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[Use of human albumin and dextran-70 in extracorporeal circulation. Postoperative function of blood platelets (author's transl)].

Human albumin and dextran 70 were used as volume expanders in extracorporeal circulation in two homogeneous series of patients. Comparative results were statistically processed. No significant differences were observed either to early postoperative bleeding or needed volume of transfused blood. Postoperative complications neither developed in the two groups of patients. The total number of platelets showed a 50 percent decrease in relation to basal extraction figures and those after immediate heparin neutralization. Results of platelet function tests were similar in both series, except for a statistical significant decrease in ADP-induced platelet aggregation in the group with dextran 70. Such decrease, however, was not followed by an increase of postoperative bleeding. Thus, dextran 70 has showed to be a valuable substitute for human albumin in extracorporeal circulation.

Albumins↗

Cardiac surgery with extracorporeal circulation: neutrophil transendothelial migration is mediated by beta1 integrin (CD29) in the presence of TNF-alpha.

Cardiac surgery with extracorporeal circulation is associated with neutrophil activation, inflammation, and edema. Endothelial hyperpermeability elicited by the interaction of activated neutrophils and/or cytokines with endothelial cells may be critical in this regard. However, the immune and cellular mechanisms involved are not fully understood. Cocultures with human endothelial cells and neutrophils from cardiac surgery patients were used to evaluate the role of beta1 integrin activity and the proinflammatory cytokine tumor necrosis factor (TNF)-alpha in neutrophil transendothelial migration and in impairment of the integrity of endothelial cell-to-cell contacts. Blocking of CD29 (heavy chain of beta1 integrins) totally prevented neutrophil adhesion and transendothelial migration. Pretreatment of neutrophils with either a CD29-stimulating monoclonal antibody or the addition of TNF-alpha (0.1-10 U/ml) to the coculture failed to induce transendothelial migration. However, coculture of endothelial cells with CD29-stimulated neutrophils in the presence of 0.1-10 U/ml TNF-alpha strongly induced neutrophil transmigration. CD29/TNF-alpha-mediated transmigration was associated with intracellular redistribution of endothelial beta-catenin. We further showed that CD29/TNF-alpha-mediated effects involved PI3K and tyrosine kinase-dependent signaling via MAPK but were independent of nuclear transcription factor (NF)-kappaB activity. Inhibition of CD29/TNF-alpha might be a therapeutic option to limit endothelial dysfunction following cardiac surgery with extracorporeal circulation.

Cell Movement↗

Extracorporeal circulation for renal cell carcinoma with supradiaphragmatic vena caval thrombi.

Extension of tumor into the vena cava occurs in 5 to 10 per cent of the cases of renal cell carcinomas. Of these cases 14 to 39 per cent may extend to or into the right atrium. Acceptable techniques for dealing with this situation include cross-clamping the atrium, using positive pressure ventilation and extracting the thrombus with a Fogarty or Foley catheter, and extracorporeal circulation or a cardiopulmonary bypass with open excision of the tumor extension. Since 1974 we have seen 2 men and 2 women, mean age 56 years, with clear cell renal carcinomas and supradiaphragmatic vena caval tumor extension (1 with additional pulmonary embolism). None had other evidence of metastatic disease determined on staging evaluation by celiac and renal angiography, liver scan, bone scan and chest tomography. Each patient was explored with the planned use of extracorporeal circulation or cardiopulmonary bypass, Greenfield vena caval filter insertion and standard radical nephrectomy. Resection was not done in 1 patient with biopsy proved tumor eroding through the right atrial wall. He died of disease in 8 months. Of the remaining 3 patients who had the tumors completely resected 1 is alive with recurrent disease in the retroperitoneum at 44 months, 1 died of metastatic disease to the bones and liver at 39 months, and 1 died 1 day postoperatively of technical complications with no evidence of residual disease at autopsy. In the absence of metastatic disease it seems reasonable to pursue a radical surgical approach in patients with renal cell carcinoma and supradiaphragmatic tumor thrombus. The use of extracorporeal circulation and post-extraction insertion of the Greenfield vena caval filter offers the surgeon the advantage of direct visualization and better vascular control in removing the thrombus, as well as protection from the possibility of post-extraction pulmonary embolism. With the combined use of these techniques, the previously hopeless situation for these patients has been improved.

Adenocarcinoma↗

Coronary flow distribution and dynamics during continuous and pulsatile extracorporeal circulation in the pig.

Four extracorporeal perfusion conditions (continuous beating, continuous fibrillating, pulsatile beating, and pulsatile fibrillating) were tested for 15 minutes each in pigs. Coronary flow, endocardial-epicardial flow ratio, phasic coronary flow, myocardial oxygen consumption, and myocardial lactate extraction were measured. No significant differences in any of these variables were found between pulsatile and continuous flow states in either fibrillating or beating hearts (p greater than 0.05). In both fibrillating conditions, significant elevations of myocardial oxygen consumption and decreases in endocardial-epicardial flow ratios were found (p less than 0.05). Lactate extraction occurred in all conditions, and phasic coronary flows were similar in both beating conditions. These data suggest caution in the expectation that pulsatile perfusion will reverse the coronary flow and myocardial oxygen consumption changes seen with fibrillation.

Animals↗

[Influencing of the kininogen-Kinin-System by means of a kallikrein-inhibitor during extracorporeal circulation in open heart surgery (author's transl)].

During extracorporeal circulation for open heart surgery an activation of the kininogen-kininsystem occurs with a decrease in plasma-kininogen-levels significantly exceeding the effect of haemodilution, and thus being due to an increased liberation of kinin. This effect could be suppressed by kallikrein inhibition by means of a protease-inhibitor.

Adult↗

Surgical correction of cor triatriatum dexter in a dog under extracorporeal circulation.

A shiba inu dog with marked abdominal distension was diagnosed with cor triatriatum dexter and surgical correction was performed under extracorporeal circulation. The total duration of cardiac arrest was 11 minutes and total perfusion time was 34 minutes. The dog had an uneventful postoperative recovery. Postoperative contrast radiography of the caudal vena cava revealed normal flow into the right heart. Abdominal distension was no longer observed. Although several methods have been used to treat cor triatriatum dexter in dogs, the authors consider surgical correction under extracorporeal circulation to be a reliable approach.

Animals↗

The effects of pulsatile versus non-pulsatile extracorporeal circulation on the pattern of coronary artery blood flow during cardiac arrest.

BACKGROUND: In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile versus non-pulsatile circulation to coronary artery flow and myocardial preservation in a cardiac arrest condition. METHODS: A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing 25-35 kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extracorporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the systemic arterial and coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of <0.05. RESULTS: The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p<0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p<0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p<0.05) except at 80 min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the systemic and coronary sinus blood (p=NS). CONCLUSION: In the cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.

Animals↗

Effects of prostaglandin E1 on platelet loss during in vivo and in vitro extracorporeal circulation with a bubble oxygenator.

Temporary inhibition of platelet function with prostaglandin E1 (PGE1) prevents platelets loss and functional alterations during extracorporeal circulation with a membrane oxygenator. This study evaluated the ability of PGE1 to prevent platelet injury in circuits containing a bubble oxygenator. During in vitro recirculation of human blood, the circulating platelet count, expressed as a percent of initial levels, decreased to 29%; platelets became insensitive to adenosine diphosphate (ADP) and to epinephrine; and plasma levels of low-affinity platelet factor 4 (LA-PF4) progressively rose to 7.4 microgram per milliliter. With PGE1 (1.2 micron), platelet counts remained stable at 92%; platelet reactivity remained normal for 1 hour; and plasma levels of LA-PF4 rose to only 3.3 microgram per milliliter. In rhesus monkeys that underwent cardiopulmonary bypass using a bubble oxygenator without PGE1, platelet counts, expressed as a percent of the prebypass platelet count, declined to 38%; platelets became insensitive to ADP; plasma levels of LA-PF4 progressively rose to 8.4 microgram per milliliter; and the mean postoperative bleeding time was 4.6 minutes. In monkeys that received PGE1, platelet counts declined to only 65%; platelets remained threefold more sensitive to ADP; platelets demonstrated delayed release of LA-PF4 and the mean postoperative bleeding time was 2.7 minutes. This report demonstrates that in a bubble oxygenator system, PGE1 reduces platelet loss, mitigates platelet injury, and shortens postoperative bleeding times following extracorporeal circulation.

Animals↗

[Microparticles in heart operations with extracorporal circulation (author's transl)].

Disturbances of the microcirculation during extracorporal circulation are not yet clearly understood. Many authors think that microembolism is reposible. In two groups of patients with different perfusion techniques we were looking for microparticles with a new constant pressure filtration method using the Agglometer r apparatus. During the by-pass no particles were found. Yet, we found particles in the priming when blood was used, in the suction blood and in special blood samples after contact with the pericardium. In these cases it was always possible to eliminate the particles with special filters. The particles in the suction blood seemed to originate from the extracardial blood portion coming from the pericardium. This portion seemed to be responsible for postoperative complications such as hemolysis and petechia. These complications could not be seen when extracardiac suction blood was eliminated or filtrated.

Adult↗

Extracorporeal circulation with perfluorochemicals (Fluosol-DA).

Experimental studies on extracorporeal circulation (ECC) with perfluorochemicals (Fluosol-DA) as a perfusate was performed to examine oxygen carrying capacity and its organ distribution using eight calves. Approximately 80% of the circulating blood volume was withdrawn before ECC and reinfused after completion of ECC. ECC time was 60 minutes in five of the calves and 120 minutes in three of the calves. Hct and Hb decreased to 4-12% and 1.7-6.6 g/dl during ECC. Fct (Fluorocrit: volume percentage of Fluosol-DA) ranged between 5 and 10%. PaO2 and PvO2 were 432-543 mmHg and 93-164 mmHg. Sixty-seven to 86% of the oxygen consumed by the tissues was delivered by Fluosol-DA. One of the complications of ECC with Fluosol-DA, hemolysis was observed in four of the calves which had a relatively high level of Fluosol-DA retention (13.9 g/kg) in the body after ECC. The retention volume of the other four calves which did not show hemolysis was 10.0 g/kg. Retention of Fluosol-DA after ECC was found to be greater in the reticuloendothelial system of the calves sacrificed earlier and became trace or minimal after 10 months.

Alanine Transaminase↗

Developing a small animal model of extracorporeal circulation.

To identify nonthrombogenic devices to be used in extracorporeal circulation (ECC), an efficient, small animal model is required. Initially, a venovenous (VV) model in rabbits was designed for this purpose and was a good representation of ECC. Technical difficulties in the VV model led to the development of a more simplistic arteriovenous (AV) model. Anesthetized, tracheotomized, 3-kg rabbits were used for both models. Circuits were constructed of PVC tubing. The VV model used 8-Fr umbilical artery catheters for both drainage and reinfusion, and the AV model used a 14-GA angiocatheter for carotid artery access and a 10-Fr thoracic catheter for venous access. The AV model included a chamber to mimic oxygenator or filter modeling. Hourly measurements included blood gases, platelet counts, and fibrinogen levels for the 4-hour studies. The VV ECC groups demonstrated platelet consumption like that seen in the clinical arena. The AV model demonstrated the same with or without additional surface area within the chamber. The AV model was deemed to be superior due to its simplicity, ability for filter modeling, and decrease in intensive monitoring. However, both models are excellent designs for nonthrombogenic surface testing.

Animals↗

The role of protein C as an inhibitor of blood clotting during extracorporeal circulation.

The plasma levels of protein C, AT III, the perioperative administration of fresh frozen plasma (FFP) and AT III concentrate were compared under the use of various drugs in a randomized, prospective double-blind study in 40 patients in whom an aortocoronary bypass operation was carried out. We formed four groups of ten patients: group A served as a control group, group B received a prostacyclin (PGI2) infusion of 10 or 20 ng/kg/min, group C high-dose aprotinin substitution, and group D was treated with a combination of prostacyclin and aprotinin. After an initial short-term rise in the inhibitors protein C and AT III, there was a fall in all groups in the further course of extracorporeal circulation. The initial preoperative values were reached again on the morning of the first postoperative day. This indicates a raised turnover and in association with this a raised rate of elimination of these factors caused by an increased thrombin activation during the extracorporeal circulation which cannot be prevented by the usual heparinization. Whereas prostacyclin had no effect on our results mediated by thrombocytic mechanisms, use of aprotinin led to a significant saving in the requirement for perioperative fresh frozen plasma and AT III substitution therapy. A clinical advantage of prostacyclin and aprotinin combination was not observed. In view of our results (individual analyses were mainly in the normal range), we consider that AT III and fresh frozen plasma should not be substituted routinely during or after extracorporeal circulation.

Aged↗

Metabolic aspects of acute tissue hypoxia during extracorporeal circulation and their modification induced by L-carnitine treatment.

In this study the authors examine the effects of acute hypoxia due to extracorporeal circulation (ECC) and the role played by L-carnitine treatment on some plasmatic metabolites linked to glycolytic cellular metabolism. To obtain biochemical data, 120 patients in extracorporeal circulation during aortopulmonary bypass surgery were evaluated. The patients received either sodium bicarbonate (40 patients), or L-carnitine during ECC (40 patients) or before and during ECC (40 patients), and plasma samples were collected before ECC, during ECC and after ECC. The levels of lactate and pyruvate showed significant alterations in sodium bicarbonate-treated patients, and there was also a considerable imbalance in the succinate/fumarate ratio. This means that tissue hypoxia due to ECC leads to cellular oxidative damage and to a considerable decrease in the intracellular energy pools. The use of L-carnitine antagonizes the oxidative stress, as is well documented by the levels of plasmatic metabolites which remain confined to normal amounts.

Bicarbonates↗

A new rotary blood pump for versatile extracorporeal circulation: the DeltaStream.

Today, rotary pumps are routinely used for extracorporeal circulation in different clinical settings and applications. A review of these applications and specific limitations in extracorporeal perfusion was performed and served as a basis for the development of the DeltaStream. The DeltaStreams is a miniaturized rotary blood pump of a new and unique design with an integrated drive unit. Despite its small design, the pump maintains a sufficient hydraulic capacity, which makes the DeltaStream very flexible for intra- and perioperative applications. It also opens the field for short-term ventricular assist devices (VAD) applications or use as a component in extracorporeal life support systems (ECLS). The DeltaStream and, specifically, its impeller design have been optimized with respect to haemolysis and nonthrombogenicity. Also, the pump facilitates an effective pulse generation in VAD applications and simulates heart action in a more physiological way than other rotary pumps or roller pumps. Hydraulic and haematological properties have been tested in vitro and in vivo. In a series of seven animal experiments in two different setups, the pump demonstrated its biocompatibility and applicability. Basic aspects of the DeltaStream pump concept as well as important console features are presented. A summary of the final investigation of this pump is given with focus on hydraulic capabilities and results from animal studies.

Animals↗

Significant reduction in blood loss in patients undergoing minimal extracorporeal circulation.

Several recent studies have shown differences in blood loss and allogeneic transfusion requirements between on-pump and off-pump coronary artery bypass grafting (CABG). Recently a new concept, the mini-extracorporeal circulation, was introduced to minimize the side effects of extracorporeal circulation. Therefore, there are no data comparing the three techniques with special emphasis to blood loss and transfusion requirements. Two hundred and eighty-five patients undergoing first-time coronary artery bypass grafting were retrospectively matched for number of grafts, age and sex. Ninety-five patients underwent surgery with the off-pump CABG (OPCAB) technique, 97 patients using conventional CABG with cold cardioplegia (CCABG) and 93 patients with the mini-extracorporeal circuit with warm blood cardioplegia (MCABG). Blood loss for the CCABG group with a mean loss of 819 +/- 557 mL and the OPCAB group with a mean loss of 870 +/- 768 mL was significant different compared to the MCABG group with a mean loss of 679 +/- 290 mL. The use of units red blood cell units was significantly higher for CCABG group and OPCAB group compared to the MCABG group. On the day of operation the use of platelet concentrate was significantly higher for the CCABG group compared to MCABG group. As a consequence of improvements of several components of the mini heart lung machine, significantly less blood products are needed in MCABG patients. The expected reduced need for transfusion when the pump was completely avoided could not be confirmed in this single retrospective cohort study.

Aged↗

[Changes in serum and urinary magnesium during and after extracorporeal circulation in cardiac surgery in children].

Magnesium plays an essential role in the processes of myocardial contraction and conduction. In cardiovascular surgery, extracorporeal circulation (ECC) in haemodilution results in various electrolyte distrubances, with invariably hypomagnesaemia. A group of 13 children undergoing open heart surgery was compared with a group of 17 children operated upon under the same conditions but with the addition of magnesium to the filling solution for the extracorporeal circulation. Changes in blood and urinary electrolytes during and after ECC were studied. Hypomagnesaemia was seen in both groups after surgery but the provision of magnesium supplements shortened the duration. In addition, blood phosphate levels remained significantly higher in the group receiving magnesium. The significance of these various findings is discussed and a technique for the provision of magnesium supplements is proposed.

Adolescent↗

[Low doses of aprotinin in reducing blood loss and allogenic transfusions in operation under conditions of extracorporeal circulation with using cell saver].

A blind prospective randomized investigation included 109 patients with ischemic heart disease undergoing operations of coronary shunting under conditions of extracorporeal circulation. It was shown that aprotinin in the dose of 3 ppm KIU in operations of coronary shunting under conditions of reserving autoblood, extracorporeal circulation and using cell saver facilitates reducing postoperative blood loss, but does not lead to less frequent allogenic transfusions.

Aprotinin↗

[Cellular injury associated with extracorporeal circulation].

Circulation of blood extracorporeally through plastic tubing causes severe shear stresses to blood cells and activates several regulatory cascades. These various pathways include the cytokine cascades, complement and coagulation. Interleukine-1, -6, -8, tumor necrosis factor-alpha have been implicated. Among various mediators of tissue injury released by activated neutrophils, elastase and metalloproteinases have been considered to be relevant in postoperative organ dysfunction in cardiac operations. Endothelial cells are extremely sensitive to insults that occur during cardiopulmonary bypass (CPB). These insults lead to disruption of barrier function and leukocyte adhesion. Immunoglobulins such as ICAM-1 and VCAM-1 are expressed on endothelium cells and act as ligands for integrins. It is also important to remember that during cardiac operations, the interest on the metabolism of in free radicals has focused on the heart and the lungs because they are exposed to ischemia and subsequent reperfusion. Increased production of free radicals during CPB is associated with myocardial and pulmonary dysfunctions. Now it is well recognized that the whole body inflammatory response induced by CPB is mainly responsible for postoperative organ dysfunctions.

Blood Coagulation↗