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 3 was a 71-year-old male with partial tear of the left rotator cuff who received an arthroscopic rotator cuff repair. The patient had an unremarkable medical history. The positioning of the patient applied during surgery was the beach chair position. An ISB combined with TIVA was planned as the anesthetic strategy. Left ISB was performed by injecting a single-dose of 1% lidocaine (20 mL) and 0.75% ropivacaine (20 mL) followed by continuous interscalene infusion of 0.2% ropivacaine at 6–8 mL/h. There was a negative aspiration test for blood and cerebrospinal fluid prior to injection. Advancement and placement of the catheter was performed in PNS technique using a stimulating catheter. Physical examination prior to surgery confirmed an effective interscalene block. Adverse cardiac or neurologic symptoms were not recorded. For the entire duration of surgery, the patient remained hemodynamically stable and the case proceeded uneventfully under general anesthesia. Immediately after termination of TIVA, and extubation in the OR, the patient presented a considerable delay of waking reactions and aphasia, left-sided gaze preference, severe right-sided central facial palsy, and right-sided severe hemiparesis graded as 1/5 according to the MRC scale for muscle strength. These symptoms persisted during postoperative monitoring in the postanesthesia care unit. Brain imaging three to four hours post-surgery did not detect any cerebral lesions.