Prolonged Cardiopulmonary Bypass is a Risk Factor for Intestinal Ischaemic Damage and Endotoxaemia.

BACKGROUND: Intestinal ischaemia-reperfusion, a frequent occurrence during cardiac surgery with cardiopulmonary bypass (CPB) induces a systemic inflammatory reaction. We hypothesised that ischaemia-reperfusion following prolonged CPB could increase intestinal permeability and thus, lead to endotoxin translocation from the intestine to the bloodstream.

MATERIAL AND METHODS: Patients subjected to coronary artery bypass grafting with CPB were included: Group 1 (CPB ≥90minutes) or Group 2 (CPB <90minutes). Intestinal Fatty Acid Binding Protein (I-FABP), TNF alpha, IL6, IL8, and endotoxin levels were measured before the induction of general anaesthesia (T1), at 6 (T2), and 24hours (T3) after surgery.

RESULTS: The low level of I-FABP at T1 increased for every patient in Group 1 at T2 (from 1015.5pg/mL to 2608.5pg/mL, p=0.02) and in Group 2 (from 1123.5pg/ml to 2284.0pg/ml, p<0.001). Furthermore, at T3, the I-FABP level was over three times higher in Group 1 than in Group 2 (2178pg/mL vs 615pg/mL; p<0.001). I-FABP correlated with CPB time (R=0.6, p<0.001) at T3. After surgery, endotoxins were elevated in 73% of patients in Group 1 and in 32% in Group 2 and correlated with CPB time (at T2, R=0.5, p=0.002; at T3, R=0.4, p=0.016).

CONCLUSIONS: The duration of CPB is linked to the release of biomarkers that indicate ischaemic-reperfusion damage to the gastrointestinal mucosa and endotoxaemia. I-FABP assay may help to identify patients presenting with intestinal damage, who are at risk of bacterial translocation.