With the relatively flexible rib cage surrounding the vital structures of the heart and lungs, the paramedic needs to maintain a high index of suspicion when presented with any trauma involving the chest. An intact rib cage does not always mean that the heart and lungs have avoided injury. Chest injuries can lead to profound respiratory and cardiovascular compromise. This section will discuss the injuries to the chest and treatments the paramedic will need to initiate.
The chest is surrounded and protected by the rib cage and sternum. The 12 pairs of ribs can be classified as either true ribs, false ribs, or floating ribs. All ribs articulate posteriorly with a thoracic vertebra. The true ribs are the first 7 pairs of ribs and connect to the sternum anteriorly. False ribs consist of the lower 5 pairs of ribs and have no direct connection to the sternum. They either connect through merging with other ribs or do not connect at all. The lowest 2 pairs of ribs have no anterior connection to the sternum and are called floating ribs. The area of the ribs closest to the sternum is made of cartilage in younger populations to allow for greater flexibility and resiliency.
The area between each rib is called the intercostal space and is numbered based on the number of the rib superior to it. Within this space are the intercostal muscles, which are responsible for raising and lowering the rib cage during respiration. Just to the inferior side of each rib is the neurovascular bundle, which contains the artery, vein, and nerves for that area.
The sternum or breastbone can be divided into 3 regions. The superior portion is called the manubrium. The center portion is known as the body of the sternum. The manubrium connects to the body of the sternum at an angle known as the angle of Louis. Finally, the most inferior part is called the xiphoid process.
The posterior chest also has ribs, but has the thoracic vertebrae at the midline. The scapula is located over the upper third of the posterior back and makes up the posterior point of articulation of the humerus in the shoulder. The clavicle joins here as well to make up the acromioclavicular joint.
Within the rib cage lie the heart, lungs, esophagus, and great vessels. The mediastinum lies on the midline and contains the esophagus, trachea and bronchi, and heart and great vessels. Lateral to the mediastinum are the lungs, 3 lobes on the right and 2 on the left. The lungs are surrounded by 2 layers of tough connective tissue called pleura. The layer closest to the lung is called the visceral pleura, and the layer closest to the chest wall is called the parietal pleura. In between the layers is a serous fluid that lubricates the pleura, allowing the lungs to slide smoothly during inhalation and exhalation. The heart is surrounded by 2 layers of fibrous tissue as well. The inner layer is called the epicardium, and the outer layer is the parietal layer and is called the pericardial sac. Its purpose is to protect itself and the surrounding structures from the constant motion of the heart.
The inferior border of the thorax is the diaphragm, which can be as high as the 5th rib during exhalation. It can then descend to cause inhalation and recede well inferior to the xiphoid.
Patients do not often suffer just a single injury to the chest when they are injured. If a patient has a rib fracture, he or she also may have a pneumothorax underlying the fracture. Chest bruising can lead to a cardiac contusion or a pulmonary contusion. For purposes of this text, isolated injuries will be described; however, the paramedic needs to know that more injuries than just those that can be seen or felt may exist. A thorough assessment of the chest will be necessary to effectively treat all the injuries the patient may have. It was mentioned at the opening to this section and is reiterated here: Maintain a high index of suspicion with any patient who has sustained a chest injury or has sustained a significant mechanism of injury.
Rib fractures are the result of blunt trauma to the chest. Occasionally, people have been known to fracture ribs during a particularly forceful cough or sneeze. Rib fractures are extremely painful for the patient, even when there are no underlying injuries. Patients with a rib fracture will often self-splint to minimize the movement of the fractured bone ends against each other. They will complain of sharp, constant pain that came on suddenly and does not radiate. The pain also will worsen during inspiration or movement. Crepitus may be palpated in the area of the fracture as a result of the pressure exerted during palpation and from the act of breathing.
Sternal fractures require a much more significant amount of force. Consequently, this fracture is associated with a high incidence of underlying injuries. The heart or lungs often are bruised in addition to the fracture. If they are still conscious, patients will complain of excruciating midline chest pain as a result of the traumatic event. Patients also will have bruising and crepitus in the area of the fracture.
Treatment of rib and sternal fractures is similar and primarily directed at splinting the fracture. The best way to accomplish this is with a pillow held in place with a couple of triangular bandages. This will minimize the movement of the bone ends, thereby alleviating pain. Because the pain often leads to reduced tidal volume on the part of the patient, administer O2 to help the patient breathe easier and prepare to treat for shock. With these injuries, be alert for the possibility of more insidious life-threatening conditions, including a cardiac contusion, cardiac tamponade, a pulmonary contusion, and pneumothorax.
A flail chest occurs when 2 or more consecutive ribs are broken in 2 or more places. This is a significant injury and very often is complicated by an underlying pneumothorax or a pulmonary contusion. It is possible to have an entire side of the rib cage flail or have the sternum flail as well.
Because the flail segment now moves independent of the rest of the rib cage, the physics of breathing is materially impacted. Remember that normal ventilation is caused by the ribs and diaphragm being able to create a negative pressure within the thorax, thus allowing atmospheric air to rush in. Similarly, during exhalation, the diaphragm relaxes, creating a higher pressure in the chest cavity than outside the body, allowing air to be pushed out. During inhalation, the flail segment also moves into the chest cavity and pushes out during exhalation. This is called paradoxical motion. This increases the amount of pain the patient is experiencing and increases the risk for a punctured lung and resulting pneumothorax, if one was not already there.
To go along with the paradoxical motion, a patient will obviously complain of shortness of breath and chest pain. There may be bruising over the flail segment. A finding of diminished or absent breath sounds on the side of the flail segment is suggestive of a pneumothorax. Be alert for other signs of pneumothorax.
Treatment for the flail segment begins by stabilizing and splinting the segment in a similar manner as for rib fractures. The patient will need supplemental O2 and may benefit from positive pressure ventilation. Intubation should be considered, especially if the patient lacks a gag reflex and is unable to protect his or her airway. If present, treat the pneumothorax. The patient also should have at least a large-bore intravenous line initiated and run wide. Monitor the heart rhythm throughout contact and treat any dysrhythmias as they present.
A pneumothorax results from a punctured lung that allows air to escape into the potential space between the visceral and parietal pleura. In a simple pneumothorax, air accumulates in this space but does not develop enough pressure or flow out of the lung fast enough to build pressure and become a tension pneumothorax. In a tension pneumothorax, the pressure in the pleural space builds to the point that the injured lung becomes compressed or collapses. As the lung collapses and air pressure and volume increase on the affected side, the pressure can force the mediastinum and its contents toward the unaffected side.
A pneumothorax also may develop as a result of a penetrating wound to the chest wall. This new hole in the chest wall will allow air in on inhalation and may or may not allow the air out on exhalation. This is known as a sucking chest wound. If this new hole is greater than 2/3 the area of the trachea, air will preferentially enter the chest wall hole over the trachea. The larger this hole, the more quickly the lung will collapse and the more rapid the decline of the patient’s status. Even though air may exit the hole on exhalation, some will remain in and build up over time with each successive breath.
The following findings are suggestive of a pneumothorax:
Treatment for a pneumothorax begins with cardiac monitoring, the establishment of at least 1 large-bore intravenous line, and the provision of high-flow supplemental O2. If the patient is not breathing or is breathing inadequately, positive pressure ventilation should be initiated. Intubation should be considered if it is expected that the patient will require extended periods of ventilation. Definitive treatment for a pneumothorax is placement of a chest tube in the hospital, but for EMS, interim definitive treatment is needle thoracostomy. A needle thoracostomy allows the air to escape from the intrapleural space giving the lung a chance to re-expand. This often immediately relieves difficulty breathing in the spontaneously breathing patient or makes positive pressure ventilation easier.
If the patient presents with most of the signs and symptoms listed above, follow these steps to perform a needle thoracostomy. Although this procedure is not usually necessary for a simple pneumothorax, it may need to be performed on a person with an open pneumothorax.
Some texts recommend using a makeshift flutter valve. They suggest cutting the finger off a medical glove and inserting the catheter through the fingertip of the glove before inserting the needle into the chest. Other texts identify that in the short period of time this will be in place, it is not likely to provide much added benefit when weighed against the benefit provided by getting the needle into the chest in a more timely fashion. Follow local protocols.
The presence of blood in the intrapleural space can have the same effect as air, given enough time to accumulate, and blood flow. The sign and symptoms of a hemothorax are similar to those of a pneumothorax but with a couple exceptions. Instead of being hyperresonant to percussion, a hemothorax is said to be dull to percussion. Also, JVD may or may not be present depending on how much blood has been lost to the pleural cavity. Finally, the patient will present with worsened tachycardia and hypotension as a result of the blood loss. Treatment is the same overall for the patient with the hemothorax, with added emphasis on fluid resuscitation. The patient should receive at least a liter of fluid during transport, and efforts should be taken to maintain the blood pressure after the needle thoracostomy is performed.
Rarely is it just 1 or the other—blood or air—present in the pleural space after chest trauma. Often both are present simultaneously. This is called a hemopneumothorax. It is treated the same way as either a hemothorax or a pneumothorax.
A pulmonary contusion is a bruise to the lung tissue. Within the first 24 hours or so, patients may not have any complaints related to the bruising of their lung, and the biggest sign may be a ventilation perfusion mismatch and some mild chest pain that worsens with inhalation. A ventilation perfusion mismatch is essentially where it appears that the patient is breathing adequately. In other words, tidal volume is appropriate, and the mechanics of breathing are within normal limits. However, the pulse oximetry reading is lower than would otherwise be expected given a normal ventilatory status. An area of the lung is no longer able to transfer O2 into the blood because of broken capillaries. Over time, this area also swells, leading to atelectasis, which can further complicate the respiratory status.
Treatment for a pulmonary contusion is largely related to increasing the FiO2. Administer high-flow O2 to the patient. Positive pressure ventilation is recommended if the patient’s respiratory status is declining. Establish an intravenous line for access, but fluid administration should be limited because it may worsen the pulmonary edema already beginning. Fluid should be administered to maintain cardiac output and improve a falling blood pressure.
Also known as pericardial tamponade, cardiac tamponade is a condition where fluid or blood accumulates within the pericardial sac surrounding the heart. Similar to what a pneumothorax does to a lung, as pressure builds up from blood in the sac, the heart begins to get compressed. Blood can accumulate slowly or rapidly depending on the source of the bleeding. As compression of the heart begins, the following signs and symptoms will become apparent.
The presence of hypotension, JVD, and muffled heart tones is collectively referred to as the Beck triad.
Treatment for cardiac tamponade includes monitoring the cardiac rhythm and treating any dysrhythmias found. Prepare for cardiac arrest, with the most likely presenting rhythm being some form of pulseless electrical activity. Initiate at least 1 large-bore intravenous line and run fluid wide to try and increase preload. Definitive care for pericardial tamponade is a procedure called pericardiocentesis, which EMS is not able to be perform. In pericardiocentesis, a needle is inserted into the pericardium, and the blood is drawn off, allowing the heart to expand and beat normally. Rapid transport to a trauma facility capable of rapid surgical intervention is necessary.
A bruise to the heart muscle can occur as a result of the rapid deceleration of the chest wall leading the heart to collide with the chest wall. This results in hemorrhage and swelling of the myocardium and can lead to electrical dysrhythmias. Anytime the cells of the heart become irritated, whether from hypoxia or structural damage—both of which are possible in a myocardial contusion—electrical disturbances are to be expected. The disturbance can be as mild as occasional ectopic beats or as lethal as VT or VF. It is essential to diligently monitor the cardiac rhythm and perform serial 12-lead ECGs on a person with this condition.
As a result of the bruising and the swelling in an area of the heart, the mechanics of the heart may be affected as well. Bleeding and edema will interfere with the full contraction of the myocytes in the area of the bruise, which can lead to decreased cardiac output. Hypotension can result from myocardial contusion.
Treatment for this condition, in addition to careful monitoring of the electrical activity of the heart includes establishing an intravenous line and providing enough fluid to maintain blood pressure. Excessive fluid may negatively impact cardiac output because the heart is not able to squeeze as hard as under normal conditions. This also can lead to pulmonary edema.
Medically, myocardial rupture is seen in a person who has had a heart attack that results in a large area of necrotic heart muscle. Such a person likely has had poorly controlled high blood pressure. The result is the necrotic area fails, and the structure of the heart is lost. Death almost always follows. The extreme forces and pressures that can occur during a traumatic event may lead to myocardial rupture, where the wall of the heart fails. Most often, this patient does not survive the event, but if he or she does, rapid transport to the nearest trauma center is required. Treatment for the patient with myocardial rupture is supportive and includes cardiac monitoring, at least 1 intravenous line, supplemental O2, ventilation, and CPR as needed.
Recall from chapter 4 that the T wave of the ECG has absolute and relative refractory periods. This means that during the absolute refractory period, no energetic impulse can cause the ventricles to depolarize. During the relative refractory period, represented on the ECG as the downslope of the T wave, at least 1 myocyte has been fully repolarized and is capable of depolarizing again and either starting or propagating another heartbeat. If that myocyte receives a sufficiently energetic impulse, it will be depolarized, causing a new wave of depolarization to be spread to the surrounding cells.
Now the heart is in an electrically confused state, where some of the cells are depolarized or actively depolarizing and others are still becoming repolarized. This results in chaotic and disorganized electrical activity in the ventricles, which often will lead to VF or VT and sudden cardiac arrest.
In commotio cordis, a direct blow to the chest, perhaps by a struck baseball or a well-timed punch, can provide this sufficiently energetic impulse. This is most likely to happen in children and teenagers because their chest wall is still pliable, which leads to the energy being easily transmitted to the heart. Electrical disturbances are likely, even in the conscious patient. Electrical defibrillation is the definitive treatment for the unconscious patient in VF or VT and should be performed as quickly as possible. Continue treatment for patients in cardiac arrest as per normal. Early CPR and early defibrillation represent the best chance of survival for this patient.
Traumatic aortic disruption is arguably the most severe of all the deceleration injuries described here. In this situation, the body stops moving suddenly from a relatively high speed, such as might be achieved during highway driving. After the body stops moving, however, the heart continues its forward momentum and swings on the aorta, which is securely attached to the posterior chest wall. With sufficient speed, the aorta wall fails and tears. With a large enough tear, the patient will bleed out into the chest cavity within 1 or 2 minutes of the collision.
Treatment for this patient is largely supportive. Only very few patients with this condition survive until EMS arrives and even fewer survive to arrive at the hospital. Maintenance of blood pressure, provision of an airway and O2, and CPR if needed are the mainstays of treatment for this patient.
Diaphragmatic rupture can occur as a result of penetrating trauma that lacerates the diaphragm or as a result of a sudden and massive increase of intra-abdominal pressure, such as might occur in a person who gets run over by a car or who has something heavy fall on top of him or her. This condition can be complicated when the abdominal contents herniate into the chest cavity. If the abdominal contents herniate into the chest, bowel sounds may be present in the chest. Patients may complain of difficulty breathing as a result of becoming reliant on the intercostal muscles for all respirations. With the diaphragm ruptured, it can no longer contract in a coordinated way to allow for normal breathing physiology. Patients also may have considerable injuries to the abdominal contents, particularly the spleen, liver, and stomach, because these organs lie just inferior to the diaphragm.
Treatment for diaphragmatic rupture begins with assisting the patient’s breathing as needed and providing supplemental O2. Because the lungs rest on the diaphragm posteriorly, remain alert for the development of a pneumothorax and, if found, treat accordingly. Patients with this injury also are likely to be profoundly hypotensive that may result from bleeding from the liver and spleen. Establish 1 or 2 large-bore intravenous lines and run fluid wide to treat for shock. Control any external bleeding that may be present but do not pack any stab or gunshot wounds.
Tracheobronchial injuries are rare and can be caused most commonly by penetrating trauma but also secondary to rib fractures or CPR. These injuries carry a high likelihood of death because of airway obstructions, bleeding into the lower airways, and the patient’s inability to ventilate the alveoli. Air will escape the laceration and can lead to a pneumothorax if it is located in 1 of the bronchi. It also could lead to a pneumomediastinum if the laceration is in the proximal bronchi or trachea.
The location of the injury plays a big role in the mortality of the patient. If the injury is located in the superior portion of the trachea, an ETT may be able to be placed past the laceration, allowing the patient to possibly breathe on his or her own or be able to be successfully ventilated. If the laceration is in the bronchi or distal trachea where an ETT cannot bypass it, positive pressure ventilation can be disastrous, resulting in inflation of the entire mediastinum all the way into the face. In this case, if the patient is breathing, positive pressure ventilation should be avoided.
Traumatic asphyxia results when the patient’s chest is compressed between 2 objects. The compression forces blood in the chest into the nearby veins and arteries of the head, neck, liver, and kidneys, causing them to rupture. This also can cause ocular and subconjunctival hemorrhage and exophthalmos (protrusion of the eyeballs). This often is a fatal injury. However, in the event that the patient survives the compressive force, assess and treat any life-threatening conditions found, including cardiac rhythm disturbances, pneumothoraces, and other injuries. Anticipate hypotension if not already present. Treatment should include large-bore intravenous lines, supplemental O2, and positive pressure ventilation. Intubation often is required.