Objective: To sttldy tl1e damaging effects of cardiopulmonary
bypass(CPB) on hllman cellu1ar immune ftlnction and the immune
modulating effect ofcilnetidine.
Methods: ln a prospective randomized study,20 patients were
divided into two 8iroups of equal size. Cimetidine g'roup patients
received 0.4g of cimetidine intravenously before bypass and 0.2g q6h
intravenous inftlsion of cimetidine after the operation, continuing unti1l
the fift1l postoperative day. Control-8iroup patients received
convel1tional perioperative theraPy. Lymphocyte subsets, lymphocyte
transformation index were measured perioperatively.
Results: Postoperative reduction in the percentages of CD',.
CD+#cells were observed to some deg'ree in both groups. In
cimetidine grotlp,tl1ese values decressed slowly and restored qtlickly,
significant reduction in CD+,was observed on postoperative days l to
3.In contrast,CD+,counts were elevated significa11tly on tl1e
postoperative days l in control-Liroup. Postoperative reduction in tl1e
level of CPM. PHA-SI al1d CD'./CD+,were obselved in control-
gro[lp,llevertlleless,in cimetidine-group,these values restored
approximately on the postoperative days 3.
Conclusion: Cell-lnediated immunity is impaired after cardic
operations involving CPB, cimetidine can counteracts this depressive
ef1bcts and may possibly reduce postoperative susceptibility to