Thread: Redistribution of blood flow in pulmonary edema

In a normal lung, more perfusion (blood flow) occurs at the lung bases than at the apices and more ventilation (air flow) at the apices than bases.

However, in patients with pulmonary edema (left ventricular failure), this distribution of blood flow is altered. As the pulmonary venous pressure rises and fluid accumulates at the lung bases the blood flow begins to get redistributed toward the apices.

Mechanism for the redistribution of blood flow in pulmonary edema:
This is not very clearly understood but probably related to "hypoxic pulmonary vasoconstriction".
Due to alveolar wall edema, that is more significant in the lower lobes in pulmonary edema, gas exchange is reduced. This results in hypoxic vasoconstriction of lower lobes resulting in increased flow to upper lobes.

Other terms used to denote this: Cephalization of blood flow; Upper lobe blood diversion; Inverted moustache sign; Antler's horn sign

Photograph:


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