Is Erythrocyte Damage Prevented by Gardos Effect in Hemodialyzed Uremic Patients?

Abstract: 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 μg/ml, respectively, and in controls 0.61 ± 0.14 μg/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).