Graham L Hall1, Z Hantos, J H Wildhaber, P D Sly. 1. Division for Clinical Sciences, Institute for Child Health Research, University of Western Australia, Perth 6840, Australia. graham@ichr.uwa.edu.au
Abstract
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.
BACKGROUND: In infants the impedance of the nasal pathways (Zn) is a significant proportion of the total respiratory impedance (Zrs). METHODS: In 11 infantsZrs 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.
Authors: Bence L Radics; Zita Gyurkovits; Gergely Makan; Zoltán Gingl; Dorottya Czövek; Zoltán Hantos Journal: Front Pediatr Date: 2022-04-04 Impact factor: 3.569