What question did this study set out to answer?

To examine the relationships among blood flow, vascular pressure gradients, and cardiopulmonary blood volume during exercise in normal dogs and dogs with a single functioning pulmonary artery.

January 1, 1961Circulation ResearchOpen Access

Flow, Pressure, and Volume Relationships in the Pulmonary Circulation During Exercise in Normal Dogs and Dogs with Divided Left Pulmonary Artery

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Why the study?

How does exercise affect pulmonary circulation hemodynamics in normal dogs and dogs with a divided left pulmonary artery?

Population

10 dogs (6 intact, 4 subjected to ligation and division of the left pulmonary artery)

Comparison

Exercise on a horizontal treadmill up to maximal… vs Rest

Design

Preclinical

Authors

RMRobert J. MarshallUniversity of Colorado Boulder YWYang WangUniversity of Minnesota HSHerbert J. SemlerOregon Health & Science University

Discussion

Member takes

Implication

Supports pulmonary vascular recruitment during high cardiac output in dogs; leaves open translation to human exercise hemodynamics.

Key Points

To examine the relationships among blood flow, vascular pressure gradients, and cardiopulmonary blood volume during exercise in normal dogs and dogs with a single functioning pulmonary artery.
Studied 6 intact dogs and 4 dogs following ligation and division of the left pulmonary artery during treadmill running up to 12–14 km/hr.
Measured pressure gradients between the main pulmonary artery and pulmonary artery wedge position, using indocyanine green indicator dilution to derive cardiac output and central vascular transit times.
In intact dogs, cardiac output increased approximately threefold from rest to severe exercise, while the driving pressure gradient rose only 12% to 50%, demonstrating a sustained drop in pulmonary vascular resistance.
In dogs with a divided left pulmonary artery, the total threefold increase in cardiac output was diverted entirely through a single lung, yet the pressure gradient rose only 37% to 50% in 3 of 4 dogs.
Central blood volume remained largely unchanged across activity levels, showing no change in most animals and up to an 18% to 20% increase only at maximal running speeds.

Structured PICO

How does exercise affect pulmonary circulation hemodynamics in normal dogs and dogs with a divided left pulmonary artery?

Population

10 dogs (6 intact, 4 subjected to ligation and division of the left pulmonary artery)

Intervention

Exercise on a horizontal treadmill up to maximal speed (usually 12 or 14 km/hr) for at least 2 minutes

Comparator

Rest

Outcome

Changes in pulmonary circulation hemodynamics (cardiac output, main pulmonary artery minus pulmonary-artery wedge pressure, pulmonary vascular resistance, and blood volume of lungs and left heart)surrogate

This preclinical study demonstrates that the pulmonary vascular bed can accommodate massive increases in blood flow during exercise with only modest increases in pressure, due to a significant fall in pulmonary vascular resistance.

Cite This Study

Marshall et al. (1961) studied this question.

synapsesocial.com/papers/6a8a87ca6099c687143356aa https://doi.org/10.1161/01.res.9.1.53

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Flow, Pressure, and Volume Relationships in the Pulmonary Circulation During Exercise in Normal Dogs and Dogs with Divided Left Pulmonary Artery

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Flow, Pressure, and Volume Relationships in the Pulmonary Circulation During Exercise in Normal Dogs and Dogs with Divided Left Pulmonary Artery

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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Also Consider