Learnability of Ultrasound-Guided Locoregional Anesthesia for Carotid Endarterectomy

Background/Objectives: There is an ongoing debate about the most advantageous anesthesia technique for carotid endarterectomy (CEA). From an anesthesiologic perspective, locoregional anesthesia (LRA) appears to offer significant benefits. However, the learning curve and complication rates for anesthesiologists newly performing ultrasound-guided LRA for CEA remain unclear and are to be examined in greater detail in this study. Methods: This retrospective, single-center study included all consecutive LRA administrations for CEA following the introduction of this procedure at a district hospital in Germany from November 2013 to November 2017. Nine board-certified anesthesiologists, initially inexperienced in LRA for CEA but with prior experience in other ultrasound-guided peripheral nerve blocks (PNBs), received theoretical training and supervision during their first six combined deep and superficial cervical plexus blocks under ultrasound guidance. The primary endpoint was the incidence of insufficient block quality, indicated by pain and restlessness or the additional need for analgesics. Secondary endpoints included LRA-associated complications. Patients were divided into four groups based on the number of previously performed LRA procedures by the attending anesthesiologist. Results: In 83 patients, LRA was performed by initially inexperienced anesthesiologists. Group A (patients managed by anesthesiologists performing their 1st to 3rd cervical plexus blockades) included 21 patients, Group B (blockades 4-6) included 12 patients, Group C (blockades 7-9) included 9 patients, and Group D (≥10 blockades) included 41 patients, respectively. The overall complication rate was 22% (18/83). Insufficient block quality occurred in 18.1% of patients (15/83), resulting in three conversions to general anesthesia (3.6%). Additional complications included dysphagia (n = 2) and Horner's syndrome (n = 1). The incidence of insufficient block quality was significantly reduced (p = 0.008) after performing the first three blockades. Conclusions: Ultrasound-guided cervical plexus block for CEA appears to be a rapidly learnable anesthesia technique for anesthesiologists experienced in other ultrasound-guided PNBs, with a low risk of complications. After three supervised blockades, the failure rate of LRA decreases significantly.