This app is used to predict the rate of change in a patient’s plasma sodium concentration during a hemodialysis treatment referred to continuous veno-venous hemofiltration (CVVH).  CVVH is an established treatment for patients with acute kidney injury receiving treatment in an intensive care setting.  During the dialysis process the patient’s blood is transported through an artificial kidney also known as a dialyzer. Inside the dialyzer, blood passes over a semipermeable membrane with replacement fluid on the opposite side of the membrane. During the transport of blood through the dialyzer, substances enter or are removed from the blood based on the relative concentration of the substance on each side of the membrane.  If the sodium concentration in the replacement fluid is higher than in the blood, sodium will be transferred from the replacement fluid into the blood.  The transfer of sodium will be from the blood to the replacement fluid if the sodium concentration in the replacement is lower than in the blood. The patient’s plasm sodium cannot be changed by more than 10 millimoles per liter in a 24 hour period.  The app is first used to determine the appropriate sodium concentration for the replacement fluid to prevent a rapid change in the patient’s plasma sodium concentration.  Once the replacement fluid concentration is determined, the app is used to generate a table and a graph that show the predicted change in the patient’s plasma sodium concentration over the next 24 hour period of CVVH therapy.  The app is then used to adjust therapy for the next period of CVVH therapy if needed.