Finicky A-Lines

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Gimlet

Gimlet

Cardiac Anesthesiologist
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Wondering if anyone has any guidance for this situation:

Popped in an A-line for my case today and it went nice and easy...pulsatile flash, wire threaded cleanly, Arrow catheter slid in super smooth. It worked great for about an hour or so, then the tracing started damping down. I could get it back by repositioning the hand or putting a little distal traction on the catheter, but after a several minutes it would start dampening again. Flushing the line didn't make a difference.

My attending finally screwed around with it long enough that it just stopped working completely so I put another one in the opposite wrist, and same story...easy insertion but only worked well for about 30 min or so until it the tracing started flattening out. Again could get it back by fiddling but eventually it just pooped out on me.

Both catheters were secured tightly and hadn't migrated near as I could tell. Is it maybe something about my technique that was causing a problem? My attending said something about the lady having small arteries, but I don't know if I buy that when the catheter is clearly well into the lumen.

Any tips?
 
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She could have bad PVD and/or existing "clot." I've seen it often enough via ultrasound.

Are your A-line setups typically made with heparinized saline? Maybe she's hypercoagulable and clotting off. We made our own A-line setups in training, and often used a plain 500mL bag of saline. In PP our blood gas techs make it with a bag of heparinized saline and they're often secured with a fancy wrist brace that places the wrist in slight extension. They still damp on me from time to time, but it "feels" like not nearly as much as during residency - I'd have to "flush" it from time to time via the pigtail to keep it from damping.
 
Hard to tell without being there, and sometimes there is no good explanation. Here are some general statements that I picked up from experience/other attendings:

1) Don't insert too distally. Insert no distal than the proximal crease at the wrist. I forget the anatomic term, but basically look at your wrist and flex it. You'll notice where it flexes there is a crease in the skin. If you go distal to it you are more likely to end up with a positional catheter.

2) Do you have enough catheter length inside? In the people with significant edema, and especially if you combine those people with a long approach to the vessel, you may not have much length in the vessel. The catheter can then slip out, and you might not realize it. This is more likely if you are doing a lot of aspirating or flushing of the line. This is probably not the case in your patient because you say the line only lasted an hour, but this is just a general tip.

3) Consider flushing the line manually with a syringe instead of the auto flush string. It'll give you a feel for any resistance. One of my attendings fixed a line by injecting a dilute solution of Heparin manually into the A-line. (I think he took 100 Units of Heparin (1 ml) and diluted it into a 10 ml syringe, and injected 5 ml).

4) I think the point your attending was trying to make was about the size of the catheter relative to the lumen of your patient's artery. If over time a lit bit of vasospasm develops, and the two factors become essentially equal your waveform may change. Don't ask me about the physics behind this because I don't know, but I have seen the effect. I was struggling with a similar problem to yours on one case when my attending suggested just putting a new line with a pediatric size catheter (22 ga. as opposed to the standard 20 ga.). Maybe it was just dumb luck, but it worked. There is probably something to what your attending is saying.
 
The other day in the icu I placed an a line. Great pulsatile flow, good waveform. Attending went back 15 mins later, no waveform. Undid the tubing, and no flow from the catheter. I rewired over it and put in a new catheter. Aline back to working. Stopped 5mins later. Rewired it and pulled out a nice clot. Aline back to working. Watched the waveform for a minute and it quit working again. Rewired it and pulled out another clot. Stopped again and attending placed another one. It clotted off also, then we decided that the patient no longer needed an a line.
 
The most common thing I see when A-lines crap out is the angle of entry is generally too steep. I have seen numerous residents approach at an angle greater than 45 to the artery. When the cath is secured against the skin it causes the cath to be bent/kinked which ultimately distorts the lumen of the cath and leads to early dampening and eventually failure of the a-line.

Try a flatter approach to the vessel and see if that makes a difference in your practice and longevity of your a-lines.

- BW
 
rsgillmd said:
3) Consider flushing the line manually with a syringe instead of the auto flush string. It'll give you a feel for any resistance. One of my attendings fixed a line by injecting a dilute solution of Heparin manually into the A-line. (I think he took 100 Units of Heparin (1 ml) and diluted it into a 10 ml syringe, and injected 5 ml).
Click to expand...

Years ago we were told not to flush more than 2-3cc at a time in the a-line. There's not a tremendous volume in the radial artery going proximal, and I guess the theoretical concern is flushing clot or air bubbles back up as high as the carotid artery.

Also, remember that flushing with a 3 or 5 cc syringe can generate a lot more pressure than a 10-20cc.
 
If you flush at <1cc/second you don't get much retrograde flow. This is a far greater concern in peds because the distance is so much shorter.

I have no evidence of this but I'm convinced that 1) Arrows die sooner than angios and 2) the Safeset or VAMP systems kill arterial lines.

At my current institution we only have safety needles for arterial lines, so I unfortunately have to use Arrows.
 
you can also get pretty bad vasospasm that will knock out your line. Especially in kids. A little dilute lido flush works magic if this is the case
 
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I use the following:

1) Jelco long 20g catheters. I prefer the teflon catheters to the polyurethane ones b/c the teflon doesn't kink or fail if I have to use seldinger and thread over a wire. I tried out the Arrow kits that the ICU apparently prefers (saying our Jelco 20s all fail eventually in the ICU) but I don't like them as much, and they're also more expensive. I believe the regular 20g catheters only fail in the ICU if the nurse is taking better care of her crops on Facebook than the patient I've sent her.

2) Insert more proximal. When I started I put them all in as distal as possible, but had more issues. The more proximal approach that rsgillmd mentioned earlier has worked well for me.

3) Wrist extension. Lately I've used a wrist extension kit that we have that often helps if the positioning of the wrist is causing dampening.

I like the ideas of a heparinized or lido flush. I'll have to try that also next time I have some issues.
 
As was mentioned and as you can imagine, vasospasm is a major issue on the peds side, and in the elderly their arteries are often more prone to vasospasm and are more "delicate"-- papaverine and heparin in combination work wonders in folks with small arteries, reactive arteries, and art lines that just need a lovin'- not sure how accessible papaverine is everywhere-- but in our picu it's the baseline. lidocaine is a great substitute if needed.
 
proman said:
If you flush at <1cc/second you don't get much retrograde flow. This is a far greater concern in peds because the distance is so much shorter.

I have no evidence of this but I'm convinced that 1) Arrows die sooner than angios and 2) the Safeset or VAMP systems kill arterial lines.

At my current institution we only have safety needles for arterial lines, so I unfortunately have to use Arrows.
Click to expand...

In my experience, the two main problems, which have already been mentioned, are taking too steep of an approach, and placing the line too distal.

As far as the "crease in the wrist," I think taking an approach that is at least 1 cm proximal to the styloid process of the distal radius is a good starting point. I sometimes go more proximal based on the anatomy and how the catheter will lie...otherwise I travel more proximal on my second attempt if necessary.

As for using IVs or angiocaths versus a traditional arterial catheter, I'm sure the patency is the same, but the longevity in my institution is much longer for the actual arrow catheter, which is important if you have to take care of the patient for several days in the ICU. I think this is because nurses are simply more comfortable caring for these catheters, and are less likely to screw them up. Also, they are more likely to be secured to the skin with a stitch or StatLock, which is hard to argue against.
 
bluewater said:
The most common thing I see when A-lines crap out is the angle of entry is generally too steep. I have seen numerous residents approach at an angle greater than 45 to the artery. When the cath is secured against the skin it causes the cath to be bent/kinked which ultimately distorts the lumen of the cath and leads to early dampening and eventually failure of the a-line.

Try a flatter approach to the vessel and see if that makes a difference in your practice and longevity of your a-lines.

- BW
Click to expand...

this is the answer, and this is also why large or edematous people have such problems with the catheters staying in, your angle HAS to be steep to get there and then you have at best 40-50% of the catheter in the vessel.

i usually take a very low angle to enter the skin in most people, probbaly less than 30 degrees
 
re: Jelco vs Arrow.

People say Arrow catheter kinks less. If you compare the two kinds of catheters, you will see it is true that the Arrow ones are harder to kink. But once they are kinked, they are done. The Jelco ones can be unkinked. So which ones do you prefer, ones harder to kink in the first place or ones that can be unkinked later? Similar to the reinforced ETTs.
 
DrN2O said:
re: Jelco vs Arrow.

People say Arrow catheter kinks less. If you compare the two kinds of catheters, you will see it is true that the Arrow ones are harder to kink. But once they are kinked, they are done. The Jelco ones can be unkinked. So which ones do you prefer, ones harder to kink in the first place or ones that can be unkinked later? Similar to the reinforced ETTs.
Click to expand...

I agree. The first insult happens when we occlude the artery taking out the needle. From that point on the catheter is weakened. I've started occluding much more proximal than before. Also the Arrow catheter is made of polyurethane, the Angiocaths are made from fluorinated ethylene propylene. I think that explains some of the difference. In addition, while both catheters are 20 ga internal diameter, the external diameter of the Arrow catheter is larger than the Angiocath.
 
In an easily inserted catheter i think clotting is a much more frequent problem than kinking. This is why flushing it with whichever solution you have; saline, lidocaine, heparine... solves the problem.
The vasospasm theory is just a cheap excuse imho: if your radial artery is clamping down on your catheter your hand would be falling off.
 
proman said:
I agree. The first insult happens when we occlude the artery taking out the needle. From that point on the catheter is weakened. I've started occluding much more proximal than before. Also the Arrow catheter is made of polyurethane, the Angiocaths are made from fluorinated ethylene propylene. I think that explains some of the difference. In addition, while both catheters are 20 ga internal diameter, the external diameter of the Arrow catheter is larger than the Angiocath.
Click to expand...

I've always wondered about that. The anesthesia team here always occludes the radial artery after line placement and most likely kinks the catheter in the process.

An equally effective way to protect your shoes from blood is to simply put your finger over the end of the catheter.....
 
huh? simply occlude the artery proximal to the tip of the catheter. no catheter kinkage, no blood on the floor. it's not rocket science.
 
dhb said:
if your radial artery is clamping down on your catheter your hand would be falling off.
Click to expand...

Huh? What about the Allen's test and the ulnar artery? Collateral circulation and all that?

Slogoff S, Keats AS, Arlund C. On the safety of radial artery cannulation. Anesthesiology 1983; 59:42-7
 
proman said:
I think most people are do not estimate where the tip truly is. Like an attending of mine would say, it's not rocket surgery.
Click to expand...

HA! i may have to use that.

are you trying to say...sometimes it's hard to tell where that tip ends up? it's just the tip, right? :meanie:
 
Idiopathic said:
well i think that just demonstrates its great specificity in the face of poor sensitivity
Click to expand...

Really? I though it told you that if you have a cubital artery occlusion and you occlude the radial artery you don't get flow to the hand?
Rocket science 'in it
Vasospasm is a good excuse for poor performance

And the hands falling was sarcastic if you missed it
 
dhb said:
Really? I though it told you that if you have a cubital artery occlusion and you occlude the radial artery you don't get flow to the hand?
Rocket science 'in it
Vasospasm is a good excuse for poor performance

And the hands falling was sarcastic if you missed it
Click to expand...

Not sure where this is coming from. The analogy to the situation described in the case report is of a patient without ulnar flow, which is what you are trying to elucidate with the Allens test and if you have a positive result (i.e. no signs of perfusion with compressed radial artery) then you should not put in an arterial line (HIGHLY SPECIFIC) and if you dont get the positive result then it doesnt mean anything (POORLY SENSITIVE)

Oh and your sarcasm needs some work.
 
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