Thoracic Trauma

Reviewed and revised 3 May 2017

OVERVIEW

Assessment of thoracic trauma requires the identification of immediately life-threatening injuries on primary survey, and delayed life threats on secondary survey.

1. Primary survey
2. Resuscitation
3. Secondary survey
4. Diagnostic evaluation
5. Definitive care

PRIMARY AND SECONDARY SURVEY

A widely used mnemonic for the 6 killer conditions to think of, and actively search for, during the primary survey is ATOM-FC:

• Airway obstruction or disruption
• Tension pneumothorax
• Open pneumothorax
• Massive haemothorax
• Flail chest
• Cardiac tamponade

With a little bit of contortion, potentially life-threatening chest injuries can also be remembered using ATOM-FC:

• Aortic injury
• Thorax injuries (non-massive hemothorax, simple pneumothorax)
• Oesphageal perforation
• Muscular diaphragmatic injury (a stretch this one, I know)
• Fistula (bronchopleural) and other tracheobronchial injury
• Contusion to the heart or lungs

Primary survey

AIRWAY OBSTRUCTION OR DISRUPTION

Recognition

• External neck deformity or hematoma, crepitus from laryngeal fracture, surgical emphysema, hoarse voice or gurgling
• Complete airway obstruction — silent chest, paradoxical chest movements
• Partial airway obstruction — stridor, respiratory distress
• Cyanosis

Management

• High flow oxygen 15 L/min via non-rebreather mask
• Use airway maneuvers and adjuncts to attempt to achieve airway patency (jaw-thrust, suction, oropharyngeal airway) and rapidly proceed to definitive airway if airway disruption confirmed
•  Surgical airway may be required as endotracheal intubation with direct laryngoscopy may not be possible due to distorted anatomy
• If a disrupted airway is visible through an open neck wound attempt to secure the distal trachea with forceps (retraction) and intubate through the wound (consider using a bougie)
• Will need bronchoscopy / thoracotomy

TENSION PNEUMOTHORAX

• Simple pneumothorax converts to a tension pneumothorax if the lung defect acts as a one way valve, which allows ongoing air leak into pleural space without letting it leak back out
• Tension pneuothorax can be rapidly fatal as intra-thoracic pressure rises cause decreased venous return and kinking of great vessels resulting in obstructive shock
• Have a high index of suspicion in any tachycardic and hypotensive patient — clinical features may not be obvious

Recognition

• Anxiety and agitation
• Respiratory distress
• Tachycardia, hypotension
• Neck vein distension
• Ipsilateral hyperexpansion and decreased chest movement
• Tracheal deviation to the contra-lateral side
• Hyper-resonance ipsilaterally
• Decreased breath sounds ipsilaterally
• Bedside ultrasound can rapidly confirm pneumothorax

Management

• High flow oxygen to maintain SpO2 target (e.g. 15L/min via non-rebreather mask)
• Immediate needle thoracocentesis or finger thoracostomy (‘decompression’).
• Proceed to formal intercostal catheter after needle decompression

OPEN PNEUMOTHORAX

• Open pneumothorax is essentially a ‘sucking chest wound’
• It is thought that once a chest wound is >2/3rds the diameter of the trachea, air will enter wound preferentially

Recognition

• Open wound on chest wall
• Anxiety and agitation
• Respiratory distress
• Tachycardia
• Decreased chest movement ipsilaterally
• Hyper-resonance ipsilaterally
• Decreased breath sounds ipsilaterally
• Bedside ultrasound can rapidly confirm pneumothorax

Management

• High flow oxygen to maintain SpO2 target (e.g. 15L/min via non-rebreather mask)
• Cover with occlusive 3-sided dressing to form a ‘flutter valve’ that allows the egress of air through the wound but prevents ‘sucking in’.
• Place formal catheter in separate intercostal space
• Will need formal exploration prior to closing

MASSIVE HAEMOTHORAX

• Massive hemothorax can result from either blunt or penetrating trauma
• The source of bleeding can be from the lungs, major vessels, intercostal vessels or even the heart

Massive hemothorax is defined by the need for thoracotomy — the indications are:

• Blood loss > 1,500 mL or 1/3rd of blood volume
• Blood loss >200 mL/h (3 mL/kg/h) for 2-4 hours

Recognition

• Anxiety and agitation
• Hemorrhagic shock — pallor, tachycardia, hypotension, cool peripheries
• External evidence of thoracic injury
• Decreased chest movement ipsilaterally
• Ipsilateral dullness
• Decreased breath sounds ipsilaterally
• Persistent blood loss following intercostal catheter insertion
• Bedside ultrasound can rapidly confirm the presence of significant pleural fluid  — to see on erect chest requires 250mL of blood

Management

• High flow oxygen to maintain SpO2 target (e.g. 15L/min via non-rebreather mask)
• Treat with rapid restoration of blood volume combined with concurrent drainage of thorax
• Immediate intercostal catheter insertion (re-expanding lung may tamponade the bleeding vessels)
• Hemostatic resuscitation — activate massive transfusion protocol, use of an autotransfuser is ideal
• Thoracotomy
• If develops from blunt chest trauma may be able to consider embolisation

FLAIL CHEST

• A flail chest is defined as fractures of 2 or more contiguous ribs in 2 or more locations
• This results in a segment of the chest wall (the ‘flail’) that is no longer in continuity with the rest of the thoracic cage
• Paradoxical movement results, the segment moves inwards on inspiration as the rest of the chest expands and outwards on expiration as the rest of the chest deflates
• Rib fractures on opposite sides of the chest can result in a ‘central flail’ involving the sternum

Recognition

• Chest pain
• Respiratory distress
• Boney crepitus
• Paradoxical chest wall movements of the affected segment (not apparent if positive pressure ventilation applied)

Management

• High flow oxygen to maintain SpO2 target (e.g. 15L/min via non-rebreather mask)
• Analgesia
  • paracetamol 1g qid po, NSAIDs if not contraindicated, titrated opiates IV (e.g. fentanyl 25 micrograms q5min prn IV), ketamine infusion
  • consider adjunctive medications (e.g. pregabalin, tapentadol)
  • Early use of regional anesthesia (e.g. intercostal nerve blocks, paravertebral block, epidural anesthesia) due to risk of respiratory depression
• Respiratory monitoring and support
  • close monitoring of SaO2, respiratory effort, and ABGs is important as patients tend to gradually deteriorate and may require intubation and mechanical ventilation
  • may benefit from non-invasive ventilation
• Surgical intervention
  • selected patients may benefit from rib fixation (e.g. failure of analgesia and non-surgical interventions prior to intubation, or failure to wean from mechanical ventilation)

CARDIAC TAMPONADE

• Pericardial tamponade is more common in penetrating thoracic trauma than blunt trauma
• As little as 75 mL of blood accumulating in the pericardial space acutely can impair cardiac filling, resulting in tamponade and obstructive shock

Recognition

• Anxiety and agitation
• Obstructive shock — tachycardia, hypotension, cool peripheries
• Beck’s triad: muffled heart sounds, hypotension and distended neck veins — not especially in a noisy trauma bay!
• Pulsus paradoxus (drop in systolic blood pressure >10 mmHg on inspiration)
• Very hard to differentiate clinically from tension pneumothorax and needs to be actively sought
• Mostly diagnosed following identification of a pericardial effusion on bedside ultrasound as part of the FAST exam  leading to formal echocardiography

Management

• High flow oxygen to maintain SpO2 target (e.g. 15L/min via non-rebreather mask)
• May transiently respond to fluid challenge
• Needle pericardiocentesis, preferably ultrasound guided, may be lifesaving may be life-saving but may fail due to clotted blood
• Pericardotomy is definitive treatment
• Emergency thoracotomy may be necessary in the event of cardiac arrest

Secondary survey

AORTIC AND GREAT VESSEL INJURY

• Aortic disruption in trauma typically involves a tear on the aortic wall due to acceleration-deceleration forces
• May result from penetrating (usually succumb in the field) or blunt injury
• Those that make it to hospital may only have the outer aortic wall layer, the adventitia, intact containing a hematoma

Recognition

• Conscious patients may experience tearing chest and back pain. Neurological deficits may also be present (e.g. dissection involvement origins of carotid arteries, spinal arteries, etc)
• Clinical signs (such as differences in blood pressure and pulses between the upper limbs) are unreliable.
• Suspect based on mechanism and the presence of other injuries (e.g. fractures of the sternum, upper ribs and scapula)
• Look for features of aortic dissection on CXR (especially widened mediastinum) — though these are often absent
• Essential to have a low threshold for definitive test: CT angiogram of the aorta
• Pericardial tamponade or an aortic dissection flap may be seen on echocardiography (TOE is more sensitive than TTE)

Management

• High flow oxygen 15L/min via non-rebreather mask
• Avoid excessive fluid resuscitation
• Lower the pulse rate to decrease aortic shear forces by commencing beta blockade (e.g. titrated esmolol infusion) then commence GTN infusion to aiming for systolic blood pressure of 90-100 mmHg and adequate tissue perfusion
• Definitive treatment is surgery, stenting or both

SIMPLE PNEUMOTHORAX

Recognition

• Evidence of thoracic trauma
• Hyper-resonance ipsilaterally
• decreased breath sounds ipsilaterally
• Bedside ultrasound can rapidly confirm pneumothorax
• CT chest may diagnose small pneumothoraces not seen on CXR

Management

• High flow oxygen 15L/min via non-rebreather mask
• Small traumatic pneumothoraces may only require observation
• Significant simple pneumothoraces require intercostal catheter insertion, especially if the patient require intubation due to the risk of conversion to tension pneumothorax.

NON-MASSIVE HAEMOTHORAX

Recognition

• Respiratory distress, ipsilateral dullness
• On supine CXR films will appear as simply a veiling
• Bedside ultrasound can rapidly confirm fluid in the pleural space

Management

• High flow oxygen 15L/min via non-rebreather mask
• Intercostal catheter insertion (re-expansion of the ipsilateral lung may help tamponade bleeding vessels and ongoing blood loss can be monitored)

OESOPHAGEAL PERFORATION

• Traumatic esophageal perforation is usually caused by penetrating trauma

Recognition

• Chest or epigastric pain, dysphagia, hematemesis
• Neck and/or chest wound
• Surgical emphysema
• Pleural effusion, especially on left side (CXR or bedside ultrasound)
• Drainage of gastrointestinal contents from an intercostal catheter
• Shock (sepsis ensues if delayed presentation due to GI contents in the thoracic cavity)

Management

• High flow oxygen 15L/min via non-rebreather mask
• Fluid resuscitation
• Nasogastric tube on free drainage
• Broad spectrum antibiotics
• Formal surgical repair

DIAPHRAGMATIC INJURY

• Diaphragmatic injuries may occur from either blunt or penetrating trauma (especially on the left side) and are easily missed.
• Blunt injury causes radial tears that tend to allow herniation of abdominal structures into the thoracic cavity early.
• Penetrating injuries can cause small defects that don’t present with herniation until years later.

Recognition

• Suspect with any penetrating injury that could extend to between the T4 and T12 levels
• Suspect with severe blunt trauma to the torso, especially if there were compressive or rapid deceleration forces
• May be asymptomatic initially
• Abdominal pain, guarding and/or rigidity
• Cardiovascular and/or respiratory compromise may occur if abdominal contents herniate into the thoracic cavity
• Herniation may be detected by hearing bowel sounds on chest auscultation, or by CXR (NG tube tip may extend into the thoracic cavity) or bedside ultrasound
• Diagnosis of diaphragmatic rupture is usually on multidetector CT, though even a normal CT does not rule out the diagnosis
• Laparoscopy or open exploration are the gold standard for diagnosis

Management

• Laparoscopy or thoracoscopy if suspected
• Most require formal surgical repair

TRACHEOBRONCHIAL INJURY

• Tracheobronchial injury usually occurs close to the carina, and is associated with severe blunt trauma

Recognition

• Hemoptysis, cough and respiratory distress
• Subcutaneous emphysema
• Pneumothorax with persistent air leak after correct placement of an intercostal catheter (continues to bubble vigorously with little resolution of pneumothorax)

Management

• High flow oxygen 15 L/min via non-rebreather mask
• Multiple intercostal catheters may be required
• Urgent bronchoscopy and operative intervention

PULMONARY CONTUSION AND OTHER INJURIES

• Pulmonary contusion can occur with any significant thoracic injury.
• Lung hemorrhage and pulmonary edema leads to impaired gas exchange and respiratory insufficiency.
• Lesions may progress over hours to days (e.g. peak at 72 hours then resolve over 7 days) then gradually improve.

Recognition

• Suspect in any significant thoracic trauma
• May occur in small children in the absence of fractures due to the high compliance of the chest wall
• Respiratory distress, hemoptysis, cyanosis
• Decreased breath sounds and crackles in the affected lung area
• Hypoxia and/ or hypercapnia on ABG
• Pulmonary contusions are detectable on bedside ultrasound
• Alveolar opacities on CXR
• MAy be complicated by nosocomial pneumonia

Management

• High flow oxygen 15 L/min via non-rebreather mask
• ‘Fluid restriction’ may reduce size of contusion but may not affect outcomes
• Analgesia for pain from associated thoracic injuries, which may impair respiratory function
• Respiratory support — severe cases require intubation and mechanical ventilation
• Pulmonary lacerations may be managed conservatively with an intercostal catheter, thoracotomy and lung repair may be required

CARDIAC CONTUSION AND OTHER INJURIES

• spectrum of injury from minor enzyme rises to fulminant cardiac failure and lethal cardiac rupture

Recognition

• Suspect if severe blunt trauma with fractures of the sternum, ribs and/ or thoracic vertebrae
• Chest pain
• Persistent unexplained tachycardia
• pericardial injury: can produce herniation and cardiac dysfunction
• valvular: aortic > mitral > tricuspid + pulmonary valves; results in murmurs and heart failure
• septal injury: loud holosystolic murmur
• Suspect cardiac contusion if any underlying ECG abnormality, including any arrhythmia, conduction defect or ischaemic changes such as ST segment deflections and T wave changes
• Troponin doesn’t alter management

Management

• Cardiology consult and admission for cardiac monitoring and echocardiogram
• medical management/PCI/stent/ CABG for coronary artery injury
• cardiac surgery may be required for valvular dysfunction and penetrating injuries
• emergency thoracotomy may be required in the event of a cardiac arrest

OTHER CHEST WALL INJURIES

Rib fractures

• multiple rib #’s, 1st and 2nd rib and scapular fractures = high energy -> need good analgesia

Sternal fracture

• consider cardiac injury, though rare with isolated sternal fractures

References and Links

LITFL

• Trauma Tribulation 004 — A Fiendish Finding

FOAM and web resources

• EMCrit — Needle versus Knife II: Needle vs. Finger Thoracostomy
• Resus.ME — Inadequate pre-hospital needle thoracostomy