Evaluating hands-free carotid Doppler ultrasound for real-time return of spontaneous circulation detection in in-hospital cardiac arrest: a multicenter randomized controlled study

OBJECTIVE: This study investigated the effectiveness and accuracy of hands-free carotid ultrasound (CADFlow, Continuous Auto Doppler Flow, Sensus Medical, Suzhou, China) for monitoring carotid blood flow in assessing the return of spontaneous circulation (ROSC), in comparison to manual palpation of major arterial pulses. METHODS: A total of 341 adult patients with in-hospital cardiac arrest were enrolled from five affiliated teaching hospitals of medical universities. Chest compression rate and depth were monitored using the Prehospital Advanced Life Support Manual Cardiopulmonary Resuscitation (PALMCPR, SunLife Science, Suzhou, China) system. In the CADFlow group, hands-free carotid ultrasound was used to monitor carotid pulsation, while the control group relied on manual palpation of the carotid artery to assess ROSC. The groups were compared in terms of ROSC success rates, time to ROSC determination, and ROSC misjudgment rates. Additionally, the relationships between chest compression parameters (depth and rate) and carotid blood flow were analyzed. RESULTS: The ROSC success rate was non-significantly higher in the CADFlow group than in the control group (43% vs. 33%, P = 0.053), corresponding to a 10-percentage-point absolute increase The mean time required to assess carotid pulsation was significantly shorter in the CADFlow group (2.9 (SD 0.8) s vs. 7.2 (SD 1.3) s, P < 0.001). Strong correlations were observed between chest compression depth and CADFlow parameters, suggesting that the system can effectively assess Cardiopulmonary Resuscitation (CPR) compression quality. CONCLUSIONS: The CADFlow hands-free carotid Doppler ultrasound system improves ROSC detection, shortens assessment time, and provides real-time feedback for CPR quality optimisation. TRIAL REGISTRATION: This clinical trial is registered with the Chinese Clinical Trial Registry (ChiCTR), with the registration number ChiCTR2200064633. The trial was registered on October 13, 2022. The full trial protocol is available upon request from the corresponding author.