An 8-year-old healthy male patient (30 kg weight and 130 cm height) with no history of epilepsy visited the dentist for tooth extraction. The patient had no known drug allergies. During his visit for extraction of deciduous second molar, the dentist injected 1.8 ml of 2% lignocaine (36 mg) with adrenaline (1:200,000) after prior aspiration at upper left maxillary vestibule with respect to deciduous second molar followed by 0.5 ml at left greater palantine nerve block. The total 46 mg lignocaine lasting over 2 min was administered. Immediately following the nerve block, the child presented with tonic-clonic convulsions. Patient was placed in supine position with elevated legs, and care was taken so as to protect from injuries. Injection diazepam was given. The vital signs and all laboratory investigations were normal. Neurological examination was unremarkable. MRI scan of the head and electroencephalogram were normal. There was no recurrence of seizures and the child was discharged after 1 day. Using Naranjo probability scale the relationship between the drug and the event was categorized as probable.
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.