TENSION PNEUMOTHORAX
DEFINITION
Air entering the pleural space under pressure, collapsing the lung
and
causing haemodynamic compromise due to mediastinal shift and
obstruction to cardiac inflow, possibly causing death if not
promptly
treated.
top D I A B M
I M P home
INCIDENCE
Incidence
Any age.
Risk Factors
Asthma
Emphysema
IPPV
CT disorders eg Marfans.
top D I A B M
I M P home
AETIOLOGY
Neonates
Spontaneous, even without IPPV.
Adults
Chest trauma with or without rib #s.
- most commonly mechanical PPV in a pt with a visceral pleural
injury.
- can follow a simple pneumothorax where a parenchymal lung injury
has
failed to heal.
- occasionally follows a chest wall injury if incorrectly covered
with
occlusive dressings or creating a flap/valve.
- may occur in markedly displaced T-spine #s.
Any procedure involving the chest can induce one.
top D I A B M
I M P home
BIOLOGICAL BEHAVIOUR
Pathogenesis
Air enters the pleural space through a defect.
The opening acts as a one way valve.
- air enters as resp effort draws a negative pressure
- but cannot escape during expiration.
Harder breathing, coughing or IPPV worsens tension.
Pathophysiology
Lung collapse causes hypoxaemia as for any pneumothorax.
- as pressure rises, mediastinal shift occurs.
--> contralateral lung is compressed.
Shift may occlude the IVC at the diaphragm.
- and SVC above heart
--> venous return is impaired --> decreased preload --> CO
diminishes.
--> cardiovascular collapse.
top D I A B M
I M P home
MANIFESTATIONS
i) Severe Respiratory Arrest
ii) Shock
Symptoms
Chest pain, often sudden and unilateral.
Air hunger.
Deteriorates rapidly
Loses consciousness
Turns blue
Appears to be dying (and is)
Signs
Observe
Progressively worsening respiratory distress
Distended neck veins
Cyanosis / hypoxia
Palpate
Shock, with hypotension & tachycardia
- become bradycardic if near death.
Tracheal deviation
Subcutaneous emphysema
Percussion
Hyper-resonance
Auscultate
Decreased / absent breath sounds on side of pneumothorax
top D I A B M
I M P home
INVESTIGATIONS
Tension pneumothorax is a clinical diagnosis.
There should never be a CXR of a tension pneumo.
Radiology
Mediastinal displacement, absent lung marking, lung border
collapsed.
top D I A B M
I M P home
MANAGEMENT
Needle Decompression
- converts tension to simple.
- commonly done by paramedics.
However, finger thoracostomy probably better in ED / resus context.
Chest Tube Insertion
As soon as able.
top D I A B M
I M P home