Seldinger Technique Based Pulmonary Artery Catheterization: A Procedure to Insert Pulmonary Artery Catheter Through the Jugular Vein in a Porcine Model

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.

1. Intravascular accesses

NOTE: Intravascular accesses are to be established in the right external jugular vein, the left external jugular vein, left carotid artery, left femoral artery, and right femoral vein. In the pig, the external jugular vein is much larger than the internal jugular vein and, therefore, easier to access. All materials required for this section are shown in Figure 1A.

1. Shave the animal at the sites of puncture for intravascular accesses.
2. Disinfect the skin with chlorhexidine (or povidone iodine) and wipe clean using isopropyl alcohol. Repeat for two more cycles.
3. Place a sterile drape at the disinfected area with a centrally located hole in the cover.
4. Use an ultrasound device with a linear probe. Cover the probe with a sterile cover and use sterile gel for vascular examination.
5. Use a 17 G sterile venous catheter to puncture the skin and guide the needle to intravascular positioning by ultrasound (Figure 1B, C).
6. Replace the needle with a guidewire using the Seldinger technique. Remove the venous catheter leaving just the guidewire in the intravascular lumen. Next, make a small skin incision (~5 mm) adherent to the guidewire to ease the insertion of the sheath.
7. Place an 8 French (F) sheath over the guidewire and into the vessel of choice (the Seldinger technique). Choose an 8F sheath in the right external jugular vein (for the right heart catheterization) and in the left carotid artery (for LV PV loop catheter). Sufficient lumen is necessary to avoid damaging the catheters.
8. Place a 7F sheath in the left external jugular vein.
9. Place a 7F sheath in the left femoral artery. The access is for invasive blood pressure measurement and blood gas sampling.
10. Place a 12F (or 14F if available) sheath in the right femoral vein for the inferior vena cava (IVC) balloon insertion. Consider using a dilator in a two-step approach for the larger sheaths.
11. Confirm and control the positioning of all sheaths by drawing blood (venous or arterial, respectively) and easy flushing with isotonic saline. The sheaths are correctly positioned inside a blood vessel if one can draw blood without resistance.
12. Fixate all sheaths with a skin suture (size 3.0) to avoid any accidental removal of a sheath. Skin sutures will be removed after protocol completion along with the removal of sheaths.
13. Connect the femoral arterial access to the pressure transducer and calibrate to atmospheric pressure. Ensure this setup generates the correct form of the arterial pressure curve.
14. Draw an arterial blood sample from an arterial sheath and analyze it on an arterial blood sampler device to evaluate pH, arterial partial pressure of carbon dioxide (PaCO₂), and oxygen (PaO₂, depending on your chosen FiO₂), as well as hemoglobin, electrolytes, blood glucose, and lactate levels.
    1. Correct electrolytes and blood glucose, if necessary, to the standard values by infusion of the needed product. Especially, consider the correction of potassium levels as potassium disturbances may increase the risk of arrhythmogenesis triggered by instrumentation.
15. If the pig was fasting prior to the experiment, consider bolus infusion of isotonic saline (10 mL/kg infused over 30-60 min) or similar crystalloid to counteract hypovolemia.
16. Consider a continuous infusion of 4 mL/kg/h isotonic saline to counteract perspiration throughout the protocol.
    NOTE: The experiment can be paused at this step.

2. Right heart catheterization

1. Flush a Swan Ganz catheter with saline and ensure the balloon is inflating correctly.
2. Connect the Swan Ganz catheter's ports to the pressure transducers. Reset the pressure to atmospheric pressure holding the two pressure ports (for pulmonary arterial and central venous pressure, respectively) at the mid-axillary level of the pig.
3. Insert the Swan Ganz catheter through the 8F sheath in the right jugular vein.
   CAUTION: Lead aprons or similar protection should be worn whenever using fluoroscopy.
4. Observe on fluoroscopy when the distal part of the Swan Ganz catheter is out of the sheath. Inflate the balloon with the associated syringe.
   NOTE: Inflation of the Swan Ganz balloon inside the sheath will damage the balloon. Anterior-posterior view of fluoroscopy is sufficient for all described procedures.
5. Advance the Swan Ganz catheter slowly following its movements on fluoroscopy. Slower advancements will allow the blood flow to guide the catheter.
6. Observe changes in the pressure signal from the distal port as it enters the RV and shortly after the pulmonary artery (Figure 2). Ensure that the catheter advances without any resistance.
   1. Ensure that the pressure changes from 5-8 mmHg in the central venous circulation to 20-30 mmHg in systole and 0-5 mmHg in diastole in the RV. After passing the pulmonic valves, the diastolic pressure will be 10-15 mmHg (see Figure 2 for changes in shapes of the pressure signal).
      NOTE: Systolic pressures in the RV and in the pulmonary artery above 40 (or a mean pulmonary arterial pressure above 25) might be a sign of pulmonary hypertension due to pneumonic infection in the animal. Please remember that positive pressure mechanical ventilation also may increase pulmonary arterial pressure.
7. Deflate the balloon and ensure that the distal pressure port is still in the main pulmonary artery. Use both fluoroscopy and the pressure signal for this verification.