Nonlinearity and harmonic distortion of dog lungs measured by low-frequency forced oscillations

B. Suki, Z. Hantos, B. Daroczy, G. Alkaysi, S. Nagy

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The nonlinearity of lung tissues and airways was studied in six anesthetized and paralyzed open-chest dogs by means of 0.1-Hz sinusoidal volume forcing at mean transpulmonary pressures (Ptp) of 5 and 10 cmH2O. Lung resistance (RL) and elastance (EL) were determined in a 32-fold range (15-460 ml) of tidal volume (VT), both by means of spectrum analysis at the fundamental frequency and with conventional time-domain techniques. Alveolar capsules were used to separate the tissue and airway properties. A very small amplitude dependence was found: with increasing VT, the frequency-domain estimates of RL decreased by 5.3 and 14%, whereas EL decreased by 20 and 22% at Ptp = 5 and 10 cmH2O, respectively. The VT dependences of the time-domain estimates of RL were higher: 10.5 and 20% at Ptp = 5 and 10 cmH2O, respectively, whereas EL remained the same. The airway resistance increased moderately with flow amplitude and was smaller at the higher Ptp level. Analysis of the harmonic distortions of airway opening pressure and the alveolar pressures indicated that nonlinear harmonic production is moderate even at the highest VT and that VT dependence is homogeneous throughout the tissues. In three other dogs it was demonstrated that VT dependences of RL and EL were similar in situ and in isolated lungs at both Ptp levels.

Original languageEnglish
Pages (from-to)69-75
Number of pages7
JournalJournal of Applied Physiology
Volume71
Issue number1
Publication statusPublished - 1991

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Dogs
Pressure
Lung
Airway Resistance
Tidal Volume
Capsules
Spectrum Analysis
Thorax

Keywords

  • airway nonlinearity
  • lung tissue nonlinearity
  • pulmonary elastance
  • pulmonary resistance

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Nonlinearity and harmonic distortion of dog lungs measured by low-frequency forced oscillations. / Suki, B.; Hantos, Z.; Daroczy, B.; Alkaysi, G.; Nagy, S.

In: Journal of Applied Physiology, Vol. 71, No. 1, 1991, p. 69-75.

Research output: Contribution to journalArticle

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AU - Nagy, S.

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