Introduction
The ability to use point of care ultrasound to detect pericardial effusions is an important skill for the acute care practitioner. In the trauma setting, the ability to rapidly identify a pericardial effusion as the cause of hemodynamic instability can focus early interventions and guide disposition decisions. Alternatively, in patients with non-traumatic chest pain or dyspnea, the ability to identify the presence or absence of a pericardial effusion can help to narrow the differential diagnosis.
POCUS allows physicians to make a rapid diagnosis of pericardial effusion in real time.
Why Ultrasound?
Currently, any urgent complete echocardiogram is done by cardiology. This can present logistical challenges; particularly after hours. POCUS is a simple and efficient way to identify a pericardial effusion, no matter the cause. It allows physicians to screen patients who would otherwise only be examined with poorly sensitive tools such as auscultation and chest radiography.
From a resource utilization perspective, this allows formal echocardiograms to be reserved for those with more complex medical needs, including congenital cardiac disease or high-risk clinical presentations. Ultrasound is low cost, portable and free of ionizing radiation. It is the diagnostic modality of choice for cardiac imaging given its ability to provide a real time look at the heart and its function [1]. Further, POCUS exams are easily repeatable and serial evaluation may be used as the patient’s status changes. This is an important consideration as the rate at which fluid may accumulate in the pericardium can vary [2]
Cardiac POCUS has been in use for many years in the emergency department. In 1988, Mayron et al found that 80% of emergency physicians felt comfortable diagnosing a pericardial effusion after only four hours of training [3]. Famously, a retrospective analysis of patients presenting to the emergency department with penetrating cardiac trauma had shown that the use of POCUS to identify pericardial effusion was associated with improved survival and time to diagnosis. In the study by Plummer et al., of 49 patients with pericardial effusions with equal predicted survival rates (according to TRISS methodology), 100% of those who had beside ultrasound survived, compared to only 57% of those who did not get bedside ultrasound [4]. In this study, it was felt that a main contributor to survival was the improved time to diagnosis. Specifically, POCUS allowed for time to diagnosis of 15.5 ± 11.4 minutes, whereas those without POCUS had an average time to diagnosis of 42.4 ± 21.7 minutes (p < 0.001) [4]. Further, many studies have looked at the sensitivity and specificity of emergency physicians in diagnosing pericardial effusions. These studies show a range of sensitivity from 83-100%, specificity of 98-99% and overall accuracy of 97.5-99% when compared to cardiologist readings [2,5,6]. Point of care ultrasound performs similarly in the hands of pediatric providers, with a sensitivity of 100% and a specificity of 99.5% for the detection of pericardial effusion in a pediatric emergency population [7].
- Sensitivity Range 83-100%
- Specificity Range 98-99%
- Accuracy Range 97.5-99%
Emergency Physician POCUS for Detection of Pericardial Effusion