Lit Matters #1: US vs. Palpation of Pulse During Cardiac Arrest

Manual pulse checks during cardiac arrest are unreliable, and femoral artery Doppler ultrasound appears substantially more accurate for detecting return of spontaneous circulation. A femoral peak systolic velocity signal may also help distinguish any flow from a more meaningfully perfusing blood pressure during pulse checks.

Femoral Doppler for ROSC Detection

• Manual palpation limits: Finger pulse checks miss too much and vary widely in accuracy, making manual palpation a weak standalone test for ROSC during cardiac arrest.
• Doppler accuracy signal: Femoral artery Doppler outperformed palpation for detecting any pulse, with about 95% accuracy versus roughly 54% for manual exam.
• Peak systolic velocity threshold: A femoral Doppler PSV above 20 cm/s tracked with a systolic pressure of at least 60 mmHg, giving clinicians a more objective pulse-check target.
• Sensitivity specificity tradeoff: Ultrasound is excellent at finding any blood flow, but that sensitivity can overcall true perfusion when the pressure is still too low to matter clinically.
• Bedside workflow reality: Measuring femoral PSV in an active code is feasible but not frictionless, especially when the same machine may also be needed for cardiac views. We get into the practical tradeoffs in the episode.