Gorin A B
Department of Internal Medicine, Houston Veterans Administration Medical Center, Baylor College of Medicine, Texas 77211.
J Appl Physiol (1985). 1988 Apr;64(4):1561-6. doi: 10.1152/jappl.1988.64.4.1561.
The noninvasive external radioflux detection method (ERD) measures net transvascular flux of tracer protein into and out of the lung extravascular compartment (EV) and time to zero flux between compartments. With this information we can now estimate regional interstitial volume in the field of the external probe (VIs). Dividing the mass of EV tracer by VIs, we obtain interstitial concentration ([Is]). Directly sampling plasma concentration of the tracer, we can construct plasma-interstitium equilibration curves that are analogous to plasma-lymph equilibration curves without invasive surgery. We completed 46 ERD studies in 21 sheep with chronic lung lymph fistulas. Sheep were studied under baseline conditions (n = 30) and after elevating left atrial pressure by mitral obstruction (n = 7), or intravascular volume infusion (n = 8), and increasing lung vascular permeability (n = 1). In each study we compared the slope of the regression through plasma-lymph concentration of tracer protein over time ([P]-[L], measured directly) with that through values of plasma-interstitial concentration ([P]-[Is], assessed noninvasively), an index of vascular permeability. For this correlation, r = 0.94, and the regression line approximates identity. Mean [Is] appears to approximate [L] in sheep.
非侵入性外部放射性通量检测方法（ERD）可测量示踪蛋白进出肺血管外间隙（EV）的净跨血管通量以及各间隙间通量降至零所需的时间。利用这些信息，我们现在可以估算外部探头探测区域的局部间质容积（VIs）。用EV示踪剂的质量除以VIs，我们就能得到间质浓度（[Is]）。通过直接采集示踪剂的血浆浓度，我们可以构建血浆-间质平衡曲线，这类似于无需进行侵入性手术的血浆-淋巴平衡曲线。我们对21只患有慢性肺淋巴瘘的绵羊进行了46项ERD研究。在基线条件下（n = 30）以及通过二尖瓣梗阻升高左心房压力后（n = 7）、或进行血管内容量输注后（n = 8）、以及增加肺血管通透性后（n = 1）对绵羊进行了研究。在每项研究中，我们将示踪蛋白的血浆-淋巴浓度随时间变化的回归斜率（[P]-[L]，直接测量）与血浆-间质浓度（[P]-[Is]，非侵入性评估）的回归斜率进行了比较，后者是血管通透性的一个指标。对于这种相关性，r = 0.94，且回归线近似于恒等线。绵羊的平均[Is]似乎近似于[L]。
