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Heart rate variability during sleep in infants with bronchopulmonary dysplasia. Effects of mild decrease in oxygen
S I Filtchev1, L Curzi-Dascalova, L Spassov
1INSERM CJF 89-09, Laboratoire de Physiologie, Hôpital Antoine Béclère, Clamart, France.
Insights
Infants with severe bronchopulmonary dysplasia (BPD) show altered autonomic nervous system control of heart rate during sleep. Mild decreases in arterial oxygen saturation (SaO2) exacerbate these autonomic dysfunctions.
Area of Science:
- Pediatric Pulmonology
- Autonomic Nervous System Physiology
- Neonatal Medicine
Background:
- Bronchopulmonary dysplasia (BPD) is a chronic lung disease in premature infants.
- Autonomic nervous system (ANS) dysfunction is common in infants with severe BPD.
- Sleep stages and arterial oxygen saturation (SaO2) can influence ANS activity.
Purpose of the Study:
- To investigate heart rate modulation by the ANS in infants with severe BPD.
- To examine the relationship between sleep stages, SaO2 levels, and ANS activity.
- To determine if mild hypoxemia exacerbates ANS abnormalities in BPD.
Main Methods:
- Polygraphic recordings in 10 oxygen-dependent infants (7-29 months) with severe BPD.
- Analysis of heart rate variability (HRV) in low (LF) and high (HF) frequency bands.
- Comparison of HRV during normal SaO2 (>95%) and mild decrease (90-94%) across sleep stages (REM, NREM stage 2).
Main Results:
- In normal SaO2, LF was lower in REM sleep than NREM stage 2, contrary to typical findings.
- Mild SaO2 decrease (<95%) led to increased heart and respiratory rates.
- Mild SaO2 decrease reduced HF in REM sleep and increased LF in NREM stage 2, amplifying existing abnormalities.
Conclusions:
- Infants with severe BPD exhibit altered autonomic control during sleep.
- Mild hypoxemia significantly exacerbates ANS dysfunction in these infants.
- Findings highlight the vulnerability of ANS regulation in BPD to oxygen level changes.
Abstract:
We sought to determine whether abnormal heart rate modulation by the autonomic nervous system occurs in patients with severe bronchopulmonary dysplasia (BPD) in relation to sleep stages and mild changes in arterial oxygen saturation SaO2. On 10 oxygen-dependent 7- to 29-month-old infants with BPD, polygraphic recordings, including heart and respiratory rate and body movement detection, were performed. Heart rate variability was evaluated in high (HF), mid, and low (LF) frequency bands. Parameters were analyzed in two ranges of SaO2: normal range, (SaO2 greater than 95%), and mild decrease in (SaO2, values of 90 to 94%). In contrast to what is normally observed, LF at normal SaO2 was less marked in rapid eye movement, (REM) sleep than in non-rapid eye movement (NREM) sleep stage 2. A mild decrease in SaO2, as compared with a normal SaO2 value, was associated with: (1) a heart and respiratory rate acceleration, (2) a decrease in HF in REM sleep (p < 0.02); (3) an increase in LF in NREM sleep stage 2 (p < 0.02), intensifying the change observed in a normal SaO2 level. These data show that a mild decrease in SaO2 increases modifications of autonomic control observed in infants with severe BPD.