What does it mean if there is a blood line inside the indwelling needle?

There may be a thin line of blood inside the indwelling catheter, which is usually caused by backflow of blood from the vessel. A small amount generally does not require treatment; however, if there is a significant amount of blood or local skin discomfort, the indwelling catheter should be replaced.

An indwelling catheter, also known as an indwelling cannula, helps reduce vascular damage caused by repeated venipuncture and can be used for continuous or intermittent infusion. After infusion, a flush solution is used to inject any remaining medication into the vessel.

If bleeding occurs in the indwelling catheter during infusion, it may be due to excessive infusion volume that was not detected promptly, necessitating catheter replacement.

If a patient is not receiving intravenous infusion but blood appears in the indwelling catheter, this is a common occurrence. It results from blood reflux caused by vascular pressure after stopping the infusion. Due to the heparin in the catheter lock solution, blood clotting within the catheter typically does not occur. After inappropriate movement, a small amount of blood from the vein may reflux into the catheter, making blood visible inside. This usually requires no intervention. However, if there is a large amount of blood or local skin discomfort, patients should promptly consult a healthcare provider for re-evaluation or removal of the indwelling catheter.