How To Succeed At Arterial Line Insertion (Anatomical Landmark-Guided)
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- Опубликовано: 8 ноя 2023
- Radial arterial cannulation is a core skill in anesthesiology, intensive care, emergency medicine, and other acute care specialities. This video summarizes key principles for success with the anatomical landmark-guided (LMG) technique while minimizing complications.
These include: (1) developing a tactile sense for locating the artery by palpation; (2) accurate alignment during cannula advancement; (3) adopting an appropriately shallow trajectory to avoid transfixion (which increases risk of complications such as hematoma, thrombosis, etc); (4) confirming intra-luminal cannula placement before attempting to thread it in.
Ultrasound guidance may still be needed to rescue difficult LMG arterial lines. Two common scenarios for this are presented: (a) anomalous superficial radial artery; (b) calcified radial artery. See a short guide to USG-arterial lines here - • Essential guide to ult...
See also a superb discussion in the comments about rescuing failed attempts with transfixion, with great tips from @mdkc . These include (a) the importance of a flat trajectory (b) not withdrawing the stylet too far back into the cannula - the rigidity that the stylet provides is needed for the floppy cannula to overcome the resistance/friction to advancement through the skin/tissues/arterial wall; it will buckle otherwise.
Chapters
00:05 - Long vs short cannula
00:32 - Position and taping
01:06 - Line of sight insertion
01:44 - Draping the hand
02:01 - Palpation of artery
02:15 - Insertion point
02:35 - "Poke" vs "Puncture" point
03:07 - Insertion trajectory
03:53 - Advancing the cannula
04:25 - Confirming intraluminal cannula tip placement
06:08 - Connection of line tubing
06:45 - Securing the cannula in place
07:39 - Redirection to locate artery
08:24 - Superficial radial artery
09:35 - Calcified radial artery
![M-TAPA Block: Anatomical Principles [2023]](/img/1.gif)
could you specify the technique using transfixion (as a rescue or otherwise)?
heard of it apocryphally, but not really seen it in clinical practice
My approach to this is:
1. Identify you have (likely) transfixed the artery.
2. Withdraw needle by a few mm so that the tip lies within the cannula
3. Flatten your insertion angle until your cannula is parallel to the skin.
4. Slowly withdraw cannula (and needle) until brisk arterial flashback is seen in the shaft (not the chamber).
5. Gently advance cannula off needle (should thread easily)
The key step is #3. Once you've transfixed the artery, you no longer need the slightly steeper angle used to puncture the vessel wall. The aim is to align your needle shaft as much as possible with the course of the artery, such that when you've withdrawn the cannula tip into the artery (signified by the flashback), you're advancing directly along the vessel lumen (as opposed to downwards into the back wall defect you've created). I reckon my success with this is about 60-70% as a rescue technique.
NB: In step #2, make sure you don't withdraw the needle too far. You want the cutting tip to be shielded within the cannula, however you also want the stiff needle shaft to act as a stylet to direct your floppy cannula along the vessel lumen.
@@mdkc thanks for detailing the technique, can grasp it much better now.
going to basics with step #1 - how do identify that you've transfixed the artery, or go about doing the transfixion? often with failed arterial cannulation one can't tell where exactly the needle/tip is
@@armuk I think I'd suspect transfixation if you've had flashback in the chamber, then when you advance the cannula off the needle/withdraw the needle you get NO flashback in the shaft. As in the video, in this situation you're very close to the artery and you've either:
a) Transfixed the artery (i.e. you're in too far)
b) Your needle tip was only just in the lumen, but the end of the cannula was still outside the vessel (i.e. you're not in far enough).
If it's a), the rescue technique will tell you when you get shaft flashback.
If b), you won't get shaft flashback. Put the needle back in and try again.
Alternatively, you can do what some people do and deliberately transfix the artery (i.e. when you get chamber flashback, advance the needle a good 5 mm further before withdrawing the needle.
@@armuk I identify it as follows:
1. I have advanced my stylet and cannula forward into the artery after getting flashback.
2. I check if the cannula tip is in the artery by withdrawing the stylet into the cannula (as described in my video). Absence of backflow along the cannula = transfixion, since I advanced the cannula forward in step 1, and so cannula not having entered the artery is very unlikely.
3. If I have any doubt about this, I will deliberately ADVANCE a bit further, so that I have clearly transfixed it.
(Note: I am NOT advocating routine transfixion! Just as a troubleshooting strategy in this scenario)
@mdkc is absolutely spot-on with the subsequent steps, especially his emphasis on FLATTENING the cannula BEFORE withdrawing.
Note that @mdkc describes a technique where he is not using a guidewire. If planning to use a guidewire, the next steps are:
4. Flatten insertion angle until cannula is almost parallel to skin. Also ensure it is aligned with the central axis of the artery and not angling to the left or right.
5. Remove stylet completely. Nothing will be flowing back from cannula.
6. Withdraw the cannula very slowly and carefully, until arterial blood starts spurting / pulsing back. (Be prepared for the mess - consider placing gauze or similar to catch the blood)
7. Carefully insert the guidewire and thread it forward gently through the cannula. There should be no resistance to advancement if it enters the lumen; any resistance indicates it is abutting the arterial wall, or has exited the back hole into the tissues. Slight rotatory motions can help the wire thread along narrowed or calcified arteries.
8. Once the wire has threaded beyond the cannula tip into the artery, advance the cannula in a gentle controlled fashion off the wire, again using some rotation, and ensuring there is no resistance.
@mdkc & @@KiJinnChin many thanks both for the detailed and illuminating responses, have greatly elucidated the technique and thinking involved.
What a great and detailed explanation, as a second year anesthesiology resident I have performed my share of arterial lines at this point, and I haven't found any written explanation as complete and clear as this video, perfectly rounds up the theory with the commonly unwritten "tips" of the experienced colleagues. Instant subscription from me 👌
Great as usual....thank you😊
Thanks! Awesome content!
Wonnderful . Very very very useful . Thank u, sir
can u demonstrate the transfixation technique or other rescue technique if failed attempt/backwall puncture? Its very commonly encountered and diffcultt to rescue.thanks !
See the superb comment thread from @armuk and @mdkc
thank you for the video. do you find this approach to be advantageous when comparing to an in-plane technique in the parasagital plane (looking for the 'bowtie' view)?
I think this comment is for the SIFI block video? If so - I think that the bow tie approach is another good and safe alternative, but that utilizes an infrainguinal insertion point, which may not always be accessible. The suprainguinal puncture point is physically closer to the target nerves, so possibly spread will be greater, and may increase probability of a good block in more patients.
It's always good to have multiple "tricks" up one's sleeve
@@KiJinnChin yes, I was refering to the SIFI block, sorry for the confusion (misclicking on the smartphone probably). your answer makes a lot of sense to me, even if I prefer an in-plane view, and the respective orientation for cathether insertion seems intuitive. thank you for the video and tips, keep up the great content :)
Do you have any recommendation about the needle bevel position (bevel up or Down)?
I've always had it facing up - for all my art lines and IVs. I can see why theoretically one might think there is a lower risk of posterior wall puncture, facing down, but IMO, it's all about the trajectory and angle of attack. Be FLAT - is the most important thing.
Thanks!👍🏻
Is advancing cannula alone while fixing stylet without withdrawing stylet be better as it avoids the risk of ensuring both stylet n cannula being in artery n thus swelling of artery if cannula wasn't yet in.
No - you should not attempt to advance the cannula unless you are quite sure its tip is lying in the artery. The best way to confirm that is what I show - withdraw the stylet into the cannula. There is no risk to injuring the artery with that motion / step.
I understand what you are trying to say - that you pierced the wall with the stylet, made a hole, but cannula tip doesn't enter this hole; and then by withdrawing the stylet, now arterial blood spills out and creates a hematoma.
However remember that leading up to that point, you have (1) seen flashback into the hub = stylet has pierced artery , (2) flattened the stylet+ cannula and advanced it the 1-2mm needed to bring the cannula tip into the artery. This second step is an essential part of the process, just like IV cannulation. It's hard not to have brought the cannula into the artery with this step - what is more likely is that the stylet +/- cannula is advanced too far or at too steep an angle, and it pierces the back wall.
That is the more common cause of the "swelling" or hematoma. In fact it is a very good reason to master a technique that does not involve transfixion and making that extra (unnecessary) hole in the back wall of the artery.
@@KiJinnChin thank you for the explanation. I do follow the same technique. But thoretically If just needle is in the artery without cannula, fixing the the stylet in the same place without withdrawing and just pushing the cannula in shouldn't the cannula enter the artery as stylet can now act as a guide wire (as in cvc insertion )? This technique should avoid stylet piercing the posterior arterial wall especially in a tortuous or small vessel. Perhaps the drawback that I think of would be it would be easy to get accidentally get the stylet out as very small length of stylet is in d artery... Can this b tried on mannequins may b if someone has the resources to do so..
@@KiJinnChin also why does the cannula lag so much behind the stylet. It would ideally be as close to the bevel as possible.?
@@anonymousstudent6608 It's a very interesting question - you could test the theory with IV insertion. If it doesn't work there, it won't work with arterial lines - since the arterial wall is thicker than the vein wall. Theoretically for now, I would worry that the edges of the cannula would catch on the edges of the hole in the vessel wall and not advance...
@@anonymousstudent6608 I see it as because manufacturers have to design it to be behind the bevel orifice. So depending on the angle and length of the bevel, this separation and distance will vary. If you inspect a range of IV cannulas, from 22G to 14 G, you will see that this distance increases as the stylet increases in size.