Although a mainstay in trauma imaging for more than two decades, the cardiac portion of focused assessment with sonography in trauma (FAST) is likely unwarranted in blunt trauma due to the extremely low prevalence of hemopericardium among these patients, according to a study in this month's issue of The Journal of Emergency Medicine. The authors recommended selective use of echo guided by high-acuity variables.
FAST pairs abdominal and cardiac imaging to diagnose blood in the peritoneal and pericardial spaces. However, observation suggests that prevalence of hemopericardium in blunt trauma is rare. In addition, the abdominal and cardiac portions of the exam are discrete billing exams, thus medical necessity must be established for each indication.
Gregory M. Press, MD, from the University of Texas at Houston Medical School, and colleagues sought to estimate the prevalence of hemopericardium in blunt trauma and to determine the sensitivity of certain variables for blunt hemopericardium.
The researchers conducted a retrospective chart review of 29,236 blunt trauma patients from January 1, 2001, to June 6, 2007, and reviewed the emergency ultrasound database to estimate the prevalence of cardiac ultrasounds positive for pericardial fluid as a result of blunt trauma from July 1, 2004, to July 1, 2007.
Press et al reported the records of 401 patients wounded by blunt mechanism contained an ICD-9 code that might suggest hemopericardium as a result of blunt trauma. Among this group, 14 patients had acute hemopericardium, and four had cardiac rupture, which translated into a prevalence of 0.06 percent. None of these patients presented without one of the following findings: major mechanism of injury, hypotension or emergent intubation.
“Based on this prevalence, more than 1,600 patients would have to undergo echocardiography to diagnose one with blunt hemopericardium or cardiac rupture,” wrote Press and colleagues.
The review of 777 cardiac ultrasound exams in the emergency ultrasound database revealed the prevalence of incidental or insignificant effusions was 0.13 percent. These findings present a management dilemma, according to the researchers. Patients may be referred for a conservative management strategy of repeat ultrasound and observation or emergent thoracotomy.
“Bedside ultrasound has revolutionized acute trauma care, but a reconsideration of the iconic FAST may be warranted … Scanning the abdomen should not obligate the physician to perform echocardiography when there is not clinical suspicion for hemopericardium,” wrote the researchers, who recommended selective performance of echocardiography guided by high-acuity variables: a major mechanism of injury, hypotension or emergent intubation.