Fast-Track Anesthesia in Minimally Invasive Cardiac Surgery: dexmedetomidine and Erector Spinae Plane Block vs Opioid-Based Anesthesia

Enhanced Recovery After Surgery (ERAS) pathways have transformed perioperative care byimplementing patient‐centered, evidence‐based protocols that improve outcomes whilereducing hospital length of stay (HLOS) and healthcare expenditure [1]. In cardiacsurgery, ERAS has driven the transition from conventional prolonged postoperativemechanical ventilation toward fast‐track extubation (FTE) strategies [1,2].Traditionally, cardiac anesthesia relied on high‐dose opioid techniques (e.g., fentanyl50‐100 mcg/kg) combined with overnight ventilation to suppress surgical stress responsesand maintain hemodynamic stability [2]. Although effective for these goals, this approachis associated with respiratory depression, delayed emergence, prolonged ICU stay,postoperative nausea and vomiting (PONV), ileus, delirium, and increased healthcare costs[1,3].Fast‐track cardiac anesthesia (FTCA) aims to achieve extubation within 6‐8 hours aftersurgery, promoting earlier mobilization, faster oral intake, and reduced ICU‐acquiredweakness [1]. Evidence from a 2016 Cochrane review demonstrated that low‐dose opioid FTCAprovides comparable mortality, reintubation, and major complication rates to traditionalhigh‐dose regimens while significantly shortening ICU stay [2]. Modern protocols reportsuccessful extubation within 4‐6 hours in more than 60% of elective cardiac surgerypatients, with mean ICU stay around 31 hours [4].Successful implementation of FTE depends on three core elements: (1) appropriate patientselection (EuroSCORE II <4%, LVEF ≥45%, absence of severe pulmonary disease), (2)optimized intraoperative management including reduced cardiopulmonary bypass (CPB)duration and careful inotrope use, and (3) structured postoperative weaning pathways [1].Despite FTCA benefits, opioids remain the dominant perioperative analgesic strategy. Highintraoperative opioid exposure suppresses respiratory drive, delaying extubation andincreasing aspiration risk [2]. Postoperative opioid‐related complications‐including PONV(20‐30% incidence), ileus, urinary retention, delirium, and pruritus‐extendhospitalization and decrease patient satisfaction [1,3].Additional concerns include opioid‐induced immunosuppression potentially increasinginfection risk after CPB and opioid‐induced hyperalgesia and tolerance complicatingpostoperative analgesia, especially in opioid‐naïve patients [6]. These concerns,together with the ongoing opioid epidemic, reinforce the need to minimize perioperativeopioid exposure in alignment with ERAS principles [1].Dexmedetomidine is a highly selective α2‐adrenergic agonist (α2:α1 selectivity ratio1620:1) providing sedation, anxiolysis, and analgesia without clinically significantrespiratory depression [3].In cardiac surgery, dexmedetomidine offers several advantages: ‐ Hemodynamic stability: attenuates sympathoadrenal responses during laryngoscopy andintubation without tachycardia; a preoperative dose of 0.5 mcg/kg effectivelyreduces heart rate and blood pressure surges [3]. ‐ Myocardial protection: lowers myocardial oxygen consumption and may reducepostoperative troponin release compared with propofol‐based anesthesia. ‐ Delirium prevention: associated with reduced postoperative delirium incidence,particularly relevant because prolonged ventilation independently increases deliriumrisk. ‐ Opioid‐sparing effect: decreases perioperative opioid requirements by approximately30‐50% [3].Importantly, preservation of respiratory drive makes dexmedetomidine particularlysuitable for FTCA protocols where early extubation is a primary objective [3].Introduced by Forero et al. in 2016 for thoracic neuropathic pain, ESPB has emerged as asimple, safe, and effective fascial plane block [5]. Local anesthetic injected betweenthe transverse process and erector spinae muscle spreads craniocaudally, reaching dorsaland ventral spinal nerve rami from T1‐T12 [1].Compared with thoracic epidural or paravertebral approaches, ESPB provides severaladvantages in cardiac surgery: ‐ Improved safety: minimal risk of spinal hematoma in anticoagulated patients, lowerpneumothorax risk, and avoidance of sympathectomy‐related hypotension [6]. ‐ Technical simplicity: ultrasound guidance permits real‐time identification ofanatomical landmarks while avoiding neural and vascular structures [6]. ‐ Bilateral applicability: suitable for median sternotomy and minimally invasivecardiac surgery (MICS) requiring bilateral analgesia [7].Clinical evidence supports its analgesic efficacy. A randomized study in minimallyinvasive coronary artery bypass grafting (MIDCAB) demonstrated a 70% reduction inintraoperative fentanyl use (0.9 mg vs. 3.0 mg; p<0.01), reduced norepinephrinerequirements, and prolonged opioid‐free analgesia for 34 hours postoperatively [8].Additional randomized evidence in MICS confirmed lower postoperative opioid consumptionand improved pain control compared with local infiltration techniques [9].Combining dexmedetomidine with local anesthetics may extend block duration through twocomplementary mechanisms: 1. Local vasoconstriction: reducing anesthetic washout from the injection site. 2. Direct analgesic action: activation of peripheral and dorsal root ganglion α2receptors, suppressing nociceptive transmission [7].A current randomized study (NCT06981949) is evaluating whether bilateral ESPB usingdexmedetomidine (0.5 mcg/kg per side) with ropivacaine 0.375% prolongs analgesia andfurther reduces opioid requirements compared with ropivacaine alone [7].MICS includes procedures performed through limited‐access approaches such asmini‐thoracotomy, mini‐sternotomy, or port‐access techniques instead of full mediansternotomy. Compared with conventional cardiac surgery, MICS reduces tissue trauma,postoperative pain, recovery time, and hospitalization duration [1,8]. Nevertheless,effective analgesia remains challenging because of chest tubes, rib retraction, andpleurotomy.Because MICS patients generally have lower operative risk (lower EuroSCORE), reducedtissue injury, and fewer contraindications to ESPB, this population represents an idealsetting to evaluate a combined dexmedetomidine‐ESPB opioid‐sparing fast‐track extubationstrategy [9].