Tension pneumoperitoneum. A cause of acute aortic occlusion.

Massive accumulation of intraperitoneal air may result in an entity known as tension pneumoperitoneum. The patient usually complains only of abdominal fullness, and the abdomen becomes ballooned, barrel-shaped, and tympanic in all quadrants. Upward displacement of the diaphragm may cause respiratory embarrassment. There may also be diminished venous return due to compression of the inferior vena cava. Abdominal paracentesis may be necessary to improve respiratory exchange before laparotomy. In one patient with a perforated peptic ulcer and tension pneumoperitoneum, an enormous increase in intra-abdominal pressure apparently led to acute aortic occlusion. This particular complication of tension pneumoperitoneum has not previously been reported, to our knowledge. The clinical findings of aortic occlusion were reproduced in a canine model by insufflation of air into the abdomen. An intra-abdominal pressure of 100 mm Hg resulted in loss of the femoral pulse wave measured by an indwelling arterial catheter.