Download How to diagnose Blunt Cardiac Injury?

How to diagnose Blunt Cardiac Injury?
Blunt cardiac injury (BCI) covers a large spectrum of injuries resulting from trauma to
the chest wall. BCI is usually the result of a high speed collision causing compression of the
heart between sternum and spine, but it can also be caused by rapid acceleration or deceleration
without direct trauma. Injuries can range from mild cardiac contusions which are the most
common injury to arrhythmias to rupture of the chambers of the heart with resulting tamponade.
Given the wide range of injuries that can be caused from a large variety of mechanisms, it
will be important to screen appropriate patients for significant disease. Patients should be
screened if they were involved in a high speed accident, had a fall from a significant height, were
a pedestrian struck by a car or had a sports collision who are complaining of chest pain or have
chest wall tenderness. Other findings that may be associated with BCI are flail chest, chest wall
bruising, and distended neck veins. Additionally, for any trauma patient who fails to respond to
appropriate resuscitation without a clear source of bleeding, BCI should be considered as a
possible cause for hemodynamic instability. While there is no clear gold standard on how to
diagnose BCI, there are some useful tests that can be employed to safely rule out BCI in
suspected patients.
EKG
The EKG remains the best test for screening BCI and it should be the first thing ordered
when suspecting BCI. The most common finding following blunt cardiac injury is non-specific
ST-T wave changes. A RBBB which can be seen in up to 9% of cases is the second most
common pattern. Other arrhythmias such as VF, atrial fibrillation, and heart blocks are possible
but much rarer. Most patients who go into VF from trauma die on scene. If there are new
findings on the EKG, the patient should be admitted for monitoring and further workup.
Multiple studies have looked into the sensitivity and specificity of EKGs for cardiac injury. In a
prospective study by Salim1, a normal EKG alone had a 95% negative predictive value. This is
tempered by other studies which have found EKGs to be less sensitive in identifying patients
with BCI. In a study by Garcia-Fernandez2, only 59% of patients with findings on TEE had an
abnormal EKG. So while an EKG is a good place to start, it is not enough by itself to rule out all
patients.
Cardiac Enzymes
1
Velmahos G, Karaiskakis M, Salim A, et al. Normal electrocardiography and serum troponin I levels preclude the presence of clinically
significant blunt cardiac injury. J Trauma. 2003;54:45Y51.
2
Garcia-Fernandez M, Lopez-Perez J, Perez-Castellano N, et al. Role of transesophageal echocardiography in the assessment of patients
withblunt chest trauma: correlation of echocardiographic findings with the electrocardiogram and creatine kinase monoclonal antibody
measurements. Am Heart J. 1998;135:476Y481.
CK and CK-MB have no role in the screening of patients for BCI. Multiple studies have
shown poor specificity and poor predictive value likely due to it being found in skeletal muscle,
lung, liver and other parts of the body. Its use is currently not recommended3.
Troponin as a test by itself is not enough to safely rule out blunt cardiac injury. In a
prospective study by Velmahos4, a normal EKG when combined with a normal troponin had a
NPV of 100%. Of note in this study, troponins were spaced 8 hours apart. The exact timing of
troponins has not yet been established. When both are negative and the patient has no other
reason for a hospital admission, these patients can be safely discharged home.
Imaging
Radiographs are part of the ATLS approach to the trauma patient. X-Rays can be helpful
in detecting other injuries which are associated with BCI such as rib fractures, pulmonary
contusions, pneumothorax, or flail chest.5
Ultrasound is also part of ATLS and is very useful in identifying pericardial effusions and
cardiac tamponade. TTE and TEE have also been shown to have a role in identifying additional
injuries in blunt trauma such as cardiac contusion. Findings seen are typically wall motion
abnormalities, increased end diastolic wall thickness in the injured section, and increased
brightness.6 The limitations with ultrasound are that it is operator dependent and TEE might not
be possible if there are head or neck injuries.
CT has become more integral in the workup of trauma and has become more reliable in
looking for BCI given the advances in multidetector CT and increases in resolution. CT is able
to pick up small pericardial effusions, tears, and other injuries that it was unable to do in the past.
In the future, it might be possible to successfully differentiate acute myocardial infarction from
BCI which could help guide treatment in certain cases.7
In conclusion, attempting to diagnose blunt cardiac injury can be challenging given the
wide spectrum of disease and the lack of a clear consensus on how to do it. The best evidence is
often in the form of prospective and retrospective studies and guidelines are based on that. The
multi-trauma patients are going to be approached through ATLS management. If BCI is
3
Clancy K, Velopulos C, Bilaniuk J, Collier B, Crowley W, Kurek S, Lui F, Nayduch D, Sangosanya A, Tucker B, and Haut E. Screening for
blunt cardiac injury: an Eastern Association for the Surgery of Trauma practice management guideline. J Trauma 73:(5) Supplement 4, S301S306, 2012.
4
Salim A, Velmahos G, Jindal A, et al. Clinically significant blunt cardiac trauma: role of serum troponin levels combined with
electrocardiographic findings. J Trauma. 2001;50:237Y243.
5
6
7
Schultz J, Trunkey D. Blunt Cardiac Injury. Crit Care Clin 20 (2004) 57-70.
Bock J, Benitez, M. Blunt Cardiac Injury. Emergency Cardiac Care 2012: From the ED to the CCU. Volume 30, issue 4: Nov 2012, 545-555.
Clancy K, Velopulos C, Bilaniuk J, Collier B, Crowley W, Kurek S, Lui F, Nayduch D, Sangosanya A, Tucker B, and Haut E. Screening for
blunt cardiac injury: an Eastern Association for the Surgery of Trauma practice management guideline. J Trauma 73:(5) Supplement 4, S301S306, 2012.
suspected based on history and physical, an EKG and troponin should be obtained and are a good
starting point. If both are negative, significant cardiac injury has been excluded in a
hemodynamically stable patient and these patients can go home if there is nothing else
precluding a safe discharge. Patients suspected to have blunt cardiac injury with an abnormal
EKG or positive troponin or who are unstable should be admitted to a monitored setting where
further workup can involve a CT or ultrasound.
References
1. Velmahos G, Karaiskakis M, Salim A, et al. Normal electrocardiography and serum troponin I
levels preclude the presence of clinically significant blunt cardiac injury. J Trauma.
2003;54:45Y51.
2. Salim A, Velmahos G, Jindal A, et al. Clinically significant blunt cardiac trauma: role of
serum troponin levels combined with electrocardiographic findings. J Trauma.
2001;50:237Y243.
3. Bock J, Benitez, M. Blunt Cardiac Injury. Emergency Cardiac Care 2012: From the ED to
the CCU. Volume 30, issue 4: Nov 2012, 545-555.
4. Garcia-Fernandez M, Lopez-Perez J, Perez-Castellano N, et al. Role of transesophageal
echocardiography in the assessment of patients with blunt chest trauma: correlation of
echocardiographic findings with the electrocardiogram and creatine kinase monoclonal antibody
measurements. Am Heart J. 1998;135:476Y481.
5. Clancy K, Velopulos C, Bilaniuk J, Collier B, Crowley W, Kurek S, Lui F, Nayduch D,
Sangosanya A, Tucker B, and Haut E. Screening for blunt cardiac injury: an Eastern Association
for the Surgery of Trauma practice management guideline. J Trauma 73:(5) Supplement 4, S301S306, 2012.
6. Schultz J, Trunkey D. Blunt Cardiac Injury. Crit Care Clin 20 (2004) 57-70.