Potential life-threatening variations of drug concentrations in intravenous infusion systems: potassium chloride, insulin, and heparin.

The investigation of concentrations of active agents in common carrier media for intravenous infusion revealed that potassium chloride tends to form a pool when it is added without mixing to carrier media in glass or polyvinyl chloride (PVC) containers which are already suspended in their functional position with ports pointing downwards. Heparin behaves in a similar fashion when added without mixing to carrier media in PVC containers. Such uneven distribution may expose a patient to potentially dangerous, possibly lethal, concentrations of a drug even when a relatively small amount of it is used. Insulin floats to the top of a Haemaccel container if its contents are not adequately mixed after addition of insulin. The resultant irregularity of insulin dosage may make the management of diabetic ketoacidosis more difficult. It is recommended that the instructions for the adequate mixing of contents should appear on all containers of carrier media for intravenous infusions.