What is the clinical evidence from this study?

Study design: Observational. Population: Normal humans (n=8). Intervention: Three-element windkessel model vs. Independent methods. Primary outcome: Pulmonary arterial compliance (Cp) (p=<0.04).

June 1, 1990

Pulmonary arterial compliance at rest and exercise in normal humans

Q: What are the key findings of this study?

The three-element windkessel model successfully estimated pulmonary arterial compliance, yielding rest values of 0.22 +/- 0.05 ml.mmHg-1.kg-1 that differed from independent methods (P<0.04).

Key Result

The three-element windkessel model successfully estimated pulmonary arterial compliance, yielding rest values of 0.22 +/- 0.05 ml.mmHg-1.kg-1 that differed from independent methods (P<0.04).

Study Design

Type

Observational (n=8)

Structured PICO

Does a parameter estimation procedure based on the three-element windkessel model accurately determine pulmonary arterial compliance at rest and exercise in normal humans compared to independent methods?

Population

8 normal patients

Intervention

Parameter estimation procedure based on the three-element windkessel model using simultaneous rest and exercise pulmonary artery pressures and flows recorded via multisensor micromanometry

Comparator

Independent methods to determine pulmonary arterial compliance (Cp), pulmonary characteristic impedance (Zc), and pulmonary vascular resistance (PVR)

Outcome

Pulmonary arterial compliance (Cp), pulmonary characteristic impedance (Zc), and pulmonary vascular resistance (PVR) at rest and exercisesurrogate

The three-element windkessel model can be successfully used to describe pulmonary artery compliance in normal humans at rest and during exercise.

Main Result

p-value: p=<0.04

Abstract

We evaluated the feasibility of determining pulmonary arterial compliance (Cp) by a parameter estimation procedure based on the three-element windkessel model. Eight normal patients studied with multisensor micromanometry technology had simultaneous rest and exercise pulmonary artery pressures (PAP) and flows recorded. These were submitted to the model and independent methods to determine Cp, pulmonary characteristic impedance (Zc), and pulmonary vascular resistance (PVR). Significant changes in heart rate, PAP, and stroke volume (P less than 0.05) occurred with exercise. In comparing rest and exercise Zc and PVR values determined by the model and independent methods, and in comparing each method for these values, there was no significant difference. Model-derived and independently derived estimates of Cp were significantly different at rest (P less than 0.04) and exercise (P less than 0.001). There was no significant difference between rest and exercise values of Cp by either method. The model estimates of PVR at rest (64 +/- 11 dyn.s.cm-5) and exercise (41 +/- 7 dyn.s.cm-5) (P = 0.06) and the model Zc value at rest (22 +/- 3 dyn.s.cm5) were appropriate. The model Cp values at rest (0.22 +/- 0.05 ml.mmHg-1.kg-1) correlated with previously reported normalized values in other species. This study reports the successful use of a parameter estimation procedure based on the three-element windkessel model to describe pulmonary artery compliance in normal humans.

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