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Updated: Aug 14, 2026
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Method of Isolated Ex Vivo Lung Perfusion in a Rat Model: Lessons Learned from Developing a Rat EVLP Program
Published on: February 25, 2015
Gas exchange and hemodynamics in experimental pleural effusion
O Nishida1, R Arellano, D C Cheng
1Department of Anesthesia, The Toronto Hospital, University of Toronto, Ontario, Canada.
Critical Care Medicine
|April 13, 1999
Summary
Acute bilateral pleural effusions cause early hypoxemia before hemodynamic changes. Oxygenation is not affected by fluid status, but hemodynamics improve with higher filling pressures.
Area of Science:
- Cardiorespiratory physiology
- Pulmonary medicine
- Anesthesiology
Background:
- Pleural effusions can significantly impact respiratory and circulatory function.
- Understanding the cardiorespiratory effects of pleural effusions is crucial for clinical management.
- The interplay between pleural fluid volume and intravascular volume requires further investigation.
Purpose of the Study:
- To investigate the cardiorespiratory effects of graded bilateral pleural effusions in anesthetized pigs.
- To determine the impact of varying pleural fluid volumes on oxygenation and hemodynamics.
- To assess the influence of intravascular volume status on these cardiorespiratory parameters.
Main Methods:
- Prospective, randomized, controlled laboratory study in 11 male Yorkshire pigs.
- Anesthetized pigs underwent mechanical ventilation with graded bilateral pleural effusions induced by saline infusion (0, 20, 40, 80 mL/kg).
- Intravascular volume was manipulated (low, normal, high) at each pleural fluid level, with cardiorespiratory parameters measured.
Main Results:
- Hypoxemia (PaO2 reduction ~50%) occurred early with low pleural volumes, independent of intravascular volume.
- Increased pleural volume led to dose-dependent hypoxemia and increased intrapulmonary shunt.
- Hemodynamics remained stable initially but were influenced by intravascular volume, particularly at higher pleural volumes.
Conclusions:
- Early hypoxemia is a key finding in acute bilateral pleural effusions, preceding hemodynamic decompensation.
- Oxygenation is primarily affected by pleural volume, not intravascular filling pressures.
- Clinical studies are warranted to explore the benefits of pleural fluid removal for impaired oxygenation during mechanical ventilation.
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