Profound and Sustained Electrocerebral Silence During Hemicolectomy Guided by the Electroencephalogram: A Case Report.

We report the case of a 77-year-old, American Society of Anesthesiologists (ASA) physical status IV man who developed profound and sustained electrocerebral silence (ECS) during a hemicolectomy. This critical electroencephalogram (EEG)-detected event, occurring in the absence of hypotension, prompted the immediate discontinuation of all anesthetic agents. The procedure, converted to an open laparotomy, was completed without hypnotic or analgesic support, guided solely by the persistent neurophysiological suppression. The patient emerged hours later, developing postoperative delirium and objective cognitive decline at one-month follow-up. This case highlights the EEG's crucial role in detecting severe cerebral vulnerability, informing unique management choices such as discontinuing all anesthetics.