Safety of Ultrasound-Guided Serratus Anterior and Erector Spinae Fascial Plane Blocks: A Retrospective Analysis in Patients Undergoing Cardiac Surgery While Receiving Anticoagulant and Antiplatelet Drugs

Abstract

Chest wall blocks are an effective strategy for postoperative pain control in minimally invasive cardiac surgery, but, in the absence of clinical trials evaluating their safety in the presence of anticoagulant and antiplatelet drugs, it still is recommended to follow the same guidelines developed for the neuraxial procedures and for peripheral blocks. Retrospective observational study. AOU Città della Salute e della Scienza di Torino, University of Turin, Italy. Between March 28, 2019 and October 19, 2020, 70 patients who underwent mitral valve surgery via right minithoracotomy were enrolled: 35 treated with continuous erector spinae plane block (ESPB) and 35 with continuous serratus anterior plane block (SAPB). The primary objective was the evaluation of the number of blocks performed or catheters removed while coagulation was abnormal or antithrombotic and anticoagulant therapies were in progress. Eleven patients (15.7%) received fascial plane block with international normalized ratio (INR) > 1.40, four patients (5.71%) with a platelet count <80×103, and one patient received ESPB block during dual-antiplatelet therapy. In 16 patients (22.9%), the catheter was removed with an INR > 1.40, in five patients (7.1%) with a platelet count <80×103, and in 53 patients (75.71%) despite low-molecular-weight heparin at therapeutic dose. The median antagonist dose of vitamin K at the time of catheter removal was 2.5 mg (range 2.5-3.44 mg) in both groups. No major adverse effects directly attributable to the blocks were observed. The authors did not find any problems related to the use of continuous ESPB and SAPB, although they were performed in the presence of anticoagulation and in a context with a high risk of bleeding such as cardiac surgery.