Endotoxaemia in multiple organ failure due to sepsis

Patients with multiple organ failure secondary to intraabdominal sepsis are often blood culture negative despite exhibiting the features of septic shock. This study examined the possible central role of endotoxin in such patients. In 15 consecutive intensive care patients with the above clinical picture endotoxin was measured by a chromogenic limulus (LAL) assay; on admission and thereafter 4 hourly. Regular blood cultures and cultures of any primary septic focus were also performed and liver function was assessed by measurement of indocyanine-green clearance from plasma (ICGC). All 15 patients had significant endotoxaemia at least intermittently. No significant difference was observed between survivors (n = 5) and non-survivors (n = 10) in either initial or peak endotoxin levels, although the pattern of endotoxaemia differed with non-survivors exhibiting consistently high or steadily increasing levels. Of 5 patients with an intra-abdominal (I/A) septic focus only one had a positive blood culture while 5 of 10 patients with extra-abdominal (E/A) infection had positive cultures. Despite this the I/A group had higher initial and peak endotoxin levels. 3 patients with Gram-positive septicaemia had significant endotoxaemia in the absence of any gram-negative infection. Changes in ICGC appeared to be of useful prognostic significance. ICGC was significantly lower in the I/A group and in both groups there was a significant negative correlation between ICGC and the level of endotoxaemia. These results suggest that endotoxin may play a central role in the syndrome of multiple organ failure and further suggest that the endotoxin is endogenous (gut-derived) secondary to failure of hepatic filtration.