Physiological instability after respiratory pauses in preterm infants

Background: The factors influencing the severity of apnea-related hypoxemia and bradycardia are incompletely characterized, especially in infants receiving noninvasive respiratory support.Objectives: To identify the frequency and predictors of physiological instability (hypoxemia-oxygen saturation (SpO2) Methods: Respiratory pause duration, derived from capsule pneumography, was measured in 30 preterm infants of gestation 30 (24-32) weeks [median (interquartile range)] receiving noninvasive respiratory support and supplemental oxygen. For identified pauses of 5 to 29 seconds duration, we measured the magnitude and duration of SpO2 and HR reductions over a period starting at the pause onset and ending 60 seconds after resumption of breathing. Temporally clustered pauses (Results: In total, 17 105 isolated and 9180 clustered pauses were identified. Hypoxemia and bradycardia were more likely after longer duration and temporally-clustered pauses. However, the majority of such episodes occurred after 5 to 9 second pauses given their numerical preponderance, and short-lived pauses made a substantial contribution to physiological instability overall. Birth gestation, hemoglobin concentration, form of respiratory support, caffeine treatment, respiratory pause duration and temporal clustering were identified as predictors of instability.Conclusions: Brief respiratory pauses, especially when clustered, contribute substantially to hypoxemia and bradycardia in preterm infants.