PERIOPERATIVE LYMPHOCYTE ADENYLYL-CYCLASE FUNCTION IN THE PEDIATRIC CARDIAC SURGICAL PATIENT

Objective: To examine intraoperative and postoperative lymphocyte aden ylyl cyclase activities in children undergoing repair of congenital ca rdiac defects with hypothermic cardiopulmonary bypass. Design: A prosp ective study. Setting: Tertiary university pediatric hospital. Patient s: Twelve children were enrolled into the study to examine intraoperat ive lymphocyte adenylyl cyclase activities and 12 children were enroll ed to examine postoperative lymphocyte adenylyl cyclase activities. In terventions: None. Measurements and Main Results: Basal (unstimulated) , isoproterenol, and prostaglandin E-1 stimulated adenylyl cyclase act ivities, and plasma norepinephrine and epinephrine concentrations were measured. Intraoperative basal (unstimulated), beta-adrenergic recept or-stimulated (in response to isoproterenol), and prostaglandin E(1) ( PGE(1))-stimulated lymphocyte adenylyl cyclase activities all increase d during cardiopulmonary bypass, then decreased immediately after card iopulmonary bypass, In the postoperative group, a significant decrease in basal (unstimulated), beta-adrenergic receptor- and PGE(1)-stimula ted adenylyl cyclase activities were observed on postoperative day 1 a s compared with precardiopulmonary bypass values. Conclusions: In the pediatric cardiac surgical patient, there was an intraoperative enhanc ement of lymphocyte adenylyl cyclase activities, This increase in aden ylyl cyclase activities was followed by reduced lymphocyte adenylyl cy clase activities, including beta-adrenergic receptor desensitization, postoperatively, as we have previously documented in adults.