Mechanisms and consequences of intra-pulmonary arteriovenous shunting

我们对肺的经典理解是，血液从右心室流经肺动脉，流向小动脉，然后流向毛细血管，在那里氧气和二氧化碳进行交换。然后，血液通过小静脉返回心脏，然后是静脉，然后到达左心房。令人惊讶的是，我们发现，正常健康人的运动会导致肺内血管重新聚集，绕过肺毛细血管(即从动脉/小动脉直接流向小静脉/静脉)。这一发现违背了我们对血液流经肺部的基本理解。这些大直径的副血管(即肺内分流)的募集似乎是：1.损害肺内氧气和二氧化碳的交换，2.降低肺内的驱动压(即肺动脉压)。拨款的目的是更仔细地研究是什么原因导致这些肺内分流在肺内开放，并进一步确定招募这些分流的后果。

Our classic understanding of the lung is that blood flows from the right ventricle, through the pulmonary arteries, to arterioles, and then to the capillaries where oxygen and carbon dioxide are exchanged. The blood then returns back to the heart through venules, then veins before reaching the left atrium. Surprisingly, we have found that exercise in normal healthy people causes blood vessels to be recruited in the lung that bypass the pulmonary capillaries (i.e. direct blood flow from arteries/arterioles to venules/veins). This finding goes against our basic understanding of blood flow through the lung. The recruitment of these large-diameter by-vessels (i.e. intra-pulmonary shunts) appears to: 1. Impair the exchange of oxygen and carbon dioxide in the lung, 2. Reduce the driving pressure (i.e. the pulmonary artery pressure) in the lung. The purpose of the grant is to more closely examine what is causing these intra-pulmonary shunts to open in the lung, and to further determine the consequences of recruiting these shunts.