CVP catheter confirmation question

  1. 0
    We all know the gold standard for confirmation of a CVP catheter is a chest x-ray. However, if that is not immediately available, has anyone heard of:

    Confirmation via ECG?

    or

    Confirmation via doppler while injecting 10mL air?


    I found some info discussing the use of premature beats on the ECG monitor to confirm CVP catheter placement. Didn't read too much about it but it seems study results varied, and the sensitivity of such a method would be low. It is however, possible it seems.

    I could not find ANYTHING about confirmation via doppler while injecting air. Anyone know about this?

    Thanks!
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  4. 18 Comments so far...

  5. 2
    Never heard of either. You're joking about injecting air, aren't you?
    worked hard and long and CCL RN like this.
  6. 0
    Thanks so much for your constructive, informed input. No, this thread is not a joke. It's supposed to be a serious scientific discussion and a request for help.

    Small quantities of air bubbles are routinely injected into central lines during cardiac ultrasound to assess flow.

    From Wikipedia:

    "An echocardiogram is an study of the heart using ultrasound. A bubble echocardiogram is an extension of this that uses simple air bubbles as a contrast medium during this study and often has to be requested specifically. Although colour Doppler can be used to detect abnormal flows between the chambers of the heart (e.g. patent foramen ovale) it has a limited sensitivity. When specifically looking for a defect such as this small air bubbles can be used as a contrast medium and injected intravenously, where they travel to the right side of the heart. The test would be positive for an abnormal communication if the bubbles are seen passing into the left side of the heart. (Normally they would exit the heart through the pulmonary artery and be stopped by the lungs.) This form of bubble contrast medium is generated on an ad-hoc basis by the testing clinician by agitating normal saline (e.g. by rapidly and repeatedly transferring the saline between two connected syringes) immediately prior to injection."

    Also, ECG can be used to detect CVP catheter position, although this is probably not a desirable method.

    From the Annals of Surgery, 1986:

    "In an attempt to improve the accuracy of central venous pressure (CVP) catheter tip location, 84 consecutive cardiac surgery patients in sinus rhythm were studied prospectively with respect to subclavian insertion of a CVP catheter using a guidewire technique. The presence of cardiac arrhythmia was used as an index of right atrial (RA) location of the guidewire tip, before threading the catheter over the guidewire. Correct catheter tip location (superior vena cava [SVC] or RA) was achieved in 100% of patients (N = 78) with premature atrial contractions (PACs) related to guidewire insertion. This fell to 50% (N = 4) if no arrhythmias were noted from the guidewire. Ventricular arrhythmias were noted in two of 84 patients (2.4%). Other problems related to the use of this technique are discussed."

    Quote from sunnycalifRN
    Never heard of either. You're joking about injecting air, aren't you?
  7. 0
    Anything done along those lines within the last 20 years? It was a different world in 1986.
  8. 0
    With the common use of US guidance for central line placement you will not see ANYONE in the US using agitated saline or ECG to verify central lines.

    1. US
    2. CXR
    3. Manometry/pressure transduction
    4. Blood fas analysis

    All of these are less invasive and/or more reliable than air injection or ECG.
  9. 1
    I haven't heard of either technique. And sorry, but under no circumstances would it ever be ok to inject 10cc of air into a central line!!!! That is definitely not a "small quantity of air bubbles." Thats a full 10cc syringe of air!
    I could see how ECG would be totally unreliable, as even if the catheter was inserted too far it wouldn't necessarily cause any ventricular ectopy, its just a possibility.
    Also, neither of these techniques would tell you about the status of the lungs and whether or not the insertion may have caused a pneumothorax, right? My mom told me a story once about a very cocky MD who told her not to bother getting a CXR after CVC insertion because he was so sure it was perfectly placed. She got one anyway, pt had a 70% pneumo.
    CCL RN likes this.
  10. 0
    As far as ECG confirmation of a CVP catheter? I've certainly never seen the catheter confirmed that way, and I wouldn't want to rely on such a method. But apparently they were doing it at one time.

    As for air bubbles, well, we still do that. But not 10mL of air, that seems dangerous. I think I've injected maybe 1mL of air mixed/agitated with 10mL NS to create bubbles used in ultrasound. That was to look for abnormalities in cardiac function though. Never heard of that being used to confirm a central line though.

    Quote from Biffbradford
    Anything done along those lines within the last 20 years? It was a different world in 1986.
  11. 0
    Yeah, I think you're right... the 10mL of air sounds like it could be extremely detrimental to the patient's health, to put it mildly. And I like your analysis of the ECG method.

    I've seen CVP catheters go all over the place as well. Good point about the pneumothorax.

    Thanks for the input.

    Quote from IheartICUnursing
    I haven't heard of either technique. And sorry, but under no circumstances would it ever be ok to inject 10cc of air into a central line!!!! That is definitely not a "small quantity of air bubbles." Thats a full 10cc syringe of air!
    I could see how ECG would be totally unreliable, as even if the catheter was inserted too far it wouldn't necessarily cause any ventricular ectopy, its just a possibility.
    Also, neither of these techniques would tell you about the status of the lungs and whether or not the insertion may have caused a pneumothorax, right? My mom told me a story once about a very cocky MD who told her not to bother getting a CXR after CVC insertion because he was so sure it was perfectly placed. She got one anyway, pt had a 70% pneumo.
  12. 0
    Thanks, all very good points.

    Quote from TakeBack
    With the common use of US guidance for central line placement you will not see ANYONE in the US using agitated saline or ECG to verify central lines.

    1. US
    2. CXR
    3. Manometry/pressure transduction
    4. Blood fas analysis

    All of these are less invasive and/or more reliable than air injection or ECG.
  13. 0
    While EKG changes are useful when placing a CVP or PA line, they'll never replace a CXR since the primary reason for a CXR following an IJ or SC line placement is to rule out a pneumo, not for tip placement.

    PICC lines however are a different story. The majority patients receiving PICC lines at my facility have their tip placement confirmed by ECG guidance and receive no CXR or other radiographic method of confirmation.


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