It is of course important that physicians be able to recognize when a patient is not adequately ventilating his/her chest. The reasons for inadequate chest ventilation include inadequate respiratory effort, airway obstruction or a combination of these two. If the patient is not breathing at all (apneic), then the physician must immediately perform a simple maneuver such as a chin lift to open the airway and commence ventilation of the chest with a bag-mask device.

If the patient is making respiratory effort but is not adequately ventilating his/her chest because of airway obstruction the physician must determine the cause and take immediate measures to alleviate the obstruction. In an unconscious patient, the cause of the obstruction will often be prolapse of the tongue into the posterior pharynx due to loss of tone in the submandibular muscles. This problem can be quickly corrected using a simple maneuver such as a head tilt-chin lift or jaw thrust and this may be all that is needed to open the airway and allow adequate chest ventilation. If the physician encounters noisy or "gurgling" respirations at this point, the upper airway should be suctioned for vomitus and excess secretions.