From the Guidelines
Pneumothorax size should be measured as 2 cm laterally or apically on a chest X-ray (CXR) or any size on a computed tomography (CT) scan that can be safely accessed with radiological support, according to the British Thoracic Society (BTS) guidelines.
Key Points to Consider
- The size of a pneumothorax is crucial in determining the management approach, with smaller pneumothoraces potentially being managed conservatively and larger ones requiring intervention such as needle aspiration or chest tube insertion 1.
- The BTS guidelines suggest that a pneumothorax of sufficient size to intervene depends on the clinical context but is generally considered to be 2 cm laterally or apically on CXR, or any size on CT scan that can be safely accessed with radiological support 1.
- The use of CT scans is recommended for difficult cases, such as patients with suspected bullae in complex cystic lung disease, or when the lungs are obscured by overlying surgical emphysema 1.
- The measurement of pneumothorax size is important for guiding management decisions, including the potential need for talc pleurodesis in high-risk patients with primary spontaneous pneumothorax (PSP) 1.
Clinical Application
- In clinical practice, the size of the pneumothorax should be assessed using a standard upright chest radiograph, with the measurement taken at the level of the hilum or laterally/apically as per the BTS guidelines 1.
- The clinical context, including patient symptoms, underlying lung disease, and risk factors, should be considered when determining the management approach for a pneumothorax 1.
From the Research
Measurement of Pneumothorax Size
To determine the size of a pneumothorax according to British Thoracic Society (BTS) guidelines, the following methods can be considered:
- The BTS guideline classifies pneumothorax size based on interpleural distances measured on inspiratory X-rays 2
- The Collins method, which is volumetrically-derived, can also be used to estimate pneumothorax size 2, 3
- Another study suggests that the Rhea inter-pleural distances method can be used to estimate pneumothorax size from chest X-rays, although it may underestimate the size of larger pneumothoraces 3
Key Considerations
When measuring pneumothorax size, it is essential to consider the following:
- The BTS guideline may classify pneumothorax size differently compared to other guidelines, such as the American College of Chest Physicians (ACCP) guideline 2, 4
- The size of the pneumothorax can impact treatment decisions, with larger pneumothoraces potentially requiring more invasive interventions 5, 6
- Imaging modalities, such as computed tomography (CT) scans, can provide more accurate estimates of pneumothorax size compared to chest X-rays 6, 3
Imaging Modalities
The following imaging modalities can be used to measure pneumothorax size:
- Chest X-rays: can be used to estimate pneumothorax size using the Rhea or Collins methods 2, 3
- Computed Tomography (CT) scans: can provide more accurate estimates of pneumothorax size and are recommended for certain patient populations, such as children with large primary spontaneous pneumothorax 5, 6