The effects of carbon dioxide versus ioxaglate in the rat kidney.

Purpose: The renal medulla seems to be particularly vulnerable to vascular injection of iodinated contrast media, particularly in patients with preexisting renal dysfunction. The gas carbon dioxide is frequently used as an alternative to iodinated contrast medium in these patients. In this study, the renal effects of CO(2) are investigated and compared with those of the iodinated contrast medium ioxaglate.
Materials and Methods: Cortical and outer medullary blood flow (measured by laser Doppler flowmetry) and oxygen tension (Po(2); measured by oxygen microelectrodes) were recorded in anesthetized Sprague-Dawley rats given an intraarterial injection of ioxaglate (320 mgI/kg body weight), a volume-matched dose of CO(2), or Ringer solution.
Results: Injection of CO(2) induced a pronounced and transient decrease in cortical blood flow and Po(2) (approximately -45%), whereas outer medullary blood flow and Po(2) were transiently increased (+21% and +29%, respectively). In contrast, injection of ioxaglate did not influence cortical blood flow and caused outer medullary blood flow to decrease by 17%. Ioxaglate injection also resulted in a decrease in cortical and outer medullary Po(2) (-15% and -33%, respectively). Ringer solution affected none of the recorded parameters.
Conclusions: Although injection of CO(2) markedly affected regional renal blood flow and Po(2), there were qualitatively different effects in the cortex and outer medulla compared with those seen after injection of ioxaglate. The pronounced decrease in medullary blood flow and Po(2) observed after injection of ioxaglate was absent in the animals injected with CO(2). This might suggest beneficial effects of the use of CO(2) instead of iodinated contrast media in patients with increased risk of developing renal failure.