Circulating endotoxin and tumor necrosis factor during pediatric cardiac surgery

OBJECTIVESTo study the hypothesis that endotoxin and tumor necrosis factor-α (TNF) are released into the circulation during the perioperative period in children undergoing open-heart surgery, and to assess the possible role of these factors in postoperative morbidity. DESIGNProspective study. SETTINGOperating room and ICU of a childrenʼs hospital. PATIENTSTwenty-four consecutive patients undergoing open-heart surgery for repair of congenital heart disease. METHODSEndotoxin and TNF concentrations were measured in blood samples withdrawn from patients at predetermined time points in the perioperative period. These concentrations were also measured in samples from all fluids and drugs administered to patients. Clinical variables were measured throughout the perioperative period, and the Pediatric Risk of Mortality score was calculated daily. RESULTSAll of the preoperative control samples were negative for endotoxin and TNF. Endotoxin or TNF was detected in the blood of 21 (88%) of 24 patients during or after surgery. Endotoxin (ranging in concentrations from 0.32 to 438 pg/mL) was detected in the blood of 16 (67%) of the 24 patients. The majority of the samples positive for endotoxin were withdrawn during cardiopulmonary bypass and were associated with positive samples from the pump, from cardiotomy suction specimens, and from autotrans-fused blood. Blood cultures of all patients, except one, were negative for bacterial growth. TNF (ranging in concentrations from 3 to 132 U/mL) was detected in the blood of nine (37%) of the 24 patients. Patients positive for TNF had significantly (p < .05) lower mean central venous pressures at 20 hrs after surgery and higher mean heart rates postoperatively compared with patients negative for TNF. No differences in other indicators of perioperative morbidity and intraoperative conditions were found, when the groups positive for endotoxin or TNF were compared with the groups negative for endotoxin or TNF, respectively. CONCLUSIONSEndotoxin and TNF are released into the circulation during and after pediatric open-heart surgery. TNF release may be related to some of the hemodynamic changes observed after open-heart surgery. (Crit Care Med 1992; 20:1090–1096)