower in the intervention arm at 4, 8 and 24 hours, respectively.

Conclusion: Combined deep and superficial single-injection serratus anterior plane block is superior to standard of care in reducing opioid requirements and postoperative pain intensity up to 24 hours after totally endoscopic aortic valve replacement.

Trial registration number: NCT04699422.

Keywords: analgesia; nerve block; pain, postoperative.

Figure 1

CONSORT participant flow diagram. BMI, body mass index; CONSORT, Consolidated Standards of Reporting Trials; ERACS, enhanced recovery after cardiac surgery; PCIA, patient-controlled intravenous analgesia; SAP, serratus anterior plane.

Figure 2

(A) Cumulative opioid consumption (MME) up to 24 hours after block placement. Significant differences (p<0.05) are marked with an asterisk (*). Strongly significant p<0.01 is marked with **. (B) Pain scores (NRS) at predefined time intervals. Statistically significant differences (p<0.05) are marked with an asterisk (*). MME, morphine milligram equivalent; NRS, Numeric Rating Scale; POD, postoperative day; SAP, serratus anterior plane.