High frequency injection ventilation was employed in 150 patients during endoscopy or laryngeal surgery. Lower mean intratracheal pressures are obtained that by conventional injection ventilation, and the respiratory pathways are protected to a greater degree. The reduced diameter of the tracheal approach provided by the use of a small transglottic catheter or a small intercricothyroidal tube enables the operative zone to be well exposed. For optimal efficacy, the method requires a frequency, equal to or less than 150 per minute, a short insufflation period, and sufficient exposure of the respiratory tract. General anesthesia is required.