ABSTRACT
Intravital microscopy has been widely used to directly observe microvascular blood flow and to measure microvascular hemodynamic variables in a number of vascular beds during physiological and pathophysiological circumstances. The pulmonary circulation consists of the output of right ventricle which, via the pulmonary artery and its branches, sends mixed venous blood to the pulmonary capillaries where it undergoes gas exchange, and returns it via the pulmonary veins to left atrium. Compared to the systemic circulation, the pulmonary circulation is a low-pressure, low-resistance circuit with a relatively uniform function of supplying blood to the alveoli for gas exchange. Pulmonary blood vessels are effective in attenuating pressure and flow oscillations, and the mechanics of the pulmonary circulation are largely influenced by the interaction of a number of mechanical forces within the lungs and thorax. An advantage of the isolated preparation is that substances can be given intra-vascularly and responses are separated from confounding secondary systemic effects that may indirectly affect the lung.
