O Ob bj je ec ct ti iv ve es s: : Acute renal failure (ARF) is a common complication following open heart surgery especially in infants. Effects of blood viscosity on renal function are well known, but have not been investigated in cardiopulmonary bypass (CPS) as yet. M Ma at te er ri ia al l a an nd d m me et th ho od ds s: : We investigated blood viscosity and different markers of glomerular and tubular renal function in a group of 37 infants below 18 month of age, receiving CPS surgery for

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... fferent diagnoses. In an experimental setting, we investigated 28 isolated pig-kidneys with different hematocrits in an autologous blood perfused model. R Re es su ul lt ts s: : In infants, creatinine clearance decreased and urinary excretion of albumin and β-NAG increased during the aortic cross clamp time (AT) and during the first hours following operation, indicating moderate glomerular and tubular damage. During AT, blood was hemodiluted to a hemoglobin of 8.4 ± 0.4 g/dl. Thus, blood viscosity during AT and hypothermia was slightly below pre-CPB values. Lower blood viscosity was related to less renal damage (P < 0.01). In isolated pig-kidneys, group I (n = 14) was perfused with a hemoglobin of 10.2 ± 0.3 g/dl and group II (n = 14) was hemodiluted to 6.5 ± 0.9 g/dl. Group II kidneys showed lower vascular resistance, elevated creatinine clearance, elevated oxygen consumption and elevated sodium reabsorption (P < 0.05). C Co on nc cl lu us si io on ns s: : Reducing blood viscosity below physiological values improves tubular as well as glomerular function under CPB conditions. Thus we hold hemodilution to be an appropriate method for optimizing CPB procedures. Uncoated and coated blood contact surfaces of a hollow-fiber oxygenator: an in-vitro comparison O Ob bj je ec ct ti iv ve e: : The hemocompatibility of oxygenators (OX) can be improved by coating of blood contact surfaces with biopolymers. In the new Trillium (TR) coating of the Affinity hollow-fiber OX, the blood-OX interaction was attempted to reduce by using two structurally different polymer layers. The aim of this in-vitro experiment was the comparison of both physical properties and hemocompatibility of TR-coated OX with the uncoated (UC) and AOThel-coated (AO) versions. M Me et th ho od d: : For the experiment, three standardized circuits used, each with a roller-pump (flow rate:5 l/min) and a separate reservoir. The priming volume was a mixture of fresh, heparinized (100 IE/ml) human blood and Ringer's lactate solution (Hb: 8.0 g/dl). During a 180-min total circulation time, the blood temperature was reduced from 37°C to 20°C for 30 min after 120 min of per fusion. At the beginning and every 30 min of the circulation, blood count, free Hb, thrombocytic hemostasis (tPA, d-dimer, prothrombin fragments F1+2, TAT), PMN-elastase and complements C3c + C5a determined. In addition, the pressure drop was obtained. Scanning electron microscopic images of fibers, heat exchangers and OXhousing were performed after completing the experiment. R Re es su ul lt ts s: : The biggest pressure drop was in TR and lowest in UC. The latter showed the lowest hemolysis ratio; however, the thrombocyte consumption in UC was higher than in AO and TR. A significant difference between AO and TR was not found. Scanning electron microscopy showed clearly more accumulations of cellular blood elements and an increased aggregation of leukocytes on the UC-surface, compared to AO and TR, which in between displayed no remarkable differences. C Co on nc cl lu us si io on ns s: : 1. The pressure drop in coated systems is higher in the UC. 2. UC shows clear disadvantages in thrombocyte consumption and cellular adhesion compared with AO and TR, while significant differences could not be verified between AO and TR. 3. UC has a lower hemolysis tendency in comparison to coated systems, which is subject of a further investigation. O Ob bj je ec ct ti iv ve es s: : During pediatric cardiopulmonary bypass (CPB), lowdose aprotinin has been shown not to influence the systemic inflammatory response syndrome (SIRS). It is well established that aprotinin has beneficial influence on postoperative blood loss Abstracts of the International Symposium on the Pathophysiology of Cardiopulmonary Bypass Aachen, December 12 1998 P2 Critical Care 1999, Vol 3 No 2 during cardiac surgery. Thus, the aim of this study was to rule out the effect of high-dose aprotinin in respect to SIRS and clinical parameters in adult patients. M Me et th ho od ds s: : In this prospective, randomized, double-blind, placebocontrolled study, twenty patients were enrolled. In Group A patients (n = 10), high-dose aprotinin was administered (2 Mio KIU pre-bypass, 2 Mio KIU in prime, 0.5 Mio KIU/h during CPB). In Group C patients (n = 10) no aprotinin was used. Proinflammatory interleukin-6, anti-inflammatory interleukin-10, and clinical parameters were measured six times perioperatively. The values are presented as mean ± SEM. R Re es su ul lt ts s: : Four hours after CPB interleukin-6 concentration reached the maximum value being significantly lower in Group A patients as compared to Group C patients (615 ± 62 vs 1409 ± 252 pg/ml, respectively; P = 0.019). At the first postoperative day the concentration of interleukin-6 in Group A patients remained lower (218 ± 23 vs 526 ± 123 pg/ml, respectively; P = 0.015). In contrast interleukin-10 concentration was higher in Group A patients as compared to Group C patients after CPB (265 ± 91 vs 59 ± 13 pg/ml, respectively; P = 0.03). Postoperative blood loss was lower in Group A patients as compared to the Group C patients (648 ± 64 vs 1284 ± 183 ml, respectively; P = 0.002). C Co on nc cl lu us si io on ns s: High-dose aprotinin treatment caused significantly less SIRS and reduced postoperative blood loss after CPB. Antiinflammatory reaction was significantly enhanced in these patients, which suggests that the physiological reaction of the organism to reduce deleterious effects to CPB is strengthened by using highdose aprotinin. O Ob bj je ec ct ti iv ve es s: : The increase in pulmonary vascular resistance (PVR) seen in children after cardiopulmonary bypass has been attributed to transient pulmonary endothelial dysfunction (PED). We therefore examined PED in children with congenital heart disease by assessing the L-arginine-nitric-oxide (NO) pathway in terms of substrate supplementation (L-arginine [L-Arg]), stimulation of endogenous nitric oxide release (substance P[Sub-P]), and end-