ABSTRACT
Bronchopulmonary anastomotic blood flow increases acutely after experimental pulmonary arterial obstruction. Hypoxia and hyperoxia both cause remodeling of the pulmonary microvasculature but the initial injury and the subsequent response of the pulmonary vasculature differ between the two. If the lung’s vasculature is to be studied the following requirements need to be identified, since they will dictate methods: the system of interest, and technique of examination. If the vasculature is not injected with a casting material, or if the study demands transmission electron microscopy, vessels are distended with fixative. When conditions closer to normal pressure or flow are desired or when the capillary bed and air-blood barrier are of interest, the fixative is perfused through the pulmonary vasculature. Like the airways, the pulmonary vasculature forms an irregular dichotomous branching system. The branches can be counted or measured in orders from the center outwards or from the periphery inwards.
