Mouth-to-mouth resuscitation, often called rescue breathing, is used when a person is unresponsive and not breathing normally. This immediate intervention forces oxygen-containing air into the victim’s lungs until professional medical help arrives. The technique’s primary goal is to provide a temporary supply of oxygen to the brain and other vital organs, slowing the process of cellular death caused by a lack of respiration. Rescue breathing is a fundamental component of life support that bridges the gap until advanced care can commence.
The Physiological Necessity of Oxygen Delivery
When a person stops breathing, the supply of oxygen to the body’s tissues ceases, leading to a condition known as hypoxia. The brain consumes roughly twenty percent of the body’s oxygen supply, making it exceptionally vulnerable to oxygen deprivation. Without an adequate supply of oxygen, brain cells begin to sustain irreversible damage, often starting within four to six minutes after breathing stops.
The air a rescuer exhales contains approximately sixteen to seventeen percent oxygen, which is a significant drop from the ambient air’s twenty-one percent. This amount, however, is still sufficient to oxygenate the victim’s blood temporarily and maintain the viability of the brain and heart tissue. The intervention aims to slow the depletion of oxygen reserves within the bloodstream and delay the onset of widespread tissue damage until advanced support can take over.
Step-by-Step Mechanics of Rescue Breathing
Delivering a breath begins with ensuring the victim’s airway is open and clear of obstruction. A rescuer must employ the head-tilt/chin-lift maneuver, which involves placing one hand on the forehead and two fingers of the other hand under the bony part of the chin. Gently tilting the head backward and lifting the chin forward moves the tongue away from the back of the throat, which is the most common cause of airway blockage in an unconscious person.
Once the airway is opened, the rescuer must pinch the victim’s nose shut with the hand on the forehead to prevent air from escaping through the nasal passages. The rescuer then takes a normal breath and creates a complete, airtight seal over the victim’s mouth with their own. Two rescue breaths are then delivered, with each breath lasting about one second, which is sufficient time to allow the air to enter the lungs.
The effectiveness of the breath is verified by watching for the visible rise of the victim’s chest, indicating that air has successfully entered the lungs. Between the two breaths, the rescuer should move away briefly to allow the victim’s chest to fall and air to exit naturally. If the chest does not rise after the first breath, the rescuer must immediately re-tilt the head and attempt the second breath, as the initial positioning may have been inadequate.
Integration with Chest Compressions (CPR)
In most emergency situations where rescue breathing is required, the victim’s heart has either stopped or is not pumping blood effectively, which necessitates the use of chest compressions. Cardiopulmonary Resuscitation (CPR) combines the artificial circulation of compressions with the artificial ventilation of rescue breaths to maximize the chance of survival. Chest compressions manually squeeze the heart between the sternum and the spine, circulating the oxygenated blood that the rescue breaths have introduced.
The standard procedure for adult resuscitation involves a ratio of thirty chest compressions to two rescue breaths for a single rescuer. This ratio prioritizes the circulation of already oxygenated blood, recognizing that maintaining blood flow to the brain and heart is important. Interruptions to compressions must be minimized to less than ten seconds to ensure continuous, though partial, blood flow is maintained.
Practical Adaptations and Safety Considerations
The technique for delivering rescue breaths must be modified when treating infants and children to account for their smaller lung capacity and delicate physiology. For a child, the head-tilt/chin-lift should be performed less aggressively than for an adult, and the breaths should be smaller and gentler. For an infant, the rescuer typically covers both the mouth and nose to form a seal, delivering small puffs of air from the cheeks rather than a full lung breath.
Safety and Barrier Devices
To mitigate the risk of disease transmission between the victim and the rescuer, barrier devices are highly recommended and widely used. These devices, which include face shields or pocket masks, incorporate a one-way valve that allows air to pass to the victim while protecting the rescuer from the victim’s exhaled air and bodily fluids. Rescue efforts should continue without interruption until the victim shows signs of life, professional help arrives and takes over, or the rescuer becomes physically exhausted and unable to continue.