Potential errors in the diagnosis of pericardial effusion on trauma ultrasound for penetrating injuries

Objective: To evaluate ultrasound error in patients presenting with penetrating injury with a potential for pericardial effusion. Methods: Residents and faculty from an emergency medicine training program at Level 1 trauma center with an active ultrasound program were asked to view digitized video clips of subxiphoid cardiac examinations in patients with chest trauma. Participants were asked to fill out a standardized questionnaire on each video clip asking whether a pericardial effusion was present. Other questions included size of effusion and presence of tamponade. The study also asked participants to rate their confidence in their impressions. Data were analyzed using interquartile ranges and confidence levels. Results: All participants had difficulty distinguishing between epicardial fat pads and true pericardial effusions. The overall sensitivity was 73% and specificity was 44%. Confidence shown by participants in their answers increased with level of training or experience, regardless of whether they were correct or incorrect. Additional views were frequently requested to help decide whether an effusion was present. Conclusions: A serious potential exists for misdiagnosing epicardial fat pads as pericardial effusion in critically ill trauma patients. Emergency physicians need to be aware of this and should consider one of two suggested alternative methods to improve the accuracy of diagnosis.