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Developmental changes in collapsibility of the passive pharynx during infancy
S Isono1, A Tanaka, T Ishikawa
1Department of Anesthesiology, Chiba University School of Medicine, Chiba, Japan. isonos@ho.chiba-u.ac.jp
Insights
Infant airway development shows increasing pharyngeal stability. Maximal velopharyngeal area grows with age, while closing pressure decreases, ensuring a patent airway in healthy infants.
Area of Science:
- Pediatric airway physiology
- Developmental biology
- Otolaryngology
Background:
- The upper airway undergoes significant changes in the first year of life.
- These changes may affect the pharyngeal airway's collapsibility.
- Understanding infant airway mechanics is crucial for assessing respiratory health.
Purpose of the Study:
- To evaluate developmental changes in passive pharyngeal mechanics in infants.
- To quantify the relationship between age and pharyngeal airway properties.
- To determine how pharyngeal mechanics mature during the first year of life.
Main Methods:
- Studied nine normal infants aged 2 to 12 months.
- Quantified the static pressure-area relationship of the passive pharynx.
- Measurements were taken under general anesthesia with complete paralysis.
Main Results:
- A direct association was found between infant age and maximal velopharyngeal area (r = 0.840, p = 0.005).
- Velopharyngeal closing pressure decreased with increasing age (r = -0.809, p = 0.008).
- Pharyngeal wall stiffness increased with maturation, indicated by steeper pressure-area curves.
Conclusions:
- Infant pharyngeal anatomy gains stability during development.
- These changes favor the maintenance of a patent airway.
- Maturation of passive pharyngeal mechanics contributes to airway stability in infants.
Abstract:
The upper airway configuration significantly changes during the first year of life in humans, possibly leading to alteration of collapsibility of the pharyngeal airway. The present study evaluated developmental changes of passive pharyngeal mechanics in nine normal infants ranging in age from 2 to 12 mo. The static pressure-area relationship of the passive pharynx was quantified under general anesthesia with complete paralysis. We found a direct association between age and maximal velopharyngeal area (r = 0.840, p = 0.005). Velopharyngeal closing pressure progressively decreased with increasing age (r = -0.809, p = 0.008) and the closing pressures were below atmospheric pressure in all infants (range: -0.7 to -9.8 cm H(2)O; mean +/- SD: -3.6 +/- 2.7 cm H(2)O). Shape of the pressure-area curves became steeper in slope with maturation, indicating increased pharyngeal wall stiffness during development. Accordingly, we conclude that anatomic properties of the pharynx gain stability in favor of maintaining patent airway during development in normal infants.