Intestinal intramural haemorrhage after abdominal missile trauma--clinical classification and prognosis

Various types of abdominal trauma, such as penetrating missile wounds, blast and severe blunt force, can cause haemorrhage within the intestinal wall. Such bleeding often is multi-sited. In a previous study on anaesthetized pigs subjected to missile trauma, the microscopic appearance of the lesions was described. Risk of perforation, even in lesions of primarily innocent appearance, was also demonstrated, in accordance with reports in the literature. The present study aimed to find a method for predicting which of such haemorrhages may be left untreated and which must be excised. For this purpose, 85 anaesthetized pigs were subjected to low-velocity missile injury to the abdomen. All intramural haemorrhages of the intestine without primary perforation was thereafter classified at laparotomy according to a few easily observed macroscopic criteria. The anaesthesia was maintained and the classification was compared with findings at a second laparatomy at the end of the observation period (maximum 4 days), when histologic study also was performed. The macroscopic criteria showed good correspondence with histologically observed mucosal ulceration and muscle damage. In 64% of the lesions there was macroscopic progression during the observation time, with perforation in 5.4%. Lesions with mean diameter larger than 10 mm, visible serosal defect and palpable mural defect carried the highest perforation risk (16%). Lesions fulfilling none of these criteria did not perforate. The study confirmed the risk of secondary intestinal perforation in primarily non-perforating intramural haemorrhage following abdominal trauma. The results also suggest that some simple macroscopic criteria may be useful for predicting this risk.