A prospective randomized study comparing volume-standardized modified and conventional ultrafiltration in pediatric cardiac surgery

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.

Preventing transfusion-associated hyperkalemia in pediatric cardiac surgery: Measure the levels of potassium in packed red blood cells before using - Invited commentary

The authors present a revolutionary study aiming to evaluate the effect of alterations in potassium concentrations in transfused packed red blood cells (PRBC) on the neonate and infant potassium levels after congenital cardiac surgery. By establishing a strict protocol that restricts the rate of transfusion, the age of the transfused PRBC, and not transfusing a PRBC with a potassium level above 15 mmol/L, they accomplished to suggest a safe and easy way for preventing transfusion-associated hyperkalemia.

Effects of modified ultrafiltration and conventional ultrafiltration combination on perioperative clinical outcomes in pediatric cardiac surgery: A meta-analysis

BACKGROUND

This meta-analysis was performed to review the effects of the addition of modified ultrafiltration (MUF) and conventional ultrafiltration (CUF) to CUF alone on postoperative hemoglobin, surgical and ultrafiltration data, and postoperative clinical outcomes in pediatric patients undergoing cardiac surgery.

METHODS

A systematic search was performed to identify randomized controlled clinical trials that compared MUF and CUF combination with CUF alone in pediatric cardiac surgery undergoing cardiopulmonary bypass (CPB) in PubMed, Embase, Cochrane Library, and Web of Science without any language or date limitation in February 2020. For each included trial, the primary outcomes including post-CPB and postoperative hematocrit, surgical and ultrafiltration data, postoperative clinical outcomes including volume of chest tube drainage within 48 hours after surgery and perioperative blood requirement, ventilation support duration, and length of stay day in the intensive care unit (ICU) and hospital were collected and analyzed. The analysis was conducted using STATA version 12.0.

RESULTS

A total of 8 trials encompassing 405 patients were included in this analysis. Analysis indicated that MUF + CUF increased the post-CPB hematocrit (Standard mean difference, SMD = 1.85, 95% confidence interval, 95% CI 0.91-2.79). Meanwhile, ultrafiltration volume was higher in CUF+MUF infants than CUF-alone infants (SMD = 1.46, 95% CI 0.51-2.41, P = .003). The clinical outcomes, including postoperative hemodynamic changes, prime volume, blood requirement, chest tube drainage volume, mechanical ventilation duration, and ICU duration, were unclear because of the unstable sensitivity analyses.

CONCLUSIONS

Beneficial effects of using MUF and CUF for pediatric cardiac surgery, including increase post-CPB hematocrit and ultrafiltration volume when compared with CUF alone. Meanwhile, MUF and CUF did not significantly influence the postoperative hospital stay duration, CPB, and aortic occlusion duration.

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.

Impact of miniaturized cardiopulmonary bypass circuits on ultrafiltration during congenital heart surgery

OBJECTIVE

To investigate whether the miniaturized cardiopulmonary bypass (CPB) system decreased the usage of ultrafiltration (UF), and to explore whether the non-UF with miniaturized CPB strategy could get good clinical results during congenital heart surgery.

METHODS

We performed a retrospective analysis of all patients undergoing congenital heart surgery with CPB at Shenzhen Children's Hospital from 1 May 2015 to 30 September 2019. We classified patients to UF with miniaturized CPB group, non-UF with miniaturized CPB group, UF with conventional CPB group and non-UF with conventional CPB group.

RESULTS

Of the 2145 patients, 721 (33.6%) were in the conventional CPB group, and 1424 (66.4%) were in the miniaturized CPB group. The UF rate was significantly lower in the miniaturized CPB group compared with that in the conventional CPB group (12.5% vs. 76.8%, p < 0.001). Compared with patients in the other groups, patients in the non-UF with miniaturized CPB group had a shorter postoperative MV time (p < 0.05), and a shorter length of stay in the ICU (p < 0.001) and hospital (p < 0.001). The age of children in the UF with miniaturized CPB group was relatively younger (median: 1.5 months, IQR: 0.3-4.6 months), and the preoperative weight was relatively lower (median: 3.9 kg, IQR: 3.2-5.4 kg). Moreover, this group of children had a relatively longer postoperative MV time and length of stay in the ICU and hospital.

CONCLUSION

The miniaturized CPB system could decrease the usage of UF. Good results were achieved in children who did not use UF based on the miniaturized CPB circuit system during congenital heart surgery.

Fluid Overload in Special Pediatric Cohorts With Anomalous Origin of the Left Coronary Artery From the Pulmonary Artery Following Surgical Repair

OBJECTIVE

To investigate the prevalence, risk factors, and clinical outcomes associated with early fluid overload (FO) in a special group of pediatric patients undergoing repair of anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA).

DESIGN

It was a retrospective study performed with multiple variable regression analysis.

SETTING

A single cardiac surgical institution.

PARTICIPANTS

Eighty-eight patients younger than 18 years of age undergoing ALCAPA surgical repair with cardiopulmonary bypass were recruited at the authors' institution from June 2010 to September 2017.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Of 88 pediatric patients with ALCAPA after surgical repair, 37.5% developed early FO, defined as fluid accumulation ≥5% within the period from surgery until midnight of postoperative day 1. Patients with early FO were younger, weighed less, and had worse preoperative cardiac dysfunction. With logistic regression analysis, being underweight was confirmed to be a risk factor for FO development (odds ratio, 8.66; 95% confidence interval, 2.83-26.52; p < 0.001). Early FO also predicted severe acute kidney injury, respiratory morbidity, and low cardiac output syndrome after reimplantation procedure. Patients with early FO also had significantly longer mechanical ventilation hours (p  <  0.001), intensive care unit length of stay (p = 0.003), and hospital length of stay (p = 0.009).

CONCLUSION

Early FO ≥5% has been linked to adverse postoperative outcomes in pediatric patients undergoing repair for ALCAPA. The use of restrictive fluid management is crucial for patients who have lower weight and poor myocardial function before and after complex surgical procedures such as in ALCAPA settings.

Ultrafiltration in Pediatric Cardiac Surgery Review

Introduction:

The use of cardiopulmonary bypass in pediatric cardiac surgery is associated with significant inflammation, fluid overload, and end-organ dysfunction yielding morbidity and mortality. For decades, various intraoperative ultrafiltration techniques such as conventional ultrafiltration, modified ultrafiltration (MUF), zero-balance ultrafiltration (ZBUF), and combination techniques (ZBUF-MUF) have been used to mitigate these toxicities and promote improved postoperative outcomes. However, there is currently no consensus on the ultrafiltration technique or strategy that yields the most benefit for infants and children undergoing open heart surgery.

Methods:

A librarian-conducted PubMed literature search from 1990 to 2018 yielded 90 clinical studies or publications on the various forms of ultrafiltration and the impact on physiologic markers and clinical outcomes. All publications were reviewed, summarized, and conclusions synthesized. The data sets were not combined for systematic or meta-analysis due to significant heterogeneity in study protocols and patient populations.

Results:

Modified ultrafiltration significantly promotes improved myocardial function, reduction in fluid overload, and reduced bleeding and transfusion complications. Furthermore, ZBUF has shown a consistent reduction in inflammatory cytokines and improved pulmonary function and compliance. There is conflicting evidence that MUF, ZBUF, and ZBUF-MUF culminate in reduced ventilation time and intensive care unit stay.

Conclusion:

Various modes of ultrafiltration have been shown to be associated with improved physiologic function or clinical outcomes in pediatric cardiac surgery. There are some inconsistent trial results that can be explained by heterogeneity in ultrafiltration, clinical staff preferences, and institution protocols. Ultrafiltration has some essential benefit as it is ubiquitously used at pediatric heart centers; however, the optimal protocol could be yet identified.

Consensus Report on Patient Blood Management in Cardiac Surgery by Turkish Society of Cardiovascular Surgery (TSCVS), Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care (SCTAIC)

Anemia, transfusion and bleeding independently increase the risk of complications and mortality in cardiac surgery. The main goals of patient blood management are to treat anemia, prevent bleeding, and optimize the use of blood products during the perioperative period. The benefit of this program has been confirmed in many studies and its utilization is strongly recommended by professional organizations. This consensus report has been prepared by the authors who are the task members appointed by the Turkish Society of Cardiovascular Surgery, Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care to raise the awareness of patient blood management. This report aims to summarize recommendations for all perioperative blood- conserving strategies in cardiac surgery.

Patient Blood Management in Pediatric Cardiac Surgery: A Review

Efforts to reduce blood product transfusions and adopt blood conservation strategies for infants and children undergoing cardiac surgical procedures are ongoing. Children typically receive red blood cell and coagulant blood products perioperatively for many reasons, including developmental alterations of their hemostatic system, and hemodilution and hypothermia with cardiopulmonary bypass that incites inflammation and coagulopathy and requires systemic anticoagulation. The complexity of their surgical procedures, complex cardiopulmonary interactions, and risk for inadequate oxygen delivery and postoperative bleeding further contribute to blood product utilization in this vulnerable population. Despite these challenges, safe conservative blood management practices spanning the pre-, intra-, and postoperative periods are being developed and are associated with reduced blood product transfusions. This review summarizes the available evidence regarding anemia management and blood transfusion practices in the perioperative care of these critically ill children. The evidence suggests that adoption of a comprehensive blood management approach decreases blood transfusions, but the impact on clinical outcomes is less well studied and represents an area that deserves further investigation.

Reevaluating the Importance of Modified Ultrafiltration in Contemporary Pediatric Cardiac Surgery

Objective(s): Modified ultrafiltration has gained wide acceptance as a powerful tool against cardiopulmonary bypass morbidity in pediatric cardiac surgery. The aim of our study was to assess the importance of modified ultrafiltration within conditions of contemporary cardiopulmonary bypass characteristics. Methods: Ninety–eight patients (overall cohort) weighing less than 12 kg undergoing surgical repair with cardiopulmonary bypass were prospectively enrolled in a randomized protocol to receive modified and conventional ultrafiltration (MUF group) or just conventional ultrafiltration (non-MUF group). A special attention was paid to forty-nine neonates and infants weighing less than 5 kg (lower weight (LW) cohort). Results: Post-filtration hematocrit was significantly higher in the MUF group for both cohorts (overall cohort p = 0.001; LW cohort p = 0.04), but not at other time points. During the postoperative course, patients in the MUF group received fewer packed red blood cells, (overall cohort p = 0.01; LW cohort p = 0.07), but required more fresh frozen plasma (overall cohort p = 0.04; LW cohort p = 0.05). There was no difference between groups in hemodynamic state, chest tube output, duration of mechanical ventilation, respiratory parameters, duration of intensive care unit, and hospitalization stay. Conclusions: If conventional ultrafiltration provides adequate hemoconcentration modified ultrafiltration does not provide additional positive benefits except for reduction in blood cell transfusion, This, however, comes at the cost of needing more fresh frozen plasma. Of particular importance is that this also applies to infants with weight bellow 5 kg where modified ultrafiltration was supposed to have the greatest positive impact.

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?

The effect of combined conventional and modified ultrafiltration on mechanical ventilation and hemodynamic changes in congenital heart surgery

Background:

Cardiopulmonary bypass is associated with increased fluid accumulation around the heart which influences pulmonary and cardiac diastolic function. The aim of this study was to compare the effects of modified ultrafiltration (MUF) versus conventional ultrafiltration (CUF) on duration of mechanical ventilation and hemodynamic status in children undergoing congenital heart surgery.

Materials and Methods:

A randomized clinical trial was conducted on 46 pediatric patients undergoing cardiopulmonary bypass throughout their congenital heart surgery. Arteriovenous MUF plus CUF was performed in 23 patients (intervention group) and sole CUF was performed for other 23 patients (control group). In MUF group, arterial cannula was linked to the filter inlet through the arterial line, and for 10 min, 10 ml/kg/min of blood was filtered and returned via cardioplegia line to the right atrium. Different parameters including hemodynamic variables, length of mechanical ventilation, Intensive Care Unit (ICU) stay, and inotrope requirement were compared between the two groups.

Results:

At immediate post-MUF phase, there was a statistically significant increase in the mean arterial pressure, systolic blood pressure, and diastolic blood pressure (P < 0.05) only in the study group. Furthermore, there was a significant difference in time of mechanical ventilation (P = 0.004) and ICU stay (P = 0.007) between the two groups. Inotropes including milrinone (P = 0.04), epinephrine (P = 0.001), and dobutamine (P = 0.002) were used significantly less frequently for patients in the intervention than the control group.

Conclusion:

Administration of MUF following surgery improves hemodynamic status of patients and also significantly decreases the duration of mechanical ventilation and inotrope requirement within 48 h after surgery.

Retrospective analysis of eliminating modified ultrafiltration after pediatric cardiopulmonary bypass

Modified ultrafiltration (MUF) is a technique which is commonly used immediately post-cardiopulmonary bypass (CPB) for open heart surgery in children. There are many advantages of MUF, but there are also a number of less reported disadvantages. At our institution, after considering all of the available data, a decision was made to no longer perform MUF. The primary motivation being the simplified and miniaturized CPB circuit would reduce hemodilution, decrease our likelihood of reaching our transfusion trigger during CPB and, potentially, improve safety. This study reports the before and after data from this practice change. A total of 160 patients less than 8kg were studied over 38 months and divided into neonatal and pediatric cohorts. Parameters reported in this study include: demographics, hematocrit, blood product transfusion, hemostasis, hemodynamics and outcomes. Although retrospective, our analysis supports an advantage of preventing hemodilution (via circuit miniaturization) versus reversing hemodilution (via MUF) at our institution with the patient population we examined.

Impact of Modified Ultrafiltration on Morbidity after Pediatric Cardiac Surgery

Cardiopulmonary bypass is a double-edged sword. Without it, corrective cardiac surgery would not be possible in the majority of children with congenital heart disease. However, much of the perioperative morbidity that occurs after cardiac surgery can be attributed to a large extent to pathophysiologic processes engendered by extracorporeal circulation. One of the challenges that has confronted pediatric cardiac surgeons has been to minimize the consequences of cardiopulmonary bypass. Ultrafiltration is a strategy that has been used for many years in an effort to attenuate the effects of hemodilution that occur when small children undergo surgery with cardiopulmonary bypass. Over the past several years, a modified technique of ultrafiltration, commonly known as modified ultrafiltration, has been used with increasing enthusiasm. Multiple studies have been undertaken to assess the effects of modified ultrafiltration on organ function and postoperative morbidity following repair of congenital heart defects. This review attempts to evaluate current available scientific evidence on the impact of modified ultrafiltration on organ function and morbidity after pediatric cardiac surgery.

Clinical outcome and blood transfusion after infant cardiac surgery with a routine use of conventional ultrafiltration

OBJECTIVE

Priming-related hemodilution is the culprit behind excessive body water accumulation, postoperative coagulopathy and enhanced blood transfusion in infant cardiac surgery patients. In this retrospective, observational study, clinical data were analyzed to assess the effect of conventional ultrafiltration on allogenic blood transfusion and patient clinical outcome.

METHODS

All infants with a bodyweight up to 10 kg who underwent consequent cardiac surgery in 2011 and 2012 were eligible for the audit. Seventy patients, operated in accordance with existing pediatric protocol, enrolled in the control group. The study group consisted of 55 patients who were operated employing conventional ultrafiltration during bypass and recently adjusted hematocrit targets. The following variables were primarily investigated: hematocrit and colloid osmotic pressure value, total volume of blood products transfused and duration of postoperative mechanical ventilation. Secondary outcome measures were: postoperative urine production, postoperative blood loss, length of stay at the intensive care unit and hospital stay.

RESULTS

There were no significant differences between the groups in relation to demographics or hematological and cardiopulmonary bypass data. The ultrafiltration volume removed from circulation during bypass in the study group was 171 ± 99 ml. No significant difference between the groups was found with regard to the total allogenic blood transfusion (study group 216 ± 92 ml versus control group 191 ±93 ml; p = 0.136). All recorded clinical end points, duration of mechanical ventilation, duration of chest tube in situ, stay in ICU and stay in hospital, were similar between the groups.

CONCLUSIONS

Routine use of conventional ultrafiltration during the cardiac surgery for patients with a bodyweight less than 10 kg was a safe technique that allowed us to achieve higher hematocrit levels at the end of the operation without additional transfusions of allogenic blood. On the other hand, ultrafiltration did not improve the clinical end points.

Modified ultrafiltration during cardiopulmonary bypass and postoperative course of pediatric cardiac surgery

Context:

The use of cardiopulmonary bypass (CPB) provokes the inflammatory responses associated with ischemic/reperfusion injury, hemodilution and other agents. Exposure of blood cells to the bypass circuit surface starts a systemic inflammatory reaction that may causes post-CPB organ dysfunction, particularly in lungs, heart and brain.

Evidence Acquisition:

We investigated in the MEDLINE, PUBMED, and EMBASE databases and Google scholar for every available article in peer reviewed journals between 1987 and 2013, for related subjects to CPB with conventional or modified ultrafiltration (MUF) in pediatrics cardiac surgery patients.

Results:

MUF following separation from extracorporeal circulation (ECC) provides well known advantages in children with improvements in the hemodynamic, pulmonary, coagulation and other organs functions. Decrease in blood transfusion, reduction of total body water, and blood loss after surgery, are additional benefits of MUF.

Conclusions:

Consequently, MUF has been associated with attenuation of morbidity after pediatric cardiac surgery. In this review, we tried to evaluate the current evidence about MUF on the organ performance and its effect on post-CPB morbidity in pediatric patients.

Limitations of early serum creatinine variations for the assessment of kidney injury in neonates and infants with cardiac surgery

Background

Changes in kidney function, as assessed by early and even small variations in serum creatinine (ΔsCr), affect survival in adults following cardiac surgery but such associations have not been reported in infants. This raises the question of the adequate assessment of kidney function by early ΔsCr in infants undergoing cardiac surgery.

Methodology

The ability of ΔsCr within 2 days of surgery to assess the severity of kidney injury, accounted for by the risk of 30-day mortality, was explored retrospectively in 1019 consecutive neonates and infants. Patients aged ≤ 10 days were analyzed separately because of the physiological improvement in glomerular filtration early after birth. The Kml algorithm, an implementation of k-means for longitudinal data, was used to describe creatinine kinetics, and the receiver operating characteristic and the reclassification methodology to assess discrimination and the predictive ability of the risk of death.

Results

Three clusters of ΔsCr were identified: in 50% of all patients creatinine decreased, in 41.4% it increased slightly, and in 8.6% it rose abruptly. Mortality rates were not significantly different between the first and second clusters, 1.6% [0.0–4.1] vs 5.9% [1.9–10.9], respectively, in patients aged ≤ 10 days, and 1.6% [0.5–3.0] vs 3.8% [1.9–6.0] in older ones. Mortality rates were significantly higher when creatinine rose abruptly, 30.3% [15.1–46.2] in patients aged ≤ 10 days, and 15.1% [5.9–25.5] in older ones. However, only 41.3% of all patients who died had an abrupt increase in creatinine. ΔsCr improved prediction in survivors, but not in patients who died, and did not improve discrimination over a clinical mortality model.

Conclusions

The present results suggest that a postoperative decrease in creatinine represents the normal course in neonates and infants with cardiac surgery, and that early creatinine variations lack sensitivity for the assessment of the severity of kidney injury.

A combined ultrafiltration strategy during pediatric cardiac surgery: a prospective, randomized, controlled study with clinical outcomes

OBJECTIVE

To investigate the clinical effects of a combined ultrafiltration strategy on the surgical treatment of pediatric patients with congenital heart diseases.

DESIGN

A prospective, randomized, controlled study.

SETTING

A single-institution study in an affiliated hospital of a university.

PARTICIPANTS

Sixty-five pediatric patients who underwent open heart surgery with cardiopulmonary bypass (CPB) to treat congenital heart disease were enrolled. The participants were randomized into 2 groups: conventional + modified ultrafiltration (MUF) (CM) group and prime + zero-balanced + MUF (PZM) group.

INTERVENTIONS

In the CM group (n = 33), conventional ultrafiltration was performed after removal of the aortic clamp, and MUF was performed after the completion of CPB. In the PZM group (n = 32), ultrafiltration was performed for the circuit prime solution, zero-balance ultrafiltration was performed after removal of the aortic clamp, and MUF was performed after the completion of CPB.

MEASUREMENTS AND MAIN RESULTS

The blood gas parameters and tumor necrosis factor alpha content in the priming solution and perioperative blood samples were analyzed. Postoperative parameters, including mechanical ventilation time, respiratory indices, intensive care unit time, and hospital time, also were recorded. One hospital death occurred in each group. No severe complications occurred in either group. The lactic acid, glucose, and tumor necrosis factor alpha contents in the priming solution and perioperative blood samples were significantly lower in the PZM group compared with the CM group. The respiratory indices were statistically significantly better in the PZM group compared with the CM group in the early postoperative period. No significant differences were found between the 2 groups regarding the postoperative ventilation time, inotropic support, homologous blood transfusion, drainage, intensive care unit time, or postoperative hospital time.

CONCLUSION

The combined use of ultrafiltration of prime solution, zero-balance ultrafiltration, and MUF strategy is associated with a modest improvement in pulmonary function compared with the combination of conventional and MUF strategies in the early postoperative period, but the principal clinical outcomes are similar.

High-dose aprotinin, blood product transfusions, and short-term outcome in neonates and infants: a pediatric cardiac surgery center experience

BACKGROUND

The efficacy of aprotinin, the most popular antifibrinolytic agent in congenital cardiac surgery, was still uncertain in small infants when its prophylactic use was suspended for safety reasons. The aim of this study is to describe associations between the prophylactic use of high-dose aprotinin, the need for blood product transfusions, and short-term outcome in neonates and infants with cardiac surgery.

METHODS/MATERIALS

This retrospective study included all patients younger than 1 year undergoing surgery with cardiopulmonary bypass through 42 months, before and after withdrawal of aprotinin. Each patient who received aprotinin was matched with a control with similar baseline and surgical characteristics, who have not received any antifibrinolytic agent. Associations between the use of aprotinin and the exposure to red blood cells, fresh frozen plasma, and platelet transfusions were estimated from a logistic regression model, and the exposure to additional transfusions from a polytomous regression model.

RESULTS

Matching resulted in two groups of 283 patients each, well balanced except for the priming volume and the ultrafiltration rate, larger in the aprotinin group. After adjustment for the priming volume and ultrafiltration rate, there was no significant association between the use of aprotinin, the exposure to any blood product transfusion, or the exposure to additional transfusions, the rate of re-exploration for bleeding, and short-term outcome. Two patients in the control group required re-exploration for bleeding.

CONCLUSIONS

No association was found between the prophylactic use of aprotinin, blood product transfusions, and short-term outcome in this population of neonates and infants.

Current ultrafiltration techniques before, during and after pediatric cardiopulmonary bypass procedures

Ultrafiltration, which is currently considered as a standard method to remove excess water administered during pediatric cardiopulmonary bypass (CPB), aims to minimize the adverse effects of hemodilution, such as tissue edema and blood transfusion. Three ultrafiltration techniques can be used before, during and after CPB procedures, including conventional ultrafiltration (CUF), modified ultrafiltration (MUF) and zero-balance ultrafiltration (Z-BUF). These methods are widely different, but they have common benefits on hemoconcentration, less requirement for blood products, and reduction of the systemic inflammatory responses (SIRS). The present review attempts to restate these ultrafiltration circuitries, application methods, end-points, and clinical impacts.

Perfusionist strategies for blood conservation in pediatric cardiac surgery

There is increasing concern about the safety of homologous blood transfusion during cardiac surgery, and a restrictive transfusion practice is associated with improved outcome. Transfusion-free pediatric cardiac surgery is unrealistic for the vast majority of procedures in neonates or small infants; however, considerable progress has been made by using techniques that decrease the need for homologous blood products or even allow bloodless surgery in older infants and children. These techniques involve a decrease in prime volume by downsizing the bypass circuit with the help of vacuum-assisted venous drainage, microplegia, autologous blood predonation with or without infusion of recombinant (erythropoietin), cell salvaging, ultrafiltration and retrograde autologous priming. The three major techniques which are simple, safe, efficient, and cost-effective are: a prime volume as small as possible, cardioplegia with negligible hydric balance and circuit residual blood salvaged without any alteration. Furthermore, these three techniques can be used for all the patients, including emergencies and small babies. In every pediatric surgical unit, a strategy to decrease or avoid blood bank transfusion must be implemented. A strategy to minimize transfusion requirement requires a combined effort involving the entire surgical team with pre-, peri-, and postoperative planning and management.

Bicarbonate-buffered ultrafiltration during pediatric cardiac surgery prevents electrolyte and acid-base balance disturbances

Pediatric cardiopulmonary bypass is still a challenge because of electrolyte disturbances and inflammation. Many investigations deal with different types of hemofiltration to reduce these potentially harmful side effects. We tested the hypothesis of whether bicarbonate-buffered hemofiltration of the priming solution minimizes electrolyte and acid-base disturbances during the initiation of cardiopulmonary bypass and whether bicarbonate-buffered hemofiltration performed during cardiopulmonary bypass could reduce cytokine levels. Twenty children younger than 2 years of age (mean age 166 ± 191 days; mean weight 6.42 ± 3.22 kg) scheduled for pediatric cardiac surgery with cardiopulmonary bypass were enrolled in this prospective clinical study. Cardiopulmonary bypass circuits were primed with a bicarbonate-buffered hemofiltration solution, gelatin and 1 unit of packed red blood cells. The priming was hemofiltered using an ultrahemofilter until approximately 1000 mL of ultrafiltrate was restored with the buffered solution. Further hemofiltration was performed throughout the whole bypass time, especially during rewarming. Blood gas analyses and inflammatory mediators were monitored during the operation. Blood gas analysis results after initiation of cardiopulmonary bypass and throughout the entire study remained within the physiologic ranges. Even potassium decreased from 4.0 ± 0.3 to 3.4 ± 0.4 mmol.l−1 after initiation of cardiopulmonary bypass. Plasma levels of tumor necrosis factor alpha decreased significantly (47 ± 44 vs. 24 ± 21 pg.mL−1) whereas complement factor C3a (5.0 ± 2.9 vs. 16.8 ± 6.6 ng.mL−1) and interleukin-6 (7.3 ± 15.2 vs. 110 ± 173 pg.mL−1) increased despite hemofiltration. In conclusion, this study shows that bicarbonate-buffered ultrafiltration is an efficient, simple and safe method for performing hemofiltration, both of the priming solution and during the entire bypass time. The use of a physiological restitution solution prevents electrolyte and acid-base balance disturbances. The elimination of inflammatory mediators seems to be as effective as other ultrafiltration methods.

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.

Plasma angiopoietin-2 levels increase in children following cardiopulmonary bypass

OBJECTIVE

The aim was to investigate the effects of cardiopulmonary bypass (CPB) on plasma levels of the vascular growth factors, angiopoietin (angpt)-1, angpt-2, and vascular endothelial growth factor (VEGF).

DESIGN

The design was a prospective, clinical investigation.

SETTING

The setting was a 12-bed pediatric cardiac intensive care unit of a tertiary children's medical center.

PATIENTS

The patients were 48 children (median age, 5 months) undergoing surgical correction or palliation of congenital heart disease who were prospectively enrolled following informed consent.

INTERVENTIONS

There were no interventions in this study.

MEASUREMENTS AND RESULTS

Plasma samples were obtained at baseline and at 0, 6, and 24 h following CPB. Angpt-1, angpt-2, and VEGF levels were measured via commercial ELISA. Angpt-2 levels increased by 6 h (0.95, IQR 0.43-2.08 ng mL(-1) vs. 4.62, IQR 1.16-6.93 ng mL(-1), P < 0.05) and remained significantly elevated at 24 h after CPB (1.85, IQR 0.70-2.76 ng mL(-1); P < 0.05). Angpt-1 levels remained unchanged immediately after CPB, but were significantly decreased at 24 h after CPB (0.64, IQR 0.40-1.62 ng mL(-1) vs. 1.99, IQR 1.23-2.63 ng mL(-1), P < 0.05). Angpt-2 levels correlated significantly with cardiac intensive care unit (CICU) length of stay (LOS) and were an independent predictor for CICU LOS on subsequent multivariate analysis.

CONCLUSIONS

Angpt-2 appears to be an important biomarker of adverse outcome following CPB in children.

Modified and conventional ultrafiltration during pediatric cardiac surgery: Clinical outcomes compared

OBJECTIVE

This prospective study compared clinical outcomes after heart surgery between three groups of infants with congenital heart disease. One group received dilutional conventional ultrafiltration (group D), another received modified ultrafiltration (group M), and a third group received both dilutional conventional and modified ultrafiltration (group B). We hypothesized that group B patients would have the best clinical outcome.

METHODS

Children younger than 1 year undergoing heart surgery for biventricular repair by the same surgeon were randomly allocated to one of the three study groups. Patient management was standardized, and intensive care staff were blinded to group allocation. Primary outcome measure was duration of postoperative mechanical ventilation. Other outcome measures recorded included total blood products transfused, duration of chest tube in situ, chest tube output, and stays in intensive care and in the hospital.

RESULTS

Sixty infants completed study protocol. Mean age and weight were as follows: group D (n = 19), 61 days, 4.3 kg; group M (n = 20), 64 days, 4.5 kg; and group B (n = 21), 86 days, 4.4 kg. Preoperative and intraoperative characteristics were similar between groups. Ultrafiltrate volumes obtained were 196 +/- 93 mL/kg in group D, 105 +/- 33 mL/kg in group M, and 261 +/- 113 mL/kg in group B. There were no significant differences between groups for any outcome variable. Technical difficulties prevented completion of modified ultrafiltration in 2 of 41 infants.

CONCLUSION

There was no clinical advantage in combining conventional and modified ultrafiltration. Because clinical outcomes were similar across groups, relative risks of the ultrafiltration strategies may influence choice.

Recent developments in the perioperative management of the paediatric cardiac patient

PURPOSE OF REVIEW

Survival of infants born with complex cardiac anomalies has dramatically improved, and the growing population of patients with congenital heart disease reaching adulthood has resulted in an increased incidence of long-term complications related to the perioperative period. This review focuses on recent advances in strategies to prevent, detect, treat, or predict early and late complications arising from open heart surgery for congenital heart disease.

RECENT FINDINGS

Aprotinine and recombinant factor VIIa may effectively reduce the risk of excessive perioperative bleeding, and the use of steroids, complement component C4A, heparin-coated circuits, and modified ultrafiltration may play a role in the control of the postoperative inflammatory response. Milrinone is becoming increasingly popular in the prevention and treatment of the reduced postoperative cardiac output, and extracorporeal life support has become a well established and successful form of support for postoperative myocardial dysfunction, even in the functionally univentricular heart. In recent years interest increased in optimizing myocardial protection using contents-differentiated and temperature-differentiated blood cardioplegia and in optimizing cerebral protection using a higher haematocrit during bypass and by using selective regional perfusion in favour of circulatory arrest.

SUMMARY

Hearts can be mended, but salvation of hearts and brains needs further rigorous attention.

Elimination of proinflammatory cytokines in pediatric cardiac surgery: analysis of ultrafiltration method and filter type

OBJECTIVE

This study was undertaken to assess whether different filter types or ultrafiltration methods influence inflammatory markers in pediatric cardiac surgery.

METHODS

Forty-one children younger than 5 years were prospectively randomized to groups A (polyamid filter with conventional ultrafiltration), B (polyamid filter with modified ultrafiltration), C (polysulfon filter with conventional ultrafiltration), and D (polysulfon filter with modified ultrafiltration). Interleukin 6, interleukin 10, tumor necrosis factor, terminal complement complex, and lactoferrin were measured before the operation (T0), before rewarming (T1), after ultrafiltration (T2), at 6 (T3) and 18 hours (T4) after the operation, and in the ultrafiltrate.

RESULTS

All markers changed with both ultrafiltration methods, both filter types, and in all groups (except tumor necrosis factor) along the T0 to T4 observation time (P <.0001). Their patterns of changes were different for terminal complement complex, with less decrease after use of the polysulfon filter (P <.05), and among groups A through D for interleukin 6 (P =.01), with more decrease in group C than group A (P <.02). Interleukin 10 decreased with the polyamid filter (P <.001) but not with the polysulfon filter. In the ultrafiltrate, tumor necrosis factor was higher with the polysulfon filter than the polyamid filter (6.8 +/- 5 pg/mL vs 4.0 +/- 3.7 pg/mL, P <.05). The ultrafiltrate/plasma ratio of interleukin 6 was higher with conventional ultrafiltration than modified ultrafiltration (0.018 +/- 0.017 vs 0.004 +/- 0.007, P <.005).

CONCLUSIONS

The polysulfon filter showed a filtration profile for inflammatory mediators superior to that of the polyamid filter for interleukin 6, tumor necrosis factor, and interleukin 10. Interleukin 6 was most efficiently removed by conventional ultrafiltration with a polysulfon filter, and tumor necrosis factor was best removed by modified ultrafiltration with a polysulfon filter, whereas other inflammatory mediators were not influenced by filter type or ultrafiltration method. Therefore combined conventional and modified ultrafiltration with a polysulfon filter may currently be the most effective strategy for removing inflammatory mediators in pediatric heart surgery.

Critical care in cardiovascular medicine

The field of cardiac intensive care is rapidly evolving with nearly simultaneous advances in surgical techniques and adjunctive therapies, respiratory care, intensive care technology and monitoring, pharmacologic research and development, and computing and electronics. The focus of care has now shifted toward reducing morbidity and improving "quality of life" while the survival of infants and children with congenital heart defects, including those with univentricular hearts has dramatically improved during the last three decades. Despite these advances, there remains a predictable fall in cardiac output after cardiopulmonary bypass. This article focuses on early identification and aggressive treatment of the low cardiac output syndrome peculiar to these patients. The authors also briefly review the recent advances in the treatment of pulmonary hypertension, mechanical support, and neurologic surveillance after cardiac surgery.

Modified ultrafiltration in surgical correction of congenital heart disease with cardiopulmonary bypass

The surgical correction of congenital heart disease using haemodilution and hypothermia with cardiopulmonary bypass (CPB) may expose patients to tissue ischaemia and initiate a systemic inflammatory response, increasing the total body water and inducing impairment, especially of heart, lung and brain function. It is possible to use ultrafiltration during CPB in the rewarming phase to remove water accumulation in the third space (conventional ultrafiltration). The reduced volume of prime used in children and the ability only to filter the reservoir blood during CPB led the Great Ormond Street Group to modify the method of ultrafiltration with regards to the placement of the filter and the timing of filtration (post-CPB). The main advantage of the modified technique is the ultrafiltration of the patient. A prospective nonrandomized study has been conducted to compare conventional with conventional + modified ultrafiltration. From January 1996 to March 1998, 41 patients underwent correction of congenital heart disease and were submitted to a comparative study (homogeneous groups), using either the conventional or the conventional + modified ultrafiltration techniques. There were no technical complications, no patient required mediastinal re-exploration due to bleeding and it was possible to close all the chests. There were significant differences in the ultrafiltrate volume balance (143.3 +/- 54.3 versus 227 +/- 71.4 mL; P < 0.001) but there were no significant differences in clinical postoperative evolution between the conventional and the conventional + modified ultrafiltration.

Risk factors prolonging ventilation in young children after cardiac surgery: Impact of noninfectious pulmonary complications

OBJECTIVE: To determine risk factors for prolonged ventilation after cardiac surgery in young children and assess the impact of noninfectious pulmonary complications on ventilatory duration. DESIGN: Retrospective case series analysis. SETTING: A tertiary pediatric cardiac center. PATIENTS: Clinical records of 222 consecutive children aged </=3 yrs undergoing cardiac surgery for congenital heart disease were reviewed. Fifteen patients, consisting of six premature babies and nine who died within 72 hrs of surgery, were excluded. MEASUREMENTS AND MAIN RESULTS: The demographic data, preoperative risk factors, surgical procedures performed, intraoperative variables, and postoperative complications of the remaining 207 children were reviewed. Univariate analysis was performed to compare patients who required prolonged ventilation (>72 hrs) to those who could be extubated at </=72 hrs, and multivariate analyses were performed to identify significant determinants on ventilatory duration and impact of noninfectious complications. Of the 182 patients undergoing open heart surgery, 45 (25%) required prolonged ventilation for a median of 8 days. The latter were significantly younger in age and lighter in weight and were more likely to have Down syndrome, preoperative pulmonary hypertension and ventilatory support, undergone more complex surgery requiring longer bypass and circulatory arrest time, postoperative cardiovascular and pulmonary complications, and extubation failure (all p values <.01). Of the 25 patients who had closed heart surgery, five (20%) required prolonged ventilation for a median of 14 days. The latter were more likely to require preoperative ventilation, have undergone more complex surgery, had postoperative cardiovascular and pulmonary complications, and had extubation failure (all p values <.05). Cox proportional hazard regression identified body weight (p <.001), Down syndrome (p =.02), need for preoperative ventilation (p <.001), complexity of surgery (p <.001), cardiovascular complications (p <.001), and infective (p <.001) and noninfective (p <.001) pulmonary complications to be significant factors that determined the ventilatory duration. Noninfectious pulmonary complications occurred in 31.9% (58/182) and 20% (5/25) of patients after open and closed heart surgery, respectively. In the absence of other risk factors, the median time to extubation was similar between patients with and without noninfectious complications (1 vs. 0.8 day). However, in the presence of other risk factors, noninfectious pulmonary complications prolonged the median time to extubation from 8 to 18 days. Logistic regression identified Down syndrome (p =.005), preoperative ventilation (p =.001), complexity of surgery (p =.006), and bypass time (p =.005) as risk factors for development of noninfectious pulmonary complications. CONCLUSIONS: Noninfectious pulmonary complications that occurred commonly after cardiac surgery in young children prolong ventilatory duration only in the presence of other risk factors, with which it acts in a synergistic fashion.