Unintentional brainstem anesthesia after prolonged sub-tenon block. Сase report

Abstract

A 64-year-old ASA 2 woman, with left eye retinal detachment was admitted for pars plana vitrectomy. There were no any neurological diseases, stroke, angina, myocardial infarction, epilepsy and allergy in her medical history. There aren’t clinical significant changes in her blood tests and ECG. General anesthesia was induced and maintained with inhalation of sevoflurane on target value of MAC 0.9–1.1. Analgesia was maintained by prolonged Sub-Tenon block — 1 % lidocaine 2 ml/h through catheter. The duration of surgery was 215 minutes. Sevoflurane and lidocaine were stopped immediately after the end of the surgery. The effective spontaneous breath has been noted by the first minute after surgery. However, the delayed recovery wasn’t allowing to discharge the patient from operating room within 50 minutes and the drowsiness was persisted 1.5 hours more after this. There wasn’t any neurological deficiency, the hemodynamic was stable and the patient had an effective breath during this time and later in postoperative period. With the exception of a possibility of inadvertent intravenous introduction of local anesthetic and development of systemic toxicity, the most probable cause of this complication was the brainstem anesthesia. The possibility of brainstem anesthesia in ophthalmology is well described when using retrobulbar and peribulbar anesthesia. The described cases of this complication of Sub-Tenon block are single. Our case presented a serious adverse event of prolonged Sub-Tenon block without life treating symptoms and neurologic consequences.