Pneumonia is the leading infectious cause of death. Early deterioration and death commonly result from progressive sepsis, shock, respiratory failure, and cardiac complications. Recent data suggest that cardiac arrest may also be common, yet few previous studies have addressed this. Accordingly, we sought to characterize early cardiac arrest in hospitalized patients with co-existing pneumonia.

METHODS:We performed a retrospective analysis of a multicenter cardiac arrest database, with data from more than 500 North American Hospitals. We included in-hospital cardiac arrest events that occurred in community-dwelling adults with pneumonia within the first 72 hours after hospital admission. We compared patient and event characteristics for patients with and without pneumonia. For patients with pneumonia we also compared events according to event location.

RESULTS:We identified 4,453 episodes of early cardiac arrest in patients hospitalized with pneumonia. Among patients with preexisting pneumonia, only 36.5% were receiving mechanical ventilation, and only 33.3% were receiving infusions of vasoactive drugs prior to cardiac arrest. Only 52.3% patients on the ward were receiving electrocardiographic monitoring prior to cardiac arrest. Shockable rhythms were uncommon in all pneumonia patients (ventricular tachycardia or fibrillation, 14.8%). Ward patients were significantly older than patients in the ICU.

CONCLUSIONS:In patients with pre-existing pneumonia, cardiac arrest may occur in the absence of preceding shock or respiratory failure. Clinicians should be alert to the possibility of abrupt cardiopulmonary collapse, and future studies should address this possibility. The mechanism may involve myocardial ischemia, a maladaptive response to hypoxia, sepsis-related cardiomyopathy, or other phenomena.