Precursors of cardiorespiratory events in infants detected by home memory monitor

Abstract

Summary. In 1,079 infants monitored for >700,000 hr at home for apnea or bradycardia, we found an association between infants having multiple events exceeding conventional or a priori defined more extreme thresholds and less favorable developmental outcome at 1 year of age than infants with few or no events. If it is necessary to prevent such events to minimize risk for developmental morbidity, there is reason to determine whether there are disturbances in advance of the apnea or bradycardia that herald their onset. In the 85 infants with at least 1 extreme event and 1 conventional event, we hypothesized that apnea and bradycardia do not occur de novo but rather are preceded by cardiorespiratory and hemoglobin O 2 saturation changes. We compared recorded time intervals preceding these events, and we analyzed three preceding time intervals for each conventional and extreme event, and each non-event recording: Time-2 hr: up to 2 hr before; Time-1 hr: up to 1 hr before; and Time-75 sec: the 75 sec immediately preceding each event. O 2 saturation progressively decreased preceding both conventional and extreme events, and progressive increases occurred in heart and breathing rate variability. Duration of respiratory pauses and of periodic breathing progressively increased preceding conventional events, respiratory rate variability increased immediately preceding conventional events and at 1 hr preceding extreme events, and O 2 saturation decreased immediately preceding both conventional and extreme events. Thus, conventional and extreme events do not occur de novo but rather are preceded by autonomic instability of the cardiorespiratory system. Pediatr Pulmonol. 2008; 43:87-98. ß 2007 Wiley-Liss, Inc.

Autonomic function, gastroesophageal reflux in apparent life threatening event

“…A decreased sympathetic response to tilt testing in infants with ALTE when compared to controls has also been reported [8]. Recently, a study of infants monitored at home documented autonomic instability prior to the event and particularly in the immediate period preceding the event [12].…”

Longitudinal Assessment of Hemoglobin Oxygen Saturation in Preterm and Term Infants in the First Six Months of Life

“…Events sufficient to trigger a monitor alarm did not occur de novo but rather were often preceded by respiratory pauses, periodic breathing, and intermittent hypoxemia. 22 It is unclear to what extent the intermittent hypoxemia occurring during non-event epochs has clinical significance only as a potential precursor to events sufficient to trigger a monitor alarm or whether the intermittent hypoxemia occurring in these clinically silent epochs may be contributing to the neurodevelopmental impairments observed in other studies. 10 Future studies in preterm infants will need to better quantify the frequency and severity of intermittent hypoxemia before and after NICU discharge, the relative contribution of each to adverse neurodevelopmental outcome, and the extent to which these adverse outcomes can be ameliorated by intervention.…”

Prescription of Home Oxygen Therapy to Very Low Birth Weight Infants in Germany

“…The British Thoracic Society (BTS) guidelines, 2 in contrast to the ones from Australia and New Zealand, 8 do not generally recommend monitoring during HOT. 9 Poets et al found similar levels of oxygen saturation in healthy preterm infants at the time of hospital discharge (median 99.5%, fifth percentile 95.7%). 2,8 As in 2001, 4 SpO 2 cutoffs for HOT showed a wide range between hospitals from 80% to 94%, with a mean value of 90%.…”