Arterial Line Question - page 2

by wonderbee 66,323 Views | 35 Comments

I'm precepting in CVICU which so far has been great. I'm curious about how an arterial line works. I understand what it's for, but don't understand how it works. Is pressure going through the line to keep the vessel open?... Read More


  1. 3
    Just to drive Papaw's point about the importance of zeroing your art lines home...

    I work with kids, everybody knows that. Our kids could be only hours old, or they could be the size of a Sherman tank. The itty-bitties are the ones who demand the utmost accuracy in monitoring, because they don't have much room for change. One night a few weeks back, we had several itty-bitties in the unit, two post-op cardiacs and a liver transplant, at opposite ends of the unit. Now these kiddies are prone to pressure issues and often need several times their circulating volume in fluid boluses in the first days post-op and may be on one or more inotropes to help 'em out. On this particular night, around 2330, all of the itty-bitties started having pressure issues. The wave-forms on their monitors had not changed, they all were text-book perfect. But the readings we were getting were dramatically lower. Cuff pressures were all very close to the previous art line pressures, and much higher than the art line was currently giving us. The kids were well-perfused and their heart rates had not risen. Our resident on call that night isn't particularly bright and has had it drilled into her that we believe the art line over the cuff at all times. So I'm helping out at the first bedside to raise the alarm (baby 48 hours out from the CV OR)... we gave fluid, a lot of fluid, with no change in pressure on the art line but a great response on the cuff. So the resident decides to start norepinephrine... Once it was running, the response was underwhelming so she had the nurse crank up the rate. Well, now we've got a great art line pressure, complete with whip, the cuff pressure is sky-high and the baby's heart rate is about 90. So now the norepi is off... That was when I made a tour around the unit to see if anyone else was needing my help. Oh, little What's-his-name in Bed 13 has the identical problem? And little Sweetie in Bed 8 too? What's going on, I'm wondering. So I took a poll. (I'm famous for taking polls.) Three for three, none of the nurses had included rezeroing their lines in their troubleshooting bag of tricks. I was stunned. It's one of the first things I do when there's a sudden and unexplained change in pressures. None of these nurses were green either. Imagine their surprise when rezeroing the lines magically fixed their kids! Later we found out that a storm front had blown in at around 2330 and dumped six inches of snow on us. Moral of the story? You might need to rezero your lines a couple of times a shift depending on the weather!
  2. 0
    janfrn,
    That was a wonderful learning experience. Thank you sooo much for sharing. I am a student nurse and I will never forget to zero the lines.
    Jessica
  3. 0
    found this thread in a search. I know it's a bit of an oldie, but I found it very helpful.

    A couple of questions about zeroing. How often do I need to re-zero? Should I re-zero when the patient is transferred to PACU from the OR? And also after I use the line to take bloods?

    Thanks in advance
  4. 1
    When you're zeroing your pressure lines you're calibrating them to the atmosphere. You should zero them when you take over care of the patient, whether from the previous shift or from the OR/PACU/ER etc, for your own assurance that it has been done. You'd rezero if the cable has been disconnected for any reason, because the monitor will probably not give you a number value, just a wave. And you should rezero if there's a sudden dramatic change in your patient's pressures without an obvious or discernible reason. Take a cuff pressure and troubleshoot your lines and then if you're still not sure you can rezero. The atmospheric pressure in the room is only going to change if the weather changes (or there's an explosion somewhere), so rezeroing when you reposition or when you draw labs is not really necessary.
    Hawkeye-RN likes this.
  5. 0
    We have a policy to re-zero all of our lines q4h.
  6. 1
    What is the rationale? How much does the atmospheric pressure change in 4 hours? Are you in a storm belt then?
    Hawkeye-RN likes this.
  7. 0
    Nope, just the midwest! We've had some late night discussions on the real point of zeroing often. Whats your policies on zeroing?
  8. 2
    That's a great question. Our nurse educator, who incidentally can't tell you what she's doing when she zeros or why exactly she's doing it, has been teaching new staff that they are to rezero EVERY time they reposition their patient. Not just level but also rezero. So when I'm precepting I ask the newb how exactly rolling a person from supine to banked on their right side has changed the pressure in the room and they give me a blank stare. Of course you want your pressure lines to be zeroed to the atmosphere at the beginning of the shift so you're sure they're giving you accurate information. But every time you reposition? Come on. I've looked all over for a policy that gives a frequency and we don't have one. We have one for EVDs (q4h) and the pressure pods on our ECMO circuits (q6h), but nothing for art, LA, RA or CVP lines. (We don't use PA lines.) AACN and many hospitals (such as Stanford) have a policy to recal q12h and/or when there has been a change in caregiver (verifying accuracy for oneself!), when the tubing is changed (no choice there!) or if there's a sudden change in readings that cannot be explained.
    Hawkeye-RN and ghillbert like this.
  9. 0
    I'm going to be relocating to the Sierra Nevada Mountain region and was wondering if there will be a difference in my a-line procedures and my lab values.
  10. 0
    Speaking of Art lines, ALWAYS make sure your alarms are on! I was standing at my patients bedside that I had just received from PACU with a labile BP. I look up and the pressure went from 100/60 to 69/30. No alarming! Good thing I was standing there. Although I should have checked my alarms when getting the room ready, I know! And the PACU nurse (bless her soul!) told me that when they received him, the ART was reading systolic in the 40s. What?! I was like "was it a good waveform?" "Oh no it wasn't" she replied. Always make sure that the wave looks crisp before you start treating it!


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