T lymphocyte changes in open heart surgery

To investigate the effect of open heart surgery on T lymphocytes and their subpopulations, 20 patients, who had undergone moderate- to high-dose fentanyl anesthesia and a cardiopulmonary bypass (CPB), were studied using flow cytometry techniques and monoclonal antibodies during and after surgery. The ages of these patients ranged from four to 61 years with eight being male and 12 being female. The disease entity consisted of four with coronary, six with congenital and 10 with valvular heart disease. No cyanotic patients were included in this study. Peripheral blood samples were collected before anesthesia, immediately before the surgical incision, on the first postoperative day (POD1) and on the second postoperative day (POD2), respectively. We found no significant changes in the percentage of total T cells (T3), or helper (T4) and suppressor (T8) T cells during anesthesia before the surgical incision. On POD1, all T lymphocyte subset percentages decreased significantly when compared to pre-operative values (total T cells: 58.4 ± 12.6 vs 24.4 ± 8.4, helper T cells: 33.3 ± 10.1 vs 15.4 ± 6.3, suppressor T cells: 23.0 ± 6.4 vs 10.0 ± 4, all p _ 0.001) but returned to preoperative levels on POD2. Throughout the study period, there were no significant changes in the T helper cell to T suppressor cell ratio. In spite of the transient decrease in T lymphocytes and their subpopulations, no clinical evidence of infection was noted in any patient. We conclude that: (1) under fentanyl, diazepam and pancuronium anesthesia befored surgical incision, T lymphocytes and their subsets do not alter significantly in percentage; (2) transient T lymphocyte depression does occur in patients after CPB; and (3) in spite of the above changes, no clinical evidence of infection was found in our patients.