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 impedes venous return both from the IVC and SVC, as well as increasing afterload on the heart, resulting in obstructive shock.
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 hemithorax.
• 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 pre-hospital setting

Needle decompression - Needle decompression can be performed at the 2nd intercostal space (ICS) on the mid-clavicular line (MCL) or the 5th intercostal space at the either the mid or anterior axillary line (with the arm in the abducted position). ⁽³⁾ The 5th ICS at the mid or anterior axillary line may not be easily accessible and in such circumstances the 2nd ICS-MCL is used. There are high rates of needles failing to penetrate the pleural cavity at the 2nd ICS-MCL; although this is based on the use of shorter catheters. (11-14) Clinicians should use their own clinical judgement in choosing the site for needle decompression; considerations should include chest wall thickness, needle catheter size and identification of landmarks on patients anatomy. ⁽¹¹⁾

Proprietary devices such as the pneumocath or the air release system (ARS) device can be used. If these are unavailable a large bore IV Cannula (14 or 16G) with a 10ml syringe attached can be used, although the length of the needle vs chest wall thickness should be considered. 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, injury to underlying structure or mispositioning. ⁽¹¹⁾

Finger Thoracostomy - Unlike needle decompression, finger thoracostomy allows for maximum and reliable release of air and liquid from the pleural cavity. Finger thoracostomy is an invasive procedure, therefore it is a paramount that this is performed under aseptic conditions to avoid secondary infection such as empyema. ⁽¹⁵⁾

Practical tips for identifying a safe insertion point and performing the procedure:

1. Identify the mid-humeral point of the adducted arm and mark the underlying skin in the mid-axillary line (this point corresponds to the 4th intercostal space when the arm is abducted)
2. The patient’s arm is fully abducted and the skin is prepared with aseptic skin prep.
3. Patient hand breadth from the axilla / hair line
4. If a patient is conscious infiltration of local anaesthetic is required. Additional IV analgesia should be considered.
5. An incision is made through skin, dermis and fascia at the fourth or fifth intercostal space, just anterior to the mid axillary line.
6. 6. 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. ⁽¹⁶⁾
7. After successfully completing the procedure, the site should be covered temporarily with a stoma bag/valve bag, commercial chest seal or if this is unavailable a three-way dressing.

**In the case that the patient deteriorates, consideration should be made to re-sweeping the site. ⁽¹⁷⁾.**

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 line. ⁽³⁾ This will relieve the intra-thoracic pressure to allow time for formal decompression and insertion of an intercostal catheter (ICC), which should be performed 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. As previously discussed this procedure is invasive, therefore aseptic technique is paramount. This includes full surgical scrub as well as face masks, gowns and sterile gloves and the area is draped on all four sides, when performed in the emergency department. The technique is the same as described as above.

The sterile insertion of an intercostal catheter connected to an underwater seal drain and administration of IV antibiotics should then follow finger thoracostomy, if there are no other immediate life threats to be addressed.

Massive Haemothorax

Haemothorax has been consistently defined as an accumulation of blood and fluid in the pleural space that prevents adequate ventilation and compresses the lung; ⁽¹⁸⁾ especially when there is >1500mls or 1/3 of the patients’ blood volume in the chest cavity. A haemothorax can be caused by a haemorrhage that has originated from the intercostal vasculature, the chest wall, great vessels, mediastinum or internal mammary arteries. (18) Massive haemothorax most commonly occurs after penetrating trauma but can also present after blunt chest trauma. These large accumulations of blood lead to respiratory failure, hypotension and shock.

Management: Diagnosis of a haemothorax is usually made via CXR and eFAST in the first instance. Ultrasound has consistently demonstrated to be more sensitive in detecting haemothorax in comparison to a CXR. ^(19-20) Initial management involves the restoration of circulating blood volume. Damage control resuscitation techniques should be employed until there is definitive control of bleeding. ⁽²²⁾ 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. Once adequate resuscitation has been performed, the insertion of an intercostal catheter should be performed. This will allow for accurate measurement of blood loss, as well as some tamponade effect on intercostal and parenchymal bleeding when allowing the lung to re-expand against the chest wall. 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. These patients can be extremely challenging, input from trauma and /or cardiothoracic teams would be of benefit to the patient.

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 thoracotomy 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 and swinging of the tube with expiration and suture in place. Bubbling is a sign of air draining from the pleural space and is normal in the early stages. Persistent bubbling may represent a broncho-pleural fistula. Placement should be confirmed with CXR or CT.

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 resuscitation bay, particularly where noise makes muffled heart sounds difficult to hear. JVP is particularly difficult to identify in the setting of hypovolaemia, or the presence of a cervical collar in place for spinal immobilisation. A plethoric face and neck that results from inflow obstruction may be noted, although this might be hard for a clinician to note in the first instance; this sign is a distinctive sign in cardiac tamponade and tends to be more pronounced than when it is noted in patients presenting with a tension pneumothorax.

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. Pericardiocentesis
Pericardiocentesis involves the insertion of a needle into the pericardium to remove blood / fluid to improve cardiac function and allow adequate ventricular filling. ⁽²³⁾ 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 three-way tap is attached. Note the improvement in output. The patient will require definitive surgery for evaluation and management of the underlying injury. Resuscitative Thoracotomy: The main aim of resuscitative thoracotomy is to treat pericardial tamponade by decompression of the pericardial sac. While internal cardiac massage can be also performed, this is not a primary indication for performing resuscitative thoracotomy.

If the patient is in refractory shock, and a trained operator e.g. Surgeon or Emergency/Retrieval Physician is available, the patient should undergo a resuscitative thoracotomy. Preferably this should be in performed in theatre (operative thoracotomy) where equipment and theatre-trained staff are available. Although if the patient is in refractory shock (SBP <70), the patient may be deemed too unstable to transfer to the operating theatre. If the patient has lost output, the procedure will need to be performed immediately in the emergency department. Resuscitative thoracotomy should only be performed by appropriately trained and credentialed operators in settings where there is access to necessary systems and equipment to manage or stabilise myocardial injury or pericardial tamponade.

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.

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:
3-sided occlusive dressing
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 during inspiration. 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 commercial dressings such as Asherman’s chest seals which can be utilised.

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.

Flail Chest & Pulmonary Contusions

Flail chest injury is defined by fractures of 2 or more ribs in continuity, in 2 or more places. 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 identified 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 life-threat. 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. Regional analgesia may assist pain control and help improve oxygenation. ABG’s should be performed regularly to monitor ventilation and response to treatment. Non-invasive ventilation (NIV) may assist patients requiring inspiratory support. All patients with flail chest are at risk of respiratory failure and worsening pneumothorax, those on NIV are at even higher risk. All patients who develop respiratory failure should receive intubation and mechanical ventilation early.

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.

Securing the airway is of priority and requires careful intubation. This additionally assists with managing the subsequent complications of Positive Pressure ventilation. Injury to the intrathoracic trachea and bronchi is usually 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.

For the majority of patients who survive their initial insult, intubation and pleural decompression will be effective temporising measures. 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 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⁾ A simple pneumothorax or haemothorax can be managed conservatively with close monitoring, in a situation where the clinician is unsure about continued management ARV can be contacted for advice 24/7.

Diaphragm injury: The diaphragm is a muscle that plays a crucial role in ventilation. Injury can result from penetrating mechanism or in blunt trauma with high intra-abdominal pressures. This injury can result in pulmonary compromise, maldistribution of peritoneal contents into the thorax 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 rapid exsanguination and death. The relatively fixed nature of these vessels within the thorax make them susceptible to tearing during sudden deceleration 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, with an associated delay to diagnosis. 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 health conditions, and lower lung capacity. These factors make them more susceptible to increased morbidity and mortality as a result of thoracic trauma. As this cohort reports pain and injury differently to others patient groups, injuries can be overlooked on the initial presentation. Therefore intensive monitoring, robust secondary and tertiary assessments, titrated oxygen therapy, adequate analgesia and early mobilisation should be considered in this patient group.

Early activation