Jonson B, Beydon L, Brauer K, Månsson C, Valind S, Grytzell H
Department of Clinical Physiology, University of Lund, Sweden.
J Appl Physiol (1985). 1993 Jul;75(1):132-40. doi: 10.1152/jappl.1993.75.1.132.
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.
呼吸系统（RS）的经典模型由一个与电容器串联的牛顿电阻器以及一个包括电阻器和电容器的粘弹性单元组成。流量中断技术经常被用于研究在恒定吸气流量下的粘弹性行为。为了研究RS在完整呼吸周期中的粘弹性行为，并在无约束条件下量化粘弹性阻力（Rve）和顺应性（Cve），我们基于一个微分方程开发了一种迭代技术。和其他人一样，我们假设Rve和Cve是恒定的，这与模型行为的体积和流量依赖性相一致。在吸气过程中，牛顿阻力（R）与流量和体积无关。在呼气过程中，R增加。静态弹性回缩没有明显的滞后现象。RS的粘弹性行为与模型一致。Rve的大小为3.7±0.7 cmH2O·l-1×s，即R的两倍。Cve为0.23±0.051 l/cmH2O，即静态顺应性的四倍。粘弹性时间常数，即Cve·Rve，为0.82±0.11s。对于0.56升的一次呼吸，克服粘弹性系统耗散的功为0.62±0.13 cmH2O×l，相当于RS内总能量损失的32%。粘弹性回缩在呼气初始阶段作为驱动力起作用。
