Abstract
Bolus injections of HS such as 50% glucose and 10% sodium chloride solution can sometimes be used as a treatment for HD-induced symptoms. Since increased fragility of red-cells is noted in uremic patients, rapid alterations of blood osmolarity causes by bolus injections of HS might affect the red-cells resulting in hemolysis during HD. We therefore undertook in vitro and in vivo studies to determine whether HS injection causes hemolysis.
1) In vitro study: 50% glucose solution was injected in 60sec into an extracorporeal-circuit model using bovine blood, and the hemolysis was assessed from measurement of the free hemoglobin. 2) 50μl of HD patient blood was mixed with 300μl of 278-2, 778mOsm/kg glucose solution or 342-3, 419mOsm/kg sodium chloride solution, the osmolarity of the resultant test mixture was then normalized immediately with 3ml of saline solution and the free hemoglobin in the mixture was measured. 3) In vivo study: determinations of hemolysis were made in 10 patients who received bolus injections of HS for 30sec or 60sec during HD. Blood samples were withdrawn from the venous side after the HS injection, and the plasma free hemoglobin was measured.
The results obtained were as follows. 1) the ratio of the increased free hemoglobin concentration to the whole blood hemoglobin concentration (hemolysis ratio) was 0.37±0.14%(mean±SD) in the circuit model study. 2) In the mixture tests, hemolysis die not occur at osmolarities of up to 1, 600mOsm/kg in both solutions, but it gradually increased at osmolarities above 1, 600mOsm/kg. Glucose solution was more effective than sodium chloride solution. The maximum free hemoglobin concentration was 136mg/dl when using glucose solution at 2, 778mOsm/kg, and 96mg/dl when using sodium chloride solution at 3, 419mOsm/kg. 3) In the clinical study, the plasma free hemoglobin was increased by 134.2±65.6mg/dl (hemolysis ratio: 134±0.60%) at 30sec, and 43.0±13.4mg/dl at 60sec.
The above results suggest that bolus injections of HS tend to cause hemolysis in vitro and in vivo experiments, and that glucose solution is more effective than sodium chloride solution. Frequent injections of HS during HD may thus be one of the causal factors of anemia. We should inject HS as slowly as possible when it is neccessary.
