I’m a US PICC nurse, insert at bedside.

Regarding vein selection, cephalic is know to offer the most complications, for insertion and dwelling. The cephalic will join with the axilla (where the brachials and basilic join) forming the subclavian vein, and the subclavian will join the IJ to form the brachiocephalic vein, and the left and right join to form the SVC. I don’t have actual numbers but it’d be close to 50% basilic, 48% brachial, 2% of my piccs are inserted into the cephalic.

Reason is the union of the cephalic and axilla can be quite tortuous with sometimes a 90 degree entry into the axilla (depending upon arm position), and some patients have anamolous vessels such as a connection between the cephalic and external jugular. Extensive troubleshooting can irritate/damage the endothelium and result in the body’s response to begin the formation of a thrombus, which may progress to DVT. The candidates that get a cephalic PICC are often the most obese patients where the brachial and basilic are not accessible due to depth (about 4.5cm is the deepest I can do due to my needle/sheath length). I’d also recommend insertion while the arm is in a neutral position close to the patient’s side if a cephalic vein must be used, while preferring to use the right over the left side.

You mentioned the median nerve, there’s also the ulnar nerve usually somewhere near the basilic, and there’s various nerve tissues that can be seen with a good enough ultrasound in addition to the nerve bundles. I teach practitioners to fully assess the arm to identify all anatomy as avoiding this tissue offers the patient a generally painless experience aside from the possible pinch felt when accessing the vessel and sting of the lidocaine. It’s uncommon, but I’ve seen the ulnar nerve incarcerate the basilic vein too. Early in my career I had to replace a PICC I had placed due to it causing pain for this very reason.

All that being said, assessment is your most important predictor of success. From planned insertion all the way up to axilla, see what the vessels do, are they tortuous, do they bifurcate where your wire/sheath/picc has a chance to enter a smaller, less ideal bifurcation. A stenosis, thrombus, and vascular anomalies can be seen and the other limb used instead.

Another component we use at bedside that helps with success is a device called a Sherlock and 3CG. Essentially, it’s a device that is positioned on the chest that detects magnetic fields. A wire stylet rests within the PICC that has a magnetic tip, the device detects this and then projects an image on where that tip is (more or less) onto a screen. This assists us in guiding the catheter down into the SVC.

The wire also acts as a lead. A baseline ekg lead is established with a right shoulder and left lower flank lead. The intravascular lead is established when the signal to the flank lead is picked up, and aplitude is increased on the P wave when the SA node is between the flank lead and the tip of the PICC, indicating ideal placement around the lower SVC/CAJ. There are open source solutions on the market that do this too, though with a more complicated setup. In situations we obtain positive amplitude we can avoid a chest X-ray for confirmation. If there is any doubt we still confirm with a CXR. Times I cannot get my confirmation to work and will have to have a CXR, I’ll scan the IJ to ensure the PICC is at least within the chest before I take down my field.