Brainstem Anesthesia During Retrobulbar Block: An Eye-Opener Clinical Case

The use of a retrobulbar anesthetic block for surgery of the posterior chamber is a common, effective, and safe practice, although not without risks. This clinical case aims to describe one of the most feared complications of this ophthalmic block, which demands a high degree of suspicion and agility for proper diagnosis and management. A 91-year-old female patient, physical status ASA III, presents for vitrectomy via pars plana of the left eye due to retinal detachment. Light sedoanalgesia was performed, as well as a left retrobulbar block with 5 mL of local anesthetic. Approximately two minutes after the injection of the local anesthetic, she developed a sudden clinical decline of consciousness, accompanied by bilateral photoplegic mydriasis, sinus tachycardia, and hypertension, followed by central apnea. Orotracheal intubation and connection to a ventilatory prosthesis were performed, maintaining adequate oxygenation, ventilation, and hemodynamic stability. No abnormal findings were found in complementary diagnostic methods. The condition progressively reversed, with a gradual return to the initial state of consciousness, and it was possible to successfully extubate the patient after four hours. The patient remained stable, under surveillance, and was discharged home after 48 hours with no neurological impairment or ophthalmological complications. The clinical findings are compatible with brainstem anesthesia, explained by the dispersion of the local anesthetic into the subarachnoid space, through an inadvertent puncture of the ophthalmic artery or the meninges that involve the optic nerve. Although this event is a rare complication, a low threshold of suspicion should be maintained, given the potential severity of the clinical condition. Early recognition should be followed by a systematic A-B-C-D-E approach, and the outcomes are often favorable. Careful surveillance and monitoring should accompany the performance of ophthalmic surgical procedures, and the presence of an anesthesiologist is essential for the quality of the services provided and patient safety.