Recovery from lymphocytopenia following extracorporeal circulation: Simpleindicator to assess surgical stress

This study investigated whether the lymphocyte count is a useful indicator to assess surgical damage following extracorporeal bypass. In Study 1, to i nvestigate the correlation between extracorporeal circulating time (ECCT) a nd lymphocyte counts, 40 elective CABG patients were studied retrospectivel y. The lymphocyte recovery ratio (LRR), which represented the actual lympho cyte count divided by the preoperative lymphocyte count, was determined pre operatively, and on postoperative day (POD) 1, POD 3, and POD 5. In Study 2 , the correlation between the interleukin-8 (IL-8) level and LRR was examin ed prospectively in elective CABG patients (n = 20). We measured the LRR an d serum IL-8 levels preoperatively and during extracorporeal circulation (E CC) at 5 min, at the end of ECC, and 1, 3, and 12 h following ECC terminati on. Study 1 showed that the LRR decreased until POD 1 and gradually increas ed thereafter. The LRR had a negative correlation with the ECCT. In Study 2 , the IL-8 level demonstrated a time course opposite to that of the LRR; it increased until 3 h after ECC termination and declined thereafter. There w as a significant negative correlation between the LRR on POD 3 and the IL-8 level at 3 h after ECC termination. In summary, long-term ECC induced sign ificant and prolonged lymphocytopenia. The LRR had a negative correlation w ith IL-8. These results indicated that the LRR may represent the degree of surgical stress following ECC; therefore, the counting of lymphocytes can b e a quite useful bedside monitor to assess surgical damage and prognosis.