Hemodynamic Effects of Prolonged Apneic Oxygenation in Laryngologic Surgery: A Randomized Controlled Pilot Trial.

BACKGROUND: Limited data exist on cardiocirculatory responses associated with extended periods of apnea during administration of high-flow nasal oxygen for laryngologic surgery (apneic oxygenation with HFNO, AO-HFNO). The possibility of hemodynamic compromise in the settings of acute hypercapnia, respiratory acidosis, hyperoxia, and IV anesthesia requires further investigation. This trial investigated the hemodynamic safety profile of prolonged AO-HFNO in adult patients undergoing laryngologic surgery. METHODS: Using invasive hemodynamic monitoring, we conducted prospective, randomized, patient-blinded, two-arm parallel pilot trial in 20 adult patients (ASA physical status 1-3) undergoing elective laser laryngologic surgery expected to last over 40 min. The patients were randomly assigned to receive either AO-HFNO or conventional mechanical ventilation using a laser endotracheal tube (ETT). The primary outcome was the effect of prolonged permissive hypercapnia and IV anesthesia on intraoperative cardiocirculatory responses. RESULTS: Extended AO-HFNO led to the development of moderate to severe hypercapnia with PaCO2 reaching as high as 113 mmHg and pH as low as 6.96. These changes were accompanied by induction of hyperdynamic state characterized by increase in heart rate (maximum median changes of ~38%), cardiac index (~36%) and decrease in systemic vascular resistance index (~46%). Maximum median decrease in mean arterial pressure was ~28% and was not associated with the need for extra vasopressor support compared to ETT group. There were no intraoperative or immediate postoperative complications. CONCLUSIONS: Prolonged AO-HFNO is associated with a safe intraoperative hemodynamic profile during extended periods of apnea for selected patients undergoing laryngologic surgery.