Femoral artery doppler ultrasound is more
accurate than manual palpation for
pulse detection during cardiac arrest
Anum Shahab, MD
Published May 20, 2024
Study Design
This was a prospective, cross-sectional, diagnostic study performed in a quaternary care emergency department.
Objective
The primary objective was to assess the accuracy of Doppler ultrasound versus manual palpation in detecting a pulse in patients in cardiac arrest. The secondary objective was to determine whether peak systolic velocity (PSV) on Doppler ultrasound could detect a pulse with a systolic blood pressure > 60 mmHg.
Methods
- This was a prospective, cross-sectional, partially blinded diagnostic accuracy study. Patients included were 18 or older with non traumatic cardiac arrest. Included patients all had a femoral arterial line placed and a Doppler ultrasound-trained Emergency Medicine attending needed to be available. Patients were excluded if they were a candidate for ECMO. The research team was trained for Doppler ultrasound for this study. The treatment team was blinded to the Doppler ultrasound exam. However, they were not blinded to the arterial line blood pressure waveforms and measurements.
- Prior to pulse check, ultrasound machine volume was turned off. During pulse checks, the research team confirmed and recorded whether a pulse wa palpated by the treating team, the present or absence of Doppler ultrasound and arterial line waveforms, the highest PSV on Doppler ultrasound, and the highest SBP on the arterial line. Repeat measurements were recorded until either ROSC was achieved or time of death.
What are some possible flaws in the methods used?
Carotid artery palpation has been shown to be more reliable than femoral artery palpation during cardiac arrest. However, here the location of manual pulse detection was not consistently recorded. Often, both carotid and femoral were simultaneously checked.
Results
- Doppler ultrasound had higher accurate than manual palpation for detection of any pulse (95.3% vs 54%; p < 0.001)
- When SBP > 60mmHg, the accuracy of Doppler ultrasound was lower, however still more accurate than manual palpation (77.6% vs 66.2%; p = 0.011)
- When SBP > 60mmHg, the sensitivity o manual palpation was low at 47.4%; however, the specificity of manual palpation was higher than Doppler ultrasound (82.3% vs. 58.4%; p < 0.001)
Discussion
Femoral artery Doppler ultrasound was more accurate than manual palpation for detection of any pulse on an arterial line. The accuracy of manual palpation of any pulse was poor at 54%.
Take Home Points
Femoral artery Doppler ultrasound was significantly more accurate than manual palpation for detecting a pulse. A PSV > 20 cm/s was found to predict a pulse with a SBP > 60mmHg, which was considered adequate for perfusion. In places were Doppler ultrasound is available, femoral artery Doppler ultrasound is an accurate and objective tool to determine presence of a pulse in cardiac arrest. However, this study needs external validation.
Study Limitations
The study was a single-center study that did not include a large patient sample. Additionally, repeat measurements for each patient were used. Treatment teams were also not blinded to the arterial line waveforms. The location of manual pulse detection (carotid vs. femoral) was not consistently recorded as they were often both simultaneously checked. Lastly, the study did not evaluate clinical outcome differences based on the method of pulse detection.
Does this study influence your practice?
This study will influence my practice. It makes me more likely to use Doppler for pulse detection in cardiac arrest patients given its higher accuracy. However, this will only be possible if Doppler ultrasound is available where I practice. While the role of ultrasound has greatly increase during during cardiac arrest, only people with appropriate skills and experience should use POCUS. THis can pose a problem in a facility where not everyone is trained in POCUS. Ultimately, this method can be used as another data point during resuscitation to assess for ROSC/pulse checks.
Cohen AL, Li T, Becker LB, Owens C, Singh N, Gold A, Nelson MJ, Jafari D, Haddad G, Nello AV, Rolston DM; Northwell Health Biostatistics Unit. Femoral artery Doppler ultrasound is more accurate than manual palpation for pulse detection in cardiac arrest. Resuscitation. 2022 Apr;173:156-165. doi: 10.1016/j.resuscitation.2022.01.030. Epub 2022 Feb 4. PMID: 35131404.