Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Pediatric Anesthesia
Introduction: Palliative surgery is an important procedure for treatment of congenital heart defects Since it includes major surgical trauma, such as thoracotomy, immune system can be suppressed . We studied the difference of the changes in lymphocyte and its subsets (count and % proportion) between patients after palliative surgery and patients after open heart surgery with cardiopulmonary bypass (CPB).
Methods: After institutional approval and informed consent from parents, 28 children were divided into two groups: Group P and Group OH. Patients in Group P received palliative surgery, such as Blalock-Taussig shunt. Patients in Group OH received open heart surgery with CPB. Blood samples were taken preoperatively (PRE) and on postoperative day (POD) 1. WBC and its differential counts were measured. Lymphocytes were stained with fluorescent dyes conjugated to specific monoclonal antibodies of lymphocyte surface antigens, and were analyzed by flow cytometer to obtain following subsets: CD3+ 19- (T-cell). CD3+4+8- (Helper/Inducer (H/I) T-cell), CD3+4-8+ (Suppressor/Cytotoxic (S/C) T-cell), and CD3-19+ (B-cell). Non paired and paired t-tests were used for comparisons between the groups and for analyses of time course changes, respectively. Statistical probability less than 0.05 was considered to indicate significance of differences.
Results: No statistical differences between the groups were found in age, body weight and duration of anesthesia. Duration of operation was longer in Group OH. In both groups, lymphocytes and T-cells decreased in both proportion and absolute number on POD 1. The number of B-cells did not change in both groups. In Group OH, the percent proportion of H/I T-cells did not change, however, the proportion of S/C T-cells increased significantly. As a result, the ratio of H/I to S/C T-cells (CD4/CD8) decreased significantly. On the other hand, in Group P, no changes were found in percent proportion of H/I and S/C T-cells, and CD4/CD8 (Table 1).
Discussion: T-cell dominant decrease in lymphocyte subsets suggests suppressed cellular immunity. Despite of longer duration of surgery and traumatic procedures such as extracorporeal circulation and hypothermia in Group OH, similar changes in lymphocyte subsets except in CD4/CD8 were observed in both groups. Although the changes in lymphocyte subsets could not fully explain the condition of immune system, attention should be made to prevention of nosocomial infection in patients received palliative surgery for congenital heart defects as well as in patients received open heart surgery.