Some inflammation-related parameters in patients following normo- and hypothermic Cardio-Pulmonary Bypass

Aims: One of the complications of Cardio-Pulmonary Bypass is the Systemic Inflammatory Response Syndrome. Cardio-Pulmonary Bypass can be performed under either normothermic or hypothermic conditions. The aim of this study was to compare some inflammation-related parameters of patients following normothermic and hypothermic bypass. Moreover, attempts were undertaken to detect endotoxin, an inflammatory agent that has been implicated in the Systemic Inflammatory Response Syndrome, in the serum of patients. Levels of serum anti-endotoxin antibodies were estimated since they have been reported to negate the effect of endotoxin in the inflammatory syndrome. Methods and Results: Seventeen normothermic and 20 hypothermic cases were studied. Blood specimens were collected pre-, off- and post-bypass. Pertinent clinical and surgical data were collected. Hematological parameters (leukocyte, neutrophil and platelet counts) and liver function tests were determined by standard procedures. Endotoxin was determined by the Limulus Lysate Assay and anti-endotoxin antibodies by an enzyme immunoassay. Complement (C3 and C4) levels were determined by radial immunodiffusion. There were increases in leukocyte and neutrophil, and a decline in platelet numbers in both groups of patients. There was a decline in C3 and C4 levels in both groups of patients. Endotoxin was not detected in sera, and anti-endotoxin antibody levels were similar, in both groups of patients. Conclusion: There were no significant differences in most of the altered inflammation-related parameters between the two groups of patients. Some of the findings might be partly due to hemo-dilution. The hydrophobic nature of endotoxin among other factors, might have hindered its detection in serum.