Effects of combined conventional and modified ultrafiltration in adult patients

Complete surgical myocardial revascularization in patients with declined renal functions: 12-month outcomes

INTRODUCTION

This retrospective observational study aimed to evaluate the feasibility and effectiveness of complete revascularization coronary artery bypass grafting (CABG) in patients with multi-vessel disease (MVD)-CAD and declined renal functions, addressing the knowledge gap regarding optimal treatment strategies and outcomes in this specific patient population.

METHODS

Between 2020 and 2022, a total of 58 patients underwent on-pump coronary artery bypass grafting surgery for complete myocardial revascularization in this study. To assess overall survival, Kaplan-Meier with the log-rank test was conducted for statistical analysis.

RESULTS

The mean age of cohort was 60.7. The findings showed a high prevalence of medical conditions such as hypertension (50.0%), diabetes (50.0%), and anaemia (41.4%) among the participants. Intraoperatively, low cardiac output syndrome was reported in 5.2% of cases, while perioperative outcomes indicated a need for transfusions in 53.5% of cases and an in-hospital mortality rate of 3.4%. At the 12-month follow-up, no redo revascularization or renal replacement therapy was required, but cardiac mortality was 5.2% and all-cause mortality was 6.9%.

CONCLUSIONS

The study concluded that complete revascularization is safe for these patients and highlights the potential benefits, emphasizing the need for further research in optimizing revascularization techniques for this population.

Association of Conventional Ultrafiltration on Postoperative Pulmonary Complications

BACKGROUND

Postoperative pulmonary complications increase mortality after cardiac surgery. Conventional ultrafiltration may reduce pulmonary complications by removing mediators of bypass-induced inflammation and countering hemodilution. We tested the primary hypothesis that conventional ultrafiltration reduces postoperative pulmonary complications, and secondarily, improves early pulmonary function assessed by the ratio of PaO2 to fractional inspired oxygen concentration.

METHODS

This retrospective analysis compared the incidence of postoperative pulmonary complications in adult patients who underwent cardiac surgery, with and without the use of conventional ultrafiltration, by using logistic regression with adjustment for confounding variables. The primary outcome was a composite of reintubation, prolonged ventilation, pneumonia, or pleural effusion. Secondarily, we examined early postoperative lung function using a quantile regression model. We also explored whether red blood cell transfusion differed between groups.

RESULTS

Of 8026 patients, 1043 (13%) received conventional ultrafiltration. After adjustment for confounding variables, the incidence of the composite primary outcome was higher in the conventional ultrafiltration group (12.1% vs 9.9%; P = .03), with an estimated odds ratio of 1.25 (95% CI, 1.02-1.53; P = .03). The median (quantiles) PaO2-to-fractional inspired oxygen concentration ratio was 373 (303-433) vs 368 (303-428), with the estimated adjusted difference in medians of 5 (95% CI, -5.9 to 16; P = .37). The estimated odds ratio of intraoperative transfusion was 1.38 (95% CI, 1.19-1.60; P < .0001) and for postoperative transfusion was 1.30 (95% CI, 1.14-1.49; P = .0001).

CONCLUSIONS

Use of conventional ultrafiltration was not associated with a reduction in the composite of postoperative pulmonary complications or improved early pulmonary function. We found no evidence of benefit from use of conventional ultrafiltration during cardiac surgery.

Role of urinary PO2 analysis during conventional versus conventional and modified ultrafiltration techniques in adult cardiac surgery

Background:

Medullary hypoxia is the initial critical event for kidney injury during cardiopulmonary bypass, and therefore urinary PO₂ with its potential of detecting medullary oxygenation for its management. Therefore, we tested the role of urinary PO₂ in predicting kidney injury in those undergoing conventional versus combined (conventional and modified) ultrafiltration during cardiac surgery in adults.

Methodology:

We prospectively evaluated 32 adults between 18 and 65 years of age undergoing elective on-pump cardiac surgery with ejection fraction >35% by conventional (group C) versus combined ultrafiltration (group CM). Urine samples were analyzed for PO₂ after induction, 30 min, 3 h, and 6 h post filtration along with blood urea and serum creatinine after induction, at 6 h, 24 h, and 48 h post filtration. Demographic variables, cardiopulmonary bypass duration, flow rates, inotropic score, ventilation duration, diuretic use, and intensive care unit (ICU) stay were assessed between two groups.

Results:

Both the groups (16 in each group) had comparable urinary PO₂ after induction (P = 0.387) with significant decrease in group C at 30 min, 3 h, and 6 h post filtration (P < 0.05). There was a statistically significant increase in serum creatinine (mg/dL) at 48 h in group C compared with group CM (1.57 vs. 1.25, respectively; P ≤ 0.05). There was an increased diuretic usage and length of ICU stay in group C.

Conclusion:

Combined ultrafiltration technique had renoprotective effect in cardiac surgery analyzed by urinary PO₂ levels.

Modified ultrafiltration reduces postoperative blood loss and transfusions in adult cardiac surgery: a meta-analysis of randomized controlled trials

OBJECTIVES

Cardiopulmonary bypass in cardiac surgery has been associated with several deleterious effects including haemodilution and systemic inflammation. Modified ultrafiltration (MUF) has been well established in paediatric cardiac surgery in counteracting postperfusion syndrome. However, MUF is less commonly used in adult cardiac surgery. In this meta-analysis, we compared clinical outcomes in adult patients who underwent cardiopulmonary bypass with and without MUF.

METHODS

Electronic searches were performed using Pubmed, Ovid Medline, EMBASE and the Cochrane Library until April 2020. Selection criteria were randomized studies of adult cardiac surgery patients comparing MUF versus no MUF. Primary outcomes were postoperative mortality, haematocrit, blood transfusion, chest tube drainage, duration of intensive care unit (ICU) stay and duration of mechanical ventilation.

RESULTS

Thirteen randomized controlled trials were included, comprising 626 patients in the MUF group, and 610 patients in the control (no-MUF) group. There was a significantly improved postoperative haematocrit [mean difference 2.70, 95% confidence interval (CI) 0.68-4.73, P = 0.009], lower chest tube drainage (mean difference -105 ml, 95% CI -202 to -7 ml, P = 0.032), lower postoperative blood transfusion rate (mean difference -0.73 units, 95% CI -0.98 to -0.47 units, P < 0.0001) and shorter duration of ICU stay (mean difference -0.13 days, 95% CI -0.27 to -0.00 days, P = 0.048) in the MUF group. There was no difference in ventilation time (mean difference -0.47 h, 95% CI -2.05 to 1.12 h, P = 0.56) or mortality rates (odds ratio 0.62, 95% CI 0.28-1.33, P = 0.22). There were no reported complications associated with MUF.

CONCLUSIONS

MUF is a safe and feasible option in adult cardiac patients, with significant benefits including improved postoperative haematocrit, as well as reduced postoperative chest tube bleeding, transfusion requirements and duration of ICU stay.

Continuous ultrafiltration during extracorporeal circulation and its effect on lactatemia: A randomized controlled trial

Introduction

Hyperlactatemia occurs during or after extracorporeal circulation in the form of lactic acidosis, increasing the risk of postoperative complications and the mortality rate. The aim of this study was to evaluate whether continuous high-volume hemofiltration with volume replacement through a polyethersulfone filter during the extracorporeal circulation procedure decreases postoperative lactatemia and its consequences.

Materials and methods

This was a randomized controlled trial. Patients were randomly divided into two groups of 32: with or without continuous high-volume hemofiltration through a polyethersulfone membrane. Five patients were excluded from each group during the study period. The sociodemographic characteristics, filter effects, and blood lactate levels at different times during the procedure were evaluated. Secondary endpoints were studied, such as the reduction in the intubation time and time spent in ICU.

Results

Lactatemia measurements performed during the preoperative and intraoperative phases were not significantly different between the two groups. However, the blood lactate levels in the postoperative period and at 24 hours in the intensive care unit showed a significant reduction and a possible clinical benefit in the hemofiltered group. Following extracorporeal circulation, the mean lactate level was higher (difference: 0.77 mmol/L; CI 0.95: 0.01–1.53) in the nonhemofiltered group than in the hemofiltered group (p<0.05). This effect was greater at 24 hours (p = 0.019) in the nonhemofiltered group (difference: 1.06 mmol/L; CI 0.95: 0.18–1.93) than in the hemofiltered group. The reduction of lactatemia is associated with a reduction of inflammatory mediators and intubation time, with an improvement in liver function.

Conclusions

The use and control of continuous high-volume hemofiltration through a polyethersulfone membrane during heart-lung surgery could potencially prevent postoperative complications. The reduction of lactatemia implied a reduction in intubation time, a decrease in morbidity and mortality in the intensive care unit and a shorter hospital stay.

Early continuous ultrafiltration in Chinese patients with congestive heart failure (EUC-CHF): study protocol for an open-label registry-based prospective clinical trial

BACKGROUND

Conventional pharmacologic therapies aim to reduce fluid overload in advanced heart failure (HF) represented by intravenous (IV) loop diuretics (LDs) have sometimes not so efficacious and been reported to have side effects such as unpredictable removal of water and sodium and electrolyte disturbance. It is not certain whether early ultrafiltration (UF) is effective than LDs in relieving edema. Given the weakness of evidence for early UF in patients with fluid overload, recommendations of UF in guidelines is considered as second-line therapy only for patients with refractory congestion, who failed to respond to LD-based strategies.

METHODS

The early continuous ultrafiltration in Chinese patients with congestive heart failure (EUC-CHF) trial is an open-label, registry-based, prospective study, recruiting patients with severe acute decompensated HF who are hospitalized for HF worsening due to overt fluid overload 24 h from hospital admission. Forty patients will be enrolled to two treatment groups (n = 20 for each group). The primary outcomes are the changes of weight loss and dyspnea severity score after treatment, as well as the occurrence of clinically overt major bleeding.

DISCUSSION

EUC-CHF trial was primarily designed to evaluate the efficacy and safety of early UF in patients with acute decompensated HF to reduce volume overload and improve clinical outcome. The trial aims to determine if early UF in acute HF is superior to IV LDs in clinical parameter improvement without adverse events and prevents rehospitalization up to 30 days. Also the trial is expected to establish a scoring system based on Chinese population to guide early UF treatment in appropriate patients. EUC-CHF is one of the first controlled trials tailored to determine the benefit of UF with 24 h from hospital admission.

TRIAL REGISTRATION

www.chictr.org.cn, ChiCTR1800019556. Registered on 18 November 2018.

The effects of modified ultrafiltration on clinical outcomes of adult and pediatric cardiac surgery

Background

Cardiopulmonary bypass (CPB) can contribute to the development of an inflammatory response and postsurgical morbidity. Conventional ultrafiltration and modified ultrafiltration (MUF) can mitigate the adverse effects of CPB by removing free water and inflammatory mediators, at least in part.

Objectives

To evaluate evidence for the effects of MUF on clinical outcomes of cardiac surgery in pediatric and adult patients.

Methods

A literature review of MEDLINE-indexed articles published between 1990 and June 2014 was conducted on PubMed. A search on the CTS.net website and the Cochrane Central Register of Controlled Trials was also performed with relevant keywords. The search was limited to English language articles and human studies.

Results

Our primary search identified 84 potential articles, of which 55 articles were relevant to conventional ultrafiltration, modified ultrafiltration, ultrafiltration, cardiopulmonary bypass, extracorporeal circulation, pediatric and adult cardiac surgery. There were 3 meta-analyses, 7 review literatures, 21 randomized controlled trials. The remainder consisted of 18 controlled and 6 observational studies. MUF has been beneficial effects on postoperative bleeding, chest drainage, transfusion requirement, and improvement cardiac function, but effects in adult cardiac surgery inconclusive because data was relatively limited.

Conclusions

MUF may improve post-CPB hemodynamic activity and cardiac function in pediatric cardiac surgery. By contrast, the clinical trials in adults are limited mostly by small sample sizes that preclude an adequately powered assessment of clinically relevant outcomes. The available data are conflicting and several studies show no differential outcomes. Further studies are required to identify patients who will most likely benefit from ultrafiltration and to establish standard protocols.

Does modified ultrafiltration reduce the systemic inflammatory response to cardiac surgery with cardiopulmonary bypass?

Cardiopulmonary bypass (CPB) is associated with an accumulation of total body water and a systemic inflammatory response syndrome (SIRS), which, in turn, is associated with organ dysfunction and postoperative morbidity. It has been suggested that modified ultrafiltration (MUF) may be capable of reducing SIRS and improving clinical outcome by filtering out the inflammatory mediators generated during CPB. This paper reviews the data regarding the use of MUF in paediatric and adult settings. Specifically, three issues will be considered: 1) Does MUF improve clinical outcome? 2) Does MUF reduce the systemic inflammatory response to cardiac surgery with CPB? 3) Is MUF more effective than conventional ultrafiltration in improving clinical outcome?

Cardiopulmonary bypass for a coronary artery bypass graft patient with heterozygous protein C deficiency and protein S deficiency

Cardiopulmonary bypass (CPB) poses great risks for hypercoagulable patients and requires management techniques to ensure an optimal outcome free from thrombotic events. This case report reviews perfusion management techniques that may contribute to a safer CPB experience for a patient deficient in both protein C and protein S. A patient with heterozygous protein C deficiency is at increased risk of thrombosis, especially in the venous circulation. Since it is an essential cofactor for activated protein C, deficiency of free protein S is also linked to a hypercoagulable condition.

A 52-year-old male presented to our institution with a past medical history of hypercoagulable state, multiple deep vein thromboses, pulmonary embolisms, and stroke. He was scheduled for two-vessel coronary artery bypass graft surgery to be followed by right carotid endarterectomy (RCEA) before discharge.

The anesthesia and perfusion teams worked closely together to ensure that fresh frozen plasma (FFP) was given intraoperatively at appropriate times. Heparin dose response and protamine dosage was determined with hemostasis management system (HMS) analysis. The closed CPB circuit and cannulae were Carmeda bonded. Rapid autologous priming, along with the use of a hemoconcentrator, kept the hematocrit above 21 during CPB. Zero-balance ultrafiltration and leukocyte depletion were initiated during rewarming to aid in attenuation of the inflammatory response. To conserve coagulation factors, all pump blood was ultrafiltrated post-CPB and returned to the patient.

Laboratory samples drawn on postoperative day (POD) one measured normal protein C activity with subnormal protein S activity. On POD six, the patient underwent RCEA and he was discharged on POD eight without complications.

Association of Hospital and Physician Characteristics and Care Processes With Racial Disparities in Procedural Outcomes Among Contemporary Patients Undergoing Coronary Artery Bypass Grafting Surgery

Background—

Previous studies have reported that black patients undergoing coronary artery bypass surgery had worse outcomes than white patients, even after accounting for patient factors. The degree to which clinician, hospital, and care factors account for these outcome differences remains unclear.

Methods and Results—

We evaluated procedural outcomes in 11 697 blacks and 136 362 whites undergoing isolated coronary artery bypass surgery at 663 Society of Thoracic Surgery Database participating sites (January 1, 2010 to June 30, 2011) adjusted for patients’ clinical and socioeconomic features, hospital and surgeon effects, and care processes (internal mammary artery graft and perioperative medications use). Relative to whites, blacks undergoing coronary artery bypass surgery were younger, yet had higher comorbidities and more adverse presenting features. Blacks were also more likely to be treated at hospitals with higher risk-adjusted mortality. The use of internal mammary artery was marginally lower in blacks than in whites (93.3% versus 92.2%, P <0.0001). Unadjusted mortality and major morbidity rates were higher in blacks than in whites (1.8% versus 2.5%, P <0.0001) and (13.6% versus 19.4%, P <0.0001), respectively. These racial differences in outcomes narrowed but still persisted after adjusting for surgeon, hospital, and care processes in addition to patient and socioeconomic factors (odds ratio, 1.17; 95% confidence interval, 1.00–1.36 and odds ratio, 1.26; 95% confidence interval, 1.19–1.34, respectively).

Conclusions—

The risks of procedural mortality and morbidity after coronary artery bypass surgery were higher among black patients than among white patients. These differences were in part accounted for by patient comorbidities, socioeconomic status, and surgeon, hospital, and care factors, as well, as suggested by the reduction in the strength of the race-outcomes association. However, black race remained an independent predictor of outcomes even after accounting for these differences.

Effect of Ultrafiltration on Pulmonary Function and Interleukins in Patients Undergoing Cardiopulmonary Bypass

OBJECTIVE

To evaluate the effect of ultrafiltration on interleukins, TNF-α levels, and pulmonary function in patients undergoing coronary artery bypass grafting (CABG).

DESIGN

Prospective, randomized, controlled trial.

SETTING

University hospital.

PARTICIPANTS

Forty patients undergoing CABG were randomized into a group assigned to receive ultrafiltration (UF) during cardiopulmonary bypass (CPB) or into another group (control) that underwent the same procedure but without ultrafiltration.

METHODS

Interleukins and TNF-α levels, pulmonary gas exchange, and ventilatory mechanics were measured in the preoperative, intraoperative, and postoperative periods. Interleukins and TNF-α also were analyzed in the perfusate of the test group.

MEASUREMENTS AND MAIN RESULTS

There were increases in IL-6 and IL-8 at 30 minutes after CPB and 6, 12, 24, and 36 hours after surgery, along with an increase in TNF-α at 30 minutes after CPB and 24, 36, and 48 hours after surgery in both groups. IL-1 increased at 30 minutes after CPB and 12 hours after surgery, while IL-6 increased 24 and 36 hours after surgery in the UF group. The analysis of the ultrafiltrate showed the presence of TNF-α and traces of IL-1β, IL-6, and IL-8. There were alterations in the oxygen index, alveolar-arterial oxygen difference, deadspace, pulmonary static compliance and airway resistance after anesthesia and sternotomy, as well as in airway resistance at 6 hours after surgery in both groups, with no difference between them.

CONCLUSIONS

Ultrafiltration increased the serum level of IL-1 and IL-6, while it did not interfere with gas exchange and pulmonary mechanics in CABG.

Venoarterial modified ultrafiltration versus conventional arteriovenous modified ultrafiltration during cardiopulmonary bypass surgery

BACKGROUND AND OBJECTIVES

Different types of modified ultrafiltration (MUF) systems evaluated showed that none of the MUF techniques adhered to the normal venous to arterial blood flow dynamics. This study compared a conventional arteriovenous modified ultrafiltration (AVMUF) system to a custom- designed venoarterial modified ultrafiltration (VAMUF) system.

DESIGN AND SETTINGS

Randomized, controlled clinical study conducted at the Northwest Armed Forces Military hospital in Tabuk, Saudi Arabia.

PATIENTS AND METHODS

Sixty patients who underwent MUF during the years 2007 and 2009 were divided into 2 groups: the AVMUF (n=30) and the VAMUF (n=30) groups. MUF was performed for a mean time of 12 minutes in both groups. In AVMUF, blood was removed from the aorta, hemoconcentrated, and infused into the right atrium (RA). In VAMUF, blood flow was from the RA through a hemoconcentrator and re-infused into the aorta.

RESULTS

Results of the study showed that the VAMUF group required a shorter ventilation time (P < .001), in.tensive care unit (ICU) (P=.003), and hospital stay (P=.007) than the AVMUF group. Results also demonstrated a lower percentage of fluid balance (P=.008) in the VAMUF group. The systolic (P < .001) and mean blood pres.sures (P < .001) were significantly higher after VAMUF, with a decrease in heart rate (P < .001) and central venous pressure (P=.002). The VAMUF group showed a significantly greater decrease of creatinine (P < .001), serum lactacte (P < .001), and uric acid (P < .027) over time with no significant differences in oximetry.

CONCLUSION

Results prove that VAMUF is a more physiological technique than AVMUF.

Techniques of extracorporeal cytokine removal: a systematic review of human studies

BACKGROUND AND AIMS

Hypercytokinemia is believed to be harmful and reducing cytokine levels is considered beneficial. Extracorporeal blood purification (EBP) techniques have been studied for the purpose of cytokine reduction. We aimed to study the efficacy of various EBP techniques for cytokine removal as defined by technical measures.

METHOD

We conducted a systematic search for human clinical trials which focused on technical measures of cytokine removal by EBP techniques. We identified 41 articles and analyzed cytokine removal according to clearance (CL), sieving coefficient (SC), ultrafiltrate (UF) concentration and percentage removed.

RESULTS

We identified the following techniques for cytokine removal: standard hemofiltration, high volume hemofiltration (HVHF), high cut-off (HCO) hemofiltration, plasma filtration techniques, and adsorption techniques, ultrafiltration (UF) techniques relating to cardiopulmonary bypass (CPB), extracorporeal liver support systems and hybrid techniques including combined plasma filtration adsorption. Standard filtration techniques and UF techniques during CPB were generally poor at removing cytokines (median CL for interleukin 6 [IL-6]: 1.09 mL/min, TNF-alpha 0.74 mL/min). High cut-off techniques consistently offered moderate cytokine removal (median CL for IL-6: 26.5 mL/min, interleukin 1 receptor antagonist [IL-1RA]: 40.2 mL/min). Plasma filtration and extracorporeal liver support appear promising but data are few. Only one paper studied combined plasma filtration and adsorption and found low rates of removal. The clinical significance of the cytokine removal achieved with more efficacious techniques is unknown.

CONCLUSION

Human clinical trials indicate that high cut-off hemofiltration techniques, and perhaps plasma filtration and extracorporeal liver support techniques are likely more efficient in removing cytokines than standard techniques.

The effect of normovolemic modified ultrafiltration on inflammatory mediators, endotoxins, terminal complement complexes and clinical outcome in high-risk cardiac surgery patients

Objective:

The clinical benefit of normovolemic modified ultrafiltration (N-MUF) after cardiac surgery is still debated. As we have shown in a previous publication, there is a significant improvement in platelet function, so we were interested in whether ultrafiltration can reduce plasma levels of endotoxins, terminal complement complexes and cytokines after cardiopulmonary bypass (CPB) in adults with increased risk profiles.

Methods:

In this single-center, prospective, randomized trial, fifty high-risk patients (mean logistic EuroSCORE II: 17.5%) who underwent cardiac surgery were randomized. After CPB, Group 1 (n = 25) served as the control and in, Group 2 (n= 25), an N-MUF of 3000 ml was performed, using a BC140plus filter after weaning from CPB. Blood samples were taken after the induction of anesthesia, before CPB, before CPB weaning, 30 minutes after CPB and at 6, 24 and 48 hours postoperatively. Primary outcomes were plasma levels of lipopolysaccharide-binding protein (LBP), terminal complement complex (C5b9) and cytokines (IL-6, IL-10, IL-1beta, TNF-α). Secondary outcomes focused on differences in the clinical outcome.

Results:

A significant reduction in LBP concentration (preoperatively: 23.8±8.4 pg/ml, postoperatively: 14.2±12.9 pg/ml) and C5b9 (preoperatively: 4.18±2.6 pg/ml, postoperatively: 3.05±2.39 pg/ml) were detected 6 hours after N-MUF. In the N-MUF group, significantly lower concentrations of lactate could be detected in the early postoperative period. Furthermore, postoperative chest tube blood loss was significantly lower in the N-MUF group at 24 and 48 hours.

Conclusions:

N-MUF leads to a significant reduction of lipopolysaccharide-binding protein and terminal complement complex and was associated with reduced blood loss and postoperative lactate concentrations shortly after surgery.

Perioperative Coagulopathy, Bleeding, and Hemostasis During Cardiac Surgery

Cardiac surgery patients use 10%-25% of the blood products transfused annually in the United States. The transfusion of red blood cells or blood products has been the subject of intense scrutiny over the past 10 years. Bleeding after cardiac surgery can be surgical or nonsurgical and lead to hemodynamic compromise and surgical reexploration. Because hemorrhage and blood product transfusions are associated with multiple negative outcomes, including increased mortality, it is prudent to understand the mechanisms responsible for nonsurgical bleeding. This review focuses on the physiology of the normal coagulation and fibrinolysis, risk factors associated with patients presenting for cardiac surgery, impairments of normal hemostasis associated with cardiac surgery and cardiopulmonary bypass (CPB), and potential interventions to reduce perioperative blood loss and blood transfusion.

ICU outcomes in adult cardiac surgery patients in relation to ultrafiltration type

Ultrafiltration (UF) is used to ameliorate the deleterious effects of cardiopulmonary bypass (CPB) in cardiac surgery patients. There are two different methods; conventional ultrafiltration (CUF), performed during CPB, and modified ultrafiltration (MUF), performed after CPB is finished. It has not been established which is better, and controversy remains regarding the optimal UF strategy. The objective of this study was to evaluate if MUF alone, or combined with CUF, could achieve greater fluid removal and contribute to better postoperative clinical outcomes. Also, the potential technique complications were studied. This was a prospective study which enrolled 125 consecutive adult patients receiving elective cardiac surgery with CPB. We analysed three treatment groups: MUF, CUF and both. Ultrafiltration was performed using a non-pulsatile CPB with a non-occlusive roller pump, Sarns 9000®, and a polysulfone ultrafilter, Minntech®. We studied pre- and intraoperative data and immediate postoperative clinical outcomes: total amount of drainage, transfusion needs, respiratory outcome, cardiac, renal and neurologic complications. Statistical analysis was performed using SPSS 11.0. All three groups were homogeneous and did not have differences in terms of demographic factors, previous history, risk scores, intervention and operative data. Volume of filtrate removal in the group which applied both techniques was larger than in the CUF or MUF groups alone (2569±823 vs 1679±651 vs 1398±353 ml, respectively, p=0.0001); however, despite this difference, there was no difference in the immediate postoperative fluid balances between the groups (596±1244 vs 880±1054 vs 986±1190 ml, p=0.30). Respiratory parameters and postoperative morbidity data analysed (total amount of drainage, transfusion needs, haemoglobin, acute lung injury, time with inotropes, ventricular failure, cardiogenic shock, neurologic complications and renal failure) were similar in all three groups, without statistical differences. Extubation time (10±7 vs 8.9±3 vs 9.4±7.9 hours, p=0.72) and ICU stay (56.6±72 vs 66.5±109 vs 44.2±25 hours, p=0.43) also were similar between the groups. We did not find any technique complication associated with any patient. In the present study, with adult patients receiving elective cardiac surgery, the combined ultrafiltration group had a larger fluid removal. However, neither type of ultrafiltration nor amount of filtered volume was accompanied by different postoperative ICU clinical outcomes. Ultrafiltration was considered a safe and reliable technique, with no related complications.

Perioperative blood transfusion and blood conservation in cardiac surgery: the Society of Thoracic Surgeons and The Society of Cardiovascular Anesthesiologists clinical practice guideline

BACKGROUND

A minority of patients having cardiac procedures (15% to 20%) consume more than 80% of the blood products transfused at operation. Blood must be viewed as a scarce resource that carries risks and benefits. A careful review of available evidence can provide guidelines to allocate this valuable resource and improve patient outcomes.

METHODS

We reviewed all available published evidence related to blood conservation during cardiac operations, including randomized controlled trials, published observational information, and case reports. Conventional methods identified the level of evidence available for each of the blood conservation interventions. After considering the level of evidence, recommendations were made regarding each intervention using the American Heart Association/American College of Cardiology classification scheme.

RESULTS

Review of published reports identified a high-risk profile associated with increased postoperative blood transfusion. Six variables stand out as important indicators of risk: (1) advanced age, (2) low preoperative red blood cell volume (preoperative anemia or small body size), (3) preoperative antiplatelet or antithrombotic drugs, (4) reoperative or complex procedures, (5) emergency operations, and (6) noncardiac patient comorbidities. Careful review revealed preoperative and perioperative interventions that are likely to reduce bleeding and postoperative blood transfusion. Preoperative interventions that are likely to reduce blood transfusion include identification of high-risk patients who should receive all available preoperative and perioperative blood conservation interventions and limitation of antithrombotic drugs. Perioperative blood conservation interventions include use of antifibrinolytic drugs, selective use of off-pump coronary artery bypass graft surgery, routine use of a cell-saving device, and implementation of appropriate transfusion indications. An important intervention is application of a multimodality blood conservation program that is institution based, accepted by all health care providers, and that involves well thought out transfusion algorithms to guide transfusion decisions.

CONCLUSIONS

Based on available evidence, institution-specific protocols should screen for high-risk patients, as blood conservation interventions are likely to be most productive for this high-risk subset. Available evidence-based blood conservation techniques include (1) drugs that increase preoperative blood volume (eg, erythropoietin) or decrease postoperative bleeding (eg, antifibrinolytics), (2) devices that conserve blood (eg, intraoperative blood salvage and blood sparing interventions), (3) interventions that protect the patient's own blood from the stress of operation (eg, autologous predonation and normovolemic hemodilution), (4) consensus, institution-specific blood transfusion algorithms supplemented with point-of-care testing, and most importantly, (5) a multimodality approach to blood conservation combining all of the above.

Cerebral oxygen saturation changes during modified ultrafiltration

Background: A number of adverse effects are associated with the use of cardiopulmonary bypass (CPB) in pediatric patients undergoing cardiac surgery. Pulmonary compliance and gas exchange are decreased, and myocardial edema may result in diastolic dysfunction. Modified ultrafiltration (MUF) after CPB in children decreases body water, removes inflammatory mediators, improves hemodynamics, and decreases transfusion requirements.

Purpose: To determine the factors that influence cerebral tissue oxygenation during MUF. Pediatric patients received the usual treatment, with MUF times from 10 to 19 min, as determined by circuit volume and patient hemodynamic stability.

Results: Preliminary results in five patients with arterial saturation >95% during MUF demonstrates four predictors of cerebral oxygenation, using stepwise multiple linear regression with cerebral oxygen saturation as the dependant variable. In order of significance, they are pCO2, ultrafiltration flow rate, mean arterial pressure, and hematocrit.

Conclusions: The results of this study will be used to determine the optimal performance of MUF. Maximizing cerebral oxygen delivery during this early post-bypass period is extremely important, and identifying the factors responsible for increased cerebral oxygen delivery during MUF allows the clinician to make the appropriate changes necessary to achieve this.

Ultrafiltration reduces blood transfusions following cardiac surgery: a meta-analysis

BACKGROUND

Although used routinely in pediatric patients, ultrafiltration techniques that reverse hemodilution are infrequently used in adults. Data from small, unblinded clinical trials suggest that the use of ultrafiltration can reduce inflammatory mediators, improve cardiac function, and reduce hemodilution. We conducted a meta-analysis of randomized trials to evaluate the effects of ultrafiltration on blood transfusions and blood loss following adult cardiac surgery.

METHODS

Medline, EMBASE, and Cochrane databases were searched and randomized controlled trials evaluating modified and/or conventional ultrafiltration, meeting pre-determined selection criteria, were obtained. Quality evaluation and data extraction were performed by two independent observers blinded to study source. Random effects models were used to determine pooled effect estimates and sources of heterogeneity were explored using meta-regression.

RESULTS

One hundred and thirty two studies were screened and 10 randomized trials evaluating 1004 patients (control, n = 495; ultrafiltration, n = 509) were identified of which only two were double-blinded. The use of ultrafiltration was associated with a reduction in postoperative blood transfusions (weighted mean difference [95% CI] of -0.73 units [-1.16, -0.31]; p = 0.001). This reduction was greater in studies evaluating modified ultrafiltration. Use of ultrafiltration was also associated with reduced postoperative bleeding (-70 ml, [-118, -21]; p = 0.005), which was driven primarily by trials evaluating modified rather than conventional ultrafiltration.

CONCLUSIONS

Use of ultrafiltration is associated with a significant reduction in postoperative blood transfusions as well as reduced bleeding in adults undergoing cardiac surgery. The efficacy and cost-effectiveness of ultrafiltration as a blood conservations strategy should be evaluated in a large, randomized, double-blinded study.

On-pump versus off-pump coronary artery bypass grafting: impact on postoperative renal failure requiring renal replacement therapy

BACKGROUND

Despite refinements in perioperative patient management postoperative renal failure requiring hemofiltration or dialysis is still a common complication after coronary artery bypass grafting associated with impaired patient outcome.

METHODS

Prospective data on 9,631 patients receiving myocardial revascularization with (coronary artery bypass grafting [n = 8,870]) or without cardiopulmonary bypass (off-pump coronary artery bypass grafting [n = 761]) between April 1996 and August 2001 were evaluated by univariate and multivariate logistic regression analysis.

RESULTS

Overall prevalence of postoperative continuous renal replacement therapy was 4.1% (coronary artery bypass grafting, 4.3%; off-pump coronary artery bypass grafting, 1.8%; p = 0.001). Thirty of 40 selected preoperative and intraoperative patient and treatment related variables had a high association with the requirement for postoperative renal replacement therapy; fifteen of these variables were independent predictors in the whole study population. Off-pump coronary artery bypass surgery was identified as having a significantly lower predictive value for postoperative continuous renal placement therapy. In the subgroup of patients undergoing off-pump coronary artery bypass grafting surgery, a second multivariate logistic regression model revealed preoperative cardiogenic shock, urgent operation, intraoperative low cardiac output, and high transfusion requirement as independent predictors for postoperative renal replacement therapy.

CONCLUSIONS

Patients with preoperative nondialysis dependent renal insufficiency are at a high risk for further decline in renal function requiring postoperative continuous renal replacement therapy. Off-pump coronary artery bypass surgery is associated with a lower prevalence of postoperative renal replacement therapy after coronary artery bypass grafting.

Effect of Modified Ultrafiltration on Inflammatory Mediators, Coagulation Factors, and Other Proteins in Blood after an Extracorporeal Circuit

Modified ultrafiltration (MUF) is a technique able to remove the excess body fluid and inflammatory mediators associated with the use of a cardiopulmonary bypass (CPB). It has been shown to reduce morbidity after cardiac operations in children. Application of MUF after adult cardiac operations has also been suggested being associated with a lower prevalence of early morbidity. However, the relationship between the concentration of mediators in the blood and postoperative morbidity remains yet to be proved. In this study, changes of various chemical mediators in the filtrate and blood before and after MUF have been evaluated in adult patients. Significant reductions of blood levels of inflammatory cytokines were not observed after MUF. On the other hand, MUF significantly elevated hematocrit, number of red cells, concentrations of albumine, coagulation Factor VII and X, platelet factor (PF)-4, and antithrombin (AT-) III.

Coronary Bypass Grafting for Patients Dependent on Dialysis: Modified Ultrafiltration for Perioperative Management

Coronary bypass grafting for patients on chronic dialysis has increased the risk of operative mortality, and long-term survival is considered poor. Thirty-three patients dependent on dialysis undergoing coronary bypass grafting were analyzed. The 33 patients were divided into two groups according to the strategy for renal support. In group A, 12 patients underwent continuous hemofiltration (CHF) during and after cardiopulmonary bypass and CHF in an intensive care unit (ICU) and then returned to regular dialysis. In group B, 21 patients underwent modified ultrafiltration (UF) immediately after cardiopulmonary bypass and continuous hemodialysis and filtration in an ICU with early reinstitution of regular dialysis. Two patients died in group A, and there were no operative deaths in group B (17% vs. 0%, p < 0.05). Three patients in group A and one patient in group B had bleeding complications requiring reoperation (25% vs. 5%, p < 0.05). Three patients in group A and one patient in group B needed intraaortic balloon pump (IABP) support postoperatively (25% vs. 5%, p < 0.05). Four patients in group A and one in group B required long-term ventilation of more than 3 days (33% vs. 5%, p < 0.05). There were five patients in group A and two patients in group B requiring long-term ICU stay of more than 4 days (41% vs. 10%, p < 0.05). Postoperative blood loss within 24 hours was 1310 ml in group A and 623 ml in group B (p < 0.05). Transfusion requirements were 9.3 units in group A and 3.0 units in group B (p < 0.05). During follow-up, the long-term survival, New York Heart Association (NYHA) functional class, and incidence of recurrent angina were considered favorable in both groups. Cardiac event-free rates after surgery at 1, 3, and 5 years were 88%, 73%, and 67%, respectively. The operative mortality, morbidity, and long-term survival for dialysis dependent patients were reasonably acceptable. As renal support, modified UF can play an important role in reducing bleeding complications, shortening the ICU stay, and decreasing blood loss and transfusion requirements.

Best Practice for Cardiopulmonary Bypass in the High-Risk Elderly Patient

The management of cardiopulmonary bypass has evolved over the last 50 years resulting in a largely consistent approach to both adult and pediatric perfusion. Very little has been written or prospectively researched on the best practice for cardiopulmonary bypass in the high-risk elderly patient, despite the challenge this patient cohort presents compared to the general adult population and the rapidly increasing number of such patients undergoing cardiac surgery. We propose a framework for perfusion strategies for the high-risk elderly patient from our current understanding of cardiopulmonary bypass. It should stimulate discussion for a consensus on perfusion strategies for the elderly and encourage further research into perfusion variables as they relate to the outcome of patients of advanced age.

The effect of race on coronary bypass operative mortality

OBJECTIVES

The study was done to determine whether race is an independent predictor of operative mortality after coronary artery bypass graft (CABG) surgery.

BACKGROUND

Blacks are less frequently referred for cardiac catheterization and CABG than are whites. Few reports have investigated the relative fate of patients who undergo CABG as a function of race.

METHODS

The Society of Thoracic Surgeons National Database was used to retrospectively review 25,850 black and 555,939 white patients who underwent CABG-alone from 1994 through 1997. A multivariate logistic regression model was developed to determine whether race affected risk-adjusted operative mortality.

RESULTS

Operative mortality was 3.83% for blacks versus 3.14% for whites (unadjusted black/white odds ratio [OR] 1.23 [1.15-1.31]). Blacks were younger, more likely female, hypertensive, diabetic and in heart failure. Nonetheless, the influence of these and other preoperative risk factors on procedural mortality was quite similar in black and white patients. After controlling for all risk factors, race remained a significant independent predictor of mortality in the multivariate logistic model (adjusted black/white OR 1.29 [1.21, 1.38]). Proportionately, these differences were greatest among lower-risk patients. The race-by-gender interaction was significant (p<0.05). The unadjusted mortality for black men, 3.30% and white men, 2.64% differed significantly (p<0.05), whereas for women there was no difference (black, 4.49%; white 4.41%).

CONCLUSIONS

Black race is an independent predictor of operative mortality after CABG except for very high-risk patients. The difference in mortality is greatest for male patients and, though statistically significant, is small in absolute terms. Therefore, patients should be referred for CABG based on clinical characteristics irrespective of race.