investigations
Last reviewed 08/2021
The diagnosis of pneumothorax is usually confirmed by imaging techniques
- chest radiology:
- presence of a white visceral pleural line separated from the parietal pleura and chest wall by a collection of gas, resulting in a loss of lung markings in this space is a hallmark of the condition
- standard erect PA chest x-ray
- inspiratory films are recommended for the initial diagnosis of pneumothorax
- expiratory films are not thought to confer additional benefit in the routine assessment of pneumothorax
- lateral x-ray
- may provide additional information when a suspected pneumothorax is not confirmed by a PA chest film. However, they are no longer used routinely in everyday clinical practice
- supine and lateral decubitus x-rays
- useful for trauma patients who cannot be safely moved, less sensitive than erect PA x-rays for the diagnosis
- chest films may need to be repeated within a short period to assess change in the size of the pneumothorax
- ultrasound
- specific features on ultrasound scanning are diagnostic of pneumothorax but is mainly used in the management of supine trauma patients
- CT
- recommended for uncertain or complex cases
- regarded as the gold standard in the detection of small pneumothoraces and in size estimation
- useful in differentiating a pneumothorax from large bullae (1,2)
In addition to imaging, arterial blood gases will show hypoxia
- hypoxaemia is greater in cases of SSP
- not required if the oxygen saturations are adequate (>92%) on breathing (1)
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