Intestinal intramural haemorrhage after blunt abdominal trauma

Intramural haemorrhage of the intestine following blunt trauma to the abdomen has been described in several clinical studies. Though such lesions may have an innocent appearance at primary laparotomy, they lead to delayed intestinal perforation in some cases. In previous experiments with similar lesions produced by penetrating abdominal missile, the histologic appearance and the clinical course were documented in pigs observed under long-term anaesthesia. In the present study anaesthetized pigs were submitted to blunt abdominal trauma in an impact machine, whereby the impact velocity could be regulated. The intra-abdominal pressure and the delivered impulse were recorded and the incidence and histologic appearance of intestinal injuries were observed at laparotomy immediately after the trauma. Intramural haemorrhage was found to occur when the impact velocity exceeded 5 m/s. At impact velocity 20 m/s, intestinal rupture occurred primarily. The observed intramural haemorrhages had the same histologic appearance as those seen after penetrating missile injury. The same clinical course, consequently, could be anticipated after blunt trauma.