Agonal respirations during cardiac arrest

Purpose of review This review examines the physiologic understanding and clinical implications of agonal respirations during cardiac arrest. Recent findings Agonal respirations originate from lower brainstem neurons as higher centers become increasingly hypoxic during cardiac arrest. No single layperson descriptor consistently identifies agonal respirations; rather, laypersons use a collection of terms to describe the abnormal breathing of agonal respirations. Animal studies demonstrate that agonal respirations can produce clinically important ventilation, oxygenation, and circulation. In human studies, agonal respirations are apparent in 40 % of persons suffering out-of-hospital cardiac arrest. Agonal respirations are associated with witnessed events, ventricular fibrillation, and survival, suggesting that agonal respirations are a marker of an arrest's early phase and may potentially directly affect cardiopulmonary function. Although agonal respirations appear to exert favorable cardiopulmonary effects, they may paradoxically inhibit rescue efforts by preventing arrest recognition. A standardized dispatch approach can help dispatches identify agonal respirations by distinguishing normal and abnormal breathing in the unconscious patient. Furure study should consider how information about agonal respirations might be integrated into the resuscitation to optimize outcomes. Summary Agonal respirations have physiologic and care implications. Efforts to identify agonal respirations and integrate this information into resuscitation care may improve outcome from cardiac arest.