Complement activation and increased systemic and pulmonary vascular resistance indices during infusion of...

In nine healthy young patients, operated on for thoracic scoliosis, a pulmonary artery catheter was inserted for the study of haemodynamic variables and blood sampling during autologous transfusion of postoperatively drained blood. At 1-3 h after wound closure, 10 ml kg/body weight of drained untreated blood from the wound was collected and recirculated over a l-h period. The concentration of the complement activation product, C3bc, increased from a mean of 5.4 (SD 1.5) AU ml-1 before infusion to 11.1 (3.9) AU ml-1 during infusion and then returned to 7.8 (2.8) AU ml-1 after infusion. The concentration of the terminal complement complex (TCC) increased from 0.5 (0.2) to 1.3 (0.5) AU ml-1 and was reduced to 0.7 (0.3) AU ml-1 after infusion. Only TCC exceeded the reference values which are 14 AU ml-1 for C3bc and 1.0 AU ml-1 for TCC. Pulmonary vascular resistance index concomitantly increased from a mean of 130 (SD 52) to 195 (88) dyn s cm-5 m-2 and was reduced to 170 (86) dyn s cm-5 m-2 after infusion. Systemic vascular resistance index increased from a mean of 1238 (SD 403) to 1349 (473) dyn s cm-5 m-2 and returned to 1196 (401) dyn s cm-5 m-2 after infusion. White blood cell count (WCC) increased from 14.4 (4.3) x 10(9) litre-1 before infusion to 17.8 (7.2) x 10(9) litre-1 during and after infusion. No change in platelet count during infusion was observed. There were no differences in WCC or platelet count between mixed venous or peripheral arterial blood. Pulmonary and systemic vascular resistance indices may be influenced by activated complement in drained untreated blood when it is recirculated.