Towards a rational approach to the treatment of peritonitis: an experimental study in rats.

Peritoneal infection progresses through defined stages: contamination, inflammation and abscess formation. An experimental model of established peritonitis without adjuvant in the rat was used to test the effect of various local and systemic agents on survival. There was significant improvement in all treatment groups except those treated with antiseptic lavage using PVP-I and noxythiolin. Intramuscular ampicillin improved survival from 40 to 60 per cent while intramuscular amikacin combined with local irrigation with metronidazole reduced mortality to nil (P less than 0.001). Both cephradine and metronidazole used as peritoneal lavage solutions improved survival (P less than 0.005) when compared with the controls but the difference was not significant when compared with irrigation with Hartmann's solution. Metronidazole given rectally also improved survival from 40 to 60 per cent but this difference was not significant. We conclude that survival in established peritonitis depends upon adequate antibiotic therapy.