多巴胺和去甲肾上腺素对肾皮质血流灌注影响的对比超声评价

Effects of Dopamine and Noradrenaline on renal cortical blood perfusion:quantification with contrast-enhanced ultrasound

目的应用对比超声定量评价多巴胺(DA)和去甲肾上腺素(NE)对肾脏皮质血流灌注的影响。方法10只实验犬分别在基础状态、以及三种不同剂量DA和NE作用下,进行对比超声(CEU)检查,并测量左肾动脉血流量。采用经静脉微泡连续输注法进行CEU,观察肾皮质的平台声强度(A),造影剂再充填速率(β)和A与β的乘积(A×β)。结果在低、中剂量DA作用时,肾皮质的β值和A×β值与静息相比明显增加,且随剂量的增加而增加(P<0.05);在高剂量DA作用时,β值和A×β值与静息相比也有明显增加(P<0.05),但与低、中剂量DA相比,增加的程度减少(P<0.05);而肾皮质的A值仅在中等剂量DA作用时,与静息相比有明显增加(P<0.05);三种剂量DA作用下,肾皮质的β值与A×β值之间有良好的正相关(P<0.05,r=0.85)。在三种剂量NE作用下,肾皮质的A值、β值和A×β值与静息相比均明显减少(P<0.05),且随剂量的增加而减少幅度增大(P<0.05)。三种剂量NE作用下,肾皮质的A值和β值与A×β值之间均有良好的正相关(P<0.05,r值分别为0.83和0.71)。结论CEU可作为定量评价多巴胺(DA)和去甲肾上腺素(NE)对肾脏皮质血流灌注影响的一种较佳方式。

Objective To quantitatively evaluate the effects of Dopamine （DA） and Noradrenaline （NE） on renal cortical blood perfusion using contrast- enhanced ultrasound. Methods 10 experimental dogs were performed with contrast - enhanced ultra- sound （CEU） and the renal artery flow （RAF） was measured simultaneously at baseline and during 3 different doses of DA （at 3, 8 and 16 μg·kg^-1·min^-1 ） and NE （at 0.2, 0.6 and 1.0 μg·kg^-1·min^-1 ）. Blood volume （A）, blood velocity （β） and blood flow （A×β） in the renal cortical tissue were determined by CEU. Results As compared to baseline, a dose - dependent increase in CEU- derived and A ×β with DA up to a dose of 8 μg·kg^-1·min^-1 （ P 〈 0.05）. Above this dose, the increase in CEU - derived β and A×β was attenuated （ P 〈 0.05）. However, CEU - derived A was significantly higher in the cortex at middle - doses of DA only （ P 〈 0.05）. There was a good relation between CEU - derived β and A ×β in all dose （ P 〈 0.05, r = 0.85）. In the presence of low - , middle - and high - doses of NE, a dose - dependent progressive decreases in CEU - derived A, β and A ×β were seen as compared with baseline （ P 〈 0.05）. There were good relations between either CEU - derived A or β versus CEU - derived A ×β in all dose （ P 〈 0.05, r = 0.83 and 0.71, respectively）. Conclusion The increase in cortical nutrient blood flow during dopamine is predominantly due to the increase in blood velocity rather than in blood volume. In the presence of noradrenaline, a dose - dependent progressive decrease in cortical blood flow is attributed to the decrease in both tissue blood volume and velocity.