Pulmonary capillary recruitment in response to hypoxia in healthy humans: A possible role for hypoxic pulmonary venoconstriction?

Bryan J. Taylor, Jesper Kjaergaard, Eric M. Snyder, Thomas P. Olson, Bruce D. Johnson

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

We examined mechanisms by which hypoxia may elicit pulmonary capillary recruitment in humans. On separate occasions, twenty-five healthy adults underwent exposure to intravenous saline infusion (30. ml/kg ∼15. min) or 17-h normobaric hypoxia (FIO2=12.5%). Cardiac output (Q̇) and pulmonary capillary blood volume (Vc) were measured before and after saline infusion and hypoxic-exposure by a rebreathing method. Pulmonary artery systolic pressure (sPpa) and left ventricular (LV) diastolic function were assessed before and after hypoxic-exposure via echocardiography. Saline infusion increased Q̇ and Vc (P< 0.05) with no change in Vc/Q̇ (P = 0.97). Hypoxic-exposure increased Vc (P< 0.01) despite no change in Q̇ (P = 0.25), increased sPpa (P< 0.01), and impaired LV relaxation. Multiple regression suggested that ∼37% of the hypoxia-mediated increase in Vc was attributable to alterations in Q̇, sPpa and LV diastolic function. In conclusion, hypoxia-induced pulmonary capillary recruitment in humans is only partly accounted for by changes in Q̇, sPpa and LV diastolic function. We speculate that hypoxic pulmonary venoconstriction may play a role in such recruitment.

Original languageEnglish (US)
Pages (from-to)98-107
Number of pages10
JournalRespiratory Physiology and Neurobiology
Volume177
Issue number2
DOIs
StatePublished - Jul 31 2011

Keywords

  • Cardiac output
  • Hypoxic pulmonary vasoconstriction
  • Left ventricular diastolic function
  • Pulmonary artery pressure
  • Pulmonary capillary blood volume

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology
  • Pulmonary and Respiratory Medicine

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