A 43-year-old male presented to the emergency department (ED) for evaluation of acute respiratory arrest. Prior to arrival, the patient was at an outpatient surgical center being prepared for a right shoulder arthroscopic surgery under regional anesthesia. The anesthesiologist injected 10 mL of bupivacaine and 30 mL of ropivacaine, of unknown concentrations, while attempting to perform an interscalene block. Soon thereafter, the patient complained of difficulty breathing and subsequently developed complete paralysis and respiratory arrest requiring emergent endotracheal intubation prior to hospital arrival. No additional medications were administered at the time of intubation.\nPhysical exam revealed dilated pupils nonreactive to light, complete flaccid paralysis and inability to withdraw from noxious stimuli. The patient immediately received two liters of 0.9% normal saline and a dopamine infusion, initiated at 5 mcg/kg/min, due to persistent bradycardia (heart rate of 44 bpm) and hypotension. The local poison control center was contacted for recommendations on potential LAT. The decision was made to administer 20% ILE, with a bolus of 125 mL (1.5 mL/kg) over one minute, about 90 minutes after presentation. Shortly after, propofol was initiated for post-intubation sedation at 10 mcg/kg/min. The remaining volume of ILE (125 mL) was then immediately infused over two hours at a rate of 0.013 mL/kg/min.\nApproximately 30 minutes after the initiation of ILE, the patient began to regain brainstem reflexes and eye movement, which progressed to head nods, then movement of his upper extremities. In addition, during that time period, his blood pressure and heart rate improved to within normal parameters. Sixty minutes later, the patient was able to communicate by writing down responses to questions. One hour after that, he had full recovery and was extubated. The patient recovered completely without any evidence of neurological sequelae and was discharged 30 hours after presentation.
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.