What is the clinical evidence from this study?

Study design: Other. Population: Healthy (isolated dog lung lobes) (n=7). Intervention: Low viscosity liquid (saline) bolus injection. Primary outcome: Longitudinal distribution of vascular resistance.

What question did this study set out to answer?

To measure the longitudinal distribution of vascular resistance and quantify intravascular pressures across pulmonary arteries, capillaries, and veins.

April 1, 1968Journal of Clinical InvestigationOpen Access

Longitudinal distribution of vascular resistance in the pulmonary arteries, capillaries, and veins

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Key result

In isolated dog lung lobes, the pulmonary arteries accounted for 46% of total lobar vascular resistance, while capillaries and veins accounted for 34% and 20%, respectively.

Population

Isolated left basal lung lobes from 7 mongrel dogs (10-14 kg) perfused with blood from donor dogs (15-25 kg).

Design

Preclinical

Authors

JBJerome S. BrodyBoston University ESEdward J. StemmlerUniversity of Pennsylvania ADArthur B. DuBoisUniversité Rennes 2

Discussion

Member takes

Implication

Facilitates segmental pulmonary resistance mapping in isolated models; leaves open human translation and clinical use.

Key Points

To measure the longitudinal distribution of vascular resistance and quantify intravascular pressures across pulmonary arteries, capillaries, and veins.
Perfused isolated canine lung lobes at constant flow using blood supplied by a donor dog.
Measured lobar vessel volumes using ether plethysmography and dye-dilution techniques.
Determined vascular resistance profiles by evaluating decreases in lobar perfusion pressure following inflow boluses of low-viscosity liquid.
Pulmonary arteries accounted for 46% of total lobar vascular resistance (322 dynes·sec·cm⁻⁵/ml), whereas capillaries accounted for 34% (112 dynes·sec·cm⁻⁵/ml) and veins accounted for 20% (115 dynes·sec·cm⁻⁵/ml).
Vascular pressures averaged 20.4 cm H2O in lobar pulmonary arteries, 13.3 cm H2O at the mid-capillary level, and 9.2 cm H2O in lobar pulmonary veins.
Peak vascular resistivity localized 2 ml proximal to the capillary bed, with the pulmonary arterial tree generating roughly 50% of upstream resistance under conditions where alveolar pressure exceeded venous pressure.

Structured PICO

Population

7 isolated lung lobes from mongrel dogs used to measure the longitudinal distribution of pulmonary vascular resistance.

Intervention

Bolus of low viscosity liquid (2 ml of 0.9% NaCl) introduced into the vascular inflow of the lobe to determine longitudinal distribution of vascular resistance.

Outcome

Longitudinal distribution of vascular resistance in the pulmonary arteries, capillaries, and veins, and pulmonary capillary pressure.surrogate

This study provides the first direct measurements of pulmonary capillary pressure and demonstrates that pulmonary arteries account for nearly half of the total pulmonary vascular resistance.

Limitations

A portion of pulmonary artery and pulmonary vein was excluded from the preparation in the process of cannulating the lobe.
The decrease in perfusion pressure produced by the saline bolus will cause a decrease in the volume of the highly compliant lung vessels, underestimating calculated resistance.
The resistance calculations became less accurate as the bolus moved downstream due to bolus distortion.
Whether the distribution of vascular resistance in the isolated lung differs from that in the intact lung is not known.
Downstream resistance is grossly underestimated when large downstream resistance is present
Accuracy of the analysis of segment distribution decreased as the bolus moved downstream

Cite This Study

Brody et al. (1968) studied Healthy (isolated dog lung lobes) (n=7). Low viscosity liquid (saline) bolus injection was evaluated on Longitudinal distribution of vascular resistance. In isolated dog lung lobes, the pulmonary arteries accounted for 46% of total lobar vascular resistance, while capillaries and veins accounted for 34% and 20%, respectively.

synapsesocial.com/papers/6a6d02ffe5469ee92bdfadd2 https://doi.org/10.1172/jci105773

View Full Paper

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Longitudinal distribution of vascular resistance in the pulmonary arteries, capillaries, and veins

Discussion

Member takes

Implication

Key Points

Structured PICO

Limitations

Cite This Study

Longitudinal distribution of vascular resistance in the pulmonary arteries, capillaries, and veins

Discussion

Member takes

Implication

Key Points

Structured PICO

Limitations

Cite This Study

Also Consider

Also Consider