Hypoproteinemia slows lung liquid clearance in young lambs

J. J. Cummings, D. P. Carlton, Francis R Poulain, J. U. Raj, R. D. Bland

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


To determine whether hypoproteinemia slows the rate at which liquid is cleared from the lung lumen, we studied 36 lambs, 18 of which underwent repeated plasmapheresis, reducing plasma protein concentration by 37% and plasma protein osmotic pressure by 39%. We killed 29 lambs (14 hypoproteinemic and 15 normoproteinemic) and removed their lungs 1, 2, or 6 h after intratracheal instillation of isotonic saline (6 ml/kg body wt). We measured extravascular lung water and determined the percentage of tracheally instilled liquid that was cleared from the lungs by comparison with control lambs that did not receive saline into their airways. The percent liquid cleared from the lungs after 1 and 2 h was significantly less in hypoproteinemic than in normoproteinemic lambs (37 vs. 65% at 1 h, 58 vs. 75% at 2 h, respectively). By 6 h nearly all the liquid (>92%) was cleared from the lungs of all lambs. Thus hypoproteinemia slows the initial rate of clearance of liquid from the lungs of lambs. To determine whether reduced plasma protein osmotic pressure might redirect this liquid into lung lymphatics, we measured lung lymph flow (Q̇(l)) in five lambs (7.7 ± 1.4 kg, 19 ± 4 days old) for ≥2 h before and 6 h after tracheal instillation of saline. In each lamb, paired studies were done 3-6 days apart; between studies the lambs underwent plasmapheresis. Baseline Q̇(l) was greater during hypoproteinemia (2.5 ± 1.6 ml/h) than during normoproteinemia (1.5 ± 0.7 ml/h), but the net increase in Q̇(l) after intratracheal saline did not differ significantly before (6.7 ± 3.7 ml) and after (10.1 ± 5.8 ml) protein reduction. Thus, although hypoproteinemia increases net lung liquid filtration, it has little if any effect on fractional clearance of luminal liquid via lung lymphatics.

Original languageEnglish (US)
Pages (from-to)153-160
Number of pages8
JournalJournal of Applied Physiology
Issue number1
StatePublished - 1993
Externally publishedYes


  • infant, newborn
  • plasmapheresis
  • pulmonary circulation
  • pulmonary edema
  • vascular permeability

ASJC Scopus subject areas

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


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