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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.
