The Serratus Anterior Plane Study: Continuous Deep Serratus Anterior Plane Block for Mitral Valve Surgery Performed in Right Minithoracotomy

Abstract

Objective: Regional anesthesia with thoracic wall blocks could represent an opioid-sparing alternative for mitral valve surgery in right minithoracotomy (mini-MVS). For the present study, an opioid-free analgesia using continuous deep serratus anterior plane block was compared with intravenous morphine.

Design: Prospective, observational cohort study.

Setting: Azienda Ospedaliero Universitaria Città della Salute e della Scienza di Torino, University of Turin, Italy.

Participants: The present study enrolled patients who underwent mini-MVS from March to October 2019 (63 patients) and divided them into the following 2 groups, according to pain control strategy: a morphine group and a serratus anterior plane (SAP) group.

Interventions: Primary outcomes were pain evaluation and total postoperative opioid consumption, and secondary outcomes were incidence of postoperative nausea and vomiting, time to extubation, mechanical ventilation duration, and bowel dysfunction.

Measurements and main results: The mean number rating scale at 24 hours was 2.15 (95% confidence interval [CI] 1.22-3.09) in the SAP group versus 3.23 (95% CI 2.28-4.29) in the morphine group (p = 0.07), whereas the mean number rating scale at 48 hours was significantly less in the SAP group compared with the morphine group (1.77 [95% CI 0.99-2.54] v 3.23 [95% CI 2.13-4.33], respectively; p = 0.03). Mean morphine consumption at 48 postoperative hours was 12.98 mg (95% CI 10.90-15.05 mg) in the morphine group and 2.22 mg (95% CI 0.99-3.44 mg) in the SAP group; p < 0.01. Cumulative morphine consumption at 24 postoperative hours was 10.44 mg (95% CI 8.36-12.52) in the morphine group and 1.16 mg (95% CI 0.37-1.95) in the SAP group; p < 0.01. There were no significant differences for secondary outcomes.

Conclusions: Continuous deep serratus anterior plane block seems to be a valid alternative to intravenous opioids in terms of efficacy for patients undergoing mini-MVS with a lower opioid requirement.

Keywords: cardiac surgical procedures; continuous peripheral techniques; postoperative pain; regional anesthesia; truncal blocks.