How to Insert a Saline Lock




Introduction: How to Insert a Saline Lock

During this Instructable, I will be using a glove and 2 balloons to make a "hand" for demonstration, because I cannot take pictures of actual patients. It still gives the same effect(s) as initiating IVs on humans, because it allows you to feel the needle going in the "vein", and you can still get flashback (if you use a dark enough liquid - I used tea, and it was not dark enough. I'll be adding a picture of what it is supposed to look like later in the instructions).

Step 1: Introduction and Verification

First, introduce yourself to the patient and ask him/her about any allergies to medications, iodine, or tape.

At this time, you should also verify your patient's identity against the EMR and the patient armband.

Picture citation: and

Step 2: Verfication

Next, verify your IV order on the EMR (electronic medical record) or patient's chart (if using a paper charting system). You should also explain why the patient is going to need the IV before continuing to the next step.

Picture citation:

Step 3: Gather Your Supplies

You should gather an IV catheter, IV start kit (which includes a cloraprep swab, tourniquet, tape, Tegaderm transparent dressing, and gauze), a 10 mL saline flush, IV extension tubing, and a pen.

Step 4: Wash Your Hands

This step is important for your patient's safety. Primarily, you do this to prevent your patient from getting an infection.

picture citation:

Step 5: Prime the Extension Tubing

Prepare (or prime) the IV catheter by attaching the extension tubing to the IV catheter, and then attaching the 10mL saline flush to the end of the extension tubing. When secure, push out the saline until a few drops come out – this prevents any air from entering into the patient.

Step 6: Position the "hand", Select a Vein, and Put on Clean Gloves

Place the patient's hand in a comfortable position. During this step, you should be looking for a vein. So, you should start to locate and palpate (or feel) for a vein.

Tip: When selecting a vein, you want to make sure that you do not choose a compromised arm. This meaning an arm that is on the same side as a mastectomy or if an AV fistula is placed for dialysis. You should avoid the arm on whichever side those procedures have occurred.

Step 7: Apply the Tourniquet and Clean the Site

During this step, you should apply the tourniquet (that comes with your IV start kit) about three to four inches above the site where you're going to insert the needle.

Next, you are going to use the cloraprep swab that comes with your IV start kit and scrub the site for 30 seconds to ensure that all bacteria is removed from the surface of the skin.

Tip: When you apply the tourniquet, you want it really tight. That will cause the vein to push against the skin, making it easier for you to see and feel, which - in turn - makes it easier for you to insert the needle. You should also make sure that you can still feel a radial pulse because you don't want to put the tourniquet too tight and compromise blood flow to the extremity.

Note: for this instruction set, I did not have enough space to apply the tourniquet three to four inches above the insertion site, so it is closer than it needs to be.

Step 8: Sticking the Patient

With your non-dominant hand, hold the skin taut against the vein, and avoid touching the site with your gloves (you don’t want to compromise the site and have to clean it again); make sure to ask the patient to remain still while performing the procedure.

Enter the skin gently with the needle at a thirty-degree angle, with the bevel of the needle up (this makes it easier to enter the skin and prevents skin tearing); and make sure that you enter either directly above the vein, or to the side of it.


Tip: Do not reinsert the needle into the patient. If you accidentally pull out the needle, you have to get another IV catheter and start over with this step. So, to be on the safe side, bring two or three IV catheters with you initially.

Warning: you are at risk for a needle-stick injury that could lead you to contract a blood-borne illness, so you have to be extremely careful, especially if you have inserted the needle into the patient.

Step 9: Flashback

When you get blood return through the lumen of the IV catheter (this is also called “flashback”), advanced the needle another 1/8” – 1⁄4” further.

Stabilize your lumen, or flashback chamber, with your middle finger and thumb while you advance the catheter with your index finger or your non-dominant hand.

Note: It is difficult to see with the tea that I used, so I added a picture of actual flashback for you to reference.

Picture citation:

Step 10: Flushing the Catheter

Stabilize the catheter with your thumb and index finger, and remove the needle.

Next, attach the flush to the end of the extension tubing (like in step 7) and push the rest of the flush into the patient to confirm that the IV catheter is fully in the vein.

Tip: make sure to release the tourniquet from around the patient. You do not want to compromise adequate blood flow to the extremity.

Tip: if the flush is hard to push in, do not force it. The catheter may be out of the vein, or the vein may have blown. Make sure to look for any signs of swelling around the insertion site when you are pushing the catheter in to make sure that you're not causing infiltration.

Step 11: Dressing Your Saline Lock

Stabilize the catheter and secure with the Tegaderm transparent dressing and apply the date/time label to the dressing.

Tip: you may or may not need to put additional tape around the catheter to better secure it to the patient. This prevents the catheter from coming out, or moving around and causing pain to the patient. Also, you add your initials, date, time, and gauge of the IV catheter so that other health care professionals can see who inserted it and when the site needs to be changed to prevent a nosocomial infection (or hospital-acquired infection).

Step 12: Cleaning Up Your Station

Congratulations! You have fully initiated a saline lock!

Now, for the final step, you clean up your station. Gather all the equipment that you used and throw away what you can in the appropriate reciprocals (trash, sharps container, etc.) Also, you should make sure the patient is comfortable before leaving the room.

Tip: Make sure that you see the needle fall into the sharps container and that the container is below 1/2 full. This prevents possible needle-stick injuries and from used needles being stolen.

Picture citation:

Be the First to Share


    • Puzzles Speed Challenge

      Puzzles Speed Challenge
    • Secret Compartment Challenge

      Secret Compartment Challenge
    • Lighting Challenge

      Lighting Challenge

    2 Discussions


    2 years ago

    This is awesome!!! I am so going to use this in a upcoming class I will be teaching! Thank you.

    DIY Hacks and How Tos

    Interesting. I always love learning little insights into other people's jobs. Thanks for sharing.