Mouth-to-mouth rescue breaths, also known as rescue ventilation, are a fundamental component of cardiopulmonary resuscitation (CPR). The primary purpose of this technique is to supply oxygen to a person who is not breathing or whose breathing is severely inadequate. This provision of oxygen helps sustain the brain and other vital organs, buying time until emergency medical services can arrive.
Identifying the Core Indication for Rescue Breaths
The most direct indication for initiating mouth-to-mouth ventilation is respiratory arrest or profound respiratory compromise. Before starting any rescue efforts, a quick assessment checks for responsiveness, normal breathing, and a pulse. If a person is unresponsive and not breathing normally, rescue breaths are needed immediately.
A person may not be breathing (apnea) or may exhibit abnormal patterns. This abnormal pattern, often referred to as agonal breathing, presents as gasping, shallow, or irregular breaths that are not effective for oxygen exchange. Agonal breathing is a reflex and should not be mistaken for normal breathing, indicating an immediate need for intervention. Providing oxygen is the immediate priority in these scenarios to prevent brain damage, which can begin within minutes of oxygen deprivation.
Integrating Rescue Breaths into Standard CPR Protocols
For a trained rescuer dealing with an unresponsive person who is not breathing, rescue breaths are incorporated into the full CPR protocol alongside chest compressions. The combination of compressions and ventilations is necessary to both circulate blood and oxygenate it. Current guidelines for adults recommend delivering cycles of 30 chest compressions followed by 2 rescue breaths.
Compressions force blood out of the heart to the brain and body, while rescue breaths replenish the oxygen supply in the lungs. To deliver the breaths, the rescuer must first ensure the airway is open by performing a head tilt-chin lift maneuver. Each breath should be delivered over approximately one second, with enough volume to cause a visible rise of the chest. Minimizing interruptions in chest compressions is a priority while delivering these two breaths.
Specific Scenarios Requiring Prioritized Ventilation
There are specific emergency situations where the cause of the arrest is primarily a lack of oxygen, making rescue breaths immediately relevant. For victims of drowning, the heart stops because of a severe lack of oxygen, not primarily due to an electrical problem. For these patients, oxygen delivery is paramount, and CPR guidelines often suggest starting with rescue breaths.
In infants and children, cardiac arrest is most frequently caused by respiratory failure, such as from severe asthma or choking. In these pediatric cases, the heart has not yet failed, but the body is quickly running out of oxygen, so immediate delivery of ventilations is prioritized. Another scenario is a known opioid overdose, where the drug suppresses the brain’s drive to breathe, leading to respiratory arrest. In these hypoxic events, providing assisted ventilation is the most effective immediate action to reverse oxygen deprivation.
Understanding Compression-Only CPR and Rescuer Reluctance
Compression-only CPR, sometimes called Hands-Only CPR, is a widely accepted recommendation for untrained bystanders witnessing an adult suddenly collapse. This simplified approach focuses solely on fast, deep chest compressions without rescue breaths. The rationale is that in the first few minutes of a witnessed cardiac arrest, residual oxygen in the blood can sustain the brain, and continuous compressions are more valuable than interruptions for breaths.
By eliminating the need for mouth-to-mouth contact, compression-only CPR addresses common fears of disease transmission and uncertainty about proper technique, encouraging more bystanders to act. However, this hands-only method is primarily intended for adult cardiac arrests of presumed cardiac origin. For a trained rescuer who is willing and able, or when the collapse is clearly due to a respiratory problem like drowning or overdose, standard CPR with rescue breaths remains the preferred and most effective technique to ensure the best possible outcome.