Model of pleural fluid turnover

G. Miserocchi, D. Venturoli, D. Negrini, M. Del Fabbro

Research output: Contribution to journalArticle

Abstract

A model of pleural fluid turnover, based on mass conservation law, was developed from experimental evidence that 1) pleural fluid filters through the parietal pleura and is drained by parietal lymphatics and 2) lymph flow increases after an increase in pleural liquid volume, attaining a maximum value 10 times greater than control. From the differential equation describing the time evolution of pleural liquid pressure, we obtained the equation for the steady-state condition ('set point') of pleural liquid pressure: P(ss) - (K(f)P(i)/(*) + K(l)P(zf))/(K(f) + K(l)), where K(f) is parietal pleura filtration coefficient, K(l) is initial lymphatic conductance, P(zf) is lymphatic potential absorption pressure, and P(i)/(*) is a factor accounting for the protein reflection coefficient of parietal mesothelium and hydraulic and colloid osmotic pressure of parietal interstitium and pleural liquid. Lymphatics act as a passive negative- feedback control tending to offset increases in pleural liquid volume. Some features of this control are summarized here: 1) lymphatics exert a tight control on pleural liquid volume or pressure so that the set point is maintained close to the potential absorption pressure of lymphatics; 2) a 10- fold increase in K(f) would cause only a 2- and 5-fold increase in pleural liquid volume with normal (1.8 g/dl) and increased (3.4 g/dl) protein concentration of the pleural fluid, respectively; and 3) the reduction in maximum lymph flow greatly reduces the range of operation of the control with increased filtration and/or protein concentration of pleural fluid.

Original languageEnglish
Pages (from-to)1798-1806
Number of pages9
JournalJournal of Applied Physiology
Volume75
Issue number4
Publication statusPublished - 1993

Keywords

  • control theory
  • lymphatic flow
  • pleural liquid pressure
  • pleural liquid volume
  • Starling flow
  • steady-state conditions

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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  • Cite this

    Miserocchi, G., Venturoli, D., Negrini, D., & Del Fabbro, M. (1993). Model of pleural fluid turnover. Journal of Applied Physiology, 75(4), 1798-1806.