Related Experiment Video
Updated: Oct 1, 2026

Conducting Respiratory Oscillometry in an Outpatient Setting
Published on: April 8, 2022
Contribution of nasal pathways to low frequency respiratory impedance in infants
Graham L Hall1, Z Hantos, J H Wildhaber
1Division for Clinical Sciences, Institute for Child Health Research, University of Western Australia, Perth 6840, Australia. graham@ichr.uwa.edu.au
Background:
In infants the impedance of the nasal pathways (Zn) is a significant proportion of the total respiratory impedance (Zrs).
Methods:
In 11 infants Zrs was partitioned into Zn and lower respiratory system impedance (Zlrs) using a nasal catheter. A low frequency oscillatory signal (0.5-20 Hz) was applied during a pause in breathing to obtain the impedance spectra. A model of the respiratory system containing an airway and tissue compartment was then fitted to Zrs and Zlrs. The airway compartment consisted of a frequency independent resistance (R) and inertance (I), while the tissue compartment was described by coefficients of tissue damping (G) and elastance (H).
Results:
Zrs could be reliably partitioned into Zn and Zlrs. The nasal pathway acted as a purely resistive-inertive impedance and contributed approximately half of the airway resistance (mean (SE) 44.6 (4.9)%) and most of the respiratory system inertance (71.7 (3.5)%).
Conclusions:
In studies investigating changes in airway resistance in nasally breathing infants, the separation of nasal and lower respiratory system mechanics will increase the sensitivity of the tests.
Related Concept Videos
Anatomy of Respiratory System I: Upper Respiratory Tract
Nose and nasal cavity
The nose and nasal cavity represent the main external openings of the respiratory tract.
Nose and Nasal Cavity
Microbiota of the Respiratory Tract
Hearing During Infancy and Toddlerhood
Anatomy of Respiratory System II: Lower Respiratory Tract
The Larynx
It is located between the pharynx and the trachea, acts as a passageway for air, and hosts several critical structures, such as the epiglottis, vocal cords, and glottis. The epiglottis acts as a gateway, guiding food to the...
Overview of Respiratory System
What is the Respiratory System?
The respiratory system consists of a series of organs responsible for taking in oxygen and expelling carbon dioxide. The primary function of the respiratory system is to...