Related Subjects: Asthma
|Acute Severe Asthma
|Exacerbation of COPD
|Pulmonary Embolism
|Cardiogenic Pulmonary Oedema
|Pneumothorax
|Tension Pneumothorax
|Respiratory (Chest) infections Pneumonia
|Fat embolism
|Hyperventilation Syndrome
|ARDS
|Respiratory Failure
|Diabetic Ketoacidosis
A clinical diagnosis - do not wait for radiology to treat a patient with Immediate needle thoracocentesis. Consider where there is a suspected PTX and a fall in BP. Pressure akin to a balloon inflating builds in pleural space and impairs cardiac filling and death ensues if untreated. Pop the balloon with a needle and let the air out!
About
- Needs to be decompressed with a needle. Will cause a "Hiss of air under pressure"
- If no tension then little harm is done - remove needle and CXR and look for other cause
Aetiology
- Air into pleural space cannot escape due to valve-like effect
- If intrathoracic pressure >Diastolic filling pressure then Cardiac output falls
- As cardiac output falls death ensues
Causes
- Trauma (traumatic pneumothorax)
- Penetrating trauma e.g. stab wound or # ribs
- Blunt trauma e.g. RTA
- Iatrogenic trauma: May be compounded by positive pressure ventilation
- Central line insertion (Jugular/subclavian)
- Pacing (Jugular/subclavian)
- Lung biopsy
- Barotrauma due to positive pressure ventilation
- Percutaneous tracheostomy
- Thoracentesis
- Bronchoscopy
- Cardiopulmonary resuscitation
- Intercostal nerve block
- Non-Iatrogenic
- Atraumatic pneumothoraxes
- Primary (unknown etiology)
- Secondary (patient with an underlying pulmonary disease)
Clinical
- Ventilated patient, post chest trauma, rub #
- Post Central venous cannulation/other procedure
- Subcutaneous emphysema as air may escape
- Cardinal signs are tachycardia, cyanotic, anxious and deteriorating
- Raised JVP due to raised intrathoracic pressures
- Absent breath sounds on the ipsilateral side.
- Hypotension is a late and deadly sign
- May be an obvious chest wound on the affected side
CXR shows TPTX - usually patients too ill to get CXR
Investigations
- CXR can usually wait if you suspect a tension pneumothorax and the patient is deteriorating and in extremis. It would be reasonable to go ahead and first insert the cannula and then the chest drain. Findings are
- A thin line vertical line representing the edge of the visceral pleura
- Effacement of lung markings distally to this line
- Complete ipsilateral lung collapse
- Mediastinal shift away from the PTX
- Subcutaneous emphysema
- Trachea deviates to the opposite side
- Flattening of the hemidiaphragm on the same side (tension)
- Ultrasound: 94% sensitive and 100% specific. Needs skilled operator. Ultrasound findings include the absence of lung sliding and the presence of a lung point
- Hypoxia is due to loss of total lung capacity and ventilation-perfusion mismatch as the lung which is collapsed is not being aerated
Management
- ABCDE assessment. Sit up and give 15L/min O₂. If the patient is stable, then diagnostic imaging (CXR) can be done prior to treatment.
- In extremis then a cannula should be inserted immediately
- Classically in the 2nd or 3rd intercostal space in the midclavicular line
- Alternative is 4th or 5th space anterior axillary line in the safe triangle
- Listen for hiss and leave in situ. If after inserting the cannulae there is no hiss, try and place another one or consider an alternative diagnosis.
- Chest drain: The side should be the more resonant and the trachea is pushed away. Do not wait for radiology. This will buy time for a quick chest drain insertion and the hiss of high-pressure air and relief of some symptoms will help confirm the diagnosis. If a chest tube is malpositioning or becomes plugged, it can cease to function, and the pneumothorax can recur.