[Calculated initial chemotherapy in mechanically-ventilated postoperative patients with peritonitis, sepsis and...

Calculated chemotherapy is based on the knowledge of the typical bacterial agents of a particular infection. From January 1983 to August 1985 bacteriological findings from surgical patients with peritonitis, septicemia or pneumonia treated in an intensive care unit were analysed. The study concentrated on those findings only which differed from previous bacteriological investigations. During the first three days 53 patients on assisted ventilation suffering from peritonitis exhibited mainly enterobacteria in their peritoneal secretions. At day 10 or later we also found bacteria from the pseudomonas group. At that time the bacterial spectrum of bronchial secretions was comparable to that of the peritoneal secretions of the same patient. After day 10, the bacterial spectrum was similar in 36 ventilated patients without peritonitis, in 56 patients suffering from post-operative pneumonia and in peritonitis patients. According to our findings, calculated chemotherapy may be based on the fact that patients with peritonitis who cannot be cured within a few days have a bacterial flora comparable to that of patients with septicemia or pneumonia. Patients with severe infections following surgery, such as potentially fatal pneumonia, generalised peritonitis or septicemia were treated with imipenem/cilastatin, according to the above definitions of calculated chemotherapy. 37 of 46 patients treated between May and December 1985, were clinically cured. Microorganisms persisted in five clinically cured patients. Development of resistance to imipenem was observed in one case. In one case treatment had to be stopped because of an allergic skin reaction. Monotherapy of peritonitis by imipenem/cilastatin appeared more satisfactory than treatment with combinations of other antibiotics.