A 56-year-old woman underwent an uncomplicated left shoulder bone spur removal under general anesthesia with 2 mg of versed, 100 mcg of fentanyl, 150 mg of propofol, and sevoflurane in an outpatient surgery center. After completion of the procedure, the anesthesiologist performed an interscalene nerve block for post-operative pain control utilizing 30 mL of bupivacaine (0.25%). Approximately 5 min after completion of the block, the patient developed bilateral mydriasis, paralysis of all extremities, and respiratory arrest. The patient was immediately intubated, administered IV fluids, ephedrine 15 mg IV, and transferred to an emergency department (ED).\nOn ED arrival the patient was being ventilated through an oral endotracheal tube and was completely paralyzed. Her vital signs were: blood pressure (BP) 108/56 mmHg; pulse 86 per minute; respiratory rate 24 breaths per minute on a ventilator. Her pupils were 6 mm and unresponsive to light bilaterally. She had no response to painful stimulation and had no spontaneous respirations on a ventilator. Her initial blood tests included a complete blood count, electrolytes, liver function tests, cardiac enzymes, and coagulation tests. The lab results were all unremarkable except for a phosphorus of 1.7 mg/dL and lactate of 4 mmol/L. In the ED she was administered a 1-L normal saline bolus and 20% intravenous lipid emulsion 85 mg. Over the next 4 h, the patient progressively regained motor and sensory functions followed by successful extubation in the ED. She was admitted to the hospital for observation and discharged home the next day without any neurologic sequelae.
Patient 2 was a previously healthy, 52-year-old male with a spontaneous complete rupture of the left supraspinatus tendon. The patient received an arthroscopic rotator cuff repair, and a single-injection ISB combined with TIVA was selected as the anesthetic strategy. Preprocedural BP was 130/60 mm Hg; HR 66 bpm; SpO2 values 99–100%. After ultrasound- and PNS-guided placement of a left ISB, the brachial nerve block was performed by injecting 1% lidocaine (10 mL) followed by 0.375% ropivacaine (10 mL). There was a negative aspiration test for blood and cerebrospinal fluid prior to injection. Physical examination revealed an effective interscalene block. Adverse cardiac or neurologic symptoms were not recorded. After induction of anesthesia, and intubation, TIVA was maintained with propofol and sufentanil. BP was measured every 5 min with a noninvasive cuff. The patient underwent an uneventful operative rotator cuff repair under the ISB and intravenous anesthesia. Intraoperatively, recorded SBP levels of 100–120 mmHg were interrupted by SBP levels of ≥90 and <100 mmHg for a maximum of 35 min due to the application of controlled hypotension. Administration of antihypertensive and/or vasoconstrictor drugs was not recorded. SpO2 (98–100%) and ETCO2 values (34–37%) were normal throughout the case. The duration of surgery was 56 min. After termination of TIVA, and extubation in the OR, the patient presented with impaired consciousness and aphasia, a left-sided gaze preference, dysphagia, mild-to-moderate right-sided central facial palsy, right-sided hemiplegia, and right-sided positive pyramidal tract signs. Brain imaging four hours post-surgery did not detect any cerebral lesions.