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Physiological parameters evaluation following apnea in healthy premature infants
L Curzi-Dascalova1, J Bloch, M Vecchierini
1Laboratoire de Physiologie, Hôpital Robert Debré, Paris, France. lilia.curzi@wanadoo.fr
Insights
Mechanisms for restarting breathing after apnea in premature infants remain unclear. This study highlights the need for control data to differentiate apnea-related events from spontaneous physiological changes.
Area of Science:
- Neonatal physiology
- Respiratory control
Background:
- Premature infants experience central and obstructive apnea.
- Understanding infant apnea responses is crucial for clinical management.
Purpose of the Study:
- To evaluate physiological responses to central and obstructive apnea in preterm infants.
- To determine if apnea events trigger specific physiological changes or central nervous system activation.
Main Methods:
- 10-hour polygraphic recordings in healthy 33-34 wGA infants.
- Paired apnea and control periods analyzed for body movements, EEG, heart rate, respiratory rate, and SaO(2).
Main Results:
- No apnea caused awakening; motor events were rare, except for obstructive apnea >10s.
- Significant changes in EEG, heart rate (deceleration), and respiratory rate observed post-apnea, but with high variability.
- Heart rate changes correlated with SaO(2) changes; EEG and respiratory rate increases were small and inconsistent markers of CNS activation.
Conclusions:
- Mechanisms for breathing resumption after apnea in preterm infants are not fully elucidated.
- Heart rate decelerations and SaO(2) changes are not indicative of CNS activation.
- Using control periods is essential for accurate interpretation of apnea-related events.
Abstract:
To assess responses to central and obstructive apnea, we performed 10-hour polygraphic recordings in healthy 33-34 wGA infants. Each apnea period was paired with a control period. The presence of body movements (BM) and augmented breaths (AB), the EEG, heart rate (HR), respiratory rate, phase relationships between thoracic and abdominal respiratory movements, and changes in SaO(2) were evaluated. No apnea caused awakening. Apnea were not usually followed by motor events (no significant differences with control periods), with the exception of most obstructive apnea longer than 10 s. The mean percentage of changes following apnea, normalized to baseline values, was significant for the EEG (frequency slightly increased, mainly after obstructive apnea), HR (deceleration), and respiratory rate (increased). However, the mean values masked heterogeneity across apnea in the direction of the change in each parameter. The only significant correlation was between changes in HR and SaO(2). The increases in EEG frequency and respiratory rate seen in our study can be considered markers of CNS activation, but were small and inconsistent. The heart rate decelerations and SaO(2) changes are not activation markers. Thus, mechanisms underlying restarting of breathing efforts following apnea remain unclear in premature babies. Our investigation establishes the importance of using control data to distinguish between spontaneous and apnea-related events.