From the Institute of Physiology, Charité-Universitätsmedizin Berlin, CCM, Berlin, Germany.
Invest Radiol. 2011 Nov;46(11):672-7. doi: 10.1097/RLI.0b013e31822311a9.
Hydration is widely accepted as an effective measure to prevent contrast media (CM)-induced acute kidney injury (AKI). Whether bicarbonate (NaHCO₃) infusion has a greater effect than saline is disputed. Effective prevention of CM-induced AKI by NaHCO₃ has been found by several clinical trials. However, others found either no effect or an enhanced incidence of CM-induced AKI after giving NaHCO₃. Because of their different tubular resorption, NaHCO₃ and saline may have a different capacity to flush the nephron. In this study, we compare the magnitudes by which NaHCO₃ and saline can enhance urinary flow, prevent a decline in glomerular filtration rate (GFR), and limit an increase in urine viscosity, as caused by CM administration.
Prewarmed (37°C) CM were administered as 1.5 mL bolus into the thoracic aorta of anesthetized rats. Following 2 CM were studied: iso-osmolar iodixanol (320 mg I/mL) and low-osmolar iopromide (370 mg I/mL). Four protocols (n = 7 rats per protocol) were followed: (1) saline + iodixanol, (2) saline + iopromide, (3) NaHCO₃ + iodixanol, and (4) NaHCO₃ + iopromide. Isotonic saline or NaHCO₃ were infused at a rate of 4 mL/h per kg BM, initiated 60 minutes before CM administration and continued throughout the observation period of 100 minutes. Urine volume was measured gravimetrically, urine viscosity was measured by a microviscometer, and GFR was determined by creatinine clearance.
As compared with saline infusions, NaHCO₃ infusions did not significantly alter the effects that iodixanol and iopromide exerted on urine flow rate, urine viscosity, and GFR. In the iopromide protocols, CM-induced increase in urine flow was about 50% greater than in the respective iodixanol protocols. Conversely, in the iodixanol protocols, urine viscosity was up to 10-fold greater than in the respective iopromide protocol. In the iodixanol protocols, GFR decreased transiently (10-30 min post-CM) by up to 50%, whereas GFR did not decrease in the iopromide protocols.
Infusing either saline or NaHCO₃ seems to make little difference with regard to urine flow, urine viscosity, and GFR. However, the CM used has a significant effect on these measures. Iopromide enhances urine flow by a greater magnitude than iodixanol, whereas the latter increases urine viscosity to a larger degree than iopromide and transiently decreases GFR.
补液被广泛认为是预防对比剂（CM）诱导急性肾损伤（AKI）的有效措施。碳酸氢钠（NaHCO₃）输注是否比生理盐水更有效存在争议。几项临床试验发现，NaHCO₃可有效预防 CM 诱导的 AKI。然而，其他研究发现给予 NaHCO₃后，CM 诱导的 AKI 发生率要么没有降低，要么增加。由于肾小管的重吸收不同，NaHCO₃和生理盐水可能具有不同的冲洗肾单位的能力。在这项研究中，我们比较了 NaHCO₃和生理盐水增强尿流、防止肾小球滤过率（GFR）下降以及限制 CM 给药引起的尿液粘度增加的程度。
将预热至 37°C 的 CM 以 1.5 毫升的剂量注入麻醉大鼠的胸主动脉。研究了两种等渗碘克沙醇（320mgI/mL）和低渗碘普罗胺（370mgI/mL）CM。遵循以下 4 种方案（每组 7 只大鼠）：（1）生理盐水+碘克沙醇，（2）生理盐水+碘普罗胺，（3）NaHCO₃+碘克沙醇，（4）NaHCO₃+碘普罗胺。在 CM 给药前 60 分钟开始，以 4mL/h/kg BM 的速度输注等渗盐水或 NaHCO₃，并在 100 分钟的观察期间持续输注。通过重量法测量尿量，用微粘度计测量尿液粘度，通过肌酐清除率确定 GFR。
与生理盐水输注相比，NaHCO₃输注并未显著改变碘克沙醇和碘普罗胺对尿流率、尿液粘度和 GFR 的影响。在碘普罗胺方案中，CM 引起的尿流增加约为碘克沙醇方案的 50%。相反，在碘克沙醇方案中，尿液粘度高达碘普罗胺方案的 10 倍。在碘克沙醇方案中，GFR 短暂下降（CM 后 10-30 分钟）高达 50%，而碘普罗胺方案中 GFR 没有下降。
输注生理盐水或 NaHCO₃对尿流、尿液粘度和 GFR 的影响似乎没有太大区别。然而，CM 的使用对这些措施有显著影响。碘普罗胺增强尿流的幅度大于碘克沙醇，而后者增加尿液粘度的程度大于碘普罗胺，并短暂降低 GFR。
