Optimizing Analgesia After Minimally Invasive Cardiac Surgery: A Randomized Non-Inferiority Trial Comparing Interpectoral Plane Block Plus Serratus Anterior Plane Block to Erector Spinae Plane Block

<b>Background:</b> Regional anesthesia techniques are increasingly used for pain management in minimally invasive cardiac surgery (MICS). We aimed to evaluate whether the combination of interpectoral plane block (IPB) and superficial serratus anterior plane block (SAPB) provides non-inferior postoperative analgesia compared to erector spinae plane block (ESPB) in adult patients undergoing MICS. <b>Methods:</b> In this prospective, single-center, double-blind, randomized, non-inferiority trial, 40 adult patients scheduled for MICS were allocated to receive either ESPB (<i>n</i> = 20) or a combination of IPB + SAPB (<i>n</i> = 20) prior to surgical incision. All patients received standardized anesthesia. Pain was assessed using the Critical-Care Pain Observation Tool (CPOT) during intubation and the Numerical Rating Scale (NRS) at 6-48 h postoperatively, following extubation. The primary outcome was the NRS score at 24 h. A non-inferiority margin of 2 NRS points was pre-specified, and non-inferiority was evaluated using between-group differences with 95% confidence intervals. Opioid consumption was recorded via PCA fentanyl and rescue analgesics, converted to morphine milligram equivalents (MMEs). Secondary outcomes included extubation time and postoperative nausea and vomiting (PONV). <b>Results:</b> Median 24 h NRS was 3.0 (0-5.0) in the ESPB group and 2.5 (0-5.0) in the IPB + SAPB group. The between-group difference remained within the predefined two-point margin (95% CI: -0.8 to 1.2). Opioid consumption (<i>p</i> = 0.394), extubation time, and PONV incidence were comparable (all <i>p</i> > 0.05). No block-related complications occurred. <b>Conclusions:</b> IPB + SAPB was non-inferior to ESPB for postoperative analgesia in MICS. Despite requiring two injections, it remains an effective alternative. Larger trials are needed to confirm these findings.