Cardiorespiratory development in extremely preterm infants: vulnerability to infection and persistence of events beyond term-equivalent age: Cardiorespiratory development in extremely preterm infants

Objective: Apnoea, bradycardia and hypoxemia occur frequently in extremely preterm infants, yet there is little longitudinal data describing cardiorespiratory development in these infants. This prospective study characterized early age-dependent changes in cardiorespiratory function and determined how activity is affected by factors such as underlying disease, postnatal insults and therapeutic interventions. Patients and Methods: Thirty-three infants born between 23 and 28 weeks gestational age (GA) were monitored weekly from birth to beyond term-equivalent age (i.e. 25-45 weeks postconceptional age, PCA). Baseline cardiorespiratory activity as well as apnoea/hypopnoea, bradycardia and hypoxemia events were examined using impedance pneumography, electrocardiography (ECG) and pulse oximetry, respectively. Results: Three hundred thirty-eight cardiorespiratory recordings lasting 3236 h were analysed. While the respiratory rate (RR) did not change during the early postnatal period, heart rate (HR) decreased and O-2 saturation improved. There were 5973 total cardiorespiratory events, and their incidence decreased with advancing age. However, they still occurred frequently at term-equivalent age and after hospital discharge (mean PCA at discharge = 38.3 +/- 0.5 weeks). Moreover, infection significantly increased apnoea/hypopnoea and hypoxemia incidence.