A patient who is not able to breathe adequately on their own will require support of their chest ventilation through artificial means. In order to push oxygen rich air into the patient's chest, some form of positive pressure ventilatory assistance is required. The simplest technique which can be easily taught and mastered is mouth to mouth ventilation. One obvious downside to this technique is that it requires contact with the patients saliva, and perhaps vomitus, and in this era of universal precautions most people are disinclined to use it. A second downside is that the physician is unable to provide supplemental oxygen while doing mouth to mouth. Students should realize however, that using equipment such as a bag-mask device will not make it easier to ventilate the patients chest. In fact the opposite is likely to be true. The technique of bag-mask ventilation is difficult even in the best of hands and will require considerable practice before it can be done effectively on a patient.

The first step in bag-mask ventilation is to select a mask that will cover the mouth and nose of the patient and create a tight seal. The mask is then attached to the bag device, which should be attached to high flow oxygen (15L/min.) such that the reservoir of the bag is fully inflated.

Generally, physicians will hold the bag device with their right hand and secure the mask to the patient's face with their left hand. While securing the mask to the patient's face you want to create a tight seal in addition to elevating the mandible to maintain an open airway. This is done by hooking the fifth finger at the angle of the jaw, holding the mandibular body with the third and fourth fingers and holding the mask between the index finger and thumb. The physician must avoid the temptation to push down on the mask in order to create a tight seal as this will occlude the patient's airway. The correct technique is to lift the mandible up with the third, fourth and fifth fingers while holding the mask tight against the patient's face with the thumb and index finger.

It is worth repeating that the technique of bag-mask ventilation is not easy under the best of circumstances by even experienced operators. The physician who is performing bag-mask ventilation must be carefully monitoring the success of his/her efforts at all times. The air should flow easily into the patient, and the patient's chest should rise and fall with each cycle of ventilation. If there is obstruction to air flow or the chest does not rise, the physician should check that there is a tight seal to the face, that the mandible is being elevated to open the airway and, if an artificial airway is being used, that it is in place.