This site is intended for healthcare professionals
Last reviewed dd mmm yyyy. Last edited dd mmm yyyy
Basic life support should be performed in all cases of cardiac arrest and only interrupted for such circumstances as defibrillation or intubation.
When ventilation is provided by mouth-to-mouth, a pocket mask, or a self-inflating bag-mask-valve circuit, then the ratio of ventilations to chest compressions should always be 2:30 irrespective of one or more rescuers.
Once the airway has been secured by an endotracheal tube or combitube, then continuous ventilations and chest compressions should be given; ventilations at a rate of 2:30. This continuous, asynchronous basic life support is uninterrupted except for pulse checks, defibrillation or other procedures.
When using a laryngeal mask airway, continuous, asynchronous basic life support may be possible. However, if it is difficult to adequately ventilate whilst chest compressions are given, then basic life support must revert back to cycles of 2:30.