부산대학교 도서관

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 (ZIrs) 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 fined to Zrs and ZIrs. 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 ZIrs. 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)%). Conclusion: 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. [ABSTRACT FROM AUTHOR]