Endotoxaemia in patients with severe sepsis or septic shock

Objective: To examine the incidence and the bacteriological and clinical significance of endotoxaemia in ICU patients with severe sepsis or septic shock. Design: Prospective review. Setting: A 15-bed general ICU in a university hospital. Patients: One hundred sixteen patients hospitalised in our ICU fulfilling Bone's criteria for severe sepsis or septic shock and with an available early endotoxin assay (chromogenic limulus assay). Interventions: None. Measurements and results: The clinical characteristics of the population were: age 63.6 ± 11.4 years; SAPS II: 45.4 ± 15.6; mechanical ventilation: 72.4 %; septic shock: 51.7 % (n = 60); bacteraemia: 28.4 % (n = 33); gram-negative bacteria (GNB) infection 47.4 % (n = 55); ICU mortality: 39.6 % (n = 46). Detectable endotoxin occurred in 61 patients (51.2 %; mean level: 310 ± 810 pg/ml). There was no relationship between detectable endotoxin and severity of infection at the moment of the assay. Endotoxaemia was associated with a higher incidence of bacteraemia (39.3 % vs 16.3 %; p = 0.01). There was a trend (p = 0.09) towards an association between positive endotoxin and gram-negative bacteraemia or GNB infection but this was non-significant. This relationship became significant only in the case of bacteraemia associated with GNB infection irrespective of the site of infection. Conclusion: Early detection of endotoxaemia appeared to be associated with GNB infection only in cases of bacteraemic GNB infection. Early endotoxaemia correlated neither to occurrence of organ dysfunction nor mortality in patients with severe sepsis or septic shock. This study suggests that the use of endotoxaemia as a diagnostic or a prognostic marker in daily practice remains difficult.