• 2x thumb forceps (rat teeth, normal)

• needle drivers
• scissors (blunt and sharp sides)

• S-D Rat, 8-12 wks (8 wks optimal "'250-280g), male, Harlan preferred
• sterile working surface
• 4x4 cotton gauze (sterile)
• cotton tipped wood applicators: Q-tip (sterile)
• 0.9% Saline Irrigation, USP with penicillin added (sterile), preventive
• Cold sterilization - iodine
• Anesthetic (inhaled or 50 mg/kg IP Phenobarbital, do not use with female rats)
• 3.0 Chromic Gut 27" Ethicon CT -3, recommended (Rachel has CT -1)
• Duro Super gel (new tube per set of operations is recommended), 2-pack can be purchased from www.action-electronics.com , or I-packs at ACE Hillcrest, Riteaid also has them.
• 18.5 g B-D Short Bevel Precision glide Needle (pink wrapping 305199), recommended (Ordered from Fisher)

• larger needle can be used to expedite CHF

• retractor (can be made from rubber band and heavy paper clip)
• if needed buprenorphine .02mg/kg for post-operative pain.

a. Under anesthetic, shave area of surgery (abdomen)

b. Sterilize with iodine and allow drying for 4-5 minutes

c. Make sure that food and water have been withheld from the rat for at least 12 hours

1. Sterilize work surface and tubes of Duro Super Gel with 95% EtOH, dry using sterile gauze.
2. Using the scissors with the blunt side down cut caudal to rostral on the abdomen of the rat (approximately from 1-2 mm rostral to the reproductive organ to the zyphoid process), trying to stay as medial as possible.
3. Use gauze to dry the underlying muscle and locate the linea albas (white midline).
4. Using the scissors (blunt side down) carefully cut along the midline.

1. Note: It may be easier to start towards the middle to prevent rupturing the bladder. Can also use the sharp point of scissors to begin the cut.

1. Use the retractor to pull the rat's right side and place unfolded gauze on rats left side.
2. Pullout the intestines and cover with gauze. Leave bladder and surrounding fat inside abdomen.
3. Using sterile cotton tipped wood applicators (Q-tip) blunt dissect the underlying adventitia. (vertical movements are recommended)
4. Locate the underlying aorta and vena cava, also locate the lumbar veins and bifurcation of the aorta (caudal). Make sure that the aorta looks oxygenated, if not reposition tongue or pinch nose.
5. Using left-hand place middle finger as rostral as possible along the aorta (but caudal to the renal arteries) and place left index finger as caudal as possible along the aorta.
6. Press down firmly to occlude arterial and venous blood flow. (If you can feel the pulse you are not pressing down firmly enough)
7. Depending on the location of the lumbar veins will determine the location of the fistula. Ideally you want to insert the fistula caudal to the lumbar veins.
8. Take the l8g needle with bevel down and insert into the aorta. Proceed into the aorta a few millimeters (you should be able to visualize the tip)
9. Next rotate the needle a quarter turn counter clockwise so that the bevel is now facing the left side of the rat or to your right side (away from the vena cava)
10. Then continue to insert the needle rostrally and the needle should puncture the middle wall between the vena cava and aorta without having to redirect the direction of the needle. (you should be able to visualize the needle in the vena cava) be wary not to completely puncture the vena cava. Also be sure to hold the syringe side of the needle with your thumb to prevent blood back flow.
11. Hold for approximately 30 seconds
12. While maintaining pressure with your left hand remove the needle, and apply pressure with Q-tip on the site of entry. Next move your middle finger caudally and continue pressure at the intersection between the lumbar veins and the vena cava. Remove the Q-tip and maintain a dry field.
13. Apply Duro Super Gel above and below the point of entry to completely seal the puncture wound. Be sure not to touch the tip to the aorta to prevent clotting. Continue holding pressure and allow to dry for approximately one minute. Remove index finger.
14. Slowly remove middle finger and check to make sure the fistula is there by pressing down on the vena cava rostrally to the fistula. The vena cava should fill with 02 rich blood and should turn a bright red but may only engorge.

1. Return as much adventitia to original location. Then replace the intestil1es into the abdomen.
2. Add about 2.5 mL of RT saline + penicillin (body temp is optimal) to each side of the abdominal cavity.
3. Suture the muscle wall back together, using gut. Be wary to suture so that the distances between each suture horizontally and vertically are equidistant. Also be wary not to use the forceps on the gut to prevent spontaneous breakage while suturing.
4. Following suturing, line one side of the skin with a thin stream of Duro gel and pinch closed with the opposite side.
5. Then staple the skin by skipping every other staple. (staple then leave a space the size of the staple and then staple again.)

1. Hind limb paralysis is most common, but is transient and should go away by 3-4 days. No Tx other than putting food and water at bottom of cage.
2. If the rat seems to be uncomfortable .02 mg/kg buprenorphine can be administered
3. The rat will not eat well for the first I -2 days and will lose about 40 g in body weight, but should bounce back fairly rapidly.
4. 25-30% sudden death incidence. Most likely due to reentry arrhythmia, where the animal cannot adapt to the sudden volume overload. Observed within the first 48 hours.
5. Rats can be kept two to a cage post op