Introduction: Point-of-care cardiac ultrasonography (POCUS) is commonly used for pulse determination in cardiac arrest. It is unknown whether pulse determination using carotid artery POCUS can be obtained more quickly and successfully than with the subxiphoid view in the prehospital environment. Our objective was to compare carotid and subxiphoid pulse determination by paramedics during out-of-hospital cardiac arrest (OHCA). We hypothesize that prehospital carotid POCUS views may be obtained more quickly and successfully than the subxiphoid approach.
Methods: We conducted an observational study comparing carotid and subxiphoid POCUS for pulse determination during OHCA among a suburban, third-service emergency medical services (EMS) agency (90,000 activations per year). Videos were recorded throughout each cardiopulmonary resuscitation (CPR) pause, and paramedics alternated carotid and subxiphoid views on the same patient. Videos were evaluated for view adequacy, interrater reliability and agreement assessed. Differences in view adequacy and compression pause duration between carotid and subxiphoid POCUS approaches were analyzed. McNemar's test was used to compare the proportion of adequate views and compression pauses.
Results: A total of 248 POCUS recordings from 107 patients were analyzed. Image quality was assessed for adequacy, demonstrating high interrater reliability (kappa = 0.85) and 93 % agreement. Overall, 73 % (n = 195) had pause lengths <10 s, and 62 % (n = 153) had an adequate view. Compression pauses <10 s, and adequate views were achieved more frequently using carotid than subxiphoid POCUS (83 % vs. 39 % and 83 % vs. 63 %, respectively).
Conclusion: Paramedic-obtained carotid POCUS demonstrated a significant increase in view adequacy and fewer extended CPR pauses, as compared to subxiphoid views.
Keywords: Cardiac arrest; Emergency medical services; Paramedics; Point-of-care ultrasound; Resuscitation.
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