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Results for “Extracorporeal Circulation”

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At least 91 records · Page 5Linked to original sources
PubMed1993

Effects of extracorporeal circulation on blood ketone body ratio reflecting hepatic energy metabolism during cardiac operation.

To examine the effects of extracorporeal circulation using an artificial heart and lung machine on hepatic energy metabolism in patients with cardiac operation using hypothermia, the arterial blood ketone body ratio (AKBR) reflecting the hepatic mitochondrial redox state was determined in 12 patients who had undergone cardiac operation using extracorporeal circulation from March to August 1991. Changes in AKBR were compared with those before and after extracorporeal circulation. AKBR decreased significantly after the beginning of extracorporeal circulation (p < 0.001) and remained at a lower level throughout extracorporeal circulation. On termination of extracorporeal circulation, the initial level was immediately resumed. The extent of decrease in ketone body ratio at ten minutes before termination of extracorporeal circulation was correlated with short term postoperative hepatic insufficiency. The patients whose ratio decreased below 0.4 showed increased levels in glutamic-pyruvic transaminase at the end of the first and second week after operation. Changes in AKBR were significantly associated with those in blood pressure (r = 0.433; p < 0.005) and body temperature (r = 0.472; p < 0.005). It was concluded that blood pressure and body temperature influence the blood ketone body ratio during extracorporeal circulation.

Adolescent↗
PubMed1992

Autacoids affecting vascular tone in the human fetal extracorporeal circulation.

1. The human fetal extracorporeal circulation is normally a vasodilated, low pressure system. 2. As this vasculature lacks innervation, autacoids have been postulated as being of great importance in controlling its tone. 3. This has now been confirmed by pharmacological in vitro techniques, particularly utilizing perfusion of the isolated umbilical cord and placental lobule. 4. The fetal umbilical-placental vessels are sensitive to a wide range of vasoconstrictor autacoids, some of which can cause intense vasospasm. 5. Thromboxane A2 receptors have been identified in both umbilical vein and placental villous vessels. 6. Prostacyclin and endothelial cell-derived relaxing factor (or nitric oxide) may be largely responsible for the low vascular resistance normally found in the fetal extracorporeal circulation. 7. Immediately after birth it is likely that stimuli such as cooling, stretching and handling of the umbilical cord cause release of eicosanoids and other autacoids from the vessels, leading to their complete closure.

Autacoids↗
PubMed2003

Surgical myocardial revascularization without extracorporeal circulation.

OBJECTIVE: To assess the immediate postoperative period of patients undergoing myocardial revascularization without extracorporeal circulation with different types of grafts. METHODS: One hundred and twelve patients, 89 (79.5%) of whom were males, were revascularized without extracorporeal circulation. Their ages ranged from 39 to 85 years. The criteria for indicating myocardial revascularization without extracorporeal circulation were as follows: revascularized coronary artery caliber > 1.5 mm, lack of intramyocardial trajectory on coronary angiography, noncalcified coronary arteries, and tolerance of the heart to the different rotation maneuvers. RESULTS: Myocardial revascularization without extracorporeal circulation was performed in 112 patients. Three were converted to extracorporeal circulation, which required a longer hospital stay but did not impact mortality. During the procedure, the following events were observed: atrial fibrillation in 10 patients, ventricular fibrillation in 4, total transient atrioventricular block in 2, ventricular extrasystoles in 58, use of a device to retrieve red blood cells in 53, blood transfusion in 8, and arterial hypotension in 89 patients. Coronary angiography was performed in 20 patients on the seventh postoperative day when the grafts were patent. CONCLUSION: Myocardial revascularization without extracorporeal circulation is a reproducible technique that is an alternative for treating ischemic heart disease.

Adult↗
PubMed2003

[Interstitial microdialysis study of changes in metabolism and blood flow in skeletal muscles during cardiac surgery with normothermic and hypothermic extracorporeal circulation].

AIM: Hypoperfusion of peripheral tissues and splanchnic organs during cardiac surgery in extracorporeal circulation may lead to the origin of serious complications. The aim of the study was to monitor metabolism and blood pressure in interstital peripheral tissue, skeletal muscle, during the operation on the patient with extracorporeal circulation (ECC) in an early post-operation period by means of microdialysis. METHODS: The interstitial microdialysis is a minimally invasive method for the biochemical monitoring of metabolic changes and blood pressure in extracellular space of tissue. The substances in interstitium pass across a semipermeable membrane of the inserted microdialysis probe and may be analyzed. Microdialysis in this study was performed by means of two microdialysis probes CMA (CMA Microdialysis AB, Sweden) inserted into the deltoid muscle of the surgically treated patient. The probes were perfused by the Ringer solution at the rate of 0.3 ml/hour. The dialysates were sampled in the following intervals: beginning of the operation, beginning of ECC, end of ECC, end of the operation, two hours during the post-operation period. Standard biochemical methods were to evaluate, in the dialysates, glucose, urea, glycerol and lactate. The blood flow in the interstitium was monitored by means of dynamic microdialysis of gentamycine as a marker. Microdialysis was performed in 40 patients with ischemic heart disease, operated on in the extracorporeal circulation. In 20 patients the ECC was performed in normothermia (NT), while in the other 20 patients it was made in hypothermia (HT). RESULTS: In both groups, NT versus HT, a similar dynamism of interstitial concentration of the observed substances in relation to the operation phase and in early post-operation period. Low initial concentrations were gradually increasing during the extracorporeal circulation and increased further after the end of extracorporeal circulation and also in the subsequent phase of the operation. The concentration values of the analytes under observation were higher in the groups operated on under normothermia, apparently due to normal cellular activity during normothermia (versus values in hypothermia). Immediately after the operation the observed values decreased in the both groups and subsequently gradually increased in the post-operation period in the both groups. The trend of dynamic changes of the observed analytes, selected as compounds indicating metabolic activity of skeletal muscles during hypothermia documents a lower metabolic activity of the cells during hypothermia and its marked increase (against NT) in the phase of subsequent normalization of the tissue temperature. Analysis of the concentrations of lactate, as a compounds mapping anaerobic metabolism of skeletal muscle, revealed similar dynamic changes in the both groups (NT vs. HT). There were no significant differences, related to the phase of the operation or the phase of immediate post-operation course when the both groups were compared. The analysis of gentamycine concentrations as a flow marker revealed lower gentamycine concentrations in dialysate during the operation, ECC and the early post-operation course in the group operated on in normotheramia (vs. HT), indicating a higher tissue flow in skeletal muscle against the group of patients operated on under hypothermia. CONCLUSION: The results of the microdialysis study demonstrated dynamic changes in interstitial concentrations of the observed compounds (glucose, urea, glycerol and lactate) related to the phase of operation on the heart in extracorporeal circulation and in early post-operation period. A higher perfusion of skeletal muscle was documented in patients operated on under normothermia. It became obvious that the dynamism in the changes of the compounds observed in the interstitium of skeletal muscle was determined by metabolic activity of the tissue as well as by blood flow in the muscle interstitium.

Aged↗
PubMed2000

[Alteration of nitric oxide production during arterial myocardial revascularization using extracorporeal circulation. Quantitative measurement of EDNO production by the internal mammary artery bypass graft].

Authors measured the concentration of stable metabolite (NO2: nitrite) of EDNO (endothelium derived nitric oxide) in the internal mammary artery (IMA) bypass graft with the help of a previously reported method (measurement of effective blood flow capacity of the IMA graft in the coronary sinus). Nitrite level in the systemic circulation prior to extracorporeal circulation (ECC)--(68.1 +/- 6.7 mumol/l) was measured, as well as nitrite concentration in the coronary circulation before and after construction of the IMA bypass graft (62.1 +/- 4.19 mumol/l and 50.26 +/- 4.0 mumol/l respectively). Furthermore, nitrite level in the IMA graft free cut end flow was also determined (64.3 +/- 5.9 mumol/l). These data compared to the nitrite levels in the normal plasma (48.1 +/- 5.9 mumol/l) were found to be higher (p = 0.1, ns.), possibly due to the enhanced EDNO production induced by total heparinization. The nitrite concentration in the IMA free cut end flow is similar or slightly higher than that of the native coronary circulation, however, after IMA bypass construction a relative reduction could be measured in the coronary sinus. Authors believe, that this may be related to the reduction of basal EDNO production caused by supernormal pO2 (215 +/- 19 mmHg) during ECC.

Adult↗
PubMed2001

Aprotinin but not epsilon-aminocaproic acid decreases interleukin-10 after cardiac surgery with extracorporeal circulation: randomized, double-blind, placebo-controlled study in patients receiving aprotinin and epsilon-aminocaproic acid.

BACKGROUND: Extracorporeal circulation induces a systemic inflammatory response, which may adversely affect organ function. One manifestation of this response is increased fibrinolysis. Antifibrinolytic drugs such as aprotinin and epsilon-aminocaproic acid have been effective in reducing fibrinolysis and blood loss after extracorporeal circulation; however, the effects of antifibrinolytic drugs on proinflammatory and anti-inflammatory mediators are not known. This study examined the effects of aprotinin and epsilon-aminocaproic acid on plasma levels of proinflammatory [interleukin-6 (IL-6)] and anti-inflammatory [interleukin-10 (IL-10)] cytokines during and after extracorporeal circulation. METHODS AND RESULTS: Seventy-two patients undergoing coronary artery bypass grafting with extracorporeal circulation were randomly assigned in a double-blind study to receive high-dose aprotinin, epsilon-aminocaproic acid, or saline placebo. Plasma levels of IL-6 and IL-10 were measured at 5 time points before, during, and after extracorporeal circulation. In all 3 groups, both IL-6 and IL-10 rose significantly after institution of extracorporeal circulation and remained elevated through the first postoperative day. Compared with saline, aprotinin significantly reduced IL-10 (P=0.02) and peak IL-6 (P=0.02) after extracorporeal circulation. In contrast, none of the reductions in IL-6 and IL-10 by epsilon-aminocaproic acid achieved statistical significance. Both aprotinin and epsilon-aminocaproic acid decreased blood loss compared with saline, but there was no significant difference in the number of patients receiving blood products among the treatment groups. CONCLUSIONS: These data suggest that aprotinin and epsilon-aminocaproic acid differ in their effects on the inflammatory response to extracorporeal circulation. Aprotinin but not epsilon-aminocaproic acid appears to attenuate the rise in the proinflammatory and anti-inflammatory cytokines IL-6 and IL-10. Further studies will be required to determine if these cytokine alterations translate to changes in clinical outcomes.

Aminocaproic Acid↗
PubMed2003

The effect of s-nitroso-glutathione on platelet and leukocyte function during experimental extracorporeal circulation.

Treatment with extracorporeal membrane oxygenation ECMO) is associated with side effects, e.g., blood cell consumption and activation. Our group has earlier shown that nitric oxide administered as a gas reduces platelet consumption and activation. In the present work we have studied the effect of the NO-donor S-nitroso-glutathione GSNO) on platelets and leukocytes in an in vitro extracorporeal circuit. Two complete ECMO circuits were perfused with fresh heparinized human blood for 24 hours. GSNO was administered as a continuous infusion to one circuit at a rate of 0.7 mg/hour in four paired experiments and at a rate of 3.5 mg/hour in another four paired experiments. The other circuit was used as a control. Blood samples were withdrawn from both circuits before the start of the experiments and at 0.5, 1, 3, 12, and 24 hours of perfusion. The samples were analyzed for red blood cell count, leukocyte count, platelet count, platelet membrane expression of glycoproteins GP) Ib and GPIIb/IIIa, leukocyte membrane expression of cluster of differentiation CD) 11b/CD18, as well as plasma concentration of tumor necrosis factor TNF)-alpha, interleukin IL)-1beta, and IL-8. No difference in these parameters between the GSNO and the control circuit at any time point was assayed. In this study, no significant effect of GSNO on circulating platelets or leukocytes during experimental extracorporeal circulation could be shown.

Blood Cell Count↗
PubMed2003

Coronary artery bypass graft with minimal extracorporeal circulation.

BACKGROUND: To evaluate the advantages and benefits of a minimized extracorporeal circulation system in the performance of coronary artery bypass grafts. METHODS: From September 2000 to February 2003, 279 consecutive patients underwent isolated coronary artery bypass grafting with minimal extracorporeal circulation. A group of 243 patients at good risk as defined by a Euro- SCORE of 3 underwent complete bypass and blood cardioplegia, and a high-risk group of 45 patients (EuroSCORE, 6) underwent operations with partial assistance and a beating heart. In a prospective substudy analysis of thrombocyte and platelet counts, transfusion requirements, PaO2/FIO2, leukocyte count, C-reactive protein level, postoperative bleeding, intensive care unit stay, and ventilation, 40 patients from the good-risk group were matched and compared with 40 patients who underwent operations with a conventional extracorporeal system. RESULTS: Revascularization was complete with a mean of 2.8 distal anastomoses in the good-risk group and 2.4 in the high-risk group. Mortality rates were 1.2% and 4%, respectively. The system provided either complete or partial bypass assistance and depended on preload and afterload. The system also allowed easy access to all territories with perfect hemodynamic stability. Priming was reduced to 400 mL, and arterial and venous saturation monitoring revealed excellent maintenance of pH values. No complications or failure of the system occurred. Hemodilution, inflammatory response, and transfusion requirements were reduced in the minimal extracorporeal circulation group. CONCLUSIONS: Minimal extracorporeal circulation allows minimal hemodilution and reduces transfusion requirements. The method allows safe and complete revascularization of either an arrested or a beating heart.

Aged↗
PubMed2003

Angiogenin: a novel inhibitor of neutrophil lactoferrin release during extracorporeal circulation.

Degranulation of polymorphonuclear leukocytes (PMNL) occurs during extracorporeal circulation. A degranulation-inhibiting protein identical to angiogenin was recently isolated from high-flux dialyzer ultrafiltrate. This protein inhibits the release of lactoferrin and metalloproteinases from PMNL in vitro. In the present study, we investigated end-stage renal disease patients undergoing regular hemodialysis treatment with either high-flux dialyzers (n = 51) or low-flux dialyzers (n = 44), and chronically uremic patients undergoing hemodiafiltration (n = 30). Hemodialysis therapy with low-flux polysulfone or cellulose triacetate membranes caused no or only minimal reduction (</=8%) of plasma angiogenin levels within 2 h of dialysis treatment associated with a 1.6-fold lactoferrin release from PMNL. Hemodialysis therapy with high-flux membranes (e.g. cellulose triacetate, polymethylmethacrylate) or hemodiafiltration resulted in a reduction of plasma angiogenin levels by 20-40% after 2 h associated with a nearly 4-fold PMNL lactoferrin release. The release of PMNL elastase was not affected by the different treatment modalities used. We conclude that high angiogenin plasma levels protect against lactoferrin release from PMNL during extracorporeal circulation in chronically uremic patients. A decrease of plasma angiogenin between 20 and 40% during extracorporeal circulation, however, results in marked PMNL lactoferrin release. This novel mechanism may explain, at least in part, PMNL degranulation also in non complement activating high-flux membranes.

Adult↗
PubMed1990

[Extracorporeal circulation as a risk factor in heart surgery].

Extracorporeal circulation has a complex influence on the biology of the various organ systems. Knowledge of interactions with biomaterials and the resultant pathophysiological reactions is still very limited. The safety of the heart-lung machine lies, to a great extent, in the hands of the operator; precautions against breakdowns and accidents are necessary. The effects of the extracorporeal circulation process manifest themselves clinically as organ malfunctions. The risk is clearly associated with the age of the patient and the duration of the procedure. The fact that the extracorporeal circulation--and with it the heart operation--affects not just a single organ, but rather the entire organism, requires detailed knowledge of the general state of health of the patient to be operated upon. Only on this basis can the necessary individual operational strategies be developed.

Aged↗