Central Vascular Access Device (CVAD): Flushing


A CVAD should be flushed as often as your doctor tells you, to keep it clear of blood and prevent clotting. If it ends in more than one line (lumen), flush them in the same order each time. Depending on the type you have, you will flush it with either heparin or saline solution. Your doctor or nurse will probably give you supplies and instructions on how to flush it. A nurse may come to your home to help you at first.

You will usually lie down when you flush the line. This helps prevent air from getting into your vein.

Preparing the syringe or cannula

  1. Be sure you have all your supplies ready. These may include the heparin or saline solution, syringes, needleless injection cannulas, alcohol swabs, and a disposal box. What you need will vary with the type you have. You may have syringes that are already filled with the solution (preloaded).
  2. Wash your hands with soap and water for 15 to 30 seconds. Dry them with paper towels.
  3. Wipe the stopper of the heparin or saline solution bottle with an alcohol swab for 15 to 30 seconds.
  4. Remove the cover from the syringe, and twist the needle or cannula on to it. (It may already be attached.)
  5. Remove the cover from the needle or cannula. Note: If you have a preloaded syringe, skip to the next section, "Flushing the line."
  6. Pull back the plunger of the syringe, and draw air into the syringe equal to the amount of heparin or saline solution you are using.
  7. Push the needle or cannula through the rubber lid of the solution bottle.
  8. Push the plunger of the syringe to force air into the bottle.
  9. Turn the bottle and syringe upside down. Position the tip of the needle or cannula so that it is below the surface of fluid in the bottle. Pull back the plunger to fill the syringe with the amount of solution you need.
  10. Before you take the needle or cannula out of the bottle, check for air bubbles in liquid in the syringe. If there are bubbles, push the plunger back in and then pull back on it again.
  11. Remove the needle or cannula from the bottle.
  12. Fill other syringes if you need to flush more than one lumen.

Flushing the line

  1. Use an alcohol swab to rub the cap of the line you want to flush. Rub for 15 to 30 seconds, and then let the cap dry.
  2. Hold the end of the line so it does not touch anything.
  3. If you have a clamp on the line, open it.
  4. Slowly inject heparin, or quickly inject saline solution. If there is resistance, stop. Do not force it. Call your doctor.
  5. If you have a clamp on the line, clamp it as you are finishing the injection and then remove the syringe. If the line has a positive pressure cap, remove the syringe and then clamp it.
  6. Put the syringe in the disposal box.
  7. Repeat the above steps for each line you are flushing.
  8. Wash your hands again with soap.


Current as of: July 26, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.