Sackner M A, Markwell G, Atkins N, Birch S J, Fernandez R J
J Appl Physiol Respir Environ Exerc Physiol. 1980 Nov;49(5):910-5. doi: 10.1152/jappl.1980.49.5.910.
The variability of three methods of calculating pulmonary capillary blood flow (Qc) and pulmonary tissue plus capillary blood volume (Vt) during rebreathing was assessed in normal humans by using as markers acetylene, ethyl iodide, and dimethyl ether. The methods of analysis were as follows. Method I, the timing of the disappearance curves of the soluble gases was corrected by assuming that the C18O-disappearance curve intercepted at unity at time O. Method II, it was assumed that the acetylene Qc calculated by method I was correct; ethyl iodide and dimethyl ether Vt were solved by an equation using the disappearance slopes of these gases and the acetylene Qc value, thereby avoiding dependence on extrapolated intercept values. Method III, Vt was calculated by solving for a unique value of Qc between pairs of disappearance slopes of acetylene and dimethyl ether, acetylene and ethyl iodide, and ethyl iodide and dimethyl ether. Among the three methods, method I gave the most reproducible values for Vt as determined with acetylene or dimethyl ether. Using method I, both acetylene and dimethyl ether were equally acceptable gases for measurement of Vt; acetylene was a better marker for Qc measurements.
通过使用乙炔、碘乙烷和二甲醚作为标记物，在正常人体中评估了重复呼吸期间计算肺毛细血管血流量（Qc）和肺组织加毛细血管血容量（Vt）的三种方法的变异性。分析方法如下。方法I，通过假设C18O消失曲线在时间0处截距为1来校正可溶性气体消失曲线的时间。方法II，假设方法I计算出的乙炔Qc是正确的；碘乙烷和二甲醚Vt通过使用这些气体的消失斜率和乙炔Qc值的方程来求解，从而避免依赖外推截距值。方法III，通过求解乙炔和二甲醚、乙炔和碘乙烷以及碘乙烷和二甲醚的消失斜率对之间的Qc唯一值来计算Vt。在这三种方法中，方法I给出的用乙炔或二甲醚测定的Vt值最具可重复性。使用方法I，乙炔和二甲醚都是测量Vt同样可接受的气体；乙炔是测量Qc更好的标记物。
