Thorvaldson J, Ilebekk A, Leraand S, Kiil F
Acta Physiol Scand. 1984 May;121(1):45-56. doi: 10.1111/j.1748-1716.1984.tb10456.x.
To examine the effects of pulmonary vascular pressures and flow on pulmonary blood volume (PBV), experiments were performed at constant heart rate and zone 3 conditions (mean left atrial pressure (LAP) above airway pressure) in six anesthetized, open-chest dogs. PBV was calculated as the product of electromagnetic aortic flow and pulmonary mean transit time for ascorbate, obtained without blood withdrawal by polarographic recording of aortic ascorbate changes. In three series of experiments LAP was raised similarly in three steps, from 4.5 to 14.8 mmHg: by mitral constriction which reduced pulmonary blood flow, by blood volume expansion which more than doubled pulmonary blood flow, or by a combination of the two procedures which kept pulmonary blood flow constant. In all three series, LAP and mean pulmonary arterial pressure (PAP) rose in proportion, but PBV was better correlated to PAP (r = 0.87 +/- 0.02) than to LAP (r = 0.66 +/- 0.09). These experiments suggest that PAP is the most important factor in determining PBV under zone 3 conditions, whether PAP is raised by increasing pulmonary blood flow or by mitral constriction.
为研究肺血管压力和血流对肺血容量（PBV）的影响，在六只麻醉开胸犬身上，于恒定心率和3区条件（平均左心房压力（LAP）高于气道压力）下进行了实验。PBV通过电磁主动脉血流与抗坏血酸的肺平均通过时间的乘积来计算，抗坏血酸的肺平均通过时间是通过极谱记录主动脉抗坏血酸变化在不抽血的情况下获得的。在三个系列实验中，LAP分三步以相似幅度升高，从4.5 mmHg升至14.8 mmHg：通过二尖瓣狭窄使肺血流量减少、通过血容量扩充使肺血流量增加一倍以上，或通过两种操作的组合使肺血流量保持恒定。在所有三个系列中，LAP和平均肺动脉压（PAP）成比例升高，但PBV与PAP的相关性（r = 0.87 +/- 0.02）优于与LAP的相关性（r = 0.66 +/- 0.09）。这些实验表明，在3区条件下，无论PAP是通过增加肺血流量还是二尖瓣狭窄升高，PAP都是决定PBV的最重要因素。
