“…Airway management for laryngeal endoscopic surgery usually involves one of four methods: controlled mechanical ventilation, jet ventilation, apnea with intermittent ventilation, and spontaneous breathing . The spontaneously breathing anesthesia technique involves oxygen insufflation: through an endotracheal tube positioned superior to the glottis along the lateral portion of the laryngeal endoscope , through a nasal suction device or nasopharyngeal catheter . With this anesthetic technique, however, one cannot accurately monitor endtidal carbon dioxide tension (PetCO 2 ) due to the presence of an open airway .…”