Is erythrocyte damage prevented by gardos effect in hemodialyzed uremic patients?

The purpose of this study was to determine the changes of calcium and potassium content in red blood cells (RBC) from uremic patients during a hemodialysis (HD) session. In 17 uremic patients on HD, the calcium and potassium content of RBC was determined in 3 blood samples collected at 0 min-HD (pre-HD), 45 min-HD, and 240 min-HD (end-HD) during a 4 h HD session. The calcium and potassium content of RBC also was determined in 20 normal subjects (controls). The mean values (+/-SD) of RBC calcium content in patients at 0 min-HD, 45 min-HD, and 240 min-HD were 1.95 +/- 0.34, 2.82 +/- 0.50, and 2. 05 +/- 0.4 microg/ml, respectively, and in controls 0.61 +/- 0.14 microg/ml. These values show that the RBC calcium in patients was generally significantly higher (p < 0.0001) in comparison to that of controls. The RBC calcium at 45 min-HD was significantly higher as compared to that at 0 min-HD and at 240 min-HD (p < 0.0001). The mean values (+/-SD) of RBCs' potassium in uremic patients at the previously mentioned measurements were 95.9 +/- 3.34, 92.5 +/- 4.32, and 93.85 +/- 3.89 mEq/L, respectively, and in controls 98.46 +/- 2. 30 mEq/L. These values show that RBC potassium of patients was generally significantly lower in comparison to controls (0 min-HD: p < 0.01, 45 min-HD and 240 min-HD: p < 0.001). Potassium decrease also was significantly lower at 240 min-HD (p < 0.01) and even lower at 45 min-HD (p < 0.001) compared to that at 0 min-HD. In conclusion, uremic patients during an HD session present a high calcium and a low potassium content of erythrocytes. These changes may prevent swelling of the cells (Gardos effect).