Hyperkalemia associated with potassium chloride administration in a cat

Addition of appropriate amounts of potassium chloride solution to fluid administered i.v. resulted in hyperkalemia in a cat. To evaluate whether incomplete mixing of potassium chloride in the fluid might have resulted in the observed hyperkalemia, 40 mEq (20 ml) of potassium chloride solution was injected into each of three 1-L vinyl bags of 5% dextrose in water, with or without attempting to mix the additive with the fluid in the bag. Measurement of potassium concentrations in the bags revealed that injecting potassium chloride solution into a bag of fluid while that fluid is being administered can result in incomplete mixing and discharge of concentrated potassium chloride from the administration set. The greatest potassium concentration measured in fluid sampled from the administration set was 194 mEq/L.