A tension pneumoperitoneum is a special and rare type of pneumoperitoneum, in which the free intra-abdominal peritoneal gas is under pressure. The mechanism is thought to be a ball-valve effect allowing the one-way accumulation of gas. This results in:
- elevation and splinting of the diaphragm reducing lung volumes
- compression of IVC and other veins resulting in reduced venous return and decreased cardiac output
Just as in pneumothorax prompt intervention is required to prevent death.
Causes are essentially the same as those of a 'normal' pneumoperitoneum with iatrogenic causes e.g. mechanical ventilation, being over-represented.
The radiographic features are the same as a routine pneumoperitoneum except that gas volumes are vast and abdominal distension is present.
- 1.S Y Chan, C M Kirsch, W A Jensen, and J Sherck "Tension pneumoperitoneum." West J Med. 1996 Jul–Aug; 165(1-2): 61–64