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Finger (or is that…probe) on the Pulse | Doppler vs Manual Palpation During Arrest

April 15, 2022

Written by Meghan Breed

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Use of pulsed-wave Doppler ultrasound by a trained emergency medicine physician to detect any femoral pulse was more accurate than manual palpation but did not necessarily confer an adequate blood pressure (i.e. SBP ≥ 60 mmHg).  Calculation of peak systolic velocity (PSV) of ≥20 cm/s had a stronger correlation with a SBP ≥ 60 mmHg.

Why does this matter?
Emergency Department codes require a large resuscitation team to complete many tasks simultaneously.  Manual palpation of a pulse during cardiac arrest can be difficult due to access to patient, body habitus, environmental stress, time limitations and assessor experience.  Prior studies have cited the accuracy of manual pulse detection anywhere between 63% and 94%.

Keep your finger (ultrasound probe) on the pulse…
Fifty-four patients (213 pulse checks) were enrolled in a prospective, cross-sectional, partially blinded diagnostic accuracy study to determine the accuracy of pulsed-wave Doppler ultrasound compared to manual palpation for detection of any pulse during non-traumatic cardiac arrests.  To be eligible for the study, patients had to have a femoral arterial line in place.  Eighteen trained emergency medicine attending physicians served as the research personnel and performed the Doppler ultrasound of the femoral artery in short axis and recorded the following data points at each pulse check: ability to palpate a pulse, presence or absence of Doppler ultrasound and arterial line waveform, highest peak systolic velocity (PSV) and highest systolic blood pressure on the arterial line.  Presence of Doppler ultrasound demonstrated higher accuracy than manual palpation for detection of any pulse (95.3% vs. 54.0%; p < 0.001) but less accurately predicted presence of a pulse with SBP ≥ 60 mmHg (77.6% vs. 66.2%; p = 0.011) and was less specific than manual palpation for predicting presence of a pulse with SBP ≥ 60 mmHg (82.3% vs. 58.4%; p < 0.001).  PSV on Doppler ultrasound demonstrated a strong correlation with SBP (Spearman correlation coefficient: 0.89; p < 0.001), with an optimal cutoff value of ≥20 cm/s to detect SBP ≥ 60 mmHg (area under the receiver operating curve = 0.975).

My takeaway – this can be used as another datapoint during resuscitation to assess for ROSC (along with other adjuncts like ETCO2) and may be able to predict whether a patient has an “adequate” pulse, which the authors defined as SBP ≥ 60 mmHg when PSV is calculated from Doppler ultrasound.  Unfortunately, using the presence of Doppler ultrasound alone would have resulted in prematurely stopping chest compressions for an “inadequate pulse” (SBP > 0 and < 60) due to the specificity of manual palpation.

Source
Femoral artery Doppler ultrasound is more accurate than manual palpation for pulse detection in cardiac arrest. Resuscitation. 2022 Feb 4;S0300-9572(22)00032-6. doi: 10.1016/j.resuscitation.2022.01.030. Online ahead of print.

3 thoughts on “Finger (or is that…probe) on the Pulse | Doppler vs Manual Palpation During Arrest

  • Hey, ER resident and long time reader here. Great write up on an interesting article. I do wonder about your editorializing in that final sentence-
    “Unfortunately, using the presence of Doppler ultrasound alone would have resulted in prematurely stopping chest compressions for an “inadequate pulse” (SBP > 0 and < 60) due to the specificity of manual palpation.”

    Hasn’t there been some literature to suggest that doing compressions in those with a pulse does not result in improved perfusion – or perhaps worse perfusion? I don’t know if these were well done studies and I think they were animal models (I’ll have to look up the articles but I’ve heard them referenced on a podcast. Maybe an EMCases one on PEA and pseudo-PEA?). Anyways your sentences implies that all of those with what you’re calling an “inadequate pulse” (A-line with SBP > 0 and < 60) should be getting compressions which we definitely don’t know for sure. Some would argue you’re actually dealing with a profound shock state to treat with pressors/fluids rather than compressions at say an A-line reading of SBP in the 50s and no palpable pulse. Anyways just some food for thought. Let me know what you think. Thanks for the write-ups!

    • Journal Feed Editor:

      Hey Brent!

      I agree with you, there’s a risk that you’re right. The authors chose 60mmHg as their cut-off seemingly without much robust evidence to back it (admittedly I didn’t deep dive on the topic myself). Also depends on how they defined ‘those with a pulse’ in the studies you’re referring to.

      I guess you also just have to consider that they were using an arterial line as their gold standard and how infrequently we have that during an arrest as well as their lack of evidence to show benefit even if you do have one. In the end what matters isn’t really your blood pressure, but rather your perfusion pressure to vital organs so some measure of that might have been a better gold standard. Really though if your SBP is <60 then your MAP is <<60 and you’re not doing well.

      Either way, it’s hard to tell how many of those could have truly been cases of prematurely stopping compressions and there’s always the argument that there’s no real difference between a SBP of 59 vs 60mmHg. If you’re running ACLS on these patients then they’re getting entire milligrams of epi though, so it’s probably not a case of having a low pressure for lack of pressors.

What are your thoughts?