At this time the patient has either just arrested or just arrived to the ED in full arrest. CPR is ongoing.
Stage 1 involves placement of percutaneous arterial and venous angiocatheters in the femoral vessels. Our institution uses commercially available central line kits (9F percutaneous sheath introducer kit, Arrow, Reading, PA or 5F central venous catheter kit, Cook, Bloomington, IN) to gain access to the femoral artery and vein, typically under ultrasound guidance. These catheters will serve as conduits for placement of the ECLS cannulas in the next stage; however,they also serve as immediate vascular resources in the resuscitation of the patient. If the patient has not achieved ROSC at the completion of Stage 1, the physicians consider moving to Stage 2.
Breaking the cannula placement of the ECMO catheters into 2 steps during cardiac arrest offers a number of advantages most notably the use of less expensive kits for initial vascular access. It is during this stage that you are likely to go through many wires and catheters; since these kits are cheaper than the ECMO insertion trays, this is more bearable. It also allows empiric usable cathether (vascular access and arterial monitoring) placement in all arrests or peri-arrests, and then if the ECMO decision is made, these existing catheters provide a conduit for an easy conversion.
Note: during arrest the vein has a tendency to swell and the artery to shrink, so the artery is what will give you trouble.While needle placement and wire advancement can be done during compressions, timing these two moves for a pulse check is beneficial for success and avoidance of needle sticks. Mechanical CPR with devices such as the LUCAS may allow a stabler field than manual compressions.
Ultrasound is almost mandatory; both for proper location of the vessels as well as to solve the problem of differentiating between the artery and the vein. Unless of course you have fluoro.
Pitfall: The artery should be cannulated ~2cm distal to the inguinal ligament. The inguinal ligament can be approximated by the line from the anterior superior iliac crest to the pubic symphysis. In many patients, especially the obese, this may be well above the inguinal crease. If the artery is cannulated too low, it is likely that the arterial puncture is at the level of the superficial femoral artery (SFA). While this location will work for arterial-pressure monitoring, this branch cannot accommodate the upsized ECMO catheter. The attempt is likely to cause trauma to the vessel, hematoma formation, and the probable need for operative repair to maintain perfusion of the leg. For additional information, see:
- Garrett, P. D., Eckart, R. E., Bauch, T. D., Thompson, C. M., & Stajduhar, K. C. (2005). Fluoroscopic localization of the femoral head as a landmark for common femoral artery cannulation. Catheterization and Cardiovascular Interventions, 65(May), 205–207. doi:10.1002/ccd.20373
- Lechner, G., Jantsch, H., Waneck, R., & Kretschmer, G. (1988). The relationship between the common femoral artery, the inguinal crease, and the inguinal ligament: a guide to accurate angiographic puncture. Cardiovascular and Interventional Radiology, 11, 165–169. doi:10.1007/BF02577111
- Tam, M. D. B. S., & Lewis, M. (2012). The effect of skin entry site, needle angulation and soft tissue compression on simulated antegrade and retrograde femoral arterial punctures: An anatomical study using Cartesian co-ordinates derived from CT angiography. Surgical and Radiologic Anatomy, 34, 751–755. doi:10.1007/s00276-011-0880-0
these references were provided by Phil Mason, MD
While Stage I is occurring, the rest of the ECMO-initiation supplies and the ECMO cart should be brought to the ED. The ECMO specialist, ECMO nurse, or perfusionist who will be managing the patient should also be brought to the bedside as soon as the possibility of ECMO initiation exists.
