Endotoxin release and endotoxin neutralizing capacity during colonoscopy

In 38 patients who underwent elective colonoscopy, endotoxin and endotoxin neutralizing capacity (ENC) were determined by use of the limulus-amebocyte -lysate test. A control group of 10 patients, prepared for colonoscopy, wer e sampled in the same manner as the study group prior to endoscopy. Elevate d endotoxin plasma levels were only found when comparing the plasma levels before endoscopy with the highest levels available during endoscopy. The ti med endotoxin plasma levels did not change significantly by use of the conv entional limulus amebocyte test. However, ENC was found to decrease signifi cantly 5 min after the onset of endoscopy. Maximal values were reached at t he end of colonoscopy which recovered completely 24 h later. These results, obtained in a population which did not receive any infusions, demonstrate that the half life of endotoxin in the circulation seems to be very short a nd therefore endotoxin cannot itself be detected. On the other hand, small amounts of endotoxin reaching the blued stream are able to reduce ENC which can be analyzed by a modified limulus-amebocyte-lysate test. With the use of ENC and plasma endotoxin determinations, we are able to show significant ; endotoxemia during a minimal invasive procedure such as colonoscopy. (C) 2001 Elsevier Science B.V. All rights reserved.