Non-invasive Monitor of Effective Chest Compressions with Carotid and Femoral Artery Ultrasound in the Emergency Department.

Abstract

Background: End-tidal carbon dioxide (EtCO₂) has been regarded as the gold standard for assessing the effectiveness of cardiopulmonary resuscitation (CPR). However, the clinically observed limitations of EtCO₂ influenced by ventilation during CPR suggest the need to implement a new, non-invasive hemodynamic monitoring method to evaluate and optimize CPR effectiveness in real time.

Methods: For this prospective study we enrolled 31 cardiac arrest (CA) patients who presented to the emergency department (ED) and 13 healthy volunteers as point-of-care ultrasound (POCUS) controls. Two physicians not involved in the resuscitation team performed POCUS of the bilateral carotid and femoral arteries during chest compression within the first 10 minutes of CPR. The clinical data and presumed CA cause were recorded. We observed the arterial pulse and measured the peak systolic velocity (PSV). The EtCO₂ values during POCUS were also recorded. We explored the correlation between arterial PSV and EtCO₂.

Results: The mean age of the patients was 69 ± 2 years, and 22 were male. Of 25 patients who experienced out-of-hospital cardiac arrest, 18 had an average no/low-flow time >30 minutes before ED arrival. Five patients achieved return of spontaneous circulation (ROSC). We found no significant difference in arterial PSV between ROSC and non-ROSC patients. The PSV of the left femoral artery was most consistently and positively correlated with EtCO₂ in CA patients (R² 0.35, P=0.003).

Conclusion: Detection of arterial peak systolic velocity by point-of-care ultrasound, especially of the left femoral artery, might be a feasible method for non-invasive, real-time monitoring of chest compression effectiveness during CPR.