Purpose: It has been demonstrated that iodinated contrast medium (CM) causes the release of potassium into the intravascular spaces, resulting in an increase of serum potassium. The purpose of the present study was to assess the effect of mixing ratio on potassium release rates by using various mixing ratios with human blood in vitro.
Materials and methods: Fresh human blood from 52 patients was mixed in vitro with iodinated CM at ratios ranging from 10:2 (blood:CM) to 10:10. Potassium release rates were determined during 30 min of exposure to CM. The test solutions used consisted of 370 mgI/ml iopamidol, 320 mgI/ml meglumine/sodium ioxaglate, and 370 mgI/ml meglumine/sodium diatrizoate.
Results: Potassium release rates increased gradually from ratios of 10:2 to 10:10. These changes were statistically significant. Among the three CM, diatrizoate induced the greatest potassium release, followed by iopamidol and then ioxaglate.
Conclusion: Increasing mixing ratios caused an increase in potassium release rates.