A heparin cannula (more commonly referred to as an intravenous (IV) cannula with a heparin or injection cap) is a medical device used primarily to maintain continuous vascular access and prevent the formation of blood clots within the catheter itself. The cap is flushed with a dilute heparin solution to keep the line patent (open and unobstructed) when it is not in active use.

Maintaining IV line patency:

The main purpose is to prevent blood from clotting inside the catheter or IV line, which can cause blockages and complications.

Intermittent access:

It allows for a way to provide a patient with medications or fluids at specific times without requiring a continuous IV drip or multiple needle sticks for each dose.

Preventing complications:

By keeping the line free of clots, it reduces the risk of catheter-related complications such as thrombosis or infection.

Facilitating blood draws:

It allows for smooth and efficient blood sampling for diagnostic purposes without the need for additional venipunctures.