**1. Introduction**

Cardiac surgery (CS) generates a unique set of challenges compared to non-cardiac surgery. Postoperative outcomes and quality of life result from several factors, including demographic characteristics, comorbidities, type and quality of surgical intervention, the extent of the systemic inflammatory response, range of organ dysfunction and pain [1–4]. Conveniently, many of these factors are amenable to optimization. To this end, enhanced recovery after surgery (ERAS) programs have evolved and are now commanded by a multidisciplinary consensus in CS [5].

Pain managemen<sup>t</sup> is a crucial element of cardiac ERAS. Adequate analgesia is a prerequisite to ensure patient comfort, low morbidity, early mobilization, and cost effectiveness. Postoperative pain is multifaceted and may result from various interventions, including sternotomy, thoracotomy, chest drains and leg vein harvesting. One study found that maximal pain intensity in CS was usually moderate [6], but severe acute postoperative pain was also reported elsewhere and more frequently associated with chronic post-sternotomy pain [7].

Traditionally, opioids were considered the mainstay for pain managemen<sup>t</sup> after CS based on a predictable hemodynamic profile. Acknowledged risks associated with their use (e.g., hyperalgesia, opioid dependence, respiratory depression, nausea and vomiting, immunosuppression, ileus, delirium, prolonged postoperative recovery) fueled that which now represents a central tenet in the ERAS paradigm–multimodal analgesia (MA) [8]. MA built on drug combinations is not faultless [9]; N-methyl-D-aspartate (NMDA) antagonists

**Citation:** Balan, C.; Bubenek-Turconi,S.-I.; Tomescu, D.R.; Valeanu, L. Ultrasound-Guided Regional Anesthesia–Current Strategies for Enhanced Recovery after Cardiac Surgery. *Medicina* **2021**, *57*, 312. https://doi.org/10.3390/ medicina57040312

Received: 11 February 2021 Accepted: 22 March 2021 Published: 25 March 2021

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may bring about sympathetic hyperactivity, central alpha-2 agonists can cause bradycardia and hypotension, and nonsteroidal anti-inflammatory agents are associated with renal dysfunction and abnormal clotting.

Regional anesthesia/analgesia (RA) represents a valid alternative for the MA repertoire. It obviates many of the drawbacks of drug-based MA strategies, albeit with its particular challenges [10]. Classical neuraxial techniques such as thoracic epidural anesthesia (TEA) and landmark-based paravertebral blocks (PVBLM) constituted the standard regional approach to ensure chest wall pain relief before ultrasound (US) virtually revolutionized RA. Bleeding complications (e.g., spinal epidural hematoma (SEH)) were the primary concern regarding the use of TEA and PVBLM in CS [11]. This may explain to some extent why CS fell behind other surgical specialties regarding the large-scale implementation of ERAS programs. Since its inception, US-guided RA (USRA) has helped improve existing techniques (i.e., PVB) and favored the design of new ones. Specifically, real-time US needle-tracking is essential to perform chest wall fascial plane blocks (CWFPB) [12]. Delivery of local anesthetics (LA) between myofascial layers spares the neuraxium and blocks the nerves as they course within that tissue plane. Reasons for the growing popularity of CWFPB include (1) ease of performance; (2) excellent safety profile; (3) good efficacy in various clinical settings. The scope of this review is to address the use of RA in CS, with particular reference to the indications, techniques, and complications of currently available CWFPB (see Table A1, Appendix A).
