Journal of Applied Physiology, Vol 63, Issue 1 36-43, Copyright © 1987 by American Physiological Society

ARTICLES

Low-frequency respiratory mechanical impedance in the rat

Z. Hantos, B. Daroczy, B. Suki and S. Nagy

A modified forced oscillatory technique was used to determine the respiratory mechanical impedances in anesthetized, paralyzed rats between 0.25 and 10 Hz. From the total respiratory (Zrs) and pulmonary impedance (ZL), measured with pseudorandom oscillations applied at the airway opening before and after thoracotomy, respectively, the chest wall impedance (ZW) was calculated as ZW = Zrs - ZL. The pulmonary (RL) and chest wall resistances were both markedly frequency dependent: between 0.25 and 2 Hz they contributed equally to the total resistance falling from 81.4 +/- 18.3 (SD) at 0.25 Hz to 27.1 +/- 1.7 kPa.l-1 X s at 2 Hz. The pulmonary compliance (CL) decreased mildly, from 2.78 +/- 0.44 at 0.25 Hz to 2.36 +/- 0.39 ml/kPa at 2 Hz, and then increased at higher frequencies, whereas the chest wall compliance declined monotonously from 4.19 +/- 0.88 at 0.25 Hz to 1.93 +/- 0.14 ml/kPa at 10 Hz. Although the frequency dependence of ZW can be interpreted on the basis of parallel inhomogeneities alone, the sharp fall in RL together with the relatively constant CL suggests that at low frequencies significant losses are imposed by the non-Newtonian resistive properties of the lung tissue.

This article has been cited by other articles:

				J. H. T. Bates and C. G. Irvin Measuring lung function in mice: the phenotyping uncertainty principle J Appl Physiol, April 1, 2003; 94(4): 1297 - 1306. [Abstract] [Full Text] [PDF]

				S. Tomioka, J. H. T. Bates, and C. G. Irvin Airway and tissue mechanics in a murine model of asthma: alveolar capsule vs. forced oscillations J Appl Physiol, July 1, 2002; 93(1): 263 - 270. [Abstract] [Full Text] [PDF]

				H. Sakai, E. P. Ingenito, R. Mora, S. Abbay, F. S. A. Cavalcante, K. R. Lutchen, and B. Suki Hysteresivity of the lung and tissue strip in the normal rat: effects of heterogeneities J Appl Physiol, August 1, 2001; 91(2): 737 - 747. [Abstract] [Full Text] [PDF]

				R. F. M. Gomes, F. Shardonofsky, D. H. Eidelman, and J. H. T. Bates Respiratory mechanics and lung development in the rat from early age to adulthood J Appl Physiol, May 1, 2001; 90(5): 1631 - 1638. [Abstract] [Full Text] [PDF]

				R. F. M. Gomes, X. Shen, R. Ramchandani, R. S. Tepper, and J. H. T. Bates Comparative respiratory system mechanics in rodents J Appl Physiol, September 1, 2000; 89(3): 908 - 916. [Abstract] [Full Text] [PDF]

				T. Hirai, K. A. McKeown, R. F. M. Gomes, and J. H. T. Bates Effects of lung volume on lung and chest wall mechanics in rats J Appl Physiol, January 1, 1999; 86(1): 16 - 21. [Abstract] [Full Text] [PDF]

				H. Sakai, M. Fukui, Y. Nakano, K. Endo, T. Hirai, Y. Oku, and M. Mishima Acute response of the lung mechanics of the rabbit to hypoxia J Appl Physiol, January 1, 1999; 86(1): 306 - 312. [Abstract] [Full Text] [PDF]

				F. Petak, G. L. Hall, and P. D. Sly Repeated measurements of airway and parenchymal mechanics in rats by using low-frequency oscillations J Appl Physiol, May 1, 1998; 84(5): 1680 - 1686. [Abstract] [Full Text] [PDF]

				F. Petak, Z. Hantos, A. Adamicza, T. Asztalos, and P. D. Sly Methacholine-induced bronchoconstriction in rats: effects of intravenous vs. aerosol delivery J Appl Physiol, May 1, 1997; 82(5): 1479 - 1487. [Abstract] [Full Text] [PDF]

				J. H. T. Bates, T. F. Schuessler, C. Dolman, and D. H. Eidelman Temporal dynamics of acute isovolume bronchoconstriction in the rat J Appl Physiol, January 1, 1997; 82(1): 55 - 62. [Abstract] [Full Text] [PDF]

				J. F. Sobh, C. M. Lilly, J. M. Drazen, and A. C. Jackson Respiratory transfer impedance between 8 and 384 Hz in guinea pigs before and after bronchial challenge J Appl Physiol, January 1, 1997; 82(1): 172 - 181. [Abstract] [Full Text] [PDF]