Order 50-70kg adult male Yorkshire swine and prepare for five study phases: (1) Animal preparation and instrumentation (2) Baseline data (3) Controlled hemorrhage (4) Hemorrhagic shock, and (5) Resuscitation.
I. Animal Preparation and Instrumentation: (Variable time)
1. Anesthetize the animal with Telazol (5mg/kg) and Xylazine (2mg/kg).
2. Transport animal to the procedure room.
3. Initiate isoflurane via facemask targeting a 1.0 MAC followed by prone intubation with a 7.0 endotracheal tube.
4. Transition to general anesthesia at 10cc/kg TV and RR of 12-14 with a target pCO2 of 30-45 and FiO2 of 40%, adjusted as needed.
5. Place Bovie pad and EKG leads after shaving as needed.
6. Place the animal in supine and restrain.
7. Insert percutaneous US-guided venous and arterial access with appropriate catheter placement:
a. 7 Fr sheath in bilateral femoral arteries.
i. Place an aortic pressure probe in either the right or left femoral artery line.
ii. Connect the Masterflex peristaltic pump to the alternate femoral artery line.
b. 7 Fr sheath in either femoral vein.
i. Place an IVC pressure probe in the femoral vein line.
c. 7 Fr sheath in either jugular vein.
i. Reserve this line or another venous line for fluid administration.
d. 7 Fr sheath in either carotid artery.
i. Reserve this line for arterial blood samples.
ii. If performing endovascular placement of the pressure catheter directly into the SMA, utilize a hydrophilic guide wire and angled catheter via the carotid artery cannula.
8. Administer 1L of 0.9% normalized saline (NS) prior to surgical exposures.
9. Perform a full abdominal laparotomy.
10. Perform a cystostomy with foley catheter placement into the bladder.
11. Perform a splenectomy to prevent autotransfusion during the hemorrhagic phase.
12. Perform a full left medial visceral rotation for exposure of the proximal SMA.
a. Place a 6mm flow probe around the SMA (adjust flow probe diameter as needed).
13. Perform a partial right medial visceral rotation for exposure of the IVC, SMV, and portal vein.
a. Place a 12mm flow probe around the distal portal vein (adjust flow probe diameter as needed).
b. Place a 16mm flow probe around the IVC (adjust flow probe diameter as needed).
c. Place a 5 Fr sheath in the portal vein directly above the flow probe, then introduce a pressure catheter.
14. Confirm fluoroscopically that all catheters and devices are appropriately positioned.
15. Perform a TIMEOUT.
a. Confirm appropriate line placements, confirm all sheaths are patent, confirm the timer is ready, confirm all pressure and flow data is transducing properly.
b. Confirm all LabChart connections and channels are appropriately labeled.
II. Baseline Phase: (60 min)
1. Initiate a timer of 60 minutes for baseline normalization period.
2. Start 0.9% NS and administer 50cc of Dextrose50 (D50).
3. Obtain a ABG and 1 tube of serum at the end of the 60 minutes.
4. Provide D50, bicarbonate, or alterations to the ventilator settings as needed for maintaining a stable physiologic state.
III. Begin Controlled Hemorrhage: (Variable time)
1. Administer 10,000 Units of Heparin intravenously prior to controlled exsanguination.
2. Connect the peristaltic pump to the femoral vein with the output end connected to a Heparinized bag.
3. Prior to beginning study protocol, program the peristaltic pump for a pressure-driven model with a target systolic blood pressure of 50 mmHg.
4. Set the peristaltic pump rate to 50mL per min until SBP of 50 mmHg is obtained.
5. Place the shed blood into a Heparinized bag.
IV. Hemorrhagic Shock Phase: (60 min)
1. Keep the animal in a state of hemorrhagic shock during this period with careful observation of SBP, MAP, and TV.
2. Collect 1 ABG and 1 serum sample per 30 minutes (Total 2 ABG, 2 Serum).
V. Resuscitation Phase: (120 min)
1. Resuscitation animal until lactic acidosis clears completely.
2. Return the shed blood to the animal via the peristaltic pump and initiate IV 0.9% NS or Lactated Ringers (LR).
3. Provide D50, calcium carbonate, norepinephrine, and epinephrine as needed throughout resuscitation to regain baseline systolic pressure.
4. Adjust ventilator settings as needed for resuscitation to normal physiologic state.
5. Collect 1 ABG and 1 serum sample per 60 minutes (Total 2 ABG, 2 Serum).
a. Obtain 5 samples of serum, centrifuge at 3,000 rpm for 15 minutes, aliquot into 1mL sample tubes, and freeze at -20°C for later analysis.
VI. End of Study:
1. Euthanize the animal and follow proper disposal protocol.
2. Clean all equipment used.