Severe Hypercapnia During Jet Ventilation Causes Reversible Frontal EEG Suppression in the Setting of Total Intravenous Anesthesia: A Case Report

Jet ventilation can limit reliable capnography, increasing the risk of unrecognized carbon dioxide (CO 2 ) retention during airway surgery. We describe a 23-year-old man undergoing tracheal costochondral graft surgery under propofol–remifentanil total intravenous anesthesia with processed frontal electroencephalography (EEG) monitoring. During prolonged apneic jet ventilation, EEG trends showed declining spectral edge frequency and increasing burst suppression with hypertension. Arterial blood gas confirmed severe hypercapnia (PaCO 2 133 mm Hg). After reintubation and controlled ventilation, hemodynamics and EEG indices normalized. This case highlights severe hypercapnia as a reversible cause of EEG suppression, supporting EEG as an adjunctive warning tool when hypercapnia is suspected.