If the unconscious person is unresponsive and not breathing normally after the airway has been opened and cleared, the rescuer must immediately begin chest compressions and then rescue breathing.
Give 30 compressions and then two breaths, allowing about one second for each ventilation following the Basic Life Support Flowchart. Those who are trained and willing to give breaths do so for all persons who are unresponsive and not breathing normally.
For mouth to mouth ventilation, it is reasonable to give each breath in a short time (one second) with a volume to achieve chest rise regardless of the cause of cardiac arrest. Care should be taken not to over-inflate the chest.
Look for rise of the chest during each inflation. If the chest does not rise, possible causes are:
If the chest does not rise, ensure correct head tilt, adequate air seal and ventilation. After inflating the lungs, lift your mouth from the person’s mouth, turn your head towards their chest and listen and feel for air being exhaled from the mouth and nose.
The mouth to nose method may be used:
The technique for mouth to nose is the same as for mouth to mouth except for sealing the airway.
In mouth-to-nose resuscitation a leak may occur if the rescuer’s mouth is not open sufficiently, or if the person’s mouth is not sealed adequately. If this problem persists, use mouth-to-mouth resuscitation. If blockage of the nose prevents adequate inflation, the rescuer should use mouth-to-mouth resuscitation.
Mouth to mask resuscitation is a method of rescue breathing which avoids mouth-to-mouth contact by using a resuscitation mask. Rescuers should take appropriate safety precautions when feasible and when resources are available to do so, especially if a person is known to have a serious infection (e.g. HIV, tuberculosis, Hepatitis B virus or SARS).
Position yourself at the person’s head and use both hands to maintain an open airway and to hold the mask in place to maximise the seal. Maintain head tilt and chin lift. Place the narrow end of the mask on the bridge of the nose and apply the mask firmly to the face. (Figure 1)
Inflate the lungs by blowing through the mouthpiece of the mask with sufficient volume and force to achieve chest movement. Remove your mouth from the mask to allow exhalation. If the chest does not rise, recheck head tilt, chin lift and mask seal.
Failure to maintain head tilt and chin lift is the most common cause of obstruction during resuscitation.
For rescuers trained in its use, bag valve mask ventilation is an alternative method of providing rescue breathing. A bag valve mask device is a self-inflating bag attached to a non-rebreathing valve and face mask. There is an option to connect the bag to a reservoir and oxygen supply. There are different size devices for infants, children, and adults. It is important to select the size appropriate to the person. Successful bag valve mask ventilation requires a patent airway, adequate mask seal, and adequate ventilation technique.
Prolonged bag valve mask ventilation or poor technique may introduce air into the stomach increasing the risk of regurgitation of gastric contents.
It is recommended that when bag valve mask ventilation is used, two trained rescuers provide ventilation for a non-breathing person: one to manage the airway, mask, and seal, and the second to operate the bag