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Relative contribution of ribcage and abdomen during augmented breaths in infants
O P Mathew1, M L Pronske, M L Clark
1Department of Pediatrics, University of Texas Medical Branch, Galveston 77550.
Insights
Infant breathing mechanics change with age. Older infants show a greater ribcage contribution to breathing during augmented breaths, unlike newborns, suggesting developmental changes in respiratory muscles.
Area of Science:
- Physiology
- Developmental Biology
- Respiratory Medicine
Background:
- Infant respiratory mechanics differ from adults.
- Understanding chest wall and abdominal contributions to breathing is crucial for assessing respiratory health in infants.
- Developmental changes in respiratory muscle function may influence breathing patterns.
Purpose of the Study:
- To investigate age-related changes in ribcage and abdominal contributions to breathing.
- To compare respiratory mechanics during augmented breaths in two infant age groups.
- To explore the impact of sleep state on breathing patterns.
Main Methods:
- Assessed ribcage and abdominal movements during augmented breaths in two infant groups (neonates and 4-12 weeks old).
- Analyzed changes in relative contributions of ribcage and abdomen during quiet and active sleep.
- Calculated ribcage to abdominal movement ratios and percent changes from control breaths.
Main Results:
- Both younger and older infants increased ribcage and abdominal movements during augmented breaths in quiet sleep.
- Older infants (4-12 weeks) demonstrated a significantly greater relative increase in ribcage contribution compared to younger infants.
- Paradoxical ribcage movement during active sleep transitioned to outward movement during augmented breaths in most older infants.
Conclusions:
- Increased tidal volume during augmented breaths is associated with a greater ribcage contribution in infants beyond the neonatal period.
- These findings suggest developmental maturation of intercostal muscle recruitment patterns.
- Age-related differences in respiratory mechanics are evident in early infancy.
Abstract:
Changes in the relative contribution of ribcage and abdomen during augmented breaths were assessed in two groups of infants (less than 2 weeks and 4-12 weeks old). In both groups ribcage and abdominal movements increased during augmented breaths in quiet sleep. In the older infants the relative increase was greater for the ribcage (P less than 0.05) when expressed either as a ribcage to abdominal movement ratio or as a percent of the respective movements during control breaths. In contrast, no significant change of the relative contribution was observed in the younger age group. During active sleep paradoxical movement of the ribcage, observed during tidal breaths, continued during the first phase of the augmented breath; however, during the second phase of inspiration, the ribcage moved outward in all but one infant. Our results show that marked increases in tidal volume are associated with greater increases in ribcage contribution in infants beyond the neonatal period. This may reflect differences in recruitment patterns of intercostal muscles during development.