Blood transfusion during versus after cardiopulmonary bypass is associated with postoperative morbidity in neonates undergoing cardiac surgery.

INTRODUCTION: Cardiac surgery on neonates for the correction of congenital heart defects is usually associated with the transfusion of packed red blood cells (PRBCs) into the cardiopulmonary bypass (CPB) circuit. We hypothesised that such transfusions of stored PRBCs directly into the arterial system may increase postoperative morbidity when compared to intravenous transfusion. PATIENTS AND METHODS: In this retrospective cohort study, data from 122 consecutive neonates who received transfusions of PRBCs in the course of corrective surgery for congenital heart defects were analysed. Group assignment was according to the timing of the first transfusion: during CPB (On-CPB) or after weaning from CPB (Post-CPB). Chi Square and rank sum tests were applied to compare clinical characteristics. Times until extubation and release from the intensive care unit were analysed by Kaplan-Meier curves and by multivariate Cox regression. RESULTS: Transfusion of PRBCs during CPB was associated with greater 48 hour blood loss (mean±standard deviation, 86±125 versus 32±16 mL/kg, p<0.001), longer duration of mechanical ventilation (214±268 versus 99±75 h, p<0.001) and longer stay on the intensive care unit (10.9±12.1 versus 5.3±3.5 days, p<0.001). However, the groups also differed in many characteristics, such as bodyweight, complexity of surgery or preoperative haemoglobin concentration, which may also affect outcome. Yet, multivariate analyses confirmed an independent association of transfusion On-CPB with an adverse clinical outcome. CONCLUSIONS: Our results are consistent with the hypothesis that the transfusion of PRBCs during CPB may increase postoperative morbidity. However, due to the limitations of this retrospective analysis, further studies are needed to confirm a causal relationship between the timing of the transfusion and the clinical outcome and to elucidate putative mechanisms of such an association.

[Levosimendan-long-term inodilation in an infant with myocardial infarction]. / Säugling mit therapie-refraktärer suprasystemischer pulmonaler Hypertonie nach MyokardinfarktIntermittierende Stabilisierung mit Levosimendan, einem neuartigen Langzeit-Inodilatator.

An infant with myocardial infarction due to congenital stenosis of the left coronary artery with consecutive left ventricular dysfunction and mitral regurgitation developed refractory pulmonary hypertension (PHT) and recurrent PHT crises. Catecholamines to support cardiac function, or pulmonary vasodilators like inhaled nitric oxide showed no effect. Treatment with Levosimendan (Simdax), a new inodilator, combining both inotropic and pulmonary vasodilating effects, improved left ventricular dysfunction, increased cardiac index, decreased pulmonary vascular resistance and reduced frequency and extent of the PHT crises. This case may suggest the use of Levosimendan as a long-term inotropic agent and pulmonary vasodilator in children with depressed cardiac function.

OPS imaging of human microcirculation: a short technical report.

Despite the pivotal role of microcirculation in numerous diseases, techniques for the direct assessment of human microcirculation are limited. A new approach based on orthogonal polarization spectral (OPS) imaging (Cytoscan microscope) allows noninvasive observation of human microcirculation in all accessible tissue surfaces. Limitations remain: application of pressure with the instrument affects blood flow, lateral movement of tissue precludes continuous investigation of a given microvascular region, and blood flow velocities above 1 mm/s cannot be measured. We addressed these problems by (a) constructing an attachment to the probe, preventing direct contact of the instrument with the observed tissue area and allowing fixation of the tissue, and (b) implementing a double-flash spatial correlation technique extending the measuring range for blood flow velocities up to approximately 40 mm/s. The modified approach was tested in vitro and in vivo. Velocity readings correlated well with velocities of an external standard (r(2) = 0.99, range 1.9-33.8 mm/s). Pulsatile flow patterns synchronous with heart rate with maximal velocities of about 10 mm/s could be detected in arterioles of the human sublingual mucosa. The modified instrument may prove useful to investigate the microcirculation in the context of research, diagnosis and therapy control.

Cariporide (HOE 642) attenuates leukocyte activation in ischemia and reperfusion.

UNLABELLED: Cariporide (HOE 642) ameliorates myocardial ischemia/reperfusion (I/R) injury, by the well established reduction of cytosolic [Ca(2+)] in cardiac myocytes through inhibition of Na(+)/H(+) exchange. However, postischemic inflammation also contributes to I/R injury. We tested the hypothesis that cariporide also modulates the inflammatory response. The effect of cariporide on L-selectin expression by human leukocytes in vitro and leukocyte adhesion and emigration in the reperfused rat cremaster muscle in vivo were studied. The rat cremaster muscle was exteriorized for intravital videomicroscopy, induction of ischemia (90 min), and reperfusion (90 min). Eleven rats were pretreated with cariporide (9 mg/kg body weight IV) whereas 11 rats received saline. Leukocyte adhesion was quantified offline. Human venous blood was incubated with cariporide (3 micromol/L) or saline, stimulated with formyl- methionine-leucine-phenylalanine (10(-10)-10(-6) mol/L), and granulocyte L-selectin expression was analyzed by flow cytometry. Cariporide reduced leukocyte rolling and adhesion by approximately 35% and 45%, respectively, after 30 min of reperfusion. Leukocyte extravasation was decreased by approximately 85% after 90 min. Cariporide increased L-selectin shedding at each formyl-methionine-leucine-phenylalanine concentration, reducing the 50% effective dose from 9.95 to 4.68 nmol/L. Thus, cariporide may ameliorate I/R injury not only by the known reduction of cytosolic [Ca(2+)] in cardiomyocytes, but also by attenuating leukocyte-dependent inflammatory responses. Promotion of L-selectin shedding from activated leukocytes may present a mechanism underlying this newly detected effect. IMPLICATIONS: This study provides evidence that inhibition of Na(+)/H(+) exchange by cariporide (HOE 642) attenuates the postischemic inflammatory response. Leukocyte adhesion and emigration, assessed by in vivo microscopy, were markedly reduced in rat cremaster muscle, possibly because of increased L-selectin shedding of activated leukocytes as demonstrated by flow cytometry.

Successful treatment of postoperative right ventricular heart failure with the HIA-Medos-assist system in a 2-year-old girl.

One year after total correction of tetralogy of Fallot, reoperation was performed in a 2-year-old infant because of an aneurysm of the right ventricular outflow tract. After removal of the aneurysm, massive right ventricular failure occurred. Maximal medical inotropic support could not reestablish sufficient right ventricular function. Therefore, it was decided to implant the new HIA-Medos system as a right ventricular assist. In the postoperative period, echocardiographic controls showed increasing contractility of the right ventricle. The assist system was removed after 3 days and the infant was discharged in good condition on the 22nd postoperative day.

Splanchnic oxygen transport and lactate metabolism during normothermic cardiopulmonary bypass in humans.

UNLABELLED: The effect of normothermic (36.2 degrees C +/- 0.6 degree C) nonpulsatile cardiopulmonary bypass (CPB) on splanchnic (hepatic) blood flow (SBF), splanchnic oxygen transport (DO2spl) and oxygen consumption (VO2spl), splanchnic lactate uptake and gastric mucosal pH (pHi, gastric tonometry) was studied in 12 adults (New York Heart Association class II, ejection fraction > or = 0.4) undergoing coronary artery surgery. SBF was estimated with the constant-infusion indocyanine green (ICG) technique using a hepatic venous catheter. DO2spl, VO2spl, and splanchnic lactate uptake were calculated using the Fick principle after the induction of anesthesia, during aortic cross-clamping, after CPB, and 2 and 7 h after admission to the intensive care unit (ICU). SBF, DO2spl, and VO2spl did not decrease during CPB but increased after ICU admission, whereas pHi decreased 7 h after ICU admission. Initial ICG extraction was 0.78, which decreased to 0.54 during aortic clamping and remained low thereafter. The increased arterial blood lactate concentrations were not associated with a decreased splanchnic lactate uptake. We conclude that normothermic CPB is not associated with deterioration in the global intestinal oxygen supply. The increase of blood lactate levels and the decrease in ICG extraction, as well as in pHi, are consistent with a systemic inflammatory response to CPB. IMPLICATIONS: This study demonstrated that normothermic cardiopulmonary bypass (at flows > 2.4 L.min-1.m-2) was not associated with deterioration in global intestinal oxygen delivery, which suggests that increased blood lactate concentrations and decreased gastric mucosal pH and indocyanine green extraction are manifestations of a systemic inflammatory response to cardiopulmonary bypass.

Clinical experience with the MEDOS HIA-VAD system in infants and children: a preliminary report.

BACKGROUND: The need of pediatric cardiac assist is growing because of the complexity of the congenital conditions operated on and the increasing number of pediatric transplantations. We evaluated the newly developed pediatric MEDOS HIA-VAD ventricular assist device. METHODS: The pneumatic paracorporeal ventricular assist device has three left ventricular sizes (10-, 25-, and 60-mL maximum stroke volume) and three right ventricular sizes (9, 22.5, and 54 mL) and can be operated effectively with up to 180 cycles/min. We used this device in 6 consecutive pediatric patients. Intention of treatment was to bridge to transplantation in 3 patients and to aid in recovery from a cardiac operation in 3. Age ranged from 5 days to 8 years. RESULTS: Two children died during assist, 2 were weaned from the system and discharged home, and 2 had successful transplantation. During assist, laboratory variables indicative of impaired renal, hepatic, or pulmonary function normalized or showed a trend toward normalization. Both deaths were related to infection. CONCLUSIONS: With the new MEDOS HIA-VAD ventricular assist device system, pediatric mechanical cardiac assist can be performed successfully. It requires timely implantation, careful monitoring, and adequate size-matched devices.