Influence of flow on pulmonary vascular surface area inferred from blue dextran efflux data

L. D. Nelin*, D. L. Roerig, D. A. Rickaby, J. H. Linehan, C. A. Dawson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Blue dextran (BD), which binds to proteins on the pulmonary endothelial surface and to plasma albumin, was used in isolated perfused dog lung lobe experiments to address the question: do changes in perfusate flow rate cause changes in perfused vascular surface area? When BD was added to a protein- free perfusate under zone 3 conditions at a high flow rate (15.8±0.7 ml/s), it was adsorbed by the endothelial surface. Then by changing the perfusate entering the lobe to an albumin-containing perfusate, the BD was eluted from the perfused surface by competitive binding to the perfusate albumin. The amount of BD eluted was measured in three experiments. In experiment 1, elution of the BD by the perfusate albumin was initiated after a balloon had been inflated within the lobar arterial tree to occlude a portion of the lobar vascular bed containing BD. Then the balloon was deflated, permitting albumin perfusate to perfuse the previously occluded part of the lobe. In experiment 2, BD elution began at a flow rate of 3 ± 0.1 ml/s under zone 3 conditions and continued after the high-flow zone 3 conditions were reestablished. In experiment 3, the BD elution began at a flow rate of 4.2 ± 0.7 ml/s under zone 2 conditions and continued after the high-flow zone 3 conditions were reestablished. Balloon inflation reduced the amount of BD recovered by 43%, demonstrating that a decrease in perfused vascular surface area could decrease BD recovery. Flow reduction in zone 3 conditions had virtually no effect on the BD recovery, demonstrating that decreasing flow in zone 3 produced little change in perfused vascular surface area. The combination of decreased flow and zone 2 conditions reduced BD recovery by 19%, demonstrating that even when changing from a high-flow zone 3 condition to a low-flow zone 2 condition, there was only a modest derecruitment of surface area in this preparation.

Original languageEnglish (US)
Pages (from-to)874-880
Number of pages7
JournalJournal of applied physiology
Volume72
Issue number3
DOIs
StatePublished - 1992

Keywords

  • dog lung lobe
  • flow rate
  • perfused vascular surface area
  • recruitment
  • zone 2
  • zone 3

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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