This epistle (it's good Friday) will consider blunt trauma to the torso. The trunk contains the cardiac, pulmonary, renal and gastrointestinal organs. It is also where the great vessels reside. The aorta and its main branches and the superior and inferior vena cava all are found in the trunk. Unlike our distant cousins such as turtles and armadillos, humans are poorly shielded from direct injuries. The rib cage offers little protection from baseball bats, falls or ejections from moving vehicles.
The main forces that lead to blunt trauma are deceleration and kinetic energy. Solid organs such as the liver, spleen, and kidneys tend to crack when they absorb enough energy (Louisville slugger to the belly or back). When the body is moving and stops abruptly (inertia again), the solid organs continue to move. If the deceleration forces are strong, the vascular attachments of the solid organs can be torn.
The lungs can suffer several types of injuries from blunt trauma. Increased pressure in the air filled lungs can cause them to "pop", or a broken rib can lacerate the lung. The result is the same, a pneumothorax. The lungs fill by the negative pressure from the contraction of the diaphragm and the other muscles of respiration. With the leaking of air from the lung into the chest cavity, the lung collapses like a deflated balloon. If air enters the chest cavity with a breath and can't exit, the pressure in the chest grows. This is known as a tension pneumothorax. If not treated rapidly, the ever increasing pressure will displace the heart, compress the intact lung, and obstruct the flow in the great vessels. The key is recognition by the EMS or ER personnel. A large needle is inserted through the chest wall, and a loud whoosh of escaping air is heard.
Tearing or shearing of large vessels in the chest can cause a hemothorax. As the chest fills with blood, the lungs are unable to inflate. A chest tube (or 2) is inserted to drain the blood and reestablish the negative pressure in the chest so that the lungs can expand.
The lungs can also be bruised by blunt trauma. A pulmonary contusion, with blood in the airsacs (alveoli), causes a loss of air exchange in the are of the contusion. The trachea, bronchi and pulmonary blood vessels are all vulnerable to deceleration forces and these injuries may prove fatal. We have all seen the ER doc on TV ask for a scalpel and rib spreader. An emergency thoracotomy is usually an exercise in frustration. Unlike the patient on TV, these patients infrequently survive, despite the heroic efforts of the trauma team.
Blunt trauma to the front of the chest can injure the heart. Commotio cordis is the medical term for sudden death from a blow to the anterior chest. The little leaguer who drops dead after being struck by a ball is a victim of this fatal disruption in the electrical activity of the heart. Portable defibrillators may decrease these tragic deaths from arrythmias. The heart can be bruised (cardiac contusion) from blunt force trauma to the chest. The injured heart muscle reacts similarly to a heart attack. Irregular rhythyms and impaired pumping by the heart can be dangerous.
The abdomen is often injured in blunt force trauma. The solid organs have some protection from the lower rib cage. The gas filled stomach and intestines may rupture from the sudden increased pressure in impact or deceleration events. The urine filled bladder is also prone to rupture. Tearing of vessels and intestines are common in high speed deceleration accidents. Stomach acid, digestive enzymes, urine, bacteria from fecal material and blood; that's the recipe for infections and sometimes late deaths from severe trauma.
CT scans and ultrasound along with careful history and physical examination are the tools of the trauma team. EKG, labs, and plain x-ray also are utilized. The "pan scan" is a CT that examines the patient from the top of the head to the base of the pelvis. It can be performed quite quickly and helps guide the trauma team to plan further testing or treatment. I would be remiss if I didn't point out that the radiation dose from a pan scan is estimated to increase the patient's lifetime risk of cancer by 1-2%.
Trauma centers have been established and certified by the American College of Surgeons. These hospitals are labelled level one to level three. I work at a level three regional trauma center. The ER docs are all certified in ATLS (advanced trauma life support). There is off-site surgical back up. My role is to rapidly diagnosis and treat or refer to a higher acuity trauma center. A level one trauma center is usually located in a large teaching hospital. All of the surgical subspecialties are available. Specialized ground and helicopter transport are utilized to get the trauma patient to the closest and most appropriate trauma center. EMS personnel are trained to provide triage. This assigns the injured patient a number corresponding to the severity of their injuries. In an accident that involves many victims, it is crucial that good triage maximizes the chances of survival for the injured.
Wear appropriate protective gear. Use your lap and shoulder belts. Drive sober and defensively.
For my young male friends, try and use the frontal lobes of your brain and ignore the testosterone infused urges of your pals.
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