Chapter 4 - Thoracic Trauma Flashcards
What percentage of thoracic trauma requires surgery?
<10% blunt and 15-30% penetrating.
What is the triad of main findings in chest injuries?
1) Hypoxia due to V/Q mismatch (caused by contusion/haematoma/alveolar collapse), changes in intrathoracic pressure and inadequate O2 delivery
2) Hypercarbia - due to decreased GCS and changes in intrathoracic pressure
3) Acidosis
How is the airway assessed in a chest injury?
Listen for air at nose/mouth/lungs. Inspect mouth for FBs. Observe intercostal muscle retractions. Associated laryngeal injury can be life-threatening.
Upper chest injuries can deform the sternoclavicular joint, pushing the clavicle head backwards and causing an upper airway obstruction, so listen for stridor or change in voice quality.
Is cyanosis an early or late sign?
Late
What are the commonest causes of a tension pneumothorax?
a) positive pressure ventilation in a visceral pleural injury
b) Blunt parenchymal lung injury which doesn’t seal
c) Failed CVC/subclavian line attempts
d) Chest wall injuries covered badly with dressings
e) (rarely) T-spine fractures
What are 8 signs of a tension pneumothorax? How is it distinguished from a cardiac tamponade?
Hypotension, tachycardia, tachypnoea, chest pain, tracheal deviation, raised JVP, decreased AE, hyper-resonance.
Distinguish from tamponade by hyper-resonance, decreased air entry and tracheal deviation.
What size needle should be used to decompress a tension pneumothorax?
a 5cm needle reaches the pleural space 50% of the time. An 8cm needle reaches it >90% of the time.
Why is an open pneumothroax so dangerous? How is it treated?
Air preferentially follows the path of least resistance through the chest wall instead of trachea (if chest wall opening is 2/3 the size of trachea), causing hypoxia and hypercarbia.
Treat with a prompt, sterile, occlusive dressing taped on 3 sides to create a ‘flutter-type’ valve so air can’t get in but can escape. Then place a chest tube remote from the wound.
What is the definition of a flail chest? How is it diagnosed?
“A segment of chest wall that does not have bony continuity with the rest of the thoracic cage” - usually involves 2+ ribs (normally adjacent) fractured in 2+ places.
Diagnose by looking for abnormal respiratory motion and crepitation of rib fractures. CXR may show several rib # but not necessarily costochondral separation.
How is a flail chest treated?
O2, ventilation, fluids, analgesia.
Analgesia can be IV opiates or local (intercostal nerve block, or intrapleural/epidural anaesthetic).
Assessing RR, PaO2 and t he work of breathing will determine if brief intubation and ventilation is needed.
What volume constitutes a massive haemothorax? What is the commonest cause?
> 1500ml
A penetrating wound disrupting systemic or hilar vessels.
In haemothorax would the JVP be raised or not?
What are the main signs of a haemothorax?
Unlikely. It doesn’t often cause enough mediastinal shift, plus the associated hypovolaemia means JVP is unlikely to be raised.
Main signs = shock, decreased air entry and dullness to percussion.
How is a haemothorax treated?
Simultaneous decompression (36 or 40Fr size tube) and fluid resus (crystalloids/type-specific blood or autotransfusion). If >1500ml immediately drained, or 200ml/hr for 2-4 hours, early thoracotomy is normally needed.
What causes cardiac tamponade? What are the signs?
Penetrating injuries or blunt rapid deceleration sternal injuries (which can also cause MI/dysrhythmias, like PEA)
Signs of cardiac tamponade = Beck’s Triad: Raised JVP, low BP and muffled heart sounds.
What are some causes of PEA?
tension pneumothorax, cardiac tamponade, profound hypovolaemia or cardiac rupture.
