A high flow ventilation system delivers oxygen-enriched air to a patient at flow rates greater than 10 L/min using only conventional wall flow meters as found in most hospitals. The ventilation system combines the output of a plurality of wall flow meters into a specially configured gas mixing apparatus. The gas mixing apparatus provides oxygen-enriched air with an FiO2 (fraction of inspired oxygen) of approximately 21-100% with a total oxygen flow rate of 10-20 L/min or higher as required for high flow ventilation therapy. The oxygen-enriched air is delivered to the patient through a bite block device that allows insertion of an endoscope while simultaneously delivering high flow ventilation therapy to the patient through a large annular air flow passage around the endoscope.
