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Infants are not obligatory nasal breathers
Insights
Infants are not obligatory nasal breathers. They can initiate mouth breathing by separating the tongue and soft palate, a response influenced by age and alertness.
Area of Science:
- Neonatal Physiology
- Respiratory Regulation in Infants
Background:
- The prevailing belief is that infants exclusively breathe through their noses.
- Understanding infant respiratory mechanisms is crucial for clinical care.
Purpose of the Study:
- To investigate the respiratory response of infants to acute nasal occlusion.
- To determine if infants can switch to oral breathing when nasal airflow is obstructed.
Main Methods:
- Studied 19 infants (1-230 days old) with acute nasal occlusion and open lips.
- Monitored oropharyngeal structures via fluoroscopy and recorded respiratory movements and oral airflow.
- Observed the response in infants with both open and closed mouths, and recorded EEG in some.
Main Results:
- Infants demonstrated tight apposition of the soft palate and tongue, blocking oral airflow.
- Upon nasal occlusion, infants initiated oral breathing after a mean of 7.8 seconds by raising the soft palate.
- The time to initiate mouth breathing correlated with age and state (awake infants responded faster).
- Nasal occlusion in sleeping infants triggered arousal followed by mouth breathing.
Conclusions:
- Infants are capable of mouth breathing and are not obligatory nasal breathers.
- The oropharyngeal isthmus can be opened by detaching the soft palate from the tongue.
- Infant respiratory flexibility is influenced by age and arousal state.
Abstract:
It is widely believed that infants are obligatory nasal breathers. We studied 19 infants, 1 to 230 days of age, for respiratory response to acute nasal occlusion. Lips were kept apart. Oropharyngeal structures were monitored by fluoroscopy, whereas respiratory movements and oral flow were recorded. We systematically observed before and during nasal occlusion tight apposition of the soft palate and the tongue, closing the oropharyngeal isthmus. After a variable time (mean 7.8 s, range 0.6 to 32 s), the soft palate rose and oral breathing was initiated. Time required to mouth-breathe was related to age and/or conscious state, older and/or awake infants responding faster than younger and/or asleep infants. In 9 others, when nasal occlusion was performed with the mouth closed, results were comparable to those obtained in infants with mouths open. In 3 infants, electroencephalograph (EEG) records showed quiet non-REM sleep. Nasal occlusion resulted in an immediate arousal reaction, followed after a variable time by mouth breathing. We conclude that infants are not obligatory nasal breathers. They can breathe through the mouth by detaching the soft palate from the tongue, thus opening the oropharyngeal isthmus.