Pneumothorax
From WardWiki - Foundation Doctor Helper
Pneumothorax is the accumulation of gas within the pleural space that causes a relative reduction, absolute reduction or even reversal of the normally negative intrapleural pressure. This causes the natural elastic recoil of the lung to be unopposed, leading to a loss of lung volume with or without caval compression. This article deals with primary or spontaneous pneumothorax as usually seen by foundation doctors. The management of secondary pneumothorax requires other considerations to be made although the immediate management of a tension pneumothorax is the same for both cases.
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Immediate management for all unwell patients
Assess the patency and protection of the airway. Take baseline observations, viewing them on a chart using an early warning system.
If evidence of airway compromise, contact anaesthetist and your senior colleague. If there is a raised or reduced respiratory rate, listen to the chest and give high flow oxygen via a non-rebreathe mask
If there is a tachycardia, low blood pressure or evidence of dehydration establish IV access and give a fluid challenge. See NICE guidelines on fluid challenges Consider now placing a urinary catheter. Send off FBC, U&E, CRP, Group and Save, and any special relevant blood tests
If there is pyrexia equal to or above 38 or less than or equal to 35 degrees, take blood cultures. If SIRS is confirmed or sepsis suspected consider the Severe Sepsis Resuscitation Bundle. If patient meets these criteria and does not respond well to initial management contact a senior team member, and a member of critical care who can see the patient or give advice immediately.
Always cross match at least two units for a patient in extremis. It is time consuming and distressing to attempt(pointlessly so) to rush the blood bank to dispense blood later on.
Note a urinary catheter is therapeutic only in cases where an empty bladder is desired (including transfer to theatre for surgery). It is important not to miss out resuscitation and diagnostics steps in the first hour in an effort to set up equipment that measures a patient only hourly. Your initial fluid challenges will, by definition, not be affected by your promptly placed urinary catheter.
History
- Sudden onset dyspnoea with a sharp pain on the affected side which is pleuritic in nature.
- Sympathetic drive causes a tachycardia seen on ECG, other ECG signs are far less reliable
- Previous history of asthma or pneumothorax are risk factors
- Assessment of respiratory distress is the first step in history taking and may prompt the immediate management of a tension pneumothorax
Please note that asthmatics suffering acute attacks are at risk of spontaneous pneumothorax both through their own increased expiratory effort and the high forces needs to deflate the lungs during bronchospasm when ventilated.
Examination
Stand back and inspect; the patient will be distressed, hyperventilating and tachycardic with significant pneumothorax although smaller ones are not immediately appreciated. A full chest examination must be undertaken but only AFTER the need for immediate management has been taken or excluded. The finding of a cursory examination are as follows
- Reduced air entry
- Increased resonance to percussion on the side affected
- Tachypnoea
- Reduced chest wall movement on the affected side
The following are very suggestive of tension pneumothorax but are often late signs:
- Hypotension
- Tracheal deviation AWAY from affected side
- Loss of chest wall movement
- Silent hemithorax
- Distended neck veins
Same day investigations
FBC, U&E, Clotting screen and Group and save are essential to prepare for treating any complications of chest tube placement. These and the vagal stimulation from pleural trauma means an Iv cannula is essential BEFORE aspiration or drainage of a pneumothorax.
In acute unstable patients a clinical diagnosis is sufficient to start decompression of a tension pneumothorax. In all other cases some primary imaging is needed. CXR must be performed but note that small anterior pneumothoraces can be missed on a trauma series, where the CXR is taken supine. If in doubt, repeat a CXR with the patient sitting if a pneumothorax is suspected. CT is used in uncertain circumstances but as an acute presentation it is best to fully consider other differentials and not order a CT alone. Unstable coronary syndrome is best not managed unmonitored on a CT bed with only a radiographer to hand!!
Do not attempt to arrange a repeat X-ray when a pneumothorax has been shown during the current admission and the patient deteriorates in a way suggesting tension - treat directly.
Management
Immediate management with high flow oxygen is essential. Following this treatment any tension must be decompressed. Breathless patients almost always need draining. If decompression is needed then insertion of chest drain is universally required. Haemodynamically stable patients rarely need immediate invasive intervention and it is hard to argue for a junior doctor to rush in when this is the case.
For all other cases the following strategies are used:
1. Observation overnight with no intervention - one must never discharge a new onset pneumothorax without observation overnight.
2. Needle aspiration of pneumothorax - always using a three way tap!!
3. Insertion of a chest drain with underwater seal
BTS guidelines state that needle aspiration is not inferior to chest tube drainage and associated with reduced length of stay. It is as a rule attempted when pneumothorax is greater than 2cm, aspiration continues until pneumothorax reduced to less than 2cm. It is not to be repeated unless the first attempt was technically inadequate. Recurrence suggests continuing air leak and requires a chest drain.
