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At least 19 recordsLinked to original sources
PubMed1989

A clinical study of cerebral circulation during extracorporeal circulation.

The objective of this study is to clarify the relationship of cerebral blood flow to extracorporeal circulation flow and mean arterial pressure during nonpulsatile extracorporeal circulation under moderate hypothermia. Cerebral blood flow was determined by an argon saturation and desaturation method after that of Pevsner and colleagues with a mass spectrometer in 21 adult patients undergoing cardiac operations. Cerebral blood flow was 25, 33, 35, and 42 ml/100 gm/min, ranging from 19 to 50 ml/100 gm/min, at extracorporeal circulation flow rates of 40, 50, 60, and 70 ml/kg/min, respectively. Cerebral blood flow increased proportionally to extracorporeal circulation flow. Cerebral blood flow scattered almost transversely to mean arterial pressure and was 31 ml/100 gm/min in a hypotensive group (mean arterial pressure 34 to 50 mm Hg) and 34 ml/100 gm/min in another group (mean arterial pressure 51 to 94 mm Hg). Mean arterial pressure did not significantly influence cerebral blood flow. Cerebral oxygen consumption did not remarkably decrease and remained in the reasonable range when cerebral blood flow was 23 to 40 ml/100 gm/min. Subsequently, we assumed that the average cerebral blood flow value of 25 ml/100 gm/min at an extracorporeal circulation flow rate of 40 ml/kg/min also would be in the safe range. All of the patients are living without cerebral complications. We conclude that (1) cerebral blood flow was extracorporeal circulation flow dependent and (2) cerebral blood flow in the safe range was maintained even in the hypotensive range, provided the extracorporeal circulation flow rate was 40 ml/kg/min or higher.

Adolescent↗
PubMed1992

[Effect of prostaglandin E1 treatment on peripheral circulation during extracorporeal circulation--with special reference to its influence on body temperature recovery].

In patients undergoing open heart surgery, we assessed the effect of prostaglandin E1 (PGE1) treatment, 0.1 micrograms/min/kg dosage, during extracorporeal circulation. This treatment resulted in a marked perfusion pressure reduction. As a result, PGE1-treated group showed less urine volume than untreated control group. However, the degree of urine volume reduction relative to the decrease in blood pressure was less in PGE1-treated group than in untreated control group, suggesting a diuretic action of PGE1. We infer from these results that renal blood flow was maintained even after PGE1-induced intense perfusion pressure reduction, allowing for avoidance of renal impairment during extracorporeal circulation. In PGE1-treated adults, recovery of rectal temperature after hypothermic extracorporeal circulation was poorer but that of muscle temperature was better than in untreated adults. This phenomenon can be interpreted as representing improvement of blood-mediated heat transfer from deep regions of trunk to muscles and superficial skin due to PGE1-induced improvement of peripheral circulation. The ameliorative effect of PGE1 on peripheral circulation during extracorporeal circulation was further confirmed by the fact that the amount of NaHCO3 required for correction of metabolic acidosis was significantly lower in PGE1-treated group than in untreated control group. These results indicate that PGE1 treatment during extracorporeal circulation makes body temperature control easier, favorably affects postoperative body temperature recovery and improves peripheral tissue metabolism.

Alprostadil↗
PubMed1987

Significant reduction in the binding of a monoclonal antibody (LYP 18) directed against the IIb/IIIa glycoprotein complex to platelets of patients having undergone extracorporeal circulation.

Extracorporeal circulation (ECC) used in open heart surgery gives rise to several hemostatic defects. This work investigates the effect of ECC on patient platelets membrane glycoproteins IIb/IIIa. A monoclonal antibody (LYP 18) directed against the IIb/IIIa complex was used on patient platelets in binding and flow cytometry studies, before and at the end of ECC. An antithrombospondin (LYP 8) monoclonal antibody and a monoclonal antibody (LYP 7) directed against an alpha-granule glycoprotein of 136 kdaltons, present on the platelet surface after secretion, were used in binding studies together with electron microscopy to assess the release of alpha-granules. Results obtained in 7 patients show a significant reduction (p less than 0.02) in the number of LYP 18 monoclonal antibody binding to platelets having undergone ECC (n = 49,725 +/- 16,275) compared to platelets drawn before ECC (n = 72,671 +/- 13,302). Flow cytometry studies indicate a decrease (p less than 0.02) in the percentage of platelets bearing the LYP 18 determinant following ECC (75 +/- 12% vs 66 +/- 14%). Binding of monoclonal antibodies LYP 8 and LYP 7 and electron microscopy studies of patient platelets having undergone ECC do not show degranulation. These results suggest possible cleavage of the IIb/IIIa complex following ECC but no release of alpha-granules.

Aged↗
PubMed1989

[Lung inflation or mechanical ventilation in extracorporeal circulation?].

Extracorporeal circulation (ECC), with its shock-like pulmonary perfusion, leads to pathomorphologic and functional pulmonary changes, the postperfusion syndrome. This study investigated the effects of different types of ventilation during ECC on postoperative pulmonary function and the resulting pulmonary blood gas changes. METHOD. Thirty patients scheduled for aortocoronary bypass surgery were studied. Patients with pre-operative left ventricular end-diastolic pressures exceeding 15 mmHg or signs of right ventricular failure, pulmonary hypertension, or pre-existing pulmonary disease were excluded. The patients were randomly assigned to one of the following three groups: Group 1 (n = 10): static pulmonary inflation during ECC, PEEP 5-10 cm H2O, F1O2 1.0; Group 2 (n = 10): low-frequency ventilation during ECC, rate 10/min, PEEP 5 cm 5H2O, F1O2 1.0; Group 3 (n = 10): medium-frequency ventilation during ECC, rate 120/min, PEEP 5 cm 5H2O, F1O2 1.0. The measurements were made under relative steady-state conditions before the start of surgery and postoperatively after an equilibrium phase of at least 15 min. During ECC using a bubble oxygenator (Bentley BOS 10 S) in moderate hypothermia, blood was aspirated from the pulmonary artery during inflation of the wedge balloon and blood gases were analyzed. Postoperative changes in pulmonary function were evaluated by venous admixture (QVA/Qt); changes in pulmonary vascular resistance after ECC were determined using the pulmonary pressure-flow relationship. RESULTS. In group 1, QVA/Qt rose significantly from 9.6 +/- 2.9% preoperatively to 13.6 +/- 3.5% postoperatively (P less than 0.05, t-test for paired samples). In groups 2 and 3, postoperative QVA/Qt was significantly lower than preoperative QVA/Qt (P less than 0.05; group 2: preoperative 11.9 +/- 3.5%, postoperative 8.1 +/- 2.6%; group 3: preoperative 11.9 +/- 3.0%, postoperative 7.8 +/- 3.2%; Fig. 1). The postoperative pulmonary pressure-flow relationship changed similarly in all three groups (Fig. 2). During ECC, blood aspirated from the pulmonary artery during inflation of the wedge balloon was fully oxygenated with a hematocrit approximating that of arterial blood. In ventilated patients, pO2 during ECC was higher in pulmonary arterial blood than in arterial blood. Pulmonary ventilation during ECC did not lead to pulmonary arterial alkalosis. CONCLUSIONS. Pulmonary ventilation during ECC can prevent a post-operative increase in venous admixture. ECC-related pulmonary vascular changes were not affected by ventilation. Middle-frequency ventilation offers no advantage over low-frequency ventilation during ECC, except that the operating field is more quiet.

Acid-Base Equilibrium↗
PubMed1976

Degradation of circulating DNA by extracorporeal circulation over nuclease immobilized on nylon microcapsules.

Studies were undertaken to determine whether deoxyribonuclease I, (DNase I) once immobilized on activated nylon microspheres, would be capable of degrading circulating DNA in vitro and in vivo in an extracorporeal circulation system in dogs. Nylon microspheres were prepared and after gentle hydrolysis and glutaraldehyde treatment, demonstrated a retention of up to 4.73 mg of Dnase I. In vitro studies showed that DNase I immobilized on microspheres degreded a significant percentage of 125I-native DNA (nDNA) within 15 min. Mongrel dogs were injected with 125I-nDNA and a variation in initial t 1/2 in individual animals was observed. Therefore, for experimental studies, 125I-nDNA was injected and decay was recorded during a control period in which untreated microcapsules were utilized in the extracorporeal system. DNase I microspheres were then introduced into the extracorporeal circuit which resulted in an acceleration of degradation of acid precipitable 125I-nDNA. When 200 mug of unlabeled DNA with 125I-nDNA was injected, a similar augmentation of DNA degradation was noted after extracorporeal circulation over DNase I microcapsules. This effect could not be attributed to release of DNase I from the microspheres since no 131I-DNase was detected in the serum or organs of the dogs at the conclusion of the experiments. 125I-nDNA:anti-DNA complexes were passively injected into dogs and after a similar control period of circulation over untreated microcapsules. DNase I microspheres were introduced. Results showed a rapid acceleration in the degradation rate of 125I-nDNA:anti-DNA complexes precipitable with (NH4)2SO4. Extracorporeal circulation over nylon microspheres resulted in no significant alteration of the host's hematocrit or platelet count, and little residual cellular debris on the microcapsules. These data suggest that DNAase immobilized on nylon microspheres may have a potential role in the specific therapy of systemic lupus erythematosus, when it is desirable to hydrolyze DNA circulating free or in combination with antibody.

Animals↗
PubMed1990

Cardiovascular and hormonal changes following haemorrhage in the anaesthetized Brattleboro rat with an extracorporeal circulation.

An extracorporeal circulation technique was developed for use in rats to provide equilibrated blood samples for multiple hormone assays. The inclusion of the extracorporeal circulation did not significantly alter arterial blood pressure, cardiac output, heart rate or central venous pressure in either Brattleboro rats with hereditary diabetes insipidus (BDI) or normal rats of the parent Long Evans (LE) strain. Plasma adrenaline and noradrenaline levels did not alter in either BDI or LE rats following inclusion of the extracorporeal circulation but the vasopressin concentration rose significantly in the LE rats. The impaired recovery of the mean arterial blood pressure following haemorrhage in the BDI rats compared with normal LE animals was not further influenced by the inclusion of the extracorporeal circulation. Plasma vasopressin and adrenaline (but not nor-adrenaline) levels were significantly raised during, and after, haemorrhage in the LE rats while in the BDI rats only plasma adrenaline levels were significantly increased. These results show that the insertion of an extracorporeal circulation into an anaesthetized BDI or LE rat does not adversely affect the cardiovascular system despite the increase in baseline plasma vasopressin concentration in normal rats, and its subsequent removal provides an additional equilibrated blood sample for multiple hormone assay within the same animal. The increased release of both adrenaline and vasopressin (but not noradrenaline) after haemorrhage in the same animal is detected using this technique, and the importance of vasopressin to the normal recovery process confirmed.

Anesthesia↗
PubMed1992

[Influence of thiopental administration on peripheral circulation during cardiac surgery with extracorporeal circulation].

The influence of thiopental administration on peripheral circulation during cardiac surgery with extracorporeal circulation was examined. The subjects were 28 patients who were divided into one group of 14 patients receiving thiopental and the other group of 14 patients receiving no thiopental. The time lag of changes in peripheral temperature (sole) from that in central temperature (forehead) according to the deep body temperature determination, and base excess were used as indices of the quality of the peripheral circulation. A single shot of thiopental at a dose of 4 mg.kg-1 was initially given i.v. at the start of extracorporeal circulation and subsequently thiopental at a dose of 2 mg.kg-1.hr-1 was continuously infused i.v. up to the time of the aortic declamping. The results indicate a significantly smaller lag in the group receiving thiopental than in the group receiving no thiopental. Base excess was maintained within normal limits in the former group compared with negative base excess in the latter group as well as a significantly smaller requirement of postoperative catecholamine in the former group. The above findings suggest that thiopental administration during cardiac surgery with extracorporeal circulation is not only useful for maintaining peripheral circulation, but also beneficial for post-operative cardiac function.

Aged↗
PubMed1975

[Renal functions and extracorporeal circulation].

During 76 extracorporeal circulations (CEC) carried out for open heart operations using an identical protocol, the authors carried out renal function tests from the time of administration of the anesthetic to the post-operative period. Various periods may be distinguished: pre-operative, anesthesia induction (CEC 1, CEC 2) post induction (CEC 1, post CEC 2) finally, the post-operative period (post-operative 1 to 4). As far as renal hemodynamics are concerned, the authors made the following observations: constant reduction in thiosulphate clearance and endogenous creatinine clearance, which reflect glomerular filtration. Reduction in PAH clearance, which reflects renal perfusion. Taking into consideration changes in the hematocrit, one may consider that there is a reduction in renal blood flow at all stages of anesthesia. Taking into consideration concomitant variations in blood pressure, one may calculate that intrarenal resistances are increased. The diuresis/minute increases in very great proportions during induction of anesthesia. Plasma osmolality also increases, urinary osmolality becomes reduced and osmolar clearance rises. The ratio between osmolar clearance and creatinine clearance rises. The clearance of free water rises from negative values. The serum sodium becomes slightly reduced, and sodium diuresis increases. Serum potassium becomes slightly reduced and urinary potassium rises. The interpretation of these phenomena is difficult and should take into consideration the experimental conditions. Comparison with published results shows that there are definite differences depending on whether pure or diluted blood is used. It is however, possible to seek the role of the anesthetic, the thoracotomy or the extracorporeal circulation itself and its load, quite independent of prior changes due to decompensation or not of the congenital heart disease, whether or not it has been treated. The study of these changes in renal function permits one to understand better the precariousness of renal perfusion during extracorporeal circulation, imperfectly corrected by osmotic diuresis and responsible for transient and reversible renal hypofunction, liable to lead however, in cases of complications and prolonged low blood flow, to organic renal failure.

Adolescent↗
PubMed1989

[In vivo protective action of urinastatin during extracorporeal circulation].

A patient undergoing extracorporeal circulation is in the state of controlled shock. The object of the present study is to investigate the prophylactic effect of ulinastatin (6000 U.kg-1 or 12000 U.kg-1 during extracorporeal circulation by a randomized study. Although the ratio of lactic acid/pyruvic acid did not show significant changes, the increase was inhibited in 12000 U.kg-1 treated group. In 12000 U.kg-1 treated group, beta-glucuronidase reflecting the function of lysosomal membrane, as well fibronectin reflecting the endothelial function, were suppressed. The results of the present study indicate that administration of ulinastatin 12000 U.kg-1 is effective and useful for the organism.

Extracorporeal Circulation↗
PubMed1990

The influence of extracorporeal circulation on erythrocytes and flow properties of blood.

The influence of extracorporeal circulation on red blood cells and flow properties of blood was studied in 10 patients undergoing aorta-coronary bypass grafting. Blood samples were drawn on admission, under general anesthesia before the operation, during extracorporeal circulation, immediately after extracorporeal circulation, and 24 hours after extracorporeal circulation. Echinocytes were found during and shortly after extracorporeal circulation, but disappeared within 24 hours. Washing the cells in buffer restored the normal discocytic shape, which indicated that a plasma factor was responsible. Red cell membrane lipids were not affected. Analysis of the membrane proteins revealed a decrease of ankyrin after extracorporeal circulation, which was prevented by protease inhibitors during preparation. This suggests an increased proteolytic activity of the plasma after extracorporeal circulation. Red cell deformability was not altered. Plasma viscosity and hematocrit were markedly reduced by hemodilution with the priming solution. Their low levels resulted in a low blood viscosity during extracorporeal circulation, which was even lower at 26 degrees C than before or after the operation at 37 degrees C. We conclude that the red cell is affected by extracorporeal circulation. The flow properties of blood, however, are not impaired, but are improved by hemodilution.

Aged↗
PubMedDate not supplied

Coronary circulation and myocardial oxygen consumption after extracorporeal circulation and after cardioplegic arrest.

The influence of haemodilution or of blood perfusion on the coronary circulation, myocardial oxygen consumption and on haemodynamic parameters was examined in two comparable groups of patients with slight congenital acyanotic cardiac malformation without indications of myocardial damage. In a third group of patients similar data were collected before and after artificial cardiac arrest by cardioplegic solutions. No findings concerning this question could be found in the literature. Coronary circulation was measured by the argon-gas-technique of Bretschneider et al. A fall in haemoglobin of 4.8% caused by haemodilution resulted in the first group in an increase in the cardiac index of about 8% and an increase in the coronary circulation of about 100% over the initial value with a simultaneous decrease in the coronary resistance due to coronary dilatation and reduction in blood viscosity. The myocardial O2 consumption was raised in spite of an increase in the coronary-venous O2 saturation and a clear reduction in the AVD O2. In contrast, the patients in the blood perfusion group showed no change in the coronary circulation and coronary resistance although a decrease of the myocardial O2 consumption was observed. The cardiac index fell to about 16% in these patients. After cardioplegic cardiac arrest there was no significant reduction in myocardial blood flow except for a decrease of myocardial oxygen consumption of about 20% The results are discussed and cantra-indications of haemodilution perfusion and cardioplegic cardiac arrest mentioned.

Cardiac Output↗
PubMed1992

Estimation of total body fluid shifts between plasma and interstitium in man during extracorporeal circulation.

Fluid transport between plasma and interstitium during extracorporeal circulation was studied in seven patients undergoing aortocoronary bypass grafting. The absolute shifts in plasma volume during hypothermia were determined as the difference between input and loss of fluid and the changes in blood volume. The change in haemoglobin concentration due to acute haemodilution when starting extracorporeal circulation was used to calculate the absolute blood and plasma volume. The Starling equation for exchange across the capillary wall was used to describe fluid shifts. The total fluid filtered during the 60- to 90-min period of extracorporeal circulation averaged 34.1 +/- 11.1 (s.d.) ml/min. The total body filtration coefficient from the Starling relationship averaged 0.046 +/- 0.012 ml/kg.mmHg.min (0.354 +/- 0.092 ml/kg.kPa.min). Haemodilution, reducing colloid osmotic pressure in plasma (COPP) by approximately 10 mmHg (1.3 kPa) will result in a loss of plasma fluid of around 2 1 per hour. When corrected for lower fluid viscosity due to hypothermia during extracorporeal circulation, CFC would be about 40% higher, and a filtered volume of nearly 3 1 in a normothermic 70-kg person would be expected. Crystalloid haemodilution for shorter periods of time does not produce excessive oedema and thus may be well tolerated.

Aged↗
PubMedDate not supplied

Prophylactic administration of tranexamic acid preserves platelet numbers during extracorporeal circulation in rabbits.

Neonatal extracorporeal life support is associated with platelet consumption and hemostatic disorders. This study in rabbits was undertaken to evaluate the effect of heparin coating and of the plasminogen and plasmin inhibitor, tranexamic acid on platelet consumption during extracorporeal circulation. Fibrinogen consumption was prevented by heparin coating, but platelet consumption was only prevented after the prophylactic administration of tranexamic acid. The authors concluded that inhibition of the fibrinolytic system had a specific effect on preserving platelet numbers, rather than improving the thromboresistance of the artificial surface. The main advantage of a heparin coating is the anticoagulant activity of the surface. Thus systemic heparinization can be reduced or omitted.

Animals↗