Respiratory muscle blood flow in exercising dogs after pneumonectomy

C. C W Hsia, M. Ramanathan, J. L. Pean, R. L. Johnson

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

In three foxhounds after left pneumonectomy, the relationships of ventilatory work and respiratory muscle (RM) blood flow to ventilation (V̇E) during steady-state exercise were examined. V̇E was measured using a specially constructed respiratory mask and a pneumotach; work of breathing was measured by the esophageal balloon technique. Blood flow to RM was measured by the radionuclide-labeled microsphere technique. Lung compliance after pneumonectomy was 55% of that before pneumonectomy; compliance of the thorax was unchanged. O2 uptake (V̇O2) of RM comprised only 5% of total body V̇O2 at exercise. At rest, inspiratory muscles received 62% and expiratory muscles 38% of the total O2 delivered to the RM (Q̇O(2 RM)). During exercise, inspiratory muscles received 59% and expiratory muscles 41% of total Q̇O(2 RM). Blood flow per gram of muscle to the costal diaphragm was significantly higher than that to the crural diaphragm. The diaphragm, parasternals, and posterior cricoarytenoids were the most important inspiratory muscles, and internal intercostals and external obliques were the most important expiratory muscles for exercise. Up to a V̇E of 120 l/min through one lung, Q̇O(2 RM) constituted only a small fraction of total body V̇O2 during exercise and maximal vasodilation in the diaphragm was never approached.

Original languageEnglish (US)
Pages (from-to)240-247
Number of pages8
JournalJournal of applied physiology
Volume73
Issue number1
DOIs
StatePublished - 1992

Keywords

  • exercise
  • microspheres
  • ventilatory power
  • work of breathing

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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