Abstract Body: Introduction
Manual pulse palpation during cardiopulmonary resuscitation has poor reliability in both hospital and prehospital settings. Recently, point-of-care ultrasonography (POCUS) of the carotid artery has been used for pulse determination in the in-hospital setting. However, this approach has not been evaluated for out-of-hospital cardiac arrest (OHCA) events where adequate views and prolonged pauses during pulse checks could be challenges. Our objective was to evaluate the potential use of POCUS for pulse determination by paramedics using carotid artery and subxiphoid cardiac views. We hypothesized that carotid POCUS views may be obtained more quickly and successfully in the prehospital setting than the traditional subxiphoid cardiac view.
Methods
This was a retrospective analysis of carotid and subxiphoid POCUS use for pulse determination at a high-volume, ground-based EMS agency. Adult patients suffering from medical OHCA with POCUS attempted were included. Those under 18 years of age, protocol deviations, missing data, or uninterpretable data were excluded. Video was recorded throughout each CPR pause in which ultrasounds were conducted. EMS clinicians alternated carotid and subxiphoid views. Pause length and view adequacy were evaluated by two expert paramedic reviewers. Disagreements were adjudicated by an EMS physician. Statistical analysis: McNemar’s test was used to evaluate for differences between adequate view and compression pauses < 10 seconds between carotid and subxiphoid approaches. Generalized estimating equations were used to evaluate the association of adequate view and compression pauses < 10 seconds to POCUS approaches.
Results
A total of 196 POCUS recordings from 94 patients were analyzed. Videos were evaluated by rates for adequate views with k=0.83 with 92% agreement. Overall, 73% (n=143) had a pause length < 10 seconds, and 62% (n=121) had an adequate view. Adequate views and compression pauses < 10 seconds were achieved more frequently using carotid POCUS (Figure). Adjusting for body mass index, carotid views had increased odds (AOR 9.3, 95% CI: 4.3-20.4) of combined adequate view and compression pause < 10 seconds as compared to subxiphoid imaging.
Conclusion
Paramedic-obtained carotid POCUS demonstrated improved view adequacy and fewer extended CPR pauses. Limitations include the high level of POCUS training for paramedics and the single agency data source, making generalizability difficult to determine.