Effects of Extracorporeal Circulation on Renal Function in Coronary Surgical Patients (original) (raw)
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Renal haemodynamics and oxygenation during and after cardiac surgery and cardiopulmonary bypass
Acta physiologica (Oxford, England), 2017
Acute kidney injury (AKI) is a common complication following cardiac surgery performed on cardiopulmonary bypass (CPB) and has important implications for prognosis. The aetiology of cardiac surgery-associated AKI is complex, but renal hypoxia, particularly in the medulla, is thought to play at least some role. There is strong evidence from studies in experimental animals, clinical observations and computational models, that medullary ischaemia and hypoxia occurs during CPB. There are no validated methods to monitor or improve renal oxygenation during CPB, and thus possibly decrease the risk of AKI. Attempts to reduce the incidence of AKI by early transfusion to ameliorate intra-operative anaemia, refinement of protocols for cooling and rewarming on bypass, optimisation of pump flow and arterial pressure, or the use of pulsatile flow, have not been successful to date. This may in part reflect the complexity of renal oxygenation, which may limit the effectiveness of individual interve...
Anesthesia & Analgesia, 1998
We prospectively studied the effects of renal protection intervention in 17 patients with preoperative abnormal renal function (plasma creatinine > 1.5 mg/dL) scheduled for elective coronary surgery. Patients were randomized to either dopamine 2.0 micrograms.kg-1.min-1 (Group 1, n = 10) or perfusion pressure > 70 mm Hg during cardiopulmonary bypass (CPB) (Group 2, n = 7). Glomerular filtration rate and effective renal plasma flow were measured with inulin and 125I-hippuran clearances before the induction of anesthesia, after sternotomy and before CPB, during hypo- and normothermic CPB, after sternal closure, and 1 h postoperatively. Plasma and urine electrolytes were measured, and free water, osmolar, and creatinine clearances, as well as fractional excretion of sodium and potassium, were calculated before and after surgery. Significant differences between groups were found before CPB for glomerular filtration rate (higher in Group 1), urine output (2.0 vs 0.29 mL/min in Group 1 versus Group 2), urinary creatinine (66 vs 175 mg/dL), urinary osmolarity (370 vs 627 mOsm/L), osmolar clearance (2.1 vs 0.7 mL/min), and urinary potassium (33 vs 71 mEq/L). There were no differences between groups during hypo- and normothermic CPB. After CPB, the only difference was a slightly higher urinary creatinine in Group 2. Renal plasma flow was lower than normal in all patients before the induction of anesthesia. A nonsignificant trend toward increased flow was seen during hypothermic CPB. Filtration fraction was high before CPB, which suggests efferent arteriolar vasoconstriction, descending toward normal during and after CPB. The same pattern of changes was present in both groups. In conclusion, there were no clinically relevant differences between the two treatment modalities during and after CPB. However, significant differences were observed before CPB, when dopamine seemed to partially revert renal vasoconstriction. Two protective interventions were compared in patients undergoing heart surgery to prevent deterioration of renal function; these were dopamine infusion throughout the operation and phenylephrine infusion during cardiopulmonary bypass. We found clinically relevant differences only during surgery before cardiopulmonary bypass.
Physiological reports, 2015
Acute kidney injury, a prevalent complication of cardiac surgery performed on cardiopulmonary bypass (CPB), is thought to be driven partly by hypoxic damage in the renal medulla. To determine the causes of medullary hypoxia during CPB, we modeled its impact on renal hemodynamics and function, and thus oxygen delivery and consumption in the renal medulla. The model incorporates autoregulation of renal blood flow and glomerular filtration rate and the utilization of oxygen for tubular transport. The model predicts that renal medullary oxygen delivery and consumption are reduced by a similar magnitude during the hypothermic (down to 28°C) phase of CPB. Thus, the fractional extraction of oxygen in the medulla, an index of hypoxia, is increased only by 58% from baseline. However, during the rewarming phase (up to 37°C), oxygen consumption by the medullary thick ascending limb increases 2.3-fold but medullary oxygen delivery increases only by 33%. Consequently, the fractional extraction o...
During the last decade, minimized extracorporeal circulation (MECC) systems have shown beneficial effects to the patients over the conventional cardiopulmonary bypass (CECC) circuits. This is a prospective randomized study of 99 patients who underwent coronary artery bypass grafting (CABG) surgery, evaluating the postoperative haematological effects of these systems. Less haemodilution (p=0.001) and markedly less haemolysis (p<0.001), as well as better preservation of the coagulation system integrity (p=0.01), favouring the MECC group, was found. As a clinical result, less bank blood requirements were noted and a quicker recovery, as far as mechanical ventilation support and ICU stay are concerned, was evident with the use of MECC systems. As a conclusion, minimized extracorporeal circulation systems may attenuate the adverse effects of conventional circuits on the haematological profile of patients undergoing CABG surgery.
Beating heart coronary surgery and renal function: a prospective randomised study
2001
Introduction: It has been suggested that mild hypothermia during cardiopulmonary bypass (CPB) may attenuate, but not completely suppress, the production of interleukin-8 (IL-8) in the brain [1]. This study examined the effect of repeated deep hypothermic circulatory arrest (DHCA) on production of IL-8 and myeloperoxidase (MPO) in the cerebrovascular bed in patients undergoing pulmonary thromboendarterectomy (PTE). Methods: After LREC approval and written informed consent, we studied eight patients undergoing PTE. Anaesthetic and surgical technique were strictly standardized [2] and all patients had a jugular bulb catheter inserted after induction. After initiation of CPB, all patients were cooled to below 20°C and underwent at least two periods of DHCA for 20 min. Each DHCA period was separated by a 10-min reperfusion interval. The levels of IL-8 and MPO were measured in paired arterial and jugular samples drawn simultaneously at specific time points, using enzyme-linked immunoassay kits. Juguloarterial (j-a) gradients were then calculated. All data are expressed as median (interquartile range) and were compared with the baseline values using the Wilcoxon signed rank sum test. J-a gradients were compared with zero using one-sample t-test. Results: The baseline arterial values before CPB [T1] for IL-8 and MPO were 12.9 (11.5-21.4) pg/ml and 4.5 (3.1-6.6) ng/ml, respectively . For both IL-8 and MPO, arterial levels significantly increased before the first DHCA [T3] to 28.3 (21.6-43.1) pg/ml and 31.2 (26.1-11.7) ng/ml, respectively, and remained elevated until 8 min following the second DHCA [T7]. However, no significant j-a differences for IL-8 and MPO were found throughout this period. Conclusions: These data imply that the cerebral activation of inflammatory processes represented as specific IL-8 and MPO production in the cerebrovascular bed are suppressed during repeated DHCA in the present study. 2. Wilson WC, Vuylsteke A: Anaesthesia for Pulmonary Endarterectomy. In Thoracic Anaesthesia. Edited by Ghosh S, Latimer RD. Oxford: Butterworth & Heinemann; 1999:223-234.
Renal Function During Cardiopulmonary Bypass
Anesthesia & Analgesia, 1996
The influence of systemic blood flow (pump flow) and arterial blood pressure on renal function was studied during hypothermic cardiopulmonary bypass (CPB) in 14 male patients where the pump flow rate was varied between 1.45 and 2.20 1. mitt-' rnm2. Renal blood flow (RBF) was measured in the left renal vein with retrograde thermodilution technique and urinary flow and circulatory variables were measured with an on-line computer setup. During CPB the RBF comprised 12-13% of the systemic blood flow and was positively related to systemic blood pressure (r=0.71; PcO.001) and pump flow rate (r=O.69;P<O.O01). These findings indicate that the renal autoregulation was not operative during the hypothermic CPB period. According to multiple regression analysis, RBF was primarily determined by the pump flow rate and systemic blood pressure was of secondary importance. Urinary flow increased during hypothermic CPB and became closely related to blood pressure and pump flow. According to multiple regression analysis, urinary flow was primarily determined by systemic blood pressure.
Renal function in patients undergoing cardiopulmonary bypass for open cardiac surgical procedures
Sri Lankan Journal of Anaesthesiology, 2013
Renal dysfunction following cardiopulmonary bypass is a frequent complication of open heart surgery. Acute renal failure requiring dialysis occurs in approximately 1.5% of patients following cardiac surgery and remains a cause of major morbidity and mortality. Method: Sixty-five patients of either sex in the age group of 10-50 years scheduled to undergo various cardiac procedures were included in this study. All patients had normal preoperative levels of serum creatinine, blood urea nitrogen, blood glucose levels, urine analysis, 24 hour urinary protein < 200 mg, and normal 24 hour creatinine clearance. After surgery, patients were transferred to an intensive care unit for postoperative management and monitoring. Patients were shifted to cardiovascular and thoracic surgery ward as soon as their clinical condition permitted. Blood urea nitrogen, serum creatinine, 24 hour creatinine clearance was performed on day one and day seven of postoperative period. Result: Postoperative oliguric acute renal failure was 7.7% and overall mortality was 6.1%. We found no association between aortic cross clamp time and postoperative renal dysfunction. Conclusion: Optimisation of cardiac performance post cardiopulmonary bypass seems to be the most important factor in the prevention of postoperative renal dysfunction in patients requiring total cardiopulmonary bypass.
Review article : Renal function and open-heart surgery
Perfusion
Renal function and open-heart surgery HM Koning Medical Centre, Leeuwarden lntroduction Postoperative acute renal failure is a frequent complication of open-heart surgery, associated with a high mortality rate. While the acute circulatory and respiratory complications of openheart surgery can be successfully managed, the prognosis and mortality of renal complications remain disappointing. In the postoperative period