What is Blunt Cardiac Contusion?
I’m Ed Smith, a Sacramento Car Crash Lawyer. A blunt cardiac injury or BCI is an injury to the cardiac tissue from a blunt trauma to the chest. It usually results from trauma in a motor vehicle accident in which the chest strikes the steering wheel or dashboard of the car. It can range from being a clinically silent injury with brief arrhythmias or a severe rupture of the cardiac wall, which is almost uniformly fatal.
Things to consider when dealing with a blunt cardiac contusion include the possibility of a severe and sustained cardiac arrhythmias, wall motion abnormalities of the heart, cardiogenic shock, and the possibility of rupture of the heart valves or any of the atrial or ventricular walls within the heart.
Blunt chest trauma not only affects the heart. It can cause a fracture of the sternum, fractured ribs, flail chest, blunt aortic injury or injury to lung tissue, including bruising of the lungs and lacerations of the lungs. The most lethal of these types of injuries is a blunt aortic injury in which the aorta is ruptured from the acceleration/deceleration of the chest during a sudden car accident.
Risk Factors for Blunt Cardiac Contusion
As mentioned, car crashes are the most common cause of major chest injuries and cardiac contusions. The major risk factors for these types of injuries include the following:
- Failure to wear a seat belt
- Having a car without an airbag
- Being in a high speed collision
- Having severe damage to the external aspect of the vehicle
- Having a deformity of the steering wheel from the crash
The highest risk of these types of injuries happens when multiple ribs are fractured, there is a higher injury severity score, and being of an advanced age.
Anatomy and Mechanism of Injury
The actual incidence of blunt cardiac injury is not known because some people have such mild injury that it is not reported or even noticed. Of those that are severe, there can be EKG findings showing a heart arrhythmia, bruising of the chest wall and a chest x-ray revealing damage to the sternum or to the ribs. In cases of cardiac rupture, there can be an x-ray finding of a widened mediastinum in the center of the chest from blood leaking out of the heart and into the pericardial sac that protects it.
Normally, the rib cage, the costal cartilage, sternum, and intercostal muscles protect the heart from sustaining an injury to the heart. There is a neurovascular bundle running beneath each rib that contains an intercostal artery, an intercostal vein, and an intercostal nerve. Beneath the ribs is a connective tissue layer known as the parietal pleura. It is affixed to the inside of the chest wall. There is also a visceral pleura, which mainly covers the surface of the lungs. Between the two layers is a fluid which allows for lubrication during inspiration and expiration.
Besides the ribs that surround the entire chest wall, there is the sternum and clavicle in the front of the body and the scapula in the back of the body. The scapula is a very dense and thick bone that takes a great deal of pressure before it can fracture.
The chest wall is important in two ways. It helps in the basic mechanics of the respiratory process and protects the organs inside the chest wall. The diaphragm and intercostal muscles contract to create a negative pressure inside the thoracic cavity so that the breath can be drawn in. When they relax, the negative pressure is released so that air is allowed to naturally leave the lungs. Muscles can be used to force air out of the lungs but this is not a normal part of respiration.
Chest Wall Injured First in Car Crashes
The chest wall is the first thing injured during the crash. This means that the ribs are fractured and the sternum can be cracked. It is rare to have a cardiac contusion without some injury to these bones. While injury to the chest wall muscles and bones is not usually life threatening, they can be very painful, which interferes with breathing and increases the risk of developing pneumonia.
Injuries to the mediastinum involve injuries to the trachea, esophagus, aorta, and heart. The mediastinum is a potential space that extends from the thoracic inlet at the top to the diaphragm at the bottom. Any one of these structures can be injured along with a cardiac contusion.
There are several forces that can be involved in blunt cardiac trauma, including the compression of the heart between the stern and the spine as well as shear forced during rapid deceleration and fluctuations in pressure in the abdomen and chest. There can be fragments from fractured ribs which can directly puncture the heart.
The part of the heart most commonly injured is the right heart. It is closest to the anterior chest wall and is therefore the nearest spot to be damaged. Other findings (usually found at autopsy) include ventricular rupture, tear in one of the valves, rupture of the valves, and laceration of the coronary artery.
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