Abstract 199: Femoral Artery Doppler Ultrasound Blood Flow Patterns Predict Intrinsic Pulsatility In Cardiac Arrest Patients Receiving Active Chest Compressions

Introduction: Pulse detection requires chest compression interruption, which is associated with poor outcomes in cardiac arrest. Currently no modality can reliably identify return of spontaneous circulation with ongoing chest compressions. Hypothesis We hypothesized that patients with intrinsic pulsatility have anterograde dominant blood flow (ADF) on arterial Doppler ultrasound; whereas those with intrinsic pulselessness have bidirectional blood flow moving antero/retrograde during chest compression/decompression. Methods: We conducted a prospective, diagnostic accuracy study on a convenience sample of adult Emergency Department (ED) cardiac arrest patients with a femoral arterial line in place. Immediately prior to a pulse check, pulsed-wave Doppler ultrasound of the common femoral artery was performed during active chest compressions. Bidirectional flow was present when the anterograde flow waveform was equal in peak systolic velocity to the retrograde flow waveform. All other Doppler waveforms were ADF. A pulse was present when there was an arterial line waveform. Sensitivity, specificity, and accuracy of ADF versus bidirectional flow for predicting pulsatility was assessed. Results: We enrolled 42 patients and performed 104 pulse checks: a pulse was present for 73 (70.2%) and absent in 31 (29.8%). ADF was present in 82 (78.9%) and bidirectional flow was present in 22 (21.2%). Sensitivity of ADF for detecting a pulse was 95.9% (95% CI: 91.3%-100.0%). Specificity of bidirectional flow for detecting pulselessness was 61.3% (95% CI: 44.1-78.4%) and accuracy was 85.6% (95% CI: 77.3-91.7%). Patients with ADF have 36.9 times the odds of having an arterial line pulse compared with patients with bidirectional flow (OR: 36.9; 95% CI: 9.5-144.4). Conclusion: In ED cardiac arrest patients, ADF on Doppler ultrasound has high sensitivity for detecting an arterial line pulse. Further studies are needed to further evaluate this novel finding.