Management of Dialysis Fluid is Important
The quality of dialysis fluid influences the health of patients. Coming into contact with the blood through the dialyzer, dialysis fluid has an influence on the blood. Abnormal levels of electrolytes in the blood can lead to a variety of symptoms and adverse health effects. Management of the quality of dialysis fluid is extremely important for dialysis.
Dialysis fluid is prepared by removing impurities and additives such as chlorine from tap water to make product water and then mixing this with dialysate concentrate.
Impurities in product water can be dangerous for health, and the purification of this water is, therefore, essential.
Bacterial growth in dialysis machine can cause infection and toxins, and it may enter the bloodstream, leading to symptoms such as fever.
Daily maintenance of dialysis equipment is important to produce pure dialysis fluid free from bacterial contamination.
Dialysis fluid must satisfy pharmaceutical quality requirements before it is supplied to dialysis centers. However, the centers are then responsible for mixing the supplied dialysis fluid just before using it in dialysis to make the final prepared dialysis fluid. Dialysis fluid becomes the final product moments before it is used in dialysis, and management of dialysis fluid quality (mixing ratio, concentration of ingredients) is, therefore, essential.
Management of the Concentration of the Prepared Dialysis
Fluid at each Center is Essential
Hemodialysis concentrate is supplied to dialysis centers in the form of powder or liquid (acid concentrate and bicarbonate concentrate). At this moment its quality is assured by manufacturers. These dialysate concentrates need to be diluted and mixed at the centers before they can be used in dialysis. The dialysis fluid has to be prepared just before use as, once diluted and mixed, it cannot be stored for prolonged periods. The dialysis fluid prepared at centers is not “quality-assured.” Without quality check at centers, it cannot be said that it is properly prepared. There is a possibility to have abnormal dialysis solution in cases such as following.
- 1. In case of an error in the dialysis fluid delivery system, there is a possibility to have the dialysis fluid with incorrect concentration.
- 2. A human error in the mixing ratio also results in the dialysis fluid with incorrect concentration.
- 3. Storage condition also effects on the concentration of dialysis fluid. If stored under a wrong condition, the quality of the solution A and solution B can be changed.
Poor dialysis fluid quality can adversely affect patient health.
Management of the concentration of the prepared dialysis fluid at each center is essential.
How to Check the Concentration of Dialysis Fluid
In Japan, which has one of the best prognosis for dialysis patients in the world, there are moves to standardize procedures for managing dialysis fluid, which were previously left to each center’s discretion.
The recommended procedure for guaranteeing that dialysis fluid is prepared according to the correct mixing ratios is to use more than one analyzers such as an electrolyte analyzer and an osmometer to verify mixing ratios. Proper performance of this procedure can be used as evidence of a hospital’s level of treatment and safety.
Following is the measurement items that are used for the management of dialysis fluid concentration.
The ratio of dilution and mixing of the prepared dialysis fluid can be verified by measuring electrolytes contained in the dialysis fluid. Whereas the quality of acid concentrate and bicarbonate concentrate are assured by the manufacturer prior to dilution, the prepared dialysis fluid is not “quality assured” because it is diluted and mixed by the centers.
The concentration of electrolytes in the dialysis fluid significantly affects levels of electrolytes in the blood. If levels of electrolytes in the blood become too high, this may cause symptoms such as headache and high blood pressure. Low levels of electrolytes can lead to symptoms such as numbness of the limbs and general fatigue.
To prevent this, it is important to verify that the prepared dialysis fluid has the optimum electrolyte composition.
To check whether the dialysis fluid has diluted and mixed correctly, it is necessary to accurately measure the ingredients derived from acid concentrate and the ingredients derived from bicarbonate concentrate. By using an electrolyte analyzer to measure K+ and Cl-, which are only contained in acid concentrate, and Na+, which is contained in both acid concentrate and bicarbonate concentrate, it is possible to verify the ratio of dilution and mixing. As shown in the figure below, it is sometimes impossible to judge whether the fluid has been diluted and mixed correctly simply by checking the total concentration of the dialysis fluid. Measurement of electrolytes is, therefore, essential.
Concentrations can also be managed by checking that the osmotic pressure of the prepared dialysis fluid is in accordance with the dialysis fluid’s theoretical value. While this does not allow verification of the ratio of dilution and mixing of the prepared dialysis fluid, it does enable verification of the dialysis fluid’s total concentration. An osmometer, which operates on the principle of the freezing point method, is often used. A key feature of the osmometer is that it can be calibrated using sodium chloride water solution as the standard substance, which means that there is little variation between manufacturers and models and it can measure concentration regardless of the type of dialysis fluid.
Device used for measurement: Osmometer
An electric conductivity meter is built into many dialysis fluid delivery systems and is used to continuously monitor the concentration of dialysis fluid and constantly check for any changes in concentration. Although an electric conductivity meter cannot verify the ratio of dilution and mixing of the prepared dialysis fluid, it can check the total concentration of the dialysis fluid. In the case of a dialysis fluid delivery system that incorporates a concentration monitoring device, if the concentration exceeds the upper or lower concentration setting, an alarm sounds and delivery of the dialysis fluid is stopped. These devices also need regular calibration and cleaning, as dirt particles on the electrode can alter measurements.
Device used for measurement:
Electric conductivity meter, Dialysis fluid delivery system with built-in electric conductivity meter.