Changes of gut barrier function during anesthesia and cardiac surgery

Area of Science:

• Cardiovascular Surgery
• Immunology
• Critical Care Medicine

Background:

• Postoperative infections are a significant concern following cardiac surgery.
• Understanding the early inflammatory cascade is crucial for predicting and preventing complications.

Purpose of the Study:

• To investigate the temporal relationship between endotoxemia, mediator release, acute phase proteins, and postoperative infections after cardiac surgery.
• To identify early markers that may predict the development of postoperative infections.

Main Methods:

• Plasma levels of endotoxin, endotoxin neutralizing capacity (ENC), leukotriene-C4 (LTC4), 6-ketoprostaglandin-F-1alpha (PGF), thromboxane-B2 (TxB2), interleukin-6 (IL-6), and C-reactive protein (CRP) were measured in 60 patients undergoing cardiac surgery.
• Intramucosal pH (I) was monitored as an indicator of splanchnic blood flow.
• Patients were categorized into groups with (n=8) and without (n=52) postoperative infections.

Main Results:

• Endotoxin levels increased significantly after anesthesia induction, peaking post-reperfusion, with a markedly higher elevation in the infection group (14-fold vs. 6-fold).
• ENC decreased significantly in both groups, while arachidonic cascade parameters and intramucosal pH showed changes without significant group differences.
• Acute phase proteins IL-6 and CRP increased later, with significant differences between groups emerging on postoperative days 2 (IL-6) and 5 (CRP).

Conclusions:

• Endotoxin appears to be the earliest trigger in the mediator cascade of the acute phase response after cardiac surgery.
• Elevated endotoxin levels and decreased ENC early in the postoperative period may indicate an increased risk of developing infections.