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Respiratory EMG findings in relation to periodic breathing in infants
Insights
Tonic activity in infant respiratory muscles influences breathing patterns. Increased tonic activity correlates with continuous breathing, while decreased activity can lead to periodic breathing, impacting respiratory control stability.
Area of Science:
- Neonatal Physiology
- Respiratory Control
Background:
- Infant breathing patterns, including periodic breathing (PB), are complex.
- Understanding the role of respiratory muscle activity in regulating these patterns is crucial for neonatal care.
Purpose of the Study:
- To investigate the relationship between tonic activity in intercostal and diaphragm muscles and shifts in infant breathing patterns.
- To explore how changes in respiratory muscle tonic activity influence the transition between periodic and continuous breathing.
Main Methods:
- Analysis of electromyography (EMG) activity in intercostal and diaphragm muscles in 13 infants.
- Polygraphic recordings were used to identify and analyze periodic breathing episodes.
- Correlations were examined between EMG tonic activity levels and breathing pattern changes.
Main Results:
- A normal level of tonic respiratory muscle activity coincided with the switch from periodic to continuous breathing.
- Periodic breathing persisted during continuous breathing states only exceptionally.
- Decreased tonic activity was associated with a switch to periodic breathing, while increased activity reduced or stopped PB.
Conclusions:
- Tonic activity in respiratory muscles plays a significant role in stabilizing infant breathing patterns.
- Changes in tonic activity may influence respiratory control stability through mechanical or chemical alterations.
- Findings suggest a link between respiratory muscle activity and the regulation of periodic breathing in infants.
Abstract:
Intercostal and diaphragm EMG activity was analysed in periodically breathing infants. The aim was to investigate relationships between changes in tonic activity in the respiratory muscles and switches in spontaneous breathing pattern from periodic to continuous and vice versa. A heterogeneous group of 13 normal and neurologically suspect infants was studied. They had all previously undergone polygraphic investigation and were selected because their polygraphic records showed at least three minutes uninterrupted periodic breathing (PB). PB appeared to represent an oscillation with a length of about 16 seconds superimposed on the basic state related irregular and regular breathing patterns. The development of a normal level of tonic activity in the respiratory muscles at the transition from state 2 to state 1 coincided with the switching from periodic to continuous breathing. Continuation of PB throughout a state 1 epoch in the presence of tonic respiratory muscle activity was exceptional. Sighs alone or sighs together with brief movements during state 1 were followed on occasion by a drop in tonic activity and a switch from continuous to periodic breathing. If the tonic activity rose again, PB either stopped or became less pronounced. TcPO2 level measured in four infants rose when tonic activity rose and was lower during PB than during continuous breathing. The observations made in this study suggest that mechanical or chemical changes caused by changes in tonic activity level may affect the stability of respiratory control in infancy.