Basic Life Support (BLS) provides a systematic approach to resuscitation for victims of sudden cardiac or respiratory arrest. Effective ventilation, or rescue breathing, is fundamental when the heart is beating but breathing has stopped. The goal is to ensure the brain receives sufficient oxygen until advanced medical help arrives. Rescuers must adhere to standardized rates and volumes to maximize oxygen delivery, avoid complications, and optimize the balance of oxygen and carbon dioxide levels.
Adult Rescue Breathing Rates
For an adult victim with a pulse but not breathing adequately, guidelines mimic a normal, resting respiratory rate. The recommended rate is to deliver one breath every five to six seconds. This frequency results in 10 to 12 rescue breaths per minute. This rate prevents the over-ventilation of the patient, which can be detrimental.
Excessive ventilation increases pressure within the chest, reducing blood return to the heart and lowering the effectiveness of existing circulation. Each rescue breath should be delivered over a duration of approximately one second. The volume of air should be just enough to cause a visible, gentle rise of the chest, confirming that the breath is entering the lungs.
Visible chest rise confirms the airway is open and prevents stomach inflation, which can cause complications like vomiting or gastric distention. Rescuers must reassess the patient’s pulse approximately every two minutes while continuing rescue breathing. If the pulse is no longer detected, the rescuer must immediately transition to full cardiopulmonary resuscitation (CPR).
Pediatric Rescue Breathing Rates
The approach to rescue breathing in children and infants differs from adults due to their unique physiological needs. Pediatric victims commonly experience cardiac arrest secondary to respiratory failure. This underlying cause necessitates a faster rate of ventilation to compensate for higher metabolic demands and quicker depletion of oxygen reserves.
The recommended rate for rescue breathing in children and infants with a pulse is one breath every three to five seconds. This translates to 12 to 20 breaths per minute, reflecting the normal, faster breathing rate of younger individuals. Similar to the adult protocol, each breath should be delivered over about one second, with the volume just sufficient to create a visible chest rise.
The breathing rate range remains the same for both infants and children within the Basic Life Support protocol. The focus remains on providing frequent ventilations to overcome the common respiratory cause of their distress. The rescuer must continue to check for a pulse every two minutes. If the pulse drops below 60 beats per minute with signs of poor perfusion, or if the pulse is absent, full CPR should begin.
Combining Breaths with Chest Compressions
When a victim is not breathing and lacks a pulse, rescue breathing is integrated into cardiopulmonary resuscitation (CPR) with chest compressions. For a single rescuer, the standard compression-to-ventilation ratio for adults, children, and infants is 30 compressions followed by 2 breaths. This ratio prioritizes minimizing interruptions to chest compressions, which manually circulate blood.
The ratio changes in pediatric cases when a second rescuer is present, shifting to 15 compressions followed by 2 breaths. This modification is made because their arrest is often caused by a lack of oxygen. The 15:2 ratio effectively doubles the number of ventilations delivered per cycle compared to the 30:2 ratio, providing more oxygen to the pediatric patient.
In the context of full CPR, the delivery of the two breaths must be highly efficient to limit the pause in chest compressions to less than 10 seconds. Continuous compressions are performed at a rate of 100 to 120 per minute. The target breath rates (e.g., 10–12 per minute for adults) are achieved by consistently applying the compression-to-ventilation ratio.