Clinical associations with immature breathing in preterm infants: part 2—periodic breathing

Abstract

Background Periodic breathing (PB) is a normal immature breathing pattern in neonates that, if extreme, may be associated with pathologic conditions. Methods We used our automated PB detection system to analyze all bedside monitor chest impedance data on all infants <35 weeks’ gestation in the University of Virginia Neonatal Intensive Care Unit from 2009-2014 (n=1211). Percent time spent in PB was calculated hourly (>50 infant-years’ data). Extreme PB was identified as a 12h period with PB >6 standard deviations above the mean for gestational age (GA) and post-menstrual age (PMA) and >10% time in PB. Results PB increased with GA, with the highest amount in infants 30-33 weeks’ GA at about 2 weeks’ chronologic age. Extreme PB was identified in 76 infants and in 45% was temporally associated with clinical events including infection or necrotizing enterocolitis (NEC), immunizations, or caffeine discontinuation. In 8/28 cases of septicemia and 10/21 cases of NEC there was a >2-fold increase in %PB over baseline in the day prior to diagnosis. Conclusion Infants <35 weeks GA spend, on average, <6% of the time in PB. An acute increase in PB may reflect illness or physiological stressors or may occur without any apparent clinical event.

Physiological instability after respiratory pauses in preterm infants

“…We also assembled a large data set of respiratory recordings, including over 55 000 respiratory pauses, allowing a more comprehensive analysis of the incidence and severity of instability than has previously been possible. Other studies with considerably larger datasets than ours have focused on the clinical correlates of more frequent respiratory pauses rather than the immediate physiological consequences …”

“…The respiratory course for a very preterm infant during first hospitalization is most usually characterized by a protracted requirement for noninvasive respiratory support and oxygen therapy . This is a period of vulnerability, with reliance on an infant's spontaneous breathing to maintain cardiorespiratory stability at a time when pauses in respiration are frequent . Respiratory pause or apnea events are a well‐recognized cause of hypoxemic and/or bradycardic episodes in preterm infants, which in turn may have lasting neurodevelopmental consequences .…”

Early postnatal exposure to intermittent hypoxia in rodents is proinflammatory, impairs white matter integrity, and alters brain metabolism

“…Many premature infants born at < 34 weeks gestation are exposed to similar levels of IH associated with apnea of prematurity and especially periodic breathing (3) which can persist beyond term equivalent age and is frequently not apparent (2, 40). Our data suggest that there may be significant deleterious effects of this persisting IH, but future studies in human infants born preterm are needed to determine if persisting IH due to immature breathing also causes acute injury and more importantly, whether this acute injury is associated with long term neurodevelopmental impairment.…”

“…With maturation, much of the IH is due to periodic breathing (3), and is often not accompanied by large heart rate decelerations, in contrast to IH during longer apneas where bradycardia is common. Repetitive cycles of re-oxygenation following each IH episode cause oxidative stress, free radical production, and the release of pro-inflammatory cytokines (4).…”

Nocturnal oximetry in pediatric respiratory disease: Urgent need for developing standardized interpretation rules

“…Although this type of cumulative frequency SpO 2 plots summarizes the distribution of all collected values during oximetry, it does not provide information about the characteristics of brief desaturations (frequency, depth, duration). Hence, a cumulative frequency plot does not allow differentiation between a patient with decreased baseline SpO 2 levels (eg bronchopulmonary dysplasia) and another one with intermittent hypoxemia due to periodic breathing . Thus, the aim of the current work by Terrill et al was to describe two additional plots in healthy infants: desaturation‐depth versus incidence of desaturation (episodes/h) ; and desaturation‐duration versus incidence .…”