Introduction

The inflammatory response in secondary peritonitis is hypothesized to be compartmentalized. Occurrence of organ failure determines the outcome in patients with this disease. The lung is frequently involved in multiple organ failure. The aim of this study is to determine the role of neutrophil migration and activation in three different compartments (abdominal, circulatory, pulmonary) during secondary peritonitis.

Methods

Patients with secondary peritonitis (n = 31) were analyzed and eight short ventilated controls (1 day postoperative) and seven long ventilated controls (5 days or more). Patients were included only if their APACHE II score exceeded 10 points (mean 17.5, range 11–31). Blood, abdominal fluid and bronchoalveolar lavage fluid were sampled on the day of the index operation for the elimination of the infectious focus (= day 0), on day 2 and day 3. Leukocytes were counted and differentiated. Parameters assessed were the chemokine IL-8, myeloperoxidase (MPO), a measure for neutrophil activation, and albumin and alpha-2-macroglobulin, to measure lung permeability.

Results

All assessed parameters were significantly higher in abdominal fluid than in the other two compartments (up to 100-fold in cell counts and 1000-fold in IL-8 concentrations compared with blood; P < 0.0001). Leukocyte count, neutrophil count/percentage and IL-8 concentrations were also significantly higher in the lung compared with blood or plasma values (P < 0.05). The absolute number, percentages and activity (MPO concentration) of neutrophils in the lung were higher at all time points in peritonitis patients (even day 0) compared with short ventilated controls (P < 0.05). Alveolar membrane permeability, as measured by the relative coefficient of excretion (a ratio between albumin excretion and alpha-2-macroglobulin excretion ratio) was increased in peritonitis patients at all time points.

Discussion

Neutrophil accumulation and activation in the abdominal cavity and the pulmonary compartment in patients with peritonitis is likely to be compartmentalized. In various compartments of the body, the host defense systems vary in extent and nature. An impressive pulmonary response develops early in secondary peritonitis: Neutrophils are activated and lung permeability is increased above normal values.