Pulmonary capillaries are recruited during pulsatile flow.

@article{Presson2002PulmonaryCA,
  title={Pulmonary capillaries are recruited during pulsatile flow.},
  author={Robert G. Presson and William A. Baumgartner and Amanda J. Peterson and Robb W. Glenny and Wiltz W. Wagner},
  journal={Journal of applied physiology},
  year={2002},
  volume={92 3},
  pages={
          1183-90
        }
}
Capillaries recruit when pulmonary arterial pressure rises. The duration of increased pressure imposed in such experiments is usually on the order of minutes, although recent work shows that the recruitment response can occur in <4 s. In the present study, we investigate whether the brief pressure rise during cardiac systole can also cause recruitment and whether the recruitment is maintained during diastole. To study these basic aspects of pulmonary capillary hemodynamics, isolated dog lungs… 

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References

SHOWING 1-10 OF 24 REFERENCES
Selected contribution: measuring the response time of pulmonary capillary recruitment to sudden flow changes.
TLDR
The pulmonary microcirculation responds rapidly to step changes in flow, even in the capillaries that are most distant from the hilum, which means that the pulmonary capillary recruitment in subpleural alveoli reaches a new steady state after sudden changes in blood flow.
Intrapulmonary blood flow redistribution during hypoxia increases gas exchange surface area.
  • R. Capen, W. Wagner
  • Medicine
    Journal of applied physiology: respiratory, environmental and exercise physiology
  • 1982
TLDR
Data show that widespread capillary recruitment during hypoxia is caused by increased vascular resistance and the resulting upward blood flow redistribution, and not by an increase in cardiac output.
Pulmonary capillary recruitment during airway hypoxia in the dog.
TLDR
There was no correlation between the recruitment of capillaries and alterations in left atrial pressure, only a weak correlation with cardiac output changes, but a very strong correlation with increased pulmonary artery pressure, which implies that recruitment was probably caused by vasoconstriction within the lung.
Pulmonary O2 transfer during pulsatile and non-pulsatile perfusion.
TLDR
The phenomenon of "cardiogenic gas mixing" in the airways in vivo is a result of a direct action of the heart on the lungs rather than arterial pulsations, suggesting a beneficial effect of flow- and pressure pulsations.
Effect of pulsatile pulmonary artery pressure on distribution of blood flow in isolated lung.
Effect of capillary pressure and lung distension on capillary recruitment.
TLDR
It is concluded that capillary perfusion begins when intracapillary pressure just exceeds alveolar pressure but that further increases in capillary pressure recruit capillaries depending on tension in theAlveolar wall, whether imposed by positive airway pressure or by gravity when the lung is suspended in an intact thorax.
Effect of pulsatile flow on microvascular resistance in adult rabbit lungs.
TLDR
It is concluded that, in isolated perfused adult rabbit lungs, vascular resistance is very high, particularly in the microvascular segment, and that pulsatile flow decreases microv vascular resistance.
Effect of increasing flow on distribution of pulmonary capillary transit times.
TLDR
Capillary transit times become more homogeneity as lobar flow increases from low to intermediate levels, and further increases in flow across a fully recruited network are associated with decreases in transit times but not with more homogeneous capillary perfusion.
Distribution of pulmonary capillary red blood cell transit times.
TLDR
The first measurements of the entire transit time distribution for red blood cells crossing single subpleural capillary networks of canine lung using in vivo fluorescence videomicroscopy are reported and those times are compared with the distribution of plasma transit times in the same capillary Networks.
Pulsatile uptake of CO in the human lung.
TLDR
The results suggest that pulmonary capillary blood volume is pulsatile during the cardiac cycle, and all of five subjects showed pulsatile CO uptake.
...
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