This article describes a detailed procedure for establishing vascular access in anesthetized pigs using ultrasound guidance. The methodology includes accessing both femoral arteries and jugular veins to facilitate invasive blood pressure monitoring.
Take an anesthetized pig in the supine position to access the femoral arteries in the inner thigh and the jugular veins in the neck.
Disinfect the sites, cover using drapes, and administer subcutaneous anesthesia for localized numbing.
Apply a coupling gel to the transducer probe of an ultrasound system.
Position the probe over the target vessel and emit ultrasound waves, which reflect off tissues to produce images.
Blood reflects fewer waves to produce weaker signals, rendering it darker than the vessel walls.
Insert a needle into the vessel, advance a guidewire to establish a track, then withdraw the needle.
Make an incision, use a dilator to enlarge the opening, and slide an introducer sheath into the vessel.
Remove the dilator and guidewire, then administer an anticoagulant to prevent blood clotting.
Attach a pressure line for invasive blood pressure measurement and secure the sheath with sutures to establish stable vascular access.
After selecting the appropriate introducer sheath, flush the sheath, Seldinger needle and the dilator with heparinized saline.
Wrap the linear ultrasound probe with a sterile cover and apply enough ultrasound gel. Use the ultrasound to identify the common femoral artery. Confirm the position of the ultrasound marker and correct depth.
Hold the ultrasound probe with the non-dominant hand on the targeted site and center the desired vessel on the screen. Using the midpoint of the ultrasound probe as a reference, puncture the skin and advance the needle at a 45-degree angle, with the needle tip bevel facing upwards. Once the needle is identified on the ultrasound screen, advance the needle until the arterial lumen is reached.
Upon denting the anterior wall of the artery, advance the needle further with a firm movement to enter into the arterial lumen. Observe the pulsating blood exiting through the needle's hub. Hold the needle in position and advance the J tip guidewire into the artery through the artery lumen.
Once the guidewire is inside the artery, remove the arterial needle and keep pressure on the entry point to avoid bleeding. Using a scalpel, make a small incision on the animal skin, ensuring the cutting edge is away from the guidewire. Over the guidewire, advance the pre-flushed introducer sheath and dilator assembly.
Subsequently, remove the guidewire and dilator. Attach a 10 to 20 cubic centimeter syringe filled with heparinized saline to the three-way stopcock. Open the stopcock towards the animal and aspirate to confirm arterial blood flow. Inject heparinized saline to wash the blood.
Connect a pressure line to the three-way stopcock to monitor invasive blood pressure. After flushing the pressure line, make sure the fluid-filled transducers are zeroed and positioned at the level of the animal's right atrium.
Secure the introducer sheath using a 2.0 silk suture to the underlying skin. Next, using the longitudinal view on the ultrasound, identify the external jugular vein in the lateral part of the animal's neck.
Using the ultrasound lateral notch as a reference, puncture the skin and advance the needle at a 45-degree angle, with the needle tip bevel facing upwards until it is in the plane of the jugular vein.
Advance the needle, keeping its tip visible, until it dents the veins wall and enters the venous lumen. Aspirate the venous blood through the needle and confirm easy flow of blood.
Remove the syringe from the needle hub, keeping the needle in place. Make a small nick in the skin using a scalpel blade, and advance the introducer sheath into the jugular vein.
After advancing the introducer sheath into the venous lumen, connect a pressure line to the three-way stopcock for central venous pressure. Flush the pressure line manually with heparinized saline to prevent blood clot formation.
Secure the introducer sheath with a suture to the skin to prevent accidental removal. For recovery, remove the sheaths and apply manual compression to the femoral puncture site for 10 to 15 minutes to achieve hemostasis.
繁體中文
