Thoracic Trauma

See also : Westmead Guidelines

Pathophysiology
Primary survey threats
Resuscitative thoracotomy
Secondary survey threats
Other manifestations of chest injury
Pitfalls

Pathophysiology

Second leading cause of trauma death behind head / brain trauma.

Hypoxia
- follows hypovolaemia, ventilation/perfusion mismatch and intrathoracic pressure changes.
--> the most serious feature and early interventions must correct this.
Hypercarbia
- inadequate ventilation due to intrathoracic pressure changes and LOC.
Acidosis
- results from shock.

Primary Survey

Airway in Chest Trauma
Laryngeal injury can accompany chest trauma.
Posterior dislocation of the SC jt can cause obstruction if the displaced fragment rests on the trachea
- this may also cause vascular injury as the aortic arch branches are lacerated.
- seen as stridor, voice change and obvious base-of-neck trauma.
- establish a patent airway (try ETT; may need to reduce #: grasp clavicle with a pointed clamp (eg towel clip) and manually reduce it --> then usually stable).

Breathing
Completely expose the chest and neck.
- observe, palpate. percuss, auscultate.
Look for subtle signs of compromise
- progressively more shallow resps.
- cyanosis is late and its absence is not sensitive.
- observe wall asymmetry, deformity, lacs, cuts, abrasions etc.
Major thoracic injuries are:
- tension pneumothorax
- open pneumothorax (sucking chest wound)
- flail chest
- massive haemothorax

Circulation
Perform circulation check as per primary survey
Attach an ECG and pulse oximeter to the chest-injured pt.
- pts with sternal or rapid deceleration injury are prone to myocardial injury and dysrhythmia.
- hypoxia and acidosis enhance this possibility.
- lidocaine may be required for premature contractions.
PEA may be present in tamponade, tension pneumothorax, profound hypovolaemia or cardiac rupture.
Consider:
- massive haemothorax
- cardiac tamponade

ABG = useful.

ED Resuscitative Thoracotomy

See notes


Secondary Survey Threats

Perform usual secondary survey.
Consider 8 lethal injuries:
- simple pneumothorax
- haemothorax
- pulmonary contusion
- tracheobronchial tree injury
- blunt cardiac injury
- aortic disruption
- diaphragmatic injury
- mediastinal traversing wounds
Unlike the immediately life-threatening injuries of the primary survey, these are rarely obvious.
- have a high index of suspicion

Other Manifestations of Chest Injury

Subcutaneous emphysema
Indicates an underlying injury that needs attention.
If PPV is required, consider tube to prevent tension pneumo

Crush injury (asphyxia)
Look for upper torso/face/arm plethora and petechiae.
- relates to acute, temporary compression of the superior vena cava.
Massive swelling and cerebral oedema may be present.
Treat associated injuries

Rib/Sternum

Ribs: splinting due to pain impairs ventilation, oxygenation and effective cough.
- atelectasis and pneumonia are risks.
Primary survey AP XRs will miss up to 70% of all rib #s.
Childrens' ribs are highly pliable; can have significant intrathoracic injuries without rib #

Ribs 1-3
are protected by bony framework of upper limb.
- #s of upper two ribs, sternum, scapula suggests major force magnitude, places head, neck, spine and intrathoracic contents at risk. 
- associated higher mortality

Sternal #

- a result of a direct blow; associated rib # common
- cardiac and pulmonary contusion can accompany sternal #s
- provide adequate analgesia, rarely operative repair if marked displacement / instability.
Rarely, posterior sternoclavicular dislocation can result in mediastinal displacement of clavicular heads with SVC obstruction
--> immediately reduce via CTx surgery.

Middle ribs 4-9

- commonly #'d, and blow out in AP compression of the thorax.
- direct force tends to drive ends of bones in, causing pneumothorax etc.
- the younger the pt, less likely to suffer rib #s
- multiple rib #s in young pts = great force

Lower ribs #

- consider spleen / liver trauma.

What to do
:
1. Detect with exam
2. CXR / CT for associated injury (finding XR evidence for rib #s is unnecessary)
- CT for contusion, flail, associated intrathoracic injury.
3. Relieve pain.
4. Chest physiotherapy
5. Do not tape, splint etc.

Scapula / clavicle
Generally manageable non-operatively.
- increasing enthusiasm for fixation with severe displacement or non-union
Scapula #s associated with substantial energy transmission to thorax

Rib fixation?
See flail chest

Blunt esophageal rupture
Very rare but possibly lethal.
--> Boerhaave's syndrome
Consider anyone:
- with a L pneumo/haemothorax without rib #s
- a severe blow to lower sternum / epigastrium and is in pain / shock out of proportion
- particular matter in chest tube after blood clears.
Wide drainage and repair is indicated, preferably within a few hours.

Chest tube insertion indications
1. As above
2. Suspected severe lung injury being transferred, undergoing anaesthesia or PPV.


Pitfalls

1. Don't overlook a simple pneumothorax
2. Evacuate simple haemothorax else lung entrapment or empyema may follow
3. Diaphragm injuries are notorious for being overlooked.
4. Don't delay evaluation of the wide mediastinum and transfer to facility capable of treating for evaluation
5. Don't underestimate rib #s, especially at extremes of age, and aggressively control pain without resp depression.
6. Don't underestimate pulmonary contusion - may deteriorate and need careful monitoring / mechanical ventilation for several days.
7. Geriatric patients tolerate chest trauma poorly due to poor reserves and comorbidities.

References
ATLS
Cameron 10th