Welch W J, Deng X, Snellen H, Wilcox C S
Division of Nephrology, University of Florida, Gainesville.
Am J Physiol. 1995 Jan;268(1 Pt 2):F175-8. doi: 10.1152/ajprenal.1995.268.1.F175.
This study validates the accuracy of miniature ultrasonic transit-time flow probes for measuring renal blood flow (RBF) in the rat. Probes for 1-mm and 2-mm vessels were calibrated ex vivo using excised arteries at varying flow rates and hematocrit (Hct). Correlation between measured and true flow rates for the 2-mm probe were identical (r = 1.0) at both normal and subnormal Hct values. Correlation for the 1-mm probe was high (r = 0.994) at normal Hct, but varied at both high flow rates and subnormal Hct values. In vivo correlation of RBF measurements using the 1-mm probe with the clearance and extraction of p-aminohippuric acid showed a high correlation (r = 0.84; n = 72, P < 0.0001) over a wide range of flow rates (0.5-21 ml/min) and Hct (36-74%). Zero flow levels remained steady, averaging -0.2 +/- 0.2 ml/min during occlusion in the living animal and -0.1 +/- 0.3 ml/min after exsanguination. This study shows that the ultrasonic transit-time flowmeter (1-mm and 2-mm probes) is a reasonably accurate and reliable method with which to measure RBF in the anesthetized, acute-instrumented rat.
本研究验证了微型超声渡越时间血流探头在测量大鼠肾血流量（RBF）方面的准确性。使用切除的动脉在不同流速和血细胞比容（Hct）下对用于1毫米和2毫米血管的探头进行离体校准。在正常和低于正常的Hct值下，2毫米探头测量的流速与真实流速之间的相关性均相同（r = 1.0）。1毫米探头在正常Hct时相关性较高（r = 0.994），但在高流速和低于正常的Hct值时均有所变化。使用1毫米探头测量的RBF与对氨基马尿酸的清除率和提取率的体内相关性在广泛的流速范围（0.5 - 21毫升/分钟）和Hct范围（36 - 74%）内显示出高度相关性（r = 0.84；n = 72，P < 0.0001）。零流速水平保持稳定，在活体动物阻断期间平均为-0.2±0.2毫升/分钟，放血后为-0.1±0.3毫升/分钟。本研究表明，超声渡越时间流量计（1毫米和2毫米探头）是一种在麻醉的、急性插管的大鼠中测量RBF的合理准确且可靠的方法。
