TY - JOUR
T1 - Pulmonary capillary recruitment in response to hypoxia in healthy humans
T2 - A possible role for hypoxic pulmonary venoconstriction?
AU - Taylor, Bryan J.
AU - Kjaergaard, Jesper
AU - Snyder, Eric M.
AU - Olson, Thomas P.
AU - Johnson, Bruce D.
N1 - Funding Information:
This work was supported by National Heart, Lung, and Blood Institute Grant HL-71478. BJT is supported by a Fulbright Commission UK Distinguished Scholar Award.
PY - 2011/7/31
Y1 - 2011/7/31
N2 - 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.
AB - 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.
KW - Cardiac output
KW - Hypoxic pulmonary vasoconstriction
KW - Left ventricular diastolic function
KW - Pulmonary artery pressure
KW - Pulmonary capillary blood volume
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U2 - 10.1016/j.resp.2011.04.005
DO - 10.1016/j.resp.2011.04.005
M3 - Article
C2 - 21513822
AN - SCOPUS:79957469273
SN - 1569-9048
VL - 177
SP - 98
EP - 107
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
IS - 2
ER -