Advanced airway management begins with an open airway and adequate chest ventilation using basic airway management techniques. At all times, it must be remembered that the most important determinant of patient outcome is adequate chest ventilation. If difficulties are encountered during attempts at endotracheal intubation, the rescuer should stop and resume basic techniques to ensure chest ventilation.

Note correct technique:

Prior to attempting endotracheal intubation, the rescuer should ventilate the chest to optimize tissue oxygenation. This will provide a reserve of oxygen in the lungs and thus allow a period of apnea during intubation.