Cardiopulmonary Resuscitation (CPR) is an emergency procedure performed when the heart stops beating, combining rhythmic chest compressions with artificial ventilation to maintain blood flow and preserve brain function. Modern emergency guidelines have introduced significant changes to the process, particularly regarding the need for mouth-to-mouth (MTM) rescue breaths. This debate has led to revised recommendations for bystanders responding to a collapse. Understanding current CPR protocols is important for anyone who might witness a cardiac emergency.
The Shift to Compression-Only CPR
For an adult who suddenly collapses in a witnessed setting, the current standard for bystander intervention is compression-only CPR, also known as Hands-Only CPR. This protocol change is based on the understanding that the victim’s cardiac arrest is likely due to an electrical problem, not primary breathing failure. An otherwise healthy adult usually retains enough oxygen in the bloodstream for the first few minutes following a sudden cardiac event.
Continuous, high-quality chest compressions at a rate of 100 to 120 per minute become the primary focus to circulate the oxygen-rich blood already present. Interrupting compressions to provide rescue breaths significantly reduces the pressure generated, lowering blood flow to the brain and heart. The loss of circulation outweighs the immediate need for new oxygen in these specific cases.
The simplicity of compression-only CPR addresses a major barrier to bystander action. Many untrained individuals hesitate to perform traditional CPR due to a lack of confidence in the MTM technique or reluctance regarding MTM contact. Removing the breathing component encourages immediate intervention, which is a significant factor in improving survival outcomes.
Critical Cases Where Rescue Breaths Are Essential
While compression-only CPR is suitable for many sudden adult collapses, rescue breaths are essential when cardiac arrest is caused by a lack of oxygen. When breathing fails first, blood oxygen levels fall critically low before the heart slows and stops. Chest compressions alone are insufficient because they circulate blood already severely depleted of oxygen.
This category of respiratory-related cardiac arrests includes victims of drowning, drug overdose (particularly involving opioids), suffocation, or prolonged exposure to toxins. For these patients, providing oxygen via rescue breaths is the necessary intervention to reverse the underlying problem of hypoxia. The brain and other organs cannot be sustained by compressions alone without the immediate introduction of oxygenated air.
The need for rescue breaths also applies to all infants and children, as pediatric cardiac arrest is most frequently caused by respiratory failure, such as from choking or severe infection. In these scenarios, the protocol shifts back to conventional CPR, combining compressions and ventilations. For a victim whose cardiac arrest is not of clear cardiac origin, providing rescue breaths with compressions offers the greatest chance of survival.
Proper Technique for Combining Compressions and Breaths
When an emergency requires both compressions and rescue breaths, such as in cases of drowning or overdose, a specific mechanical sequence must be followed. Conventional CPR involves alternating 30 chest compressions with 2 rescue breaths, known as the 30:2 ratio. This ratio balances the need to maintain blood circulation with the need to replenish the oxygen supply.
To deliver the two breaths, the rescuer must first open the airway using the head tilt-chin lift maneuver, moving the tongue away from the back of the throat. The rescuer then pinches the victim’s nose shut, creates a tight seal over the mouth, and delivers a breath lasting about one second. The goal is to make the chest visibly rise, but not to over-inflate the lungs, which can cause complications.
The two rescue breaths should be delivered quickly, taking less than ten seconds, before immediately resuming the compressions. This minimizes the interruption to blood flow, maintaining the high quality of the procedure. While direct mouth-to-mouth is effective, a barrier device, such as a pocket mask, can be used for safety and hygiene when available. The cycle of 30 compressions and 2 breaths should be continued until emergency medical services arrive or the victim shows definitive signs of recovery.