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Mechanics of respiratory system in healthy anesthetized humans with emphasis on viscoelastic properties

Jonson, B LU ; Beydon, L; Brauer, K LU ; Månsson, C; Valind, S LU and Grytzell, H (1993) In Journal of Applied Physiology 75(1). p.40-132
Abstract

The classic model of the respiratory system (RS) is comprised of a Newtonian resistor in series with a capacitor and a viscoelastic unit including a resistor and a capacitor. The flow interruption technique has often been used to study the viscoelastic behavior under constant inspiratory flow rate. To study the viscoelastic behavior of the RS during complete respiratory cycles and to quantify viscoelastic resistance (Rve) and compliance (Cve) under unrestrained conditions, we developed an iterative technique based on a differential equation. We, as others, assumed Rve and Cve to be constant, which concords with volume and flow dependency of model behavior. During inspiration Newtonian resistance (R) was independent of flow and volume.... (More)

The classic model of the respiratory system (RS) is comprised of a Newtonian resistor in series with a capacitor and a viscoelastic unit including a resistor and a capacitor. The flow interruption technique has often been used to study the viscoelastic behavior under constant inspiratory flow rate. To study the viscoelastic behavior of the RS during complete respiratory cycles and to quantify viscoelastic resistance (Rve) and compliance (Cve) under unrestrained conditions, we developed an iterative technique based on a differential equation. We, as others, assumed Rve and Cve to be constant, which concords with volume and flow dependency of model behavior. During inspiration Newtonian resistance (R) was independent of flow and volume. During expiration R increased. Static elastic recoil showed no significant hysteresis. The viscoelastic behavior of the RS was in accordance with the model. The magnitude of Rve was 3.7 +/- 0.7 cmH2O.l-1 x s, i.e., two times R. Cve was 0.23 +/- 0.051 l/cmH2O, i.e., four times static compliance. The viscoelastic time constant, i.e., Cve.Rve, was 0.82 +/- 0.11s. The work dissipated against the viscoelastic system was 0.62 +/- 0.13 cmH2O x 1 for a breath of 0.56 liter, corresponding to 32% of the total energy loss within the RS. Viscoelastic recoil contributed as a driving force during the initial part of expiration.

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keywords
Adult, Air Pressure, Anesthesia, Elasticity, Female, Humans, Lung Compliance, Male, Mathematics, Middle Aged, Models, Biological, Respiratory Mechanics, Respiratory Physiological Phenomena, Tidal Volume, Ventilators, Mechanical, Viscosity, Work of Breathing, Journal Article, Research Support, Non-U.S. Gov't
in
Journal of Applied Physiology
volume
75
issue
1
pages
9 pages
publisher
American Physiological Society
external identifiers
  • scopus:0027240474
ISSN
8750-7587
language
English
LU publication?
yes
id
c0dc70a1-e3c3-42a5-89d1-9aad747ecd24
date added to LUP
2017-06-13 14:05:09
date last changed
2017-11-19 04:40:44
@article{c0dc70a1-e3c3-42a5-89d1-9aad747ecd24,
  abstract     = {<p>The classic model of the respiratory system (RS) is comprised of a Newtonian resistor in series with a capacitor and a viscoelastic unit including a resistor and a capacitor. The flow interruption technique has often been used to study the viscoelastic behavior under constant inspiratory flow rate. To study the viscoelastic behavior of the RS during complete respiratory cycles and to quantify viscoelastic resistance (Rve) and compliance (Cve) under unrestrained conditions, we developed an iterative technique based on a differential equation. We, as others, assumed Rve and Cve to be constant, which concords with volume and flow dependency of model behavior. During inspiration Newtonian resistance (R) was independent of flow and volume. During expiration R increased. Static elastic recoil showed no significant hysteresis. The viscoelastic behavior of the RS was in accordance with the model. The magnitude of Rve was 3.7 +/- 0.7 cmH2O.l-1 x s, i.e., two times R. Cve was 0.23 +/- 0.051 l/cmH2O, i.e., four times static compliance. The viscoelastic time constant, i.e., Cve.Rve, was 0.82 +/- 0.11s. The work dissipated against the viscoelastic system was 0.62 +/- 0.13 cmH2O x 1 for a breath of 0.56 liter, corresponding to 32% of the total energy loss within the RS. Viscoelastic recoil contributed as a driving force during the initial part of expiration.</p>},
  author       = {Jonson, B and Beydon, L and Brauer, K and Månsson, C and Valind, S and Grytzell, H},
  issn         = {8750-7587},
  keyword      = {Adult,Air Pressure,Anesthesia,Elasticity,Female,Humans,Lung Compliance,Male,Mathematics,Middle Aged,Models, Biological,Respiratory Mechanics,Respiratory Physiological Phenomena,Tidal Volume,Ventilators, Mechanical,Viscosity,Work of Breathing,Journal Article,Research Support, Non-U.S. Gov't},
  language     = {eng},
  number       = {1},
  pages        = {40--132},
  publisher    = {American Physiological Society},
  series       = {Journal of Applied Physiology},
  title        = {Mechanics of respiratory system in healthy anesthetized humans with emphasis on viscoelastic properties},
  volume       = {75},
  year         = {1993},
}