Q: What is the advantage of Chest x-ray (CXR) in lateral decubitus position to confirm pneumothorax (PTX)?
Answer: In comparison to regular one-view CXR either in supine, sitting, or standing position, lateral decubitus position is more sensitive in detecting PTX. As little as 5 mL of pleural air is enough to show PTX in this position as air rises to the non-dependent lateral area. In other positions, it may require up to 50 mL of air to show evidence of PTX.
Said that, with new modalities like ultrasound available, and laborious task it can be as well as counting safety of the patient, x-ray in lateral decubitus position is seldom obtained in ICU.
1. Carr JJ, Reed JC, Choplin RH, et al. Plain and computed radiography for detecting experimentally induced pneumothorax in cadavers: implications for detection in patients. Radiology 1992; 183:193.
2. de Lassence A, Timsit JF, Tafflet M, Azoulay E, Jamali S, Vincent F, et al. Pneumothorax in the intensive care unit: incidence, risk factors, and outcome. Anesthesiology. 2006 Jan. 104 (1):5-13.
3. Ball CG, Kirkpatrick AW, Feliciano DV. The occult pneumothorax: what have we learned?. Can J Surg. 2009 Oct. 52 (5):E173-9.
4. Thiam K, Guinde J, Laroumagne S, et al. Lateral decubitus chest radiography or chest ultrasound to predict pleural adhesions before medical thoracoscopy: a prospective study. J Thorac Dis. 2019;11(10):4292-4297. doi:10.21037/jtd.2019.09.54