Central (Line) Station

There are lots of things that are central to the identify of a paediatric anaesthetist. Most of us think children are pretty ace. We are generally not scared away by having to keep a close eye on patients operating within pretty small margins of safety. And quite a lot of us probably view an excuse to blow bubbles as a perk of the job.

But one other thing that we have in common is finding the technical bits, which are just a little more challenging in kids than bigger people, an attractive part of the work. That applies to some elements of airway management, putting cannulas in small vessels and, of course, siting central lines.

Some of the challenging bits with central lines are pretty mundane things. There are facts and fiddle factors you can mostly figure out from a little reading coupled with a little thinking. That applies to things like choosing an appropriate line, or getting it to the right position.

The bits that take time to learn are the tips and tricks for getting that very long, fancy catheter into that pesky vein. The practice points that [*cough*] senior anaesthetists have learnt over years of success (punctuated by a few bitter failures) don’t get captured in journal articles or textbooks. They are more often confined to the corridor chat.

Except for here, where we’ve collected a range of tips and tricks from a whole slumber of anaesthetists who happen to be presently working around The Children’s Hospital at Westmead, but who have spent time spread across four continents.

This clump of concepts has been provided by Drs Brie Miller (BM), Sarah Johnston (SJ), Gail Wong (GW), Ian Miles (IM), Stuart Ross (SR), Deane Murfin (DM), Matt Hart (MH) and Andrew Weatherall (AW). They aren’t guidelines and you’ll have to figure out what works for you. They are just tips that work for this motley bunch. And they start with a bit of a simple wisdom.

1. First Things First

“Your first shot is your best shot.” (SR)

“You have to set things up right to give yourself the best first shot.” (GW)

2. Choose Carefully

“Check with your ultrasound that you have a decent vessel before you set the patient up and scrub. Especially in repeat offenders. Nothing more frustrating than setting up and draping only to discover a piddly vein at the site you’ve chosen.” (SJ)

“Scan up and down the whole vein, especially if they have had a previous central line. It is worth confirming there are no issues with vessel lumen size. And measure your vessel diameter (antero-posterior and side-to-side) – the vein should have a bigger diameter than your planned catheter size (using French gauge). This will mean your catheter diameter is less than a third of the vein diameter which matters for things like thrombosis.” (IM)

“Check everywhere, but always consider the brachiocephalic vein as an insertion site. The sizing of the line and the depth of insertion for a left brachiocephalic is the same as a right IJ. It is well described in the literature as safe. The vessel also tends to remain open even when the patient is volume-depleted. And as bonus points it allows an in-plane cannulation technique with good visualisation of critical structures like the pleura and eventually the CVL sits in the contour of the clavicle elegantly rather than flapping around in the neck.” (MH)

[Ed: While a lot of the points in this post assume internal jugular access, the brachiocephalic approach is worth understanding. Luckily, Matt has put up something to read over at the part of the site about central access - it’s here.]

Consider all your options.

3. Setting Things Up

“Positioning matters. Take your time to set them up. For neck lines, a shoulder roll is essential I think but you do not want them too extended. Tilt the head to the side but not too much. And check that vessel again with the ultrasound as you position to find the patient position that has the vein in the best shape and position for your attempt. Also don’t forget the value of a fluid bolus if the patient seems dry or the boost in vessel size that can be added with gentle pressure on the liver (that’s what kind colleagues are for).” (SJ)

“I find the patient’s initial face-mask is an excellent support to stop too much lateral rotation of the head. And if I have a patient with the sort of skin folds that makes them very cute but also not so helpful when placing a central line, I pre-tension the skin with tape (usually over the ear and pull superiorly.” (BM)

“As well as setting up the patient, it makes life so much easier if you set up your equipment well. Once you are in that vessel you should have everything in easy reach and laid out so you can just grab the next item because it’s what you need without having to turn your head to look for it. For me that means the needle I’ll use to make a hole in the skin, the cannula that will go into that hole next, and the wire that will go down the cannula.  In order, in my field of vision and under my right hand.” (AW)

“It is also really important to set up your trolley in an orderly fashion with everything lined up in order before you start. This is not just my OCD. It really streamlines the insertion process.” (SJ)

4. Probe Pointers

“This is a practical tip for the ultrasound probe. Having the cable for the ultrasound suspended from something higher than the patient is handy. It helps ergonomics and takes pressure off the vein while stopping the horizontal slide force of the cable wanting to go somewhere.” (SR)

“Particularly for smaller patients, I find resting the hand holding the probe somewhere pretty solid (e.g. on the clavicle) really helps. That way I can palm the probe itself so it is just floating through the ultrasound medium with zero pressure on the skin. It makes a huge difference to vessel calibre.” (AW)

5. Making a Hole

“I don’t see people do this as much as for tricky cannulas, but if it works there why not here? I make a hole in the skin with a needle a tiny bit bigger than the cannula I then use to access the vein. The same as elsewhere it just means the vein gets compressed less as I approach it. Combined with a little tension on the skin with my middle finger (unless I’ve used a pre-tensioning tape) as I advance the cannula, it keeps the vein standing up.” (AW)

Not such a big hole. But a hole.

6. The Needle and Syringe

“I’m a needle fan over a cannula although there are times when I go for a cannula in desperation. I guess it’s what you’re most comfortable with. I’ve learnt to follow the needle tip further into the vein even after blood flashback after watching colleagues do this and I find there is less hassle getting the wire to feed (probably because you’re more definitely in the vessel that half in the anterior or posterior wall).” (SJ)

“Vascular Access needles with two stage bevels [Ed: a tip designed to light up under ultrasound imaging] really help in preventing posterior wall punctures, especially in the really small kids. Also, maintaining ultrasound needle tip visualisation throughout the attempt is key in preventing posterior wall puncture.” (DM)

“I use the needles that are designed for use with ultrasound now. It is not just that they are more echogenic. The bevel allows you to feel the front wall more obviously. I have found this has reduced my episodes of through and through.” (BM)

“Even with good flashback into the syringe, I try to verify on ultrasound that my needle tip is in the middle of the vessel before I put in the wire so easy passage is more certain. If using a needle, hand position on the syringe plunger to push/pull at the same time is critical. Small baby vessels can be unforgiving so if a trainee has a very awkward needle-holding technique that is not easily corrected, I subtly (actually not so subtly) suggest they use a cannula (sans syringe) instead!” (GW)

“I try to use a Luer slip syringe. Then when I obtain flashback, keep a really firm grip on the needle hub and break the seal before testing for flashback again. Now removal of the syringe should be a ‘no force’ effort and the tip of the needle should not move. A Luer lock syringe works, but a Luer slip is better.” (IM)

7. Wire Wizardry

“I always use a short, straight wire first through the needle. This is especially useful for small babies. And have the wire close so you don’t need to turn to get it as millimetres matter in tiny bubs. Then I pass a long cannula over this short wire, before switching from the short wire to the long wire in the CVC kit.” (SJ)

“Once I’ve placed the needle, I use a straight wire down the needle. I also make sure that wire is sitting raised by a piece of gauze so that it is easily picked up without moving the hand stabilising the needle.”  (BM)

“A few things with the wire and the needle. I really like the idea of using a straight wire rather than a J-tip in really small vessels. I have had the unfolding J tip push the needle out a good couple of times. Do not attempt to insert a wire unless you have really good back flow (active or passive) and you have seen the tip of the needle is in the centre of the vessel. And another thing, inadequate needle stabilisation and awkward hand positions are a really common source of failure. Setting up the patient so you can rest the heel of your hand gently on them for probe stabilisation or maintaining needle position is useful.” (DM)

“If the vein is huge I pass the J tip of the wire from the kit (pull it back into the plastic introducer during preparation and place it somewhere accessible so you do not move the needle tip while picking up the wire. For small veins I use the straight tend first because the J-tip can get a bit stuck as it unwinds and can push the vein off the needle. Either way I pick up the (longish) wire near the insertion end, and roll my wrist into supination to lay the wire along my forearm to keep the free end from dropping out of the sterile field.” (IM)

“The J tip guidewire doesn't need to have the tip on to thread it. An alternative approach is to pinch the wire between your thumb and forefinger just proximal to the J-tip, then with your other hand pull on the wire about 5 cm more proximally. This makes the J tip straighten out for insertion. A radiologist showed me this and it is a great tip to feed the wire down the cannula.” (MH)

“Personally I always took the long wire out of its circular holder and pull the J-tip back into the introducer. I find I have a much better feel for how easily the wire is feeding with the gentle hold of my thumb and index finger than when rolling the wire forward with my thumb. Think about every interventional radiology procedure or cardiac catheter you’ve seen. The wire is laid out straight so they can feed it in gently with your hand. Seems like the same situation.” (AW)

Not the same type of wizard but we respect all wizards.

8. The Cannula Alternative

“I find I hear people sharing lots of tips for solving problems related to the needle and the wire. Issues with posterior wall puncture. The challenge of needle stabilisation. Getting the syringe off the needle. Wires pushing the whole needle out or needing to reverse them or use an alternate wire because you are worried about the needle tip moving while picking up the wire. And everyone I observe seems to change the hand stabilising the needle when they put down the ultrasound probe to pick up the wire. That’s just another stabilisation problem. In my experience none of those problems exist with a well-positioned cannula in the vessel. So I use a cannula. They are generally easy to visualise and it works.” (MH)

“If it comes to rescuing a problem where a haematoma has been created and I am trouble-shooting, I would always use a small cannula instead of the needle to make wire manipulation easier.” (GW)

“A cannula to access the vein just seems to solve lots of fundamental problems. I mean I cannulate small peripheral vessels and arteries but for some reason I used to pick up an inherently less stable needle to access central veins. It sort of makes no sense to me. Cannulas are generally easy to visualise and place well into the vessel so they are both centrally in the vein and stabilised by the patient’s tissues. It is really rare to puncture the posterior wall. The cannula usually ends up far enough in that the J-tip wire feeds easily without anything  moving. I reckon it’s a technique that will hold up better as I inevitably develop a tremor with age. And as a bonus, having seen really delicate needle-wire technique still end up with a wire being damaged by the needle, I can’t see a way that is likely to happen if the wire only ever passes gently through a cannula. Most of the solutions I hear to deal with the problems of a needle seem to be solved with a cannula. And given that plenty of people seem to say ‘well when it’s difficult I pick up a cannula’ it seems like you might as well just start with the cannula.” (AW)

9. Rescue Manoeuvres

“If at the first step the wire won’t feed despite gushing blood backflow,  I try repositioning head a bit and then try the longer wire from the CVC kit (both ends). Finally some form of radiology wire (like a Glidewire) might do the trick.” (SJ)

“Trouble-shooting the small percentage that are problematic is what I sometimes find myself taking trainees through. This usually occurs after a haematoma has formed from multiple vessel pokes, back wall puncture (unintended or intended), too much needle movement when trying to introduce the wire in little babies (common) or just bad luck. If the lumen of the IJ now becomes heart-sinkingly small, you could cannulate below the haematoma. However this is usually already attempted and the vessel there is frequently much smaller by now. Also, in small babies there may just be no more room. Before moving elsewhere, an option is to cannulate above the haematoma where the vessel lumen is usually still of decent calibre. If it comes to this, I would always use a small cannula instead of the needle so as to make wire manipulation easier. You'd likely need to use a Glidewire or some other hydrophilic wire to get past the haematoma. If these slippery hydrophilic wires are used, and there are no ectopics, the wire could be a variety of places and you may still need to consider fluoroscopy may be required. Alternatively, use the slippery wire to just get past the haematoma then switch the small cannula for a longer cannula (like the one in most kits). Once cannulated past the haematoma, use the usual kit wire for the rest (vessel dilation, catheter insertion).” (GW)

“Sometimes the best rescue manoeuvre is getting a colleague to take over. We’ve all been there.” (AW)

Sometimes a call for help is the right call.

10. The Check Step

“I think it is worth strongly considering using some form of transducer prior to dilating. This can be as simple as some IV tubing flushed with saline (a column of fluid) connected to the cannula. If the column drops, you are not in an artery. Dilating an artery is a catastrophic and preventable outcome, and data suggests that pressure transduction is one of the most reliable ways to exclude arterial puncture. Plus it’s very easy to do.” (MH)

“With tricky insertions I always check with IV tubing flushed with saline connected to the long cannula I’ve placed to confirm that the cannula is definitely venous. Once I’m sure, I put the long wire back down then proceed to dilation.” (SJ)

11. The Dilation Dance

“When it comes to dilating, my first preference is not to make a skin nick. I apply counter-traction, and try to dilate gently but firmly using a corkscrew motion. This usually works, and the allows the CVC to be placed snuggly in the tract with less bleeding than can occur with making an incision. That said, don't be afraid to make a cut if the above isn't working.” (MH)

“Particularly for a 4Fr line (but pretty much for all lines) I dilate gently with 1 pass only. One dilation is generally enough and more than that just seems to increase ooze around the catheter later.” (IM)

“Lastly, place the dilator on the wire to just above the skin before you nick the skin. Then you can just slide/corkscrew the dilator in. It can save lots of blood loss compared to making a nick first then trying to get the dilator onto the end of that wiggly wire.” (SJ)

“When you’ve worked hard to get a line in, there’s not much that’s more frustrating than kinking the wire with the dilator. An adult intensivist showed me the simplest thing to help avoid that. Just maintain a little backwards traction on the wire as you dilate. Obviously not so much you actually pull the line out. That little bit of tension keeps the wire straighter as you dilate. And this means the dilator doesn’t have that risk of pushing a slightly less taut wire and creating a kink as that delicate bit of metal gets a little stuck in the tissues in front of the dilator. Game changer.” (AW)

12. Maybe Place the Line Now

“Particularly with neonates, when having a short amount of the long wire in the patient, bending the remaining wire outside the patient into a circle loop is an attractive solution to not let the wire dangle over the head end of the patient whilst you are trying to threat the actual CVC onto it. But bending a wire into a loop makes a spring - be careful to not let the inside wire spring out when you remove pressure on the neck to steady the wire.” (SR)

“When threading the catheter over the wire I rest the free ends of the lumens over the wrist of the hand that's holding the wire. That way I can concentrate on threading the wire while the rest of the line is nice and controlled. It also means I won’t accidently drop the free ends of the CVC out of the sterile field.” (IM)

“And another thing - only connect things to the end of your line once the CVC is secured. In a small baby, the weight of various connectors, 3-way taps, or chook-foot things can be enough to make that whole line slip out. No one wants to return to square one at this point.” (SR)

That might be enough for now. You could probably have already had a CVC in place by the time you got to the end of reading it.

Of course that’s not the end of the story. It’s worth noting that all the tips above include the assumption that the clinician has the option of ultrasound to guide placement. There is every chance that some readers may not have that option but have immense technical skill to share. In which case we’d love to hear it.

And they’re mostly written assuming that an upper body line, and most likely an internal jugular line, is the one being placed. That said, a lot of the tips apply everywhere.

And almost everyone will have noticed we didn’t get on to the topic of how to secure a line. But securing the line is pretty important if you went to the trouble of putting it in.

The thing is there were so many passionate exchanges with tips on that particular part of the process that we’ve elected to do a whole separate thing on that.

So Part [the next bit] is coming. Some time.

A Few Extra Things

This is not one of those ‘lots of references’ types of things. However it really should come with extra stuff. So we have simultaneously put up some extra stuff.

If you go here, you’ll find a guide on choosing the right line and right size. But you’ll also find a thing all about getting the position right. And on top of that you’ll find Matt Hart’s bit of work on the brachiocephalic approach. It’s this week’s 3-for-1 offer.

And as always all tips and tricks you can share would be amazing.