Immediately life threatening injuries

Pathophysiology and early management

Immediately life threatening injuries from thoracic trauma that require immediate interventions are noted below. Interventions to treat these conditions should be familiar to anyone involved in trauma management. These injuries should be identified and treatment initiated during the primary survey. In smaller facilities ARV can assist with identifying injuries and treatment options.

Tension pneumothorax

Tension pneumothorax occurs when injury to pleural parenchyma creates a one-way valve defect allowing air to enter the pleural space but not leave, resulting in increasing pressure within the pleural cavity. This rise in intra-thoracic pressure impedes ventilation, while the collapsed lung impairs gas exchange, both resulting in tachypnoea and hypoxia. Raised intra-thoracic pressure also impedes venous return both from the IVC and SVC, as well as increasing afterload on the heart. Obstructive shock soon develops.  
The common symptoms and signs of tension pneumothorax include:
  • Respiratory distress.
  • Agitation with tachypnoea.
  • Hypoxia.
  • Tachycardia.
  • Hypotension.
  • Decreased or absent breath sounds on the affected side.
  • Hyper-expansion.
  • Decreased movement of the affected hemi-thorax.
  • Subcutaneous emphysema.
     
    Distended neck veins may be noted if the patient is not hypovolemic, however examination is usually limited by the cervical collar. Tracheal deviation is a late sign. A patient may be experiencing significant inflow obstruction to the right heart, compounded by hypovolemia before there is noticeable tracheal deviation.  Tension pneumothorax may result from blunt or penetrating chest trauma.
Management: If tension pneumothorax is suspected, or cannot be excluded in the hypotensive multi-trauma patient who is not responding to volume resuscitation, then chest decompression must be performed without delay.Chest decompression in the field (Needle decompression & Finger thoracostomy)

Needle decompression is performed preferably at the 5th intercostal space, mid axillary line (with the arm in the abducted position)3. This location may not be easily accessible, and in such circumstances the 2nd intercostal space, mid axillary line is used. A large bore IV Cannula (14 or 16G) with a 10ml syringe attached is inserted, and air is drawn. Alternatively a pneumocath can be used. Needle decompression will allow time to transport the patient to a medical facility for definitive decompression and intercostal catheter insertion. Potential pitfalls of needle decompression include kinking of the tube or malpositioning.
Unlike needle decompression, finger thoracostomy allows for maximum release of air and liquid from the pleural cavity. It may be appropriate to proceed to finger thoracostomy in the field, particularly if evacuation is to be delayed. Finger thoracostomy is an invasive procedure, so every effort should be made to perform this under aseptic conditions. The patient’s arm is fully abducted and the skin is prepared with aseptic skin prep. An incision is made through skin, dermis and fascia at the fourth or fifth intercostal space, just anterior to the mid axillary line. (Prior infiltration of local anaesthetic is required if the patient is conscious). The intercostal space is then traversed using a curved forceps via blunt dissection and decompression through the pleura, completed with a sweep with a sterile gloved finger.6 The site is then covered with a three way dressing, or a valve-bag. Re-sweeping of the site can also be performed if the patient deteriorates.7

Chest decompression in the emergency department

If the patient is conscious, and equipment for finger thoracostomy is not immediately at hand, then a needle decompression should be performed at the 5th intercostal space, mid axillary line3. This will relieve the intra-thoracic pressure to allow time for formal decompression and insertion of an intercostal catheter (ICC), which should be performed immediately after the needle decompression.
For patients who are either unconscious, or who are in extremis and equipment and clinician is ready, then finger thoracostomy is the treatment of choice for tension pneumothorax. Finger thoracostomy is an invasive procedure, so every effort should be made to perform this under aseptic conditions. This includes full surgical scrub as well as face masks, gowns and sterile gloves when performed in the emergency department. The patient’s arm is fully abducted, skin is prepared with aseptic skin prep from midline to bed, and axilla to costal margin. The area is draped on all four sides. The procedure is then performed, as described above. In most emergency departments, finger thoracostomy can be performed just as quickly as needle decompression which only has a 42.5% success rate.8
The sterile insertion of an intercostal catheter connected to an underwater seal drain should then immediately follow finger thoracostomy.

Massive Haemothorax

Accumulation of blood and fluid in the hemi thorax prevents adequate ventilation and compresses the lung, especially when there is >1500mls or 1/3 the patients’ blood volume in the chest cavity. It most commonly occurs after penetrating trauma but can also be present in blunt trauma. Bleeding can be due to injury from the lungs, major vessels, intercostal vessels or the heart. These large accumulations of blood lead to respiratory failure, hypotension and shock.  
Management: Initial management involves the restoration of circulating blood volume and the insertion of a chest drain. Large bore IV cannulas or intraosseous access if unable should obtained and volume resuscitation commenced. Damage control resuscitation techniques should be employed until there is definitive control of bleeding. This involves minimal (if any) use of crystalloid, early use of blood products and the rate of infusion being titrated to an adequate (though not normal) systolic blood pressure. The insertion of an intercostal catheter will allow for accurate measurement of blood loss, as well as some tamponade effect when allowing the lung to re-expand against the chest wall. This will have some effect on intercostal bleeding and parenchymal bleeding. Where >1,500ml is drained, thoracotomy is likely required. Activate the massive transfusion protocol as the patient is likely to require large amounts of blood to restore perfusion.
 
Chest Tube Insertion
Re-expanding the lung may tamponade any bleeding vessels, as well as draining a pneumothorax. Insertion site is as described for finger thoracotomy. Once the chest is decompressed via finger thoracostomy under aseptic technique, an ICC is inserted, and is directed posterior and apical. Tube size is important and should be a large bore (28-32Fr) ­­­­­­­­­­­­­­­­­­­­­­­­­ in order to facilitate rapid drainage, prevent air leaks and to allow large blood clots to be removed. Once advanced, ensure fogging of the tube with expiration and suture in place. Placement should be confirmed with CXR. Auto transfusion could be considered in some circumstances if capabilities exist.
 

Cardiac Tamponade

Cardiac tamponade occurs when blood, fluid or air enters the pericardium, restricting cardiac activity and interfering with filling. It primarily results from penetrating trauma however is also possible in cases of severe blunt chest trauma that results in right heart injury. The symptoms and signs evolve and may develop within minutes, or less commonly over the better part of an hour. The classic presentation of Becks Triad (hypotension, raised JVP, muffled heart sounds) may be difficult to identify in the ED, particularly where noise makes muffled heart sounds difficult to hear, or in the setting of hypovolaemia where a raised JVP may not be present.  What is often seen is the plethoric face and neck that results from inflow obstruction. This tends to be more pronounced than when seen in tension pneumothorax, and is a distinctive sign.

Management: The definitive management of pericardial tamponade involves decompression of the pericardial sac and repair of the myocardial defect. The technique used is dependent on the patient’s physiology and resources available. Permissive hypotension and minimal volume resuscitation should be employed until decompression is achieved.
If the patient is in shock, and a surgeon is available, the patient should undergo a resuscitative thoracotomy. Preferably this should be in theatre (operative thoracotomy) if time allows, however if the patient loses output it will need to be performed in the emergency department.

If there are no surgical services available, nor anyone trained in the procedure of resuscitative thoracotomy and cardiac repair, then the patient should be transferred as a matter of urgency. If the patient is in severe shock (or has lost output), with tamponade confirmed on ultrasound, and all other causes have been eliminated or treated, then a pericardiocentesis can be performed.Resuscitative Thoracotomy
The aims of resuscitative thoracotomy are to treat pericardial tamponade by decompression of the pericardial sac and temporary or definitive repair of the myocardial defect. While internal cardiac massage can be also performed, this is not a primary indication for performing resuscitative thoracotomy.  Ideally it should be performed in the operating room where equipment and theatre-trained nursing staff are available. If the patient has lost output however, it should be performed immediately in the emergency department.
Resuscitative thoracotomy should only be performed by appropriately trained and credentialed medical practitioners in settings where there is access to necessary systems and equipment to manage or stabilise myocardial injury or pericardial tamponade.

Pericardiocentesis
Pericardiocentesis involves the insertion of a needle into the pericardium to remove blood / fluid in order to improve cardiac function and allow adequate ventricular filling. Under ultrasound guidance, a long 18-22g needle attached to a syringe, is inserted into the subxiphoid space and directed towards the left shoulder at a 40 degree angle, with continual aspiration as the needle approaches the right ventricle. Once pericardial fluid is aspirated, the cannula is advanced into the pericardial space and a 3 way tap is attached. Note the improvement in output. The patient will require definitive surgery for evaluation and management of the underlying injury.

Open pneumothorax

 Air will follow the path of least resistance, therefore if an opening in the chest wall is approximately 2/3rd of the diameter of the trachea or greater, air will pass through the chest wall defect with each respiratory effort, rather than down the trachea. Hypoxia and hypercarbia will ensue as ventilation is impaired.3

Management: involves promptly closing the opening in the chest with a sterile dressing, occluded on 3 (of four) sides.  This will allow air to escape during expiration but not enter in inspiration. This should then be followed by the insertion of a chest tube at a site away from the wound. Once the intercostal catheter is in place, then the dressing can be converted to a 4-sided, occlusive dressing. These sorts of wounds will likely require definitive surgical closure.

3-sided occlusive dressing
The sterile occlusive dressing should be large enough to overlap the wounds edges and then taped securely on 3 sides to provide a flutter type valve effect. As the patient breathes in the dressing prevents air from entering but in expiration allows air to escape. There are some pre-made dressings such as Asherman’s chest seals which can be utilised.

Flail Chest & Pulmonary Contusions

Spontaneous breathing relies on the ability to create negative pressure within the thorax. Flail chest injury is defined by fractures of 2 or more ribs in continuity, in 2 or more locations. This injury results in a segment of the chest wall that is no longer in continuity with the rest of the thoracic cage, causing disruption of its integrity. It may result in paradoxical chest movement where the flail segment moves inwards on inspiration and outwards on expiration. (This is known as a clinical flail, as opposed to a radiological flail which is defined on imaging). The work of breathing is increased significantly in patients with clinically evident flail chest injury, and they may quickly develop respiratory failure.

Flail chest injury is usually the result of a significant energy force applied to the thoracic cage. Flail injury is therefore usually associated with injury to the underlying lung as well as pain leading to hypoxemia, hypercarbia and decreased lung compliance. Patients with flail chest injury and pulmonary contusions are at particular risk for further complications such as atelectasis, respiratory failure and pneumonia.  

Management: Flail chest injury represents a severe form of chest trauma, and is considered an immediate threat to life.  Adequate oxygenation and analgesia, as well as judicious fluid administration is the cornerstone of management. For some patients, simple measures to support respiratory effort and oxygen saturation may be enough. Epidural analgesia may assist pain control and help improve oxygenation.  ABG’s should be performed regularly to monitor ventilation and response to treatment. Non-invasive positive pressure ventilation (NIPPV) may assist breathing by overcoming the need to create negative pressure during inspiration. Patients who develop early respiratory failure however require immediate mechanical ventilation.

Major tracheobronchial injuries – larynx/ trachea

Injuries to the larynx, trachea and major bronchi are not common, however they do represent an immediate threat to life. Assessment of airways during the primary survey has a particular focus on airway integrity, and symptoms and signs of upper airway trauma. Injury to the intrathoracic trachea and bronchi is detected on assessment of breathing- through identification of pneumothorax, tension pneumothorax and subcutaneous emphysema, and the identification of a significant air-leak upon insertion of an intercostal catheter. It may also be suggested on chest x-ray when completing the adjuncts to the primary survey.
While the definitive management of intrathoracic airways injuries is challenging, and requires specialist input, the early management follows EMST/ATLS principles. For the majority of patients who initially survive, chest decompression will suffice. These patients often have a large or tensioning pneumothorax with a significant air-leak. They may require two intercostal catheters to allow the affected lung to fully inflate. Trauma that results in major tracheobronchial injury usually results in associated chest injuries, such as multiple fractured ribs including flail, pulmonary contusions and haemothorax / pneumothorax.

Potentially Life-Threatening Injuries

A number of injuries considered potentially or soon to be life threatening, may be detected in the pre-hospital setting, during the investigations performed as adjuncts to the primary survey, and during the secondary survey. These injuries are:
  • Simple pneumothorax
  • Diaphragm injury
  • Blunt aortic injury
  • Oesophageal injury
     
Simple pneumothorax: Simple pneumothorax results from air collecting between the visceral and parietal pleura as a result of blunt or penetrating trauma. Injury to the pleura disrupts surface tension between the visceral and parietal pleura resulting in lung collapse and altered ventilation/perfusion.3
 
Diaphragm injury: The diaphragm is a muscle that plays a crucial role in ventilation. Injury can result from penetrating mechanism or blunt trauma from high intra-abdominal pressures. This injury can result in pulmonary compromise and complications to peritoneal contents and may be associated with other significant injuries. Left sided diaphragmatic ruptures are seen more commonly that the right possibly due to protection by the liver. These injuries can be difficult to diagnose initially as chest x-rays can be misinterpreted.3
 
Blunt aortic injury: The thoracic aorta and its branches carry large volumes of blood and can therefore result in fast massive exsanguination and death. Due to the relatively fixed nature of these vessels make them susceptible to sudden decelerative forces in trauma.  Patients having a mechanism of injury consistent with aortic injury who do not respond to resuscitative measures require rapid diagnosis and preparation for surgical intervention if available.
 
Oesophageal injury: Oesophageal injuries are more commonly associated with penetrating trauma and may have concomitant injuries to adjacent structures. Evidence of oesophageal injury may be subtle, but delay in diagnosis can result in associated sepsis. These injuries need to be managed by specialist surgical intervention.

Elderly patients

Patients over the age of 65 years are increasingly victims of major trauma. With the projected increase in this population over the coming decades, along with their improved mobility, it is anticipated that numbers will increase further.
Chest trauma represents a significant injury for the older patient due to the physiological changes, pre-existing conditions and lower lung capacity. These factors make them more susceptible to increased morbidity and mortality as a result of thoracic trauma.