Pulmonary blood flow heterogeneity during hypoxia and high-altitude pulmonary edema

Susan R. Hopkins, Joy Garg, Divya S. Bolar, Jamal Balouch, David L. Levin

Research output: Contribution to journalArticlepeer-review

131 Scopus citations

Abstract

Uneven hypoxic pulmonary vasoconstriction has been proposed to expose parts of the pulmonary capillary bed to high pressure and vascular injury in high-altitude pulmonary edema (HAPE). We hypothesized that subjects with a history of HAPE would demonstrate increased heterogeneity of pulmonary blood flow during hypoxia. A functional magnetic resonance imaging technique (arterial spin labeling) was used to quantify spatial pulmonary blood flow heterogeneity in three subject groups: (1) HAPE-susceptible (n = 5), individuals with a history of physician-documented HAPE; (2) HAPE-resistant (n = 6), individuals with repeated high-altitude exposure without illness; and (3) unselected (n = 6), individuals with a minimal history of altitude exposure. Data were collected in normoxia and after 5, 10, 20, and 30 minutes of normobaric hypoxia (FI O2 = 0.125). Relative dispersion (SD/mean) of the signal intensity was used as an index of perfusion heterogeneity. Oxygen saturation was not different between groups during hypoxia. Relative dispersion was not different between groups (HAPE-susceptible 0.94 ± 0.05, HAPE-resistant 0.94 ± 0.05, unselected 0.87 ± 0.06; means ± SEM) during normoxia, but it was increased by hypoxia in HAPE-susceptible (to 1.10 ± 0.05 after 30 minutes, p < 0.0001) but not in HAPE-resistant (0.91 ± 0.05) or unselected subjects (0.87 ± 0.05). HAPE-susceptible individuals have increased pulmonary blood flow heterogeneity in acute hypoxia, consistent with uneven hypoxic pulmonary vasoconstriction.

Original languageEnglish (US)
Pages (from-to)83-87
Number of pages5
JournalAmerican journal of respiratory and critical care medicine
Volume171
Issue number1
DOIs
StatePublished - Jan 1 2005

Keywords

  • Hypoxic pulmonary vasoconstriction
  • Magnetic resonance imaging
  • Pulmonary circulation

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

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