Agreement on Interpretation of Point-of-Care Ultrasonography for Cardiac Tamponade Among Emergency Physicians

Cardiac tamponade is an impending calamitous disorder that emergency physicians need to consider and diagnose rapidly. A pericardial effusion with right atrial systolic collapse (earliest sign) or right ventricular diastolic collapse (most specific sign) and a plethoric inferior vena cava are indicators of cardiac tamponade physiology and may be identified with point-of-care ultrasonography (POCUS). The goal of this study is to assess the agreement among emergency physicians with varying levels of sonographic training and expertise in interpreting echocardiographic signs of cardiac tamponade in adult patients.  Methods: Emergency physicians at different levels of training as sonographers were surveyed at didactic conferences at three major academic medical centers in northern New Jersey. Two cardiologists were also included in the study for comparison. Survey respondents were shown 15, 20-second video clips of patients who had presented to the emergency department (ED) with or without significant pericardial effusions and were asked to rate whether tamponade physiology was present or not. Data were collected anonymously on Google Forms (Google LLC, Mountain View, CA) and included self-reported levels of POCUS expertise and level of training. Data were analyzed using Fleiss' kappa (k). All patients had an echocardiogram performed by the department of cardiology within 24 hours of the POCUS, and the results are presented in the paper.  Results: There were 97 participant raters, including attendings, fellows, and resident physicians specializing in adult emergency medicine and two cardiologists. There was a fair degree of inter-rater agreement among all participants in interpreting whether tamponade physiology was present or not. This low level of agreement persisted across self-reported training levels and self-reported POCUS expertise, even at the expert level in both emergency medicine and cardiology specialties.

According to the results of our study, there appears to be a low level of agreement in the interpretation of cardiac tamponade in adult patients. The lack of agreement persisted across specialties, self-reported training levels, and self-reported ultrasonographic expertise. This low level of agreement seen among both specialists indicates that emergency physicians are not limited in their ability to determine cardiac tamponade on POCUS. This highlights the technical nature of POCUS clips and strengthens the importance of physical exam findings when diagnosing cardiac tamponade in emergency department patients. Further research utilizing POCUS for the diagnosis of tamponade is warranted.