Begin by testing for pinch reflexes on the anesthetized mouse pup's tail to confirm the depth of anesthesia. Next, disinfect the skin with three alternating rounds of Betadine and 70%ethanol using sterile cotton swabs. Cut the abdominal wall and peritoneum from the lower abdomen to the subxiphoid to fully expose the peritoneal cavity.
Use cotton swabs to gently pull away the gastrointestinal tract and the bladder to visualize the vertical abdominal aorta or AA and the inferior vena cava or IVC under the retroperitoneum. After rotating the operating table 90 degrees counterclockwise, adjust the microscope magnification to view the two horizontal vessels clearly. Using an 11-0 suture needle having a 0.7 millimeter diameter, puncture the fistula obliquely from the AA into the IVC.
Verify the successful puncture by observing the swelling and mixing of the venous and arterial blood in the IVC. Press the bleeding point with dry cotton swabs for 15 seconds to compress it rapidly. Immediately place the stomach, intestines and bladder back into the abdominal cavity to promote hemostatic compression.
Make a blanket stitch on the abdominal wall and peritoneum using a 9-0 suture thread, then place the mouse on a warm pad.