Pneumothorax Trauma

• Pneumothorax is an abnormal accumulation of air in the pleural space that can occur secondary to blunt or penetrating trauma and can even occur spontaneously.
• This is one of the most common serious thoracic traumatic injuries.
• The presence of a pneumothorax will cause varying degrees of lung collapse on the involved hemi thorax and has the potential for interfering with adequate oxygenation and ventilation.
• An open pneumothorax, also know as a communicating pneumothorax, is caused by penetrating trauma that violates the integrity of the patients chest wall and the pleura causing air to directly enter the pleural space leading to lung collapse.
• A simple, closed or no communicating pneumothorax, which may occur secondary to blunt trauma presents with an intact chest wall.
• A tension pneumothorax occurs in the presence of a one-way tissue valve that can occur with a traumatic penetrating injury of the chest wall or lung parenchyma.
• During the process of respiration, air is forced into the pleural space but subsequently has no way to escape. As this process continues the intrapleural pressure on the involved side becomes progressively higher causing compression of the lung. The mediastinal structures are compressed and displaced to the opposite side of the patient’s chest. This mediastinal compression decreases venous return to the heart and subsequently cardiac output falls. The opposite lung also becomes partially compressed, further interfering with adequate oxygenation and ventilation. This situation can lead to rapid development of cardiopulmonary arrest if not identified and treated immediately.

Clinical Evaluation

• The patients clinical presentation may vary from asymptomatic to severe dyspnea depending on the amount of lung collapse or tissue injury.
• A decrease in breath sounds and hyper resonance to percussion on the involved side of the chest can be present.
• A tension pneumothorax presents with tracheal deviation, jugular venous distention, respiratory distress, tachycardia, hypotension, absence of breath sounds on the involved side of the chest, hyper resonance to percussion and cyanosis.
• All patients suspected of having any type of pneumothorax should be placed on supplemental oxygen, pulse oximetry, cardiac monitor and have a stat chest radiograph.
• Intravenous access should be obtained.

Treatment

• A tension pneumothorax should always be a clinical diagnosis as any delay in treatment can be life threatening. This includes any delay to obtain a chest radiograph.
• The initial treatment for a tension pneumothorax is to rapidly decompress the involved side of the chest by placing a 14 gauge angiocath in the second intercostals space in the midclavicular line.
• Successful placement is met with a rush of air from the needle with improvement in the patient’s symptoms.
• Subsequently, a thoracostomy tube (chest tube) should be placed and connected to a water seal system for definitive treatment.
• In the case of an open or communicating pneumothorax, initial treatment should be directed at placing a sterile occlusive type dressing over the tissue defect on the patient’s chest wall.
• This occlusive dressing should be taped down on only 3 of its 4 sides serving a valve like function allowing air to escape during the exhalation phase of respiration and preventing air from entering during inspiration.
• Subsequently, a thoracostomy tube should be placed along with surgical repair of the chest wall defect.
• A simple or noncommumicating pneumothorax is treated by thoracostomy tube in most cases.
• A small apical pneumothorax can be treated in some cases by hospitalization and subsequent observation without thoracostomy tube placement.

Hemothorax

• Hemothorax is an accumulation of blood in the pleural space.
• The traumatic event causes injury to the internal organs of the patient’s chest and /or injury to vascular structures in the chest wall leading to the accumulation of blood in the pleural space.
• Lacerations of the lung parenchyma represent the most common intrathoracic organ injury that serves as the source of the hemothorax.
• Chest wall injuries most frequently involve the intercostal blood vessels or internal mammary arteries and these often serve as a source of persistent bleeding.
• Varying degrees of hemorrhaging may occur, and if the size of the hemothorax is significant enough compromise of respiratory function may develop along with hypovolemic shock.
• Pneumothorax frequently occurs simultaneously with a hemothorax.

Clinical Evaluation

• The clinical presentation of the patient with an acute traumatic hemothorax is often directly related to its size.
• The patient may present with clinical evidence of hypovolemia.
• Signs and symptoms of respiratory distress may be seen such as dyspnea, tachypnea, cyanosis and the use of accessory muscles of respiration.
• There may be a decrease in breath sounds on the involved side of the thorax, along with dullness to percussion.
• In some cases a decrease in the patient’s oxygen saturation by pulse oximetry can be observed.
• The diagnosis will be verified by obtaining a chest film.
• It requires 200-300 ml of blood in an upright chest film to be able to visualize the presence of a hemothorax.
• In a supine film a much larger volume of blood is usually required for visualization of the hemothorax, often close to 1000 ml.
• A bedside hemacue should be performed to allow rapid evaluation of the patient’s hemoglobin level prior to the availability of the CBC results.

Treatment

• The presence of a small hemothorax may not require any specific treatment other than close observation.
• In most cases the presence of a significant hemothorax requires a thoracostomy tube (chest tube) be placed and connected to a water seal system for drainage.
• Approximately 5% or less of all patients presenting with a hemothorax require a thoracotomy for control of intrathoracic hemorrhage.
• Operative thoracotomy is indicated for persistant significant intrathoracic hemorrhage.
• The presence of 1500 ml of blood with the initial thoracostomy tube placement, or continuing blood loss at 200-300 ml per h, are indications for a thoracotomy.

Traumatic Asphyxia

• Traumatic asphyxia is a relatively rare injury that occurs secondary to a severe crush injury to the patient’s chest.
• Classically a purplish discoloration and/or petechiae are noted to the patient’s upper thorax, neck and facial area secondary to retrograde venous blood flow caused by compression of the superior vena cava.
• Facial edema and subconjunctival hemorrhages also can be observed.
• The amount of force applied to the chest places this patient at risk for many of the intrathoracic injuries
• discussed elsewhere in this section. These injuries when identified should be treated accordingly.
• A CT scan of the chest is routinely indicated to rule out intrathoracic injuries.
• A CT scan of the head is indicated in the presence of any neurological deficits although intracranial hemorrhage is a rare occurrence in these patients.
• Transient loss of consciousness may occur in up to 30% of patients.

Pericardial Tamponade

• The pericardial space is very small and is extremely limited in its capacity to accumulate fluid.
• Abnormal accumulation of fluid in the pericardial space leads to the restriction of proper function of both the atria and ventricles. As the myocardium begins to fill with blood it significantly increases intrapericardial pressure thereby compressing the heart which limits both atrial and ventricular filling. This compression subsequently leads to decreased cardiac output.
• A volume of 150 ml in the pericardial space can create a pericardial tamponade.
• Pericardial tamponade can be secondary to either blunt or penetrating trauma.

Clinical Evaluation

• Pericardial tamponade should always be considered in the differential diagnosis for any patient presenting with thoracic trauma especially penetrating trauma.
• Clinical manifestations of pericardial tamponade can best be described by Beck’s triad.
• This triad consists of hypotension, jugular venous distention (JVD) and muffled heart tones.
• Dyspnea and tachycardia are usually also present.
• Pulsus paradoxus can also be a manifestation of pericardial tamponade.
• Bedside ultrasound performed by the emergency physician is rapidly becoming a popular diagnostic tool for making a quick diagnosis.
• This ultrasound is normally performed as part of the routine trauma Fast Scan.
• A chest film should be obtained but is rarely diagnostic in the setting of an acute pericardial tamponade.
• It should be noted that tension pneumothorax presents with many of the same diagnostic features as pericardial tamponade and also occurs much more frequently.

Treatment

• Definitive treatment is an emergent thoracotomy. Evacuation of the constricting blood clot followed by repair of the underlying injury is necessary.
• Pericardiocentesis should be performed only as a temporizing measure until thoracotomy is performed.

Traumatic Aortic Injuries

• The most common cause of traumatic aortic injuries is sudden deceleration usually secondary to motor vehicle accidents or falls from a significant height.
• In many cases if the aorta is traumatically ruptured death occurs immediately at the scene.
• Those patients that survive to reach the emergency department have a chance for survival if the injury is rapidly identified and appropriate treatment is initiated.
• The location where these aortic injuries most commonly occur is in the descending aorta below the level of the left subclavian artery in the area of the ligamentum arteriosum.
• Many of those patients that survive the initial injury have partial tears of the wall of the aorta with only adventitia maintaining the integrity of the aortic wall.
• Blood in some cases can leak into the mediastinum forming a contained hematoma.
• Other serious intrathoracic injuries may occur simultaneously further complicating the patient’s management.

Clinical Evaluation

• The mechanism of injury with regards to a trauma patient should raise our suspicions about the presence of a possible aortic injury. This is especially true in the presence of a history of sudden severe decelerating forces.
• Specific clinical findings are often difficult to identify because of other associated thoracic injuries occurring at the same time.
• Hypertension can initially be seen in some cases of aortic injury because of activation of stretch receptors at the area of the aortic isthmus secondary to aortic wall stretching secondary to the sheering injury.
• The presence of hypotension is an ominous sign indicating some degree of aortic rupture with hemorrhage.
• The patient may complain of chest pain or intrascapular back pain.
• The patient may have a loud systolic murmer heard throughout the precordium.
• A decrease in lower extremity pulses such as the femoral can be noted along with ischemic pain to the extremities.
• Paraplegia and ischemic stroke can occur in some cases.
• Dyspnea, dysphagia, voice hoarseness and stridor may occur secondary to compression of other intrathoracic structures by the aorta or periaortic hematoma.
• Obtaining a stat portable chest radiograph is extremely valuable in helping to make the diagnosis.
• One of the most common findings suggestive of aortic injury is a widened mediastinum of >6 cm in an upright PA film and >8 cm ina supine AP film.
• Although there are many other traumatic and nontraumatic causes of mediastinal widening, given the correct history and mechanism of injury a high level of suspicion is warranted until traumatic aortic injury is ruled out by further radiological evaluation. Further radiographic findings are listed in Table 16.5.
• If further radiographic evaluation is needed, a spiral CT scan of the chest is the next appropriate step and has in many cases eliminated the need for aortography.
• Unfortunately, spiral CT scans may be difficult to obtain in the extremely unstable patient.
• One effective option for use in the unstable trauma patient that brings diagnostic capabilities to the patient’s bedside is the transesophageal echo (TEE).
• A TEE is performed at the bedside in a manner similar to an endoscopic procedure.
• The major contraindication to performing a TEE is the presence or suspicion of an esophageal injury.
• The patient will require intravenous sedation, which in selected patients may require associated endo tracheal intubation for airway protection.

  Table Chest radiographic findings associated with traumatic aortic injury

• Mediastinal widening-(most common finding)
• Deviation of the trachea to the right
• Obscured aortic knob/irregular aortic knob contour
• Depression of the left main stem bronchus
• Deviation of the nasogastric tube / esophagus to the right
• Mediastinal width/chest width ratio of greater than 0.25
• Hemothorax
• Left apical pleural cap
• Disappearance of the clear space between the aorta and pulmonary artery
• Right mainstem bronchus elevation
• Aortography is another option in the stable patient, but is being used with declining frequency since the spiral CT scan has become widely available.

Treatment

• Once the diagnosis is suspected or made of traumatic aortic injury immediate surgical consultation should be obtained.
• The patient should receive continuous cardiac, blood pressure and pulse oximetry monitoring.
• Two large bore intravenous accesses should be obtained should intravascular volume resuscitation be needed.
• The patient should be maintained on supplemental oxygen, and the airway and breathing should be managed as dictated by the individual clinical presentation.
• Routine lab work should be obtained along with serial hemoglobins.
• The patient should be typed and cross matched for multiple units (6) of PRBC should massive hemorrhage occur.
• Pending operative repair of a diagnosed aortic injury, the patients blood pressure should be controlled between 100-120 mm Hg systolic.
• By avoiding excessive blood pressure elevations, a decrease in shearing forces that are applied to the aorta during systole occurs.
• Pharmacologic agents that are useful for blood pressure control include intravenous
• labetalol and esmolol because of their ß-blocking properties.
• Beta-blockers further decrease the shearing forces on the damaged aortic wall.
• Surgical consultation is necessary for definitive management with admission being directly to the operating room or the SICU.

Esophageal Injuries

• The most common cause of esophageal injuries is penetrating trauma.
• The most common traumatic cause of penetrating esophageal injuries is iatrogenic secondary to various procedures such as endoscopy.
• Blunt trauma is a relatively rare cause of esophageal injuries. In blunt trauma patients the usual mechanism of injury is that the gastric contents are forced into the esophagus in an explosive manner secondary to a severe sudden force applied to the abdomen.
• The esophagus is located in the central mediastinum protecting it from an isolated injury. Esophageal injuries therefore usually occur with significant injuries to neighboring structures.
• Any delay in recognizing and treating traumatic esophageal injuries causes a significant increase in a patient’s morbidity and mortality.
• Injuries of other structures near the esophagus may cause the patient to present so dramatically that an esophageal injury can potentially be overlooked during the initial evaluation.

Clinical Evaluation

• Pain is present in virtually all cases of esophageal trauma.
• Many of the other clinical findings are nonspecific such as dyspnea, tachycardia, dysphagia, and odynophagia. Pneumothorax and pneumomediastinum may also occur.
• Subcutaneous emphysema may be noted on the upper chest and neck areas.
• Chest X-ray findings include: evidence of pneumothorax, left-sided pleural effusion, widening of the mediastinum and pneumomediastinum.
• A contrast esophagram using water soluble contrast such as Gastrografin is helpful in identifying esophageal injuries.
• Endoscopy is another diagnostic option in this situation and if available should be attempted first saving the esophagram to clarify equivocal findings noted on endoscopy.
• The use of CT scan in this situation is of limited diagnostic value usually only demonstrating indirect evidence in some cases of esophageal trauma. CT scan does however help evaluate other possible intrathoracic injuries that may have occurred simultaneously.

Treatment

• The treatment of patients with esophageal trauma involves appropriate airway management and volume resuscitation as needed.
• Evaluation for other injuries must be thorough and meticulous.
• Appropriate trauma laboratory evaluation should be obtained keeping in mind that there is in general no specific laboratory testing that identifies esophageal trauma.
• The presence of any associated pneumothorax or hemothorax should be treated in the usual manner.
• The patient must be kept NPO and prophylactic broad-spectrum antibiotic therapy should be initiated early.
• Emergent surgical consultation should be obtained and the patient admitted.