Subdiaphragmatic free gas is one of the ways of detecting presence of free intraperitoneal gas (i.e. pneumoperitoneum). It is the presence of free, extraluminal gas in the anterior subhepatic space.
As little as 1 mL of free gas can be detected but the patient may be needed to be kept in upright position for about 10 minutes for the gas to rise.
Erect chest x-rays covering the upper abdomen are often considered the best for detecting free subdiaphragmatic gas but an erect abdominal x-ray covering the lung bases will be just as sensitive.
When there is a large amount of free subphrenic gas the continuous diaphragm sign may be present.
- Chilaiditi sign/syndrome
- subdiaphragmatic abscess
- omental fat interposed between the liver and diaphragm
- subpulmonary pneumoperitoneum
- enlarged gastric bubble
- gas-containing liver hematoma
- 1. Radiological Differential Diagnosis. Jaypee Brothers Medical Publishers. (2005) ISBN:8180615006. Read it at Google Books - Find it at Amazon
- 2. SCHENCK S. COLLECTION OF AIR IN THE RIGHT SUBDIAPHRAGMATIC SPACE: WITH SPECIAL REFERENCE TO HEPATODIAPHRAGMATIC INTERPOSITION OF THE COLON. Arch Surg. 01;36 (5): 766-777. doi:10.1001/archsurg.1938.01190230045004
- 3. R Saa, A Sarriugarte, M Guerra, L Agirre, H Marin, M Prieto, A Colina. Gas Containing Liver Hematoma: An Unusual Complication Of ERCP. The Internet Journal of Surgery. 2010 Volume 27 Number 2.