SPIP vs ESP Block in Cardiac Surgery

This multicenter, parallel‐group, randomized controlled non‐inferiority trial willcompare bilateral SPIP block with bilateral ESP block for postoperative analgesia inadults undergoing first‐time on‐pump cardiac surgery through median sternotomy.Patients aged 18‐80 years will be enrolled across tertiary cardiac surgery centres inTürkiye and randomly assigned in a 1:1 ratio, stratified by center, to receive eitherbilateral SPIP block or bilateral ESP block. Both interventions will be performed beforeinduction of general anesthesia. Participants in the SPIP group will receiveultrasound‐guided injection between 4th and 5th ribs, whereas participants in the ESPgroup will receive bilateral ultrasound‐guided injection at the T5 transverse process.Perioperative anesthesia, postoperative multimodal analgesia, and patient‐controlledmorphine analgesia will be standardised across participating centers. Postoperativeoutcome assessors will remain blinded to treatment allocation. Block success will beassessed using cold sensation testing before induction.The primary outcome is cumulative opioid consumption from extubation to 24 hours afterextubation, expressed as intravenous morphine milligram equivalents (IV‐MME). The primaryobjective is to determine whether SPIP block is non‐inferior to ESP block using aprespecified non‐inferiority margin of 3 mg IV‐MME. Secondary outcomes includetime‐weighted average pain intensity at rest and during coughing over the first 24 hoursafter extubation, Quality of Recovery‐15 scores at 24 hours and hospital discharge, andthe incidence of chronic postsurgical pain at 3 months. Exploratory outcomes includerescue analgesic requirements, postoperative nausea and vomiting and other opioid‐relatedadverse effects, time to extubation, intensive care unit and hospital length of stay,block failure, and block‐related complications.The primary non‐inferiority analysis will be performed in both the intention‐to‐treat andper‐protocol populations. The between‐group location shift in 24‐hour IV‐MME consumptionwill be estimated using the Hodges‐Lehmann method with a two‐sided 95% confidenceinterval. Non‐inferiority will be concluded if the upper bound of the confidence intervalfor the SPIP minus ESP difference is less than 3 mg IV‐MME.