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Liquid volume, Na+ and mannitol concentration in a hypertonic mannitol-Ringer hydrothorax
L Zocchi1, D Cremaschi, E Agostoni
1Istituto di Fisiologia umana, Università di Milano, Italy.
Respiration Physiology
|September 1, 1992
Summary
Hypertonic mannitol in rabbit pleural effusions reduced sodium levels, indicating active sodium transport out of the pleural space. This suggests the mesothelium restricts solute diffusion.
Area of Science:
- Physiology
- Cell Biology
Background:
- The pleural space is a potential site for fluid and solute exchange.
- Understanding solute transport across the mesothelium is crucial for managing pleural diseases.
Purpose of the Study:
- To investigate the transport of sodium and mannitol across the rabbit pleural mesothelium.
- To assess the role of active transport and diffusion in pleural fluid dynamics.
Main Methods:
- Induction of hypertonic mannitol-Ringer hydrothorax in anesthetized rabbits.
- Measurement of sodium and mannitol concentrations in pleural fluid over time.
- Assessment of diffusional permeability using labeled mannitol and pleural space surface area.
Main Results:
- 30 mM/L mannitol maintained hydrothorax volume for 60 min.
- Pleural fluid sodium decreased significantly (P<0.01) compared to controls, suggesting active sodium transport.
- Mannitol concentration decreased, with significant diffusion observed between 30-60 min.
- Mesothelial diffusional permeability was lower than in vitro findings.
Conclusions:
- Active sodium transport occurs across the pleural mesothelium without inhibitors.
- The mesothelium presents a significant barrier to small solute diffusion.
- Mannitol's osmotic pressure influences water movement and sodium transport dynamics.