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Intravenous Therapy: Discontinuing the IV and Changing To A Heparin Lock

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What is a heparin lock?

A heparin lock, also known as a saline lock, is a plastic device with a covered rubber entry screwed into the hub of an existing IV catheter.

It allows access to the vein without having to run IV fluids into the body.

When is an IV line changed into a heparin lock?

These are the two occasions when heparin lock is placed:

  1. when IV line has been discontinued but the access to the vein is needed for continuous infusion of fluid or medication changes
  2. when client requires IV medications but does not necessarily need continuous fluid infusions

What are the advantages of having a heparin lock?

Changing to a heparin lock allows:

  • an improved client mobility
  • quick medication administration during emergency cases
  • access to vein without necessarily having an IV line

What is the main disadvantage of a heparin lock?

The main disadvantage of a heparin lock is blood clotting.

This can be prevented through a Saline Flush wherein a normal saline is regularly flushed into the heparin lock.

Materials Needed:

  • Gloves
  • Syringe with saline flush solution
  • Sterile needles
  • Alcohol swab

Discontinuing the IV And Changing To A Heparin Lock



1. Check health care provider’s order to discontinue IV and to insert a saline lock. Ensures accurate placement of saline lock.
2. Wash hands and put on clean gloves. Reduces number of microorganisms.
3. Check client’s identification bracelet. Ensures correct procedure is performed for the client.
4. Explain procedure and reason for discontinuing IV to client. Decreases anxiety.
5. Prepare supplies at bedside. Ensures smooth procedure.
6. If inserting a new heparin lock: Prime the extension tubing with saline and place the saline lock on it. Follow the procedures for starting an IV, including assessing and preparing the site, inserting the IV catheter. Do not attach the IV catheter to the IV tubing. Instead, attach it the to the extension tubing. Dress the site per protocol. Priming the extension tubing prevents air from being forced into the vein.
7. If discontinuing an IV and converting to a heparin lock: Stop IV infusion.

  • For IV tubing,roll clamp to close IV tubing.
  • For infusion pump,turn switch to off.
Stops the flow of fluid in the IV tubing.
8. Place heparin lock:

  • Open sterile package with needleless adapter heparin lock.
  • For existing IV, loosen IV tubing and remove.
  • Screw heparin lock into hub of tubing
  • To check for patency remove cap from one-way valve following vigorous scrubbing with alcohol at the connection site. Connect needleless Leur-locking syringe to the valve. Inject solution into IV site per protocol, using gentle pulsating motions to create turbulence. Remove syringe and replace sterile cap at end of tubing.
Secures the heparin lock.
9. Check for patency of IV:

  • Clean heparin lock with antiseptic solution (usually alcohol wipe).
  • Insert saline syringe with 25-gauge needle into center of diaphragm. (Needleless system will not require needle.)
  • Pull back gently on syringe and watch for blood return.
  • Inject saline slowly into lock.
  • Assess client’s pain at site.
Ensures the IV is patent so that the heparin lock will function. Flushing with saline clears the lock.

  • Flushing should be done slowly.
  • Assess for pain to ensure site is patent.
10. Keep lock patent with heparin or normal saline. Every 8 hours:

  • Clean the rubber diaphragm with an antiseptic swab (not applicable if needleless system).
  • Insert the syringe or needleless adapter with heparin or saline into the diaphragm.
  • Inject heparin or saline slowly into lock.
Ensures patency of saline lock.
Only use heparin if prescribed as “flush with heparin” or if institutional policy requires it. Needleless system reduces risk of needle sticks.
11. Remove the syringe or needleless adapter from the diaphragm and swab it with an antiseptic swab. Discard needle or adapter in sharps container. Reduces transmission of microorganisms. Reduces risk of needle sticks.
12. Assess the site for any signs of leakage, irritation, or infiltration. Detects problems with the site that need additional assessment and intervention.
13. Remove gloves and dispose with all used materials. Wash hands. Reduces transmission of microorganisms.

Note. Adapted from Fundamental and Advanced Nursing Skills. Third Edition, p. 1056-1059, by G. B. Altman, 2010,
Delmar: Cengage Learning.

What to document?


  • date and time the IV line was discontinued and heparin lock was placed
  • abnormal findings at the IV insertion site
  • type of solutions infused in lock – whether it’s heparin or saline

Key Considerations:

  • Discontinuing the IV line and changing to a heparin lock is a responsibility of a nurse that cannot be delegated to an unlicensed or untrained personnel.
  • Many institutions, adapting recent studies, flush heparin locks with normal saline solution rather than heparin before and after a medication is administered to maintain patency of a heparin lock.
  • If swelling is noted at IV site, stop pushing the heparin lock. Pull back the plunger and check for blood return. If there is no blood, remove and start a new heparin lock in another site and flush with saline.