Ventilation support during resuscitation involves providing breaths to a person who is not breathing adequately, typically using rescue breathing, a bag-valve-mask (BVM), or a mechanical ventilator. The specific delivery rate is determined by international emergency guidelines, such as those published by the American Heart Association (AHA). These rates balance the need for oxygen delivery with maintaining effective blood circulation through uninterrupted chest compressions. The approach changes significantly depending on whether a standard or advanced airway is in place.
Ventilation Rates During Standard CPR (No Advanced Airway)
When an advanced airway is not in place, the delivery of breaths is linked to the cycle of chest compressions. For adult single-rescuer cardiopulmonary resuscitation (CPR), the standard is a 30:2 compression-to-ventilation ratio: 30 chest compressions followed by two rescue breaths. The compression rate is standardized at 100 to 120 compressions per minute.
Because the rescuer must pause compressions to deliver the two breaths, the overall ventilation frequency is a function of the compression cycle. If 30 compressions take approximately 15 to 18 seconds, the person receives about 8 to 10 breaths per minute overall. The primary goal of this synchronized ratio is to minimize the interruption of chest compressions, as blood flow ceases when compressions stop.
Each pause for ventilation must be brief, lasting no more than five seconds for the delivery of both breaths. By limiting the pauses and prioritizing compressions, the ventilation rate is intentionally kept low to maintain coronary perfusion pressure.
Continuous Ventilation Rates with Advanced Airway Placement
The strategy for delivering breaths changes fundamentally once a definitive airway, such as an endotracheal tube, is in place. With an advanced airway, ventilations are delivered asynchronously, meaning breaths are no longer coupled to the compression cycle. Chest compressions should continue without pause at 100 to 120 per minute.
The recommended rate for continuous ventilation in adults is one breath every six seconds, equating to 10 breaths per minute. This asynchronous delivery allows for continuous, high-quality chest compressions.
The rationale for this specific rate is avoiding hyperventilation, or excessive breathing. Delivering too many breaths increases intrathoracic pressure, which severely impedes the return of blood to the heart (venous return). This lowers the effectiveness of chest compressions and decreases the chances of survival.
Specific Guidelines for Pediatric Ventilation
Ventilation rates for infants (under one year) and children (one year to puberty) differ from adult guidelines because pediatric cardiac arrests are frequently caused by respiratory failure. This makes ventilation a more immediate priority, resulting in generally higher ventilation rates.
In standard pediatric CPR without an advanced airway, the compression-to-ventilation ratio depends on the number of rescuers. A single rescuer uses the 30:2 ratio, while two or more rescuers use a 15:2 ratio (15 compressions followed by two breaths).
Once an advanced airway is secured, the continuous, asynchronous ventilation rate is faster than the adult rate. The recommended rate for infants and children is one breath every two to three seconds, translating to 20 to 30 breaths per minute. This faster rate accounts for the higher physiological respiratory rates and the respiratory cause of collapse.
Essential Technique Considerations for Optimal Ventilation
Beyond the numerical rate, the quality of each breath delivered is important for effective ventilation support. Each rescue breath, whether delivered mouth-to-mouth or via a bag-valve-mask, should be provided over approximately one second. This slow, controlled delivery prevents a rapid increase in airway pressure that could push air into the stomach.
The volume of air delivered should be just enough to cause a visible, gentle rise of the chest. A volume of about 500 to 600 mL, or 6 to 7 mL per kilogram of body weight, is appropriate for an average-sized adult. Rescuers must focus on delivering only the necessary volume to achieve a slight chest rise, ensuring the breath is effective without causing harm.