Risk factors for extreme events in infants hospitalized for apparent life-threatening events.

Objective: To determine whether known risk factors for cardiorespiratory illnesses will help identify infants who could experience extreme events during an admission for an apparent life-threatening event (ALTE) or later at home.

Study Design: Retrospective cohort study of all patients admitted for ALTE between 1996 and 2006. Extreme events included central apnea >30 seconds, bradycardia >10 seconds, and desaturation >10 seconds at hemoglobin-oxygen saturation value with pulse oximetry <80%.

Results: Of the 625 patients included in the study, 46 (7.4%) had extreme cardiorespiratory events recorded, usually within 24 hours of hospital admission. The most frequent diagnosis was upper respiratory tract infection (URTI, 30 infants). These factors increased the likelihood of having extreme events (P < .0001): post-conceptional age <43 weeks (5.2-fold increase), premature birth (6.3-fold), and URTI symptoms (11.2-fold). The most frequent events were extreme desaturations (43/46 infants), preceded by a central apnea. Seven infants had extreme events recorded later during home monitoring (4 with URTI); all 7 infants had sustained extreme events in the hospital.

Conclusion: Extreme events were identified mostly in association with symptoms of URTIs, in infants born prematurely, and in infants <43 weeks post-conceptional age. Monitoring with a pulse oximeter should identify infants who sustain these events.