A spiritual successor to 8 advanced tricks for central line placement.
Vascular access is a core procedural skill for any critical care-ologist, and the basic skill of obtaining it should be acquired early. After that, though, continued growth comes mostly from a growing bag of tricks for addressing special situations. Here are five.
The patient who can’t lie flat
Many journeyman proceduralists are most comfortable placing central lines in the IJ vein. With this site, optimal patient positioning is with the head dependent, ie. the Trendelenburg position. This improves ease of access by distending the veins, and improves safety by minimizing the chance of air embolism.
Some patients cannot be positioned this way. The most common are those with congestive heart failure, where orthopnea may limit the ability to recline, or with elevated intracranial pressure, which may spike when the head is lowered. What to do?
The best solution: set up your kit, drape the site, infiltrate lidocaine, and otherwise get fully prepared with the head still up. You can even enter the skin with your needle, if you’re bold and good. Only when approaching the vessel will you have an assistant briefly lower the head, at which point you can puncture the vessel, thread your wire, and remove the needle. Once your wire is safely in the vessel, the head can come back up, after a period of less than 30 seconds flat. Just use a modicum of caution after the catheter is placed and before it’s capped (the one remaining moment when it will be open to air) and most patients will do fine.
The backup solution, for experts only: stand beside the patient and perform the entire procedure with their head up. (Do lower it as much as possible—the majority of patients can tolerate a flat or slightly elevated position—but in rare cases you might consider performing the procedure in a fully upright position.) Just use maximal precautions to limit air embolism. Use the Raulerson syringe as it’s intended, threading your wire through the back without removing the syringe and opening the needle to air. Cover your ports with a finger whenever they’re exposed to air, promptly cap and clamp your lumens, and in cooperative patients, consider a breath-hold or Valsalva maneuver during the high-risk moments.
The patient gasping for air
In non-intubated patients with vigorous respiratory effort, pulling and gasping large tidal volumes using high negative inspiratory pressures, some special considerations should be used.
Like the patients described above, and unlike many others, there is a serious risk of air embolism here; these are the patients who actually might entrain enough air through a small venotomy to cause cardiac collapse. Place them in deep Trendelenburg if tolerated, and be scrupulous about preventing air entry. If performing fluid column manometry, don’t let the tubing fill passively by gravity, as the negative thoracic pressure may easily suck the tube dry and aspirate air before an adequate “buffer” of blood can enter it; instead, pre-fill the tube by drawing from the proximal end with a syringe before opening it to atmosphere. Or better yet, just skip this maneuver.
The vein tends to be collapsible in such patients, particularly the floppy IJ. Consider accessing the femorial or subclavian vessels, although the latter may be difficult due to chest movement. If the vessel completely collapses with each breath, you may not be able to puncture it without transfixing it (exiting the back wall), and you may need to accept this and get your flash while withdrawing the needle instead. While advancing the wire, you may find it intermittently “catches” as the vessel collapses, and can only be advanced during exhalation. In more extreme cases of hypovolemia, it may be difficult to advance the wire at all. Confirm that it’s intravascular using ultrasound, then try lowering the head further or bolusing some volume. Some operators have luck with using the Raulerson syringe to push fluid while advancing the wire to distend the vessel ahead of it. As a last resort, if you’re quite certain the wire is at least partially intravascular, you can try just crossing your fingers and railroading the catheter—but don’t expect it to pass much better than the wire.
The artery that overlies the vein
Arteries and veins tend to run together, and sometimes get in each other’s way, most often when an artery overlies a vein you’re trying to access (particularly for the IJ and femoral). Start by using the ultrasound, or else you’ll never even notice this, and in fact can easily transfix one vessel en route to the other, a great recipe for creating pseudoaneurysms and other problems. Then, try a few tricks.
First, reposition the patient. Rotating the head may help with the IJ, as over-rotating the head contralaterally—although it gives a flatter working surface—tends to twist the vessels over each other. For the femoral, play with rotating the hip, particularly by creating slight external rotation (“frog-legging”) the leg.
If you can shift the artery even slightly off-center, a skilled proceduralist can usually sneak around it. Make your initial skin puncture from the side, creating an angled approach that helps avoid the artery, and use scrupulous technique with a transverse, out-of-plane ultrasound view to follow your needle tip dynamically; this should allow you to work right up to the vein without tagging the nearby artery. You can also consider entering the skin in an accessible spot, then “tunneling” for some ways (not tunneling in the literal sense just beneath the skin, but traversing the subcutaneous tissue with a quite flat angle to cover a lot of distance) before finally puncturing the vessel in a rather distant spot, where the vessels may be more favorably positioned. This is quite challenging even for skilled users, although a useful ability to have, as it can be useful for other situations as well, such as creating clean distal femoral sticks that still enter the common femoral vein.
The patient prone to bleeding
This was discussed in the last line discussion. Get a sense for the patient’s clotting profile more from the clinical picture than by their numbers: assess for ecchymosis, check for “oozing” from existing lines, and ask the nurse about other signs of inappropriate bleeding.
If concerned, perform the procedure with ultrasound and a micropuncture needle, and attempt to break the skin only a single time. The femoral is traditionally considered the safest site, as hematomas here are relatively benign, but don’t stick so proximally that you enter the retroperitoneum, which can absorb infinite amounts of blood. The IJ is fairly safe unless a hematoma compresses the trachea, making it carefree solely in intubated patients. The subclavian is probably only safe if using the ultrasound, since blind subclavians tend to be in non-compressible sites.
Infiltrate lidocaine as you go rather than with separate needlesticks, don’t back-wall the vessel, don’t make a scalpel nick, and use an adhesive device rather than sutures to secure the line.
The catheter that goes the wrong way
A catheter tip that threads into the wrong vessel occurs most often with IJ or subclavian placements, since there aren’t many other places a femoral line can end up. If confirming your tip placement with chest xray, like most operators (alternatives do exist, such as guided devices or using ultrasound), you may not recognize this until the procedure is over. Since it’s a pain and a loss of sterility to break down your dressing and reposition or even rewire the catheter, consider obtaining your xray while the field is still sterile, similar to intraoperative x-rays. With digital machines, you can view the line and reposition it immediately.
You can also accept these placements. A catheter tip that lands in a brachiocephalic (innominate) vein is probably acceptable in most cases, particularly if it’s facing the right direction (i.e. it’s simply too short). I usually leave these unless they are extremely lateral and approaching the axilla. Most people would reposition lines that course up an IJ to avoid infusing nasty things towards the brain. Finally, when a line doesn’t quite make the turn down the IVC and ends up facing sideways, I sometimes adjust these so that vesicant drugs aren’t infusing directly into the vessel wall.
If needed, reposition your line by threading a wire down the catheter, removing it, then railroading the angiocath (the small IV) from the kit, without its needle. Once this has secured your intravascular position, you can remove the wire and then rethread it using various tricks, such as pointing the J-tip in the desired direction, or placing pressure in the supraclavicular fossa (the Ambesh maneuver) to occlude the IJ. Once you’re happy, thread in a fresh catheter and you’re golden.
Conclusions
It’s easy to place easy lines in easy patients. Overcoming obstacles in everyone else without throwing up your hands in surrender is the work of a career. Develop a flexible toolkit, and practice, practice, practice.
One Reply to “5 special circumstances for vascular access”