Background and aims The application of thoracic wall blocks for breast surgery has been expanded from adjunctive analgesia to the primary anesthetic technique for challenging cases¹ not suitable for general anesthesia (GA). We describe a case of local anesthetic toxicity due to a serratus fascial plane block intended as the primary anesthetic technique for breast surgery.

Methods 41 year old female with dilated myocardiopathy (estimated left ventricular ejection fraction of 40%), severe mitral insufficiency, moderate pulmonary hypertension, and left humerus osteosarcoma requiring limb amputation and multiple reconstructive surgeries involving the scapular girdle and ipsilateral pectoral region. She was scheduled for bilateral extraction of breast prostheses including pectoral mobilization and capsulotomy for spontaneous implant rupture.

Results Anesthetic plan was regional anesthesia via ultrasound guided bilateral serratus plane and bilateral pectoral nerve blocks (PECS I) with sedation in order to avoid using GA. Left side ultrasound showed cephalad displacement of anatomic landmarks of pectoral muscles, but block was performed uneventfully. 15 minutes after regional anesthesia delivery, the patient developed symptoms of local anesthetic neurotoxicity without cardiac symptoms, requiring intravenous lipid emulsion and supportive measures.

Conclusions Although regional anesthesia via fascial block can be a useful anesthetic technique for breast surgery, adequate analysis of individual risk factors for local anesthetic toxicity should be taken into account to prevent adverse events,² in this case the preexisting anatomic alterations. Therefore, we suggest that regional anesthesia as the primary anesthetic technique for breast surgery in high risk patients should be discussed by a multidisciplinary team to improve outcomes.³