Lakshminarayan S, Kowalski T F, Kirk W, Graham M M, Butler J
Department of Medicine, University of Washington, Seattle.
Respir Physiol. 1990 Oct;82(1):65-73. doi: 10.1016/0034-5687(90)90024-s.
It is generally accepted that the bronchial blood flow from extrapulmonary airways drains to the systemic veins through the bronchial veins, while that from the intrapulmonary airways drains into the pulmonary vasculature and eventually the left heart. This concept has not been confirmed by physiologic studies in live animals. We measured the routes taken by radionuclide-labeled Diethylenetriamine pentaacetate (DTPA) deposited in the extrapulmonary and the intrapulmonary airways in dogs. In living, anesthetized open chest animals, the pulmonary circulation of the left lower lobe was isolated and perfused with autologous heparinized blood. 99mTc DTPA was deposited on the mucosa of the extrapulmonary left mainstem bronchus just beyond the main carina (extrapulmonary deposition) and 111In DTPA on that of an intrapulmonary left lower lobe segmental bronchus (intrapulmonary deposition). Sequential blood samples from the right heart and from the isolated left lower lobe pulmonary circuit were counted for radioactivity, corrected for the volume in which they were distributed and for the bronchial blood that flowed into the isolated left lower lobe circuit, and expressed as the ratio of systemic to pulmonary drainage from each deposition site. The extrapulmonary tracer drained mostly to the systemic veins (84% of total) but also into the pulmonary circulation (16% of total). The intrapulmonary tracer drained mostly into the pulmonary circulation (70% of total) but also into the right heart (30% of total). Since tracers from both deposition sites drained to both circulations, the bronchial vasculature is continuous between the systemic (right heart) and the pulmonary circulation. Thus, it may provide a pathway for blood flow between the right and left heart.
一般认为，肺外气道的支气管血流通过支气管静脉引流至体静脉，而肺内气道的支气管血流则流入肺血管系统并最终进入左心。这一概念尚未在活体动物的生理学研究中得到证实。我们测量了放射性核素标记的二乙三胺五乙酸（DTPA）沉积在犬肺外和肺内气道后所走的路径。在麻醉开胸的活体动物中，分离左下叶的肺循环并用自体肝素化血液进行灌注。将99mTc DTPA沉积在主支气管分叉处稍远处的肺外左主支气管黏膜上（肺外沉积），将111In DTPA沉积在左下叶肺内段支气管黏膜上（肺内沉积）。对来自右心和分离的左下叶肺循环的连续血样进行放射性计数，校正其分布体积以及流入分离的左下叶循环的支气管血流，并表示为每个沉积部位的体循环引流与肺循环引流的比值。肺外示踪剂大部分引流至体静脉（占总量的84%），但也流入肺循环（占总量的16%）。肺内示踪剂大部分流入肺循环（占总量的70%），但也流入右心（占总量的30%）。由于来自两个沉积部位的示踪剂都引流至两个循环，因此支气管血管系统在体循环（右心）和肺循环之间是连续的。因此，它可能为左右心之间的血流提供一条途径。
