Hypoxic pulmonary vasoconstriction does not contribute to pulmonary blood flow heterogeneity in normoxia in normal supine humans

T. J. Arai, A. C. Henderson, D. J. Dubowitz, D. L. Levin, P. J. Friedman, R. B. Buxton, G. K. Prisk, S. R. Hopkins

Research output: Contribution to journalArticlepeer-review

41 Scopus citations

Abstract

We hypothesized that some of the heterogeneity of pulmonary blood flow present in the normal human lung in normoxia is due to hypoxic pulmonary vasoconstriction (HPV). If so, mild hyperoxia would decrease the heterogeneity of pulmonary perfusion, whereas it would be increased by mild hypoxia. To test this, six healthy nonsmoking subjects underwent magnetic resonance imaging (MRI) during 20 min of breathing different oxygen concentrations through a face mask [normoxia, inspired O2 fraction (FIO2) = 0.21; hypoxia, FIO2 = 0.125; hyperoxia, FIO2 = 0.30] in balanced order. Data were acquired on a 1.5-T MRI scanner during a breath hold at functional residual capacity from both coronal and sagittal slices in the right lung. Arterial spin labeling was used to quantify the spatial distribution of pulmonary blood flow in milliliters per minute per cubic centimeter and fast low-angle shot to quantify the regional proton density, allowing perfusion to be expressed as density-normalized perfusion in milliliters per minute per gram. Neither mean proton density [hypoxia, 0.46(0.18) g water/cm3; normoxia, 0.47(0.18) g water/cm3; hyperoxia, 0.48(0.17) g water/cm3; P = 0.28] nor mean density-normalized perfusion [hypoxia, 4.89(2.13) ml·min-1·g-1; normoxia, 4.94(1.88) ml·min-1·g-1; hyperoxia, 5.32(1.83) ml·min-1·g-1; P = 0.72] were significantly different between conditions in either imaging plane. Similarly, perfusion heterogeneity as measured by relative dispersion [hypoxia, 0.74(0.16); normoxia, 0.74(0.10); hyperoxia, 0.76(0.18); P = 0.97], fractal dimension [hypoxia, 1.21(0.04); normoxia, 1.19(0.03); hyperoxia, 1.20(0.04); P = 0.07], log normal shape parameter [hypoxia, 0.62(0.11); normoxia, 0.72(0.11); hyperoxia, 0.70(0.13); P = 0.07], and geometric standard deviation [hypoxia, 1.88(0.20); normoxia, 2.07(0.24); hyperoxia, 2.02(0.28); P = 0.11] was also not different. We conclude that HPV does not affect pulmonary perfusion heterogeneity in normoxia in the normal supine human lung.

Original languageEnglish (US)
Pages (from-to)1057-1064
Number of pages8
JournalJournal of applied physiology
Volume106
Issue number4
DOIs
StatePublished - Apr 2009

Keywords

  • Arterial spin labeling
  • Fractal dimension
  • Hyperoxia
  • Log normal distribution
  • Magnetic resonance imaging
  • Regional pulmonary blood flow
  • Relative dispersion

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Fingerprint Dive into the research topics of 'Hypoxic pulmonary vasoconstriction does not contribute to pulmonary blood flow heterogeneity in normoxia in normal supine humans'. Together they form a unique fingerprint.

Cite this