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Upper airway measurements during inspiration and expiration in infants
1St Helens Hospital, Auckland University, New Zealand.
Insights
Accurate infant airway measurements are crucial for diagnosing obstruction. This study found upper airway dimensions vary significantly with breathing phase, not sex or size, providing reliable roentgenographic data.
Area of Science:
- Pediatric radiology
- Respiratory physiology
- Craniofacial anatomy
Background:
- Accurate infant upper airway assessment is vital but challenging due to respiratory variations.
- Existing methods may lack reliability in capturing dynamic airway changes.
Purpose of the Study:
- To establish reliable roentgenographic methods for measuring infant upper airway dimensions.
- To provide normal values for upper airway changes during inspiration and expiration in neonates and 6-week-old infants.
- To investigate the influence of age, sex, and physical parameters on these measurements.
Main Methods:
- Lateral upper airway X-ray films were taken during inspiration and expiration in healthy infants.
- A respiration monitor synchronized with the X-ray machine ensured accurate timing.
- Cephalometric measurements were performed on 44 neonates and 29 6-week-old infants.
Main Results:
- Upper airway measurements were significantly smaller during inspiration than expiration (P < .01).
- Measurements increased from the middle to the posterior airway space.
- The middle airway space decreased during inspiration from neonate to 6 weeks (P < .01), while the posterior airway space increased during expiration (P < .01).
- Measurements were independent of infant weight, head circumference, and sex, except for nasion to sella length in boys.
Conclusions:
- The described roentgenographic method provides reliable measurements of infant upper airway dimensions.
- Normal values for respiratory-induced airway changes are established.
- This technique can aid in evaluating infants with suspected upper airway obstruction.
Abstract:
Accurate measurements of the upper airway of the infant are important but are difficult to obtain reliably because of the normal variation that occurs during respiration. X-ray films of the lateral upper airway were obtained during inspiration and expiration in healthy infants, by using as a timing device a respiration monitor which was wired to the x-ray machine and was attached to the abdominal wall of the infant. Cephalometric measurements were made of 44 "normal" full-term neonates and 29 infants at 6 weeks of age. Despite significant differences in head circumference between the sexes, only the nasion to sella length was significantly longer in the boys (P less than .01). The lateral upper airway measurements were independent of weight, head circumference, and sex in the neonates and infants at 6 weeks of age but were significantly smaller during inspiration than expiration (P less than .01). The measurements progressively increased from the middle to the posterior airway space at both ages. The middle airway space behind the caudal end of the hard palate was smaller during inspiration at 6 weeks of age compared to the neonate (P less than .01). During expiration, the posterior airway space was larger at 6 weeks compared to the neonate (P less than .01). The method described in this report enables reliable roentgenographic measurements to be made of the upper airway of the infant; normal values for the changes during inspiration and expiration are provided. This may assist in the evaluation of infants with suspected upper airway obstruction.