IV Catheters

Overview

IV catheters are most commonly placed in the cephalic vein in dogs and cats. In the hind limb, they are most commonly placed in the lateral saphenous vein. Other veins used often for catheterisation include the accessory cephalic, and the jugular vein.

Realistically, you want the largest catheter you can comfortably place in your patient, that will do the job necessary. Most dogs will easily take a 22g, larger dogs a 20g, and dogs under 5lbs a 24g. If you are infusing fluids are a high rate, you want a larger bore catheter, rather than a smaller one.

If you are asked to help place a catheter, as the assistant it is your job to restrain the patient. Generally, you will do this with the patient in sternal recumbency and you will hold out the leg that the catheter is going in.

The following video is a good reference for how to place an IV catheter in a dog.

Equipment

The following equipment should be available for the procedure:

• Hair clippers

• Cleaning solutions (chlorhexidine, povidone-iodine, or alcohol)

• Appropriate sized catheter needles (24 for small dogs up to 18 for large dogs)

• T-set adaptor or injection cap

• Syringe with heparin flush

• Tape and vet-wrap

Make sure to prepare your area and equipment before retrieving the animal.

Procedure

See http://veterinaryteam.dvm360.com/step-step-photo-gallery-how-place-cephalic-catheter image/photo gallery.

The typical steps are:

1. Use clippers to remove the hair from the the arm or leg at the location of the target placement

2. Locate the vein

3. Disinfect the area

4. Insert the catheter

5. Troubleshoot catheter placement if necessary

6. Check final placement for signs of failure (swelling, bleeding, etc)

7. Place an adapter or line

8. Confirm flow

9. Tape and secure

Detailed Instructions

This section of detailed instructions can be used if the above procedure is not sufficiently clear.

Hair should be clipped large enough that the entire catheter hub, connections and of course insertion site, are hair free. To sterilize the area, scrub with Pivodine, then alcohol, and repeat two times.

Get your assistant to hold up the vein by rolling their thumb across the soft tissue, being careful to avoid twisting the elbow itself. (A tourniquet can be used for difficult veins or if you’re placing it solo).

Insert the catheter into the vein, until you see a blood ‘flash’ in the stylet. Advance the catheter & stylet together a little more, then push off the catheter, holding the stylet to prevent it from going further into the vein. If you try to advance the catheter off at the first sign of blood, you may run into issues as the catheter itself may still lie outside the vein. That little extra advance before pushing off helps ensure the catheter tip is located within the vein.

Ask your assistant to ‘hold off’ the catheter. This is by placing their thumb at the end (not the insertion site, the tip that is under the dog's skin) of the catheter. Place the cap end of the stylet into the catheter hub to collect blood for a PCV/TP/BG.

Pass one of the thin pieces of tape under the catheter hub sticky side up, fold a small amount over the hub, then take the rest and flip it over in the opposite direction and secure it. Take the notched piece and slide in under the taped hub sticky side down, and wrap it. Remove the cap (once it is full of blood) and replace it with the T-Port. With the other thin piece of tape, slip it under the T-Port sticky side up, and criss cross it over the top and secure it.

Slide the notched Vet Wrap under the T=Port and wrap the leg. Tape down the T-Port to the dog’s leg using the last piece of tape so that the catheter stays secure when the line is tugged on.

Catheter Issues

Always check the IV catheter site for swelling. If there is swelling, the catheter is most likely not in the vein and the dog is not getting its medications and fluids. Medications given IV can be very harmful if exposed under the skin.

• Swelling above the catheter indicates the vein may have ruptured, or blown, and the patient needs a new catheter

  • A blown vein will leak blood/IV fluids in the surrounding area, causing swelling 

  • Swelling from a blown vein is generally above the catheter site due to the direction of blood and IV fluid flow

  • A different vein/arm must be used for a new catheter.

  • The swelling can be painful depending on severity. A special bandage may be needed to prevent infection.

• Swelling below the catheter, or ‘Megapaw’, indicates the tape or vet wrap is too tight and should be loosened

If completely resistant to flushing (unable to push any flush), there is likely a blood clot. Push syringe with lots of force to push clot through, try a 1cc flush instead of 3cc, or unhook the T-Port and "fish out" the clot with a sterile needle. IV pump alarm/occlusion error will be going off with an occluding blood clot.

Remove catheters immediately if they've been chewed through or if they're not needed anymore (e.g. only needed the catheter for Vitamin C and finished the 6 doses). Failing to do so can lead to infection. If you don't know if you should pull it or not ask a vet.