Surgical Instruction: Right Ventricular Pressure-Volume via Jugular in Rat

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Right Ventricular Pressure-Volume via Jugular in Rat

Instructions on jugular vein catheterization using a Millar 2F catheter
for right ventricular pressure-volume measurement in rats.

Surgery performed at the René Remie Surgical Skills Centre by Prof. René Remie. Animal handling and surgical procedures all strictly follow Dutch Legislation on Laboratory Animals and was approved by the IACUC.

Hardware:

Catheter:

  • The Millar SPR-869 PV catheter was connected to the MPVS Ultra.
    Note:This catheter was chosen for its 6mm spacing between the conductance electrodes. This is better suited to the right ventricle as it is anatomically smaller than the left ventricle, where you would normally use the SPR-838 catheter with 9mm spacing in a rat this size. It is also possible to use a 1.4F catheter, the SPR-839, which has a 4.5mm spacing, should the length of the right ventricle be even smaller. 

Software used to record and analyze the pressure signal:

Anesthetic:
The rat was anesthetized using injectable anesthetics and analgesics.

Procedure: 

Make a simple catheter guide

Before beginning the surgery, make a simple catheter guide from some PE-60 tubing. The purpose of the guide is to facilitate the insertion of the catheter into the right atrium via the jugular. The inner diameter of the PE-60 tubing is 0.76mm / 0.3 inches, which is large enough for a 2F catheter to pass through.

  • Using a permanent marker, make a mark at 40mm from the end of the tubing. This will give an indication of where the tip is situated inside the animal. 
  • On average the apex of the right ventricle is around 35-40mm from the midline of the neck.
  • Bend the tubing at about 1cm from the end at a 45-degree angle and quickly dip this in hot water. The tubing should now hold its shape when removed from the hot water. 
  • You can now attach this guide to a syringe needle for easy handling, as shown later in this video.

Procedure begins: Incision

After disinfecting the skin with some alcohol, the procedure can be started after the alcohol has evaporated.

  • Looking closely at the neck of the animal, you will notice movement at this location. This is the point where the jugular vein passes under the pectoral muscle. This is where the vein will be catheterized.
  • Make an incision from this point to approximately 2 cm rostrally.
  • Holding the tissue in the rostral direction, first make a small incision.
  • Then, using the tissue forceps and scissors, make an incision towards where the movement under the skin was identified earlier.
  • By freeing up the submandibular gland using blunt dissection, the bifurcation of the external jugular vein will become visible.

Find the jugular vein

After freeing up the submandibular gland using blunt dissection, the bifurcation of the external jugular vein will become visible. First, you will see the maxillary vein.
The maxillary vein joins up with the linguofacial vein to form the external jugular vein.

You will clearly see the linguofacial branch and the maxillary branch [see video at 03.58].

Separate the jugular vein 

  • Free the bifurcation area using sharp forceps and separate the vein from the surrounding tissue.
Pro Tip

Tip: A good trick is to spread the vessel over the legs of the forceps and then carefully insert the second pair of forceps between the vein and any surrounding tissue [video at 04.28].

  • The cleaner the vein, the easier it will be to catheterize.
  • Once the bifurcation is clearly visible, you can clamp the vessel using artery forceps.
Pro Tip

Tip: Do not use the tip of the forceps for clamping, as the forceps might fall into the surgical area. Rather use the middle of the jaws, as demonstrated in the video [video at 05.10].

  • With the vessel clamped, zoom in further to allow for further cleaning of the vessel.
  • Always remember to moisten the vessel with warm saline as it will rapidly dry out.

Ligature 

First, place the obstructive ligature. 

  • Place the obstructive ligature on the rostral end.
  • Pass one end of the ligature under the clamp [video at 05.57 ].
  • Pass the other end of the ligature under the vessel and then under the tip of the artery forceps. In doing so both the maxillary and linguofacial veins will be closed off by the suture.
  • Tie off the suture.

Place the second ligature.

  • Next, a second ligature will be placed over the vein with half a knot in preparation for tying off the catheter guide to hold it in place.

Prepare the catheter guide

Now your catheter guide made from PE tubing will be inserted into the vein.

  • The guide should be filled with heparinized saline all the way to the tip.
  • A black dot is visible at 35-40 mm from the tip. Here you see another mark on the end of the tubing, where it connects to a syringe needle.
  • The purpose of this mark is to give an indication of when the bend in the catheter guide is facing towards the right atrium while it’s in the animal. In this case, the marker should face upwards when the catheter guide tip is facing in the right direction.

Insert the catheter guide into the jugular vein

First, create a hole for the catheter in the vein.

  • With small vascular scissors make an incision.
  • It is advisable to spread the vessel using the scissors so that the lumen is clearly visible. 
  • You should see a small amount of blood coming out of the vessel, but be aware it could also mean that you have only cut some of the nutritional vessels, and not the jugular vein itself.  This would mean that you will be attempting to catheterize the adventitia, which is not ideal.

Next, introduce the catheter guide.

  • To facilitate this, use sharp jeweler’s forceps. 
  • Make sure that before you introduce the catheter guide it is nicely lined up with the vessel.
  • Spread the legs of the forceps and bring the catheter guide into position. 
  • Push the catheter guide into the jugular vein. You will notice that some blood will enter the catheter which is a good sign that the catheter guide is in the vessel.

Advance the catheter guide towards the heart. 

  • It helps to pull a little on the artery forceps in a rostral and lateral direction and at the same time push the catheter in.
Pro Tip

Tip: When you experience resistance, just turn the catheter to a different angle. The resistance is usually caused by the vein going under the pectoral muscle.

  • You know you are near or in the heart when the black mark is near the hole in the vein.
  • Now you are going to tie off the second ligature around the catheter guide, to hold it in place. 
  • Remember to keep the vessel moist using warm saline. This will make it easier to reposition the catheter guide, should you need to do so.

Check that the catheter guide is facing the right atrium.

  • Make sure that the second mark is facing upwards, which ensures that the end of the catheter guide is facing towards the right atrium.
  • Another way to check whether you are in the correct position is to disconnect the catheter guide from the syringe needle. You should see respiratory movement as well as the movement caused by the filling of the atria. This is clearly visible in the video at 11.35. If this beating is not observed, it means that the catheter has passed the heart.

Insert the catheter via the catheter guide

  • The Millar catheter will be introduced into the catheter guide. Make sure the solder mark on the end is facing up!
  • A small amount of blood will come out the end of the catheter guide, but this can be easily stopped by slightly lifting the tube. Doing this also facilitates the catheterization.
  • The catheter can be pushed forward until it comes up against the right ventricle apex wall. 
  • Next, the tubing guide should be pulled back slightly while carefully pushing forward on the catheter.

Completion of procedure 

  • You should now be able to see the right ventricular PV Loops on LabChart (or your own analysis software).
  • If the loops don’t look satisfactory, you can always turn the catheter to get it better situated in the right ventricle.

We hope you found these surgical instructions useful.

Please visit our comprehensive Ventricular Pressure Volume + PV Loops Application page for specialized information and useful resources relating to Pressure Volume Loop applications and research.

If you have any questions, please contact your ADInstruments support representative who will be happy to provide specific information and assistance with your research requirements.


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Additional resources


Find out more about Pressure Volume (PV) Loop
recording and analysis:

Everything you need for ventricular pressure volume loop recording and analysis, in one place »

LV Pressure Volume| Research software | LabChart ADI

PV loop pressure volume analysis software LabChart ADI

LabChart software - PV Loop 2.5 for left and right ventricle studies

The PV Loop Analysis Software Module for LabChart is specifically designed for the analysis of in vivo ventricular pressure-volume data in small and large animals, or ex vivo, using working heart systems. Our PV loop module provides workflows for acquiring PV loop data from small and large animal models as well as tools for analyzing left and right ventricular PV data in real-time or post-acquisition. Contact us for more information.