What is the sum of 4 and 9?

08 patency test

Rat abdominal aorta model patency test

04.08 Rat Abdominal Aorta Model Patency test

Patency test

Once the clamps are released, evaluate the pulsation of the vessel. Pulsation proximal and distal to the anastomosis is a good indicator of patency. If the anastomosis is obstructed, the vessel will only pulsate proximally. Longitudinal pulsation caused by blood hammering against an occluded anastomosis should be differentiated from normal pulsation. If pulsation is weak, the anastomosis will have to be carefully observed.
The empty and refill test, patency test or Acland test delivers very clear results and should be performed for every anastomosis. Since it is somewhat traumatic, it should be performed with care and not more often than necessary. First, occlude the vessel with a forceps immediately distal to the anastomosis. Then occlude it with a second forceps immediately distal to the first. Push the blood out of the vessel by sliding the closed second forceps even more distal on the vessel. Then open the first forceps to allow blood from proximal to the anastomosis to refill the vessel. Instant filling of the vessel proves that the anastomosis is patent. You can perform this test immediately after finishing the anastomosis to check for backstitches, and after about 20 minutes to check for thrombosis and clotting. Until then, cover it up with moist gauze and leave it alone. Performing the test more frequently or squeezing the forceps jaws together too firmly may damage the intimal layer leading to thrombosis.


Final suggestions

If your anastomosis is patent, cover it up with moist gauze and leave it alone for 20 minutes. Then test its patency once more.
If you have handled the abdominal aorta gently and assume damage to the intimal layer to be minimal you can perform further anastomoses on it for as often as you can approximate the vessel ends.
If the anastomosis is patent you can also work on the femoral vessels or inferior vena cava. If it is not patent you can work on the neck vessels.
However we deem the inferior vena cava and neck vessels to be somewhat more
difficult to work on and suggest working on the abdominal aorta and femoral
vessels first.
Before starting to work on the next model, place the intestines back into the
abdominal cavity and cover the wound with moist gauze to keep them viable.