Modified ultrafiltration improves left ventricular systolic function in infants after cardiopulmonary bypass

Strategies to attenuate maladaptive inflammatory response associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) initiates an intense inflammatory response due to various factors: conversion from pulsatile to laminar flow, cold cardioplegia, surgical trauma, endotoxemia, ischemia-reperfusion injury, oxidative stress, hypothermia, and contact activation of cells by the extracorporeal circuit. Redundant and overlapping inflammatory cascades amplify the initial response to produce a systemic inflammatory response, heightened by coincident activation of coagulation and fibrinolytic pathways. When unchecked, this inflammatory response can become maladaptive and lead to serious postoperative complications. Concerted research efforts have been made to identify technical refinements and pharmacologic interventions that appropriately attenuate the inflammatory response and ultimately translate to improved clinical outcomes. Surface modification of the extracorporeal circuit to increase biocompatibility, miniaturized circuits with sheer resistance, filtration techniques, and minimally invasive approaches have improved clinical outcomes in specific populations. Pharmacologic adjuncts, including aprotinin, steroids, monoclonal antibodies, and free radical scavengers, show real promise. A multimodal approach incorporating technical, circuit-specific, and pharmacologic strategies will likely yield maximal clinical benefit.

Safety and utility of modified ultrafiltration in pediatric cardiac surgery

INTRODUCTION

Modified ultrafiltration (MUF) is employed at the termination of cardiopulmonary bypass (CPB) in pediatric and neonatal patients undergoing congenital heart surgery to reduce the accumulation of total body water thus increasing the concentration of red blood cells and the other formed elements in the circulation. Modified ultrafiltration has been reported to remove circulating pro-inflammatory mediators that result in systemic inflammatory response syndrome (SIRS) postoperatively.

METHODS

Four hundred patients undergoing cardiac surgery requiring cardiopulmonary bypass and weighing less than or equal to 12 kg were retrospectively evaluated for the effectiveness of MUF. After the termination of CPB, blood was withdrawn through the aortic cannula and passed through a hemoconcentrator attached to the blood cardioplegia set and returned to the patient through the venous cannula. The entire CPB circuit volume in addition to the patient's circulating blood volume were concentrated until the hematocrit value displayed on the CDI cuvette within the MUF circuit reached 45% or there was no more volume to safely remove. At the same time a full unit of FFP can be infused as water is being removed, thus maintaining euvolemia.

RESULTS

MUF was performed in all 400 patients with no MUF-related complications. Following the conclusion of MUF, anecdotal observations included improved surgical hemostasis, improved hemodynamic parameters, decreased transfusion requirements, and decreased ventilator times.

CONCLUSIONS

Complete MUF enables the clinician to safely raise the post-CPB hematocrit to at least 40% while potentially removing mediators that could result in SIRS. In addition a full unit of FFP can be administered while maintaining euvolemia.

Recent advancements in pediatric cardiopulmonary bypass technology for better outcomes of pediatric cardiac surgery

Background

Pediatric cardiac surgery is in itself very enigmatic and individualized. Presently, there has been a slew of new developments aimed primarily toward pediatric cardiopulmonary bypass for safer, patient-centered pediatric cardiac surgery. Still, lot of technological challenges need to be resolved, and their safer application in pediatric and neonate patients requires further refinement.

Main body of the abstract

Considering various significant yet unresolved issues of pediatric cardiac bypass, an exhaustive literature search was done on various internet databases with standard keywords. There are various new recent improvements; as the first oxygenator explicitly designed for neonatal patients; pediatric oxygenators with low prime volumes and surface areas that allow flows up to 2 L/min; pediatric oxygenators with integrated arterial filters; and miniature ultrafiltration devices that allow for high rates of ultrafiltrate removal. These advancements can significantly reduce cardiopulmonary bypass circuit surface areas and prime volumes. These advancements could reduce or eliminate the requirement for homologous red blood cells during or after surgery with reduction or eliminate bypass-related hemodilution, and inflammation. Because of the immaturity of the neonatal hemostatic system, conventional coagulation tests alone are insufficient to guide neonatal hemostatic therapy. Myocardial preservation techniques, safe temperature with duration are still debatable and yet to be fully explored.

Short conclusion

This review is based on Standards for Quality Improvement Reporting Excellence guidelines to provide a framework for reporting new knowledge to find better management strategy for pediatric cardiac cases.

Study protocol and statistical analysis plan for the Early Peritoneal Dialysis in Infants after Cardiac Surgery (EPICS) trial

Background: Peritoneal dialysis (PD) is a commonly used therapy after infant cardiac surgery. It is unclear whether early PD commenced soon after admission to an intensive care unit (ICU) after cardiac surgery results in better outcomes. Objective: To describe the study protocol and statistical analysis plan for the Early Peritoneal Dialysis in Infants after Cardiac Surgery (EPICS) trial. Design, setting, participants and intervention: The EPICS trial is an open, randomised, two-group, single-centre clinical study of infants ≤ 180 days of age who had cardiac surgery (in Risk-Adjusted Classification for Congenital Heart Surgery version 1 categories 3-6) with cardiopulmonary bypass. Participants will be randomly assigned 1:1 to early PD (treatment group) or no early PD (control group). Those assigned to the treatment group will begin receiving PD soon after ICU admission and continue receiving it for 24 hours. Those in the control group will not receive PD during the first 24 hours. Main outcome measures: The primary outcome is a composite measure consisting of one or more of death, cardiac arrest, emergency chest reopening, and requirement for extracorporeal membrane oxygenation (ECMO) within 90 days. The main secondary outcomes are duration of mechanical ventilation, ICU length of stay, hospital length of stay, vasoactive-inotropic score at 24 hours, and cumulative per cent fluid balance by end of Day 2. At Day 90, events such as mortality, requirement for ECMO, cardiac arrest, chest reopening, volume of packed red blood cell transfusion, postoperative infection, readmission to ICU, renal injury and brain injury will be assessed. Conclusions: The EPICS trial aims to evaluate the role of early PD after infant cardiac surgery in lowering the rate of a composite major outcome. In addition, it will test the effect of early PD on duration of mechanical ventilation, and on ICU and hospital length of stay. Trial registration: ACTRN12617001614381.

Higher total ultrafiltration volume during cardiopulmonary bypass-assisted infant cardiac surgery is associated with acute kidney injury and fluid overload

BACKGROUND

Ultrafiltration (UF) is used for fluid removal during and after infant cardiopulmonary bypass (CPB) surgery to reduce fluid overload. Excessive UF may have the opposite of its intended effect, resulting in acute kidney injury (AKI), oliganuria, and fluid retention.

METHODS

This is a single-center, retrospective review of infants treated with conventional and/or modified UF during CPB surgery. UF volume was indexed to weight. AKI was defined using serum creatinine "Kidney Disease Improving Global Outcome (KDIGO)" criteria. Fluid balance was defined according to: [Formula: see text]. Peak fluid overload was determined on postoperative day 3. Multivariable logistic regression adjusted for multiple covariates was used to explore associations with UF, AKI, and fluid overload.

RESULTS

Five hundred thirty subjects < 1 year of age underwent CPB-assisted congenital heart surgery with UF. Sixty-four (12%) developed postoperative AKI. On multivariable regression, higher indexed total UF volume was associated with increased AKI risk (OR 1.11, 95% CI=1.04-1.19, p = 0.003). UF volume > 119.9 mL/kg did not reduce peak fluid overload. Subjects with AKI took longer to reach a negative fluid balance (2 vs. 3 days, p = 0.04). Those with more complex surgery were at highest AKI risk (STAT 3 [25-75 percentile: 3-4] in AKI group versus STAT 3 [25-75 percentile: 2-4] in non-AKI group, p = 0.05). AKI was reduced in subjects undergoing more complex surgery and treated with UF volume < 119.9 mL/kg.

CONCLUSIONS

Judicious use of UF in more complex congenital cardiac surgery reduces the risk of AKI.

Contemporary Trends and Risk Factors of Hemodynamic and Myocardial Mechanics Derived by the Pressure Recording Analytical Method After Pediatric Cardiopulmonary Bypass

Objective: Adverse factors of postoperative hemodynamic and myocardial performance remain largely unexplored in children with congenital heart disease following cardiopulmonary bypass due to technical limitations. Pressure recording analytical method (PRAM) is a continuous hemodynamic and myocardial performance monitoring technique based on beat-to-beat arterial pressure waveform. Using PRAM, we examined the temporal trends and adverse factors, in clinical management, of these performances.

Methods: We monitored blood pressure, cardiac index, cardiac cycle efficiency (CCE), dP/dT_max, and systematic vascular resistance index in 91 children (aged 186 ± 256 days) during their first 48 h after cardiopulmonary bypass. Above parameters, inotropic and vasoactive drug dosages, and serum lactate were recorded 3-hourly. NT-proBNP was measured daily.

Results: CCE and dP/dT_max gradually increased (Ps < 0.0001), while systematic vascular resistance index, diastolic blood pressure and inotrope dosages decreased (Ps < 0.0001) over time. Cardiac index, systolic blood pressure, and heart rate did not change significantly (Ps ≥ 0.231). Patients undergoing deep hypothermic circulatory arrest had significantly higher heart rate and lower CCE (Ps ≤ 0.006) over time. Multivariate analyses indicated that epinephrine dose significantly correlated with systolic blood pressure, cardiac index, CCE, and dP/dT_max after polynomial transformation, with the peak ranging from 0.075 to 0.097.

Conclusions: Systemic hemodynamic and myocardial performance gradually improved in the first 48 h after cardiopulmonary bypass without the “classic” nadir at 9–12 h. Deep hypothermic circulatory arrest and higher epinephrine doses were adversely associated with these performances. CCE, rather than cardiac index or other common-used parameters, was the most sensitive and consistent indicator.

Surgical repair for canine tricuspid valve dysplasia: Technique and case report

Tricuspid valve dysplasia (TVD) is a congenital malformation of the right atrioventricular valve characterized by restricted leaflet motion, annular dilation, and tricuspid regurgitation (TR). Severe cases typically exhibit progressive right-sided congestive heart failure, affecting the quality of life and survival. This article describes a technique for surgical repair of TVD and a case report with long-term follow-up. A 1.5-year-old intact male Labrador retriever with severe TR underwent surgical repair for TVD. Valve repair was performed under cardiopulmonary bypass and consisted of neochord mobilization of the valve leaflets and partial band annuloplasty. Transthoracic echocardiogram performed 5 days after surgery showed mild TR, a 93% decrease in anatomic regurgitant orifice area, and decreased right chamber dimensions. Forty-eight months after repair, the patient was free of clinical signs, did not have a heart murmur, and was receiving no cardiac medications. Based on this case, surgical repair of TVD is feasible with long-term durability, and the outcome suggests that the described technique may be a viable treatment option for patients with severe TVD.

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.

Recent achievements and future developments in neonatal cardiopulmonary bypass

A primary goal of improving neonatal cardiopulmonary bypass has been making the circuit smaller and reduce the blood contacting surfaces. As bypass circuit size has decreased, bloodless surgery has become possible even in neonates. Since transfusion guidelines are difficult to construct based on existing literature, these technical advances should be taken advantage of in conjunction with an individualized transfusion scheme, based on monitoring of oxygen availability to the tissues. For the majority of neonatal heart operations, several centers have shifted toward normothermic bypass even for complex neonatal surgeries, in order to avoid the adverse effects of hypothermia. Deep hypothermic circulatory arrest is no longer a necessity but an option, and selective antegrade cerebral perfusion has become common practice; however, technical uncertainties with regard to this technique have to be addressed, based on reliable neurologic monitoring. Maintenance of patient-specific heparin concentrations during bypass is another key goal, since neonates have lower baseline antithrombin concentrations and, therefore, a higher risk for inadequate thrombin inhibition and postoperative bleeding. Due to the immaturity of their hemostatic system, the standard coagulation tests alone are inappropriate to guide hemostatic therapy in neonates. The use of indirect heparin concentration assays and global viscoelastic assays in the operating room is likely to represent the optimal strategy, and requires validation in neonates. Monitoring of global and regional indexes of oxygen availability and consumption on bypass have become possible; however, their use in neonates still has outstanding technical issues which should be addressed and hence needs further validation. Due to the immaturity of the neonatal myocardium, single-shot cold cardioplegia solutions are thought to confer the best myocardial protection; their superiority when compared to more conventional modalities, however, remains to be demonstrated.

Early Peritoneal Dialysis and Major Adverse Events After Pediatric Cardiac Surgery: A Propensity Score Analysis

OBJECTIVES

Early peritoneal dialysis may have a role in modulating the inflammatory response after cardiopulmonary bypass. This study sought to test the effect of early peritoneal dialysis on major adverse events after pediatric cardiac surgery involving cardiopulmonary bypass.

DESIGN

In this observational study, the outcomes in infants post cardiac surgery who received early peritoneal dialysis (within 6 hr of completing cardiopulmonary bypass) were compared with those who received late peritoneal dialysis. The primary outcome was a composite of one or more of cardiac arrest, emergency chest reopening, requirement for extracorporeal membrane oxygenation, or death. Secondary outcomes included duration of mechanical ventilation, length of intensive care, and hospital stay. A propensity score methodology utilizing inverse probability of treatment weighting was used to minimize selection bias due to timing of peritoneal dialysis.

SETTING

Cardiac ICU, The Royal Children's Hospital, Melbourne, VIC, Australia.

PATIENTS

From 2012 to 2015, infants who were commenced on peritoneal dialysis after cardiac surgery were included.

MEASUREMENTS AND MAIN RESULTS

Among 239 eligible infants, 56 (23%) were commenced on early peritoneal dialysis and 183 (77%) on late peritoneal dialysis. At 90 days, early peritoneal dialysis as compared with late peritoneal dialysis was associated with a decreased risk of primary outcome (relative risk, 0.16; 95% CI, 0.05-0.47; p < 0.001 and absolute risk difference, -18.1%; 95% CI, -25.1 to -11.1; p < 0.001). Early peritoneal dialysis was also associated with a decrease in duration of mechanical ventilation and intensive care stay. Among infants with a cardiopulmonary bypass greater than 150 minutes, early peritoneal dialysis was also associated with a survival advantage (relative risk, 0.14; 95% CI, 0.03-0.84; p = 0.03 and absolute risk difference, -7.8; 95% CI, -13.6 to -2; p = 0.008).

CONCLUSIONS

Early peritoneal dialysis in infants post cardiac surgery is associated with a decrease in the rate of major adverse events. The role of early peritoneal dialysis warrants the conduct of randomized trials both in high and low-to-middle income countries; any beneficial effects if confirmed have the potential to strongly influence outcomes for children born with congenital heart disease.

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.

Perioperative and Anesthetic Considerations in Interrupted Aortic Arch

Interrupted aortic arch (IAA) is defined as the loss of luminal continuity between the ascending and descending aorta and is classified based on the anatomic level of interruption. IAA is associated with a number of intracardiac anomalies with the most common being patent ductus arteriosus, ventricular septal defect, and left ventricular outflow obstruction. There is also a strong association between type B interruption and 22q11 deletion syndrome. The perioperative management of the neonate with IAA begins in the intensive care unit with optimization of end-organ perfusion and function. Survival depends on the prompt initiation of prostaglandin E1 in order to maintain ductal patency, careful management of the patient’s ratio of pulmonary to systemic blood flow (Qp:Qs), and a thorough understanding of the physiologic implications of the surgical plan, type of interruption, and associated syndromes and anomalies. This review will focus on the anatomy, physiology, and perioperative anesthetic management considerations specific to the management of IAA.

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?

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.

Management of the Low Cardiac Output Syndrome Following Surgery for Congenital Heart Disease

The purpose of this review is to discuss the management of the low cardiac output syndrome (LCOS) following surgery for congenital heart disease. The LCOS is a well-recognized, frequent post-operative complication with an accepted collection of hemodynamic and physiologic aberrations. Approximately 25% of children experience a decrease in cardiac index of less than 2 L/min/m2 within 6-18 hours after cardiac surgery. Post-operative strategies that may be used to manage patients as risk for or in a state of low cardiac output include the use of hemodynamic monitoring, enabling a timely and accurate assessment of cardiovascular function and tissue oxygenation; optimization of ventricular loading conditions; the judicious use of inotropic agents; an appreciation of and the utilization of positive pressure ventilation for circulatory support; and, in some circumstances, mechanical circulatory support. All interventions and strategies should culminate in improving the relationship between oxygen supply and demand, ensuring adequate tissue oxygenation.

Modified Ultrafiltration in Children

Pediatric cardiopulmonary bypass (CPB) results in increased total body water and capillary permeability. Ultrafiltration has been effective in removing this excess water. The con ventional method of ultrafiltration is restricted by the vol ume in the venous reservoir and therefore is inefficient in smaller children and neonates, whose blood volume is dis proportionately smaller than the circuit volume. Modified ultrafiltration, performed in the immediate post-CPB period, is more effective in these patients. Blood from the aorta is pumped through the ultrafilter, and warm concentrated blood is returned to the right atrium. This removes excess water from the patient and provides a method of salvaging volume from the circuit. Modified ultrafiltration results in consistent improvements in systolic blood pressure, cardiac index, and lung compliance, as well as a reduction in pul monary vascular resistance. Removal of various inflamma tory mediators, such as tumor necrosis factor a, interleu kin-6, and interieukin-8, has been reported after modified ultrafiltration. Other advantages include an increase in he matocrit, colloid osmotic pressure, and coagulation factors, resulting in decreased bleeding and a decreased need for transfusions. In the animal model, improvement in cerebral recovery after deep hypothermic circulatory arrest has been reported. The disadvantages of this technique include the risk of air entrapment, delay in heparin reversal, and poten tial for cooling.

Cardiopulmonary Bypass-Induced Inflammatory Response: Pathophysiology and Treatment

OBJECTIVES

The objectives of this review are to discuss the pathophysiology of the pro-inflammatory response to the cardiopulmonary bypass circuit, the impact of ischemia reperfusion injury on post-operative organ function, the compensatory anti-inflammatory response and the evidence for immune-modulatory strategies and their impact on outcomes.

DATA SOURCE

MEDLINE, PubMed.

CONCLUSION

Innovations such as the development of more biocompatible surfaces and miniaturized circuits, as well as the increasing expertise of surgeons, anesthesiologists and perfusionists has transformed cardiac surgery and the use of cardiopulmonary bypass into a relatively routine procedure with favorable outcomes. Despite these refinements, the attendant inflammatory response to bypass, ischemia reperfusion injury and the compensatory anti-inflammatory response contribute to post-operative morbidity and mortality. Additional studies are needed to further delineate the impact of immunomodulatory strategies on outcomes.

Effect of modified ultrafiltration on the inflammatory response in paediatric open-heart surgery: a prospective, randomized study

Modified ultrafiltration (MUF) is often used in conjunction with paediatric cardiac surgery with cardiopulmonary bypass (CPB) and is thought to improve clinical outcome. It is unclear whether these improvements (if any) are due to the removal of inflammatory mediators. In this prospective study, 18 children aged 12-24 months undergoing uncomplicated cardiac surgery with methylprednisolone added in the pump prime were randomized to receive CPB with ( n= 10) and without ( n= 8) MUF. Cytokines (TNFα, IL-6, IL- 1β, IL-10, IL-1ra), complement split products (C3d, C4d) and coagulation system activation (F1+ 2, ATIII) were measured pre-, peri- and up to 48 h postoperatively. For clinical outcome, the alveolar-arterial oxygen (A-a) gradient, transfusion requirement, drain loss, mean blood pressure and requirement for inotropic support were registered up to 24 h postoperatively. Our results show an improvement in postoperative oxygenation as well as a tendency towards decreased drain loss and improved haemodynamics in the MUF group. There were no intergroup differences detectable for TNFα, IL-1β, IL-1ra, complement and coagulation markers. We conclude that MUF in itself does not significantly influence TNFα, IL-1β, IL-1ra and the complement and coagulation profiles in children undergoing cardiac surgerywith CPB. Despite this, there was some evidence for improved clinical outcome. Our results do not support that MUF improves postoperative organ function by modulation of the measured markers of inflammation.

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.

Immunologic and Infectious Diseases in Pediatric Cardiac Critical Care: Proceedings of the 10th International Pediatric Cardiac Intensive Care Society Conference

Since the inception of the Pediatric Cardiac Intensive Care Society (PCICS) in 2003, remarkable advances in the care of children with critical cardiac disease have been developed. Specialized surgical approaches, anesthesiology practices, and intensive care management have all contributed to improved outcomes. However, significant morbidity often results from immunologic or infectious disease in the perioperative period or during a medical intensive care unit admission. The immunologic or infectious illness may lead to fever, which requires the attention and resources of the cardiac intensivist. Frequently, cardiopulmonary bypass leads to an inflammatory state that may present hemodynamic challenges or complicate postoperative care. However, inflammation unchecked by a compensatory anti-inflammatory response may also contribute to the development of capillary leak and lead to a complicated intensive care unit course. Any patient admitted to the intensive care unit is at risk for a hospital acquired infection, and no patients are at greater risk than the child treated with mechanical circulatory support. In summary, the prevention, diagnosis, and management of immunologic and infectious diseases in the pediatric cardiac intensive care unit is of paramount importance for the clinician. This review from the tenth PCICS International Conference will summarize the current knowledge in this important aspect of our field.

A single-center strategy to minimize blood transfusion in neonates and children undergoing cardiac surgery

BACKGROUND

The transfusion of blood products in the setting of uncontrolled bleeding is unquestionably lifesaving. However, in many instances, the decision to transfuse is based on physician gestalt rather than medical evidence. When indications for transfusion are unclear, the benefits of blood products must be balanced against their significant risks and associated costs. As our institution is a referral center for patients of Jehovah's Witness faith, this population has pushed our development of techniques to achieve the goal of bloodless surgery. Our practices in caring for this population have become our standard practice for managing all patients undergoing congenital cardiac surgery.

OBJECTIVES

To evaluate our success in minimizing the use of blood products during pediatric cardiac surgery.

METHODS

After IRB approval, we retrospectively reviewed all patients who underwent cardiac surgery utilizing cardiopulmonary bypass (CPB), for biventricular repair procedures. The study was conducted at a single institution (Nationwide Children's Hospital (NCH)) during the period: January 1, 2013 and December 31, 2013.

RESULTS

A total of 209 patients were included. Overall, 81 patients (38.8%) and 81 of 136 (59.6%) weighing more than 6 kg received no blood products (bloodless) during their entire hospital stay. Bloodless surgery was most successful in patients weighing more than 18 kg, followed by patients weighing 6-18 kg. All 73 patients who weighed <6 kg received blood transfusion during their hospitalization.

CONCLUSION

The techniques that we have developed to initially care for our Jehovah's Witness families may be applied to other pediatric and adult surgical procedures.

Normothermia for pediatric and congenital heart surgery: an expanded horizon

Cardiopulmonary bypass (CPB) in pediatric cardiac surgery is generally performed with hypothermia, flow reduction and hemodilution. From October 2013 to December 2014, 55 patients, median age 6 years (range 2 months to 52 years), median weight 18.5 kg (range 3.2-57 kg), underwent surgery with normothermic high flow CPB in a new unit. There were no early or late deaths. Fifty patients (90.9%) were extubated within 3 h, 3 (5.5%) within 24 h, and 2 (3.6%) within 48 h. Twenty-four patients (43.6%) did not require inotropic support, 31 (56.4%) received dopamine or dobutamine: 21 ≤5 mcg/kg/min, 8 5-10 mcg/kg/min, and 2 >10 mcg/kg/min. Two patients (6.5%) required noradrenaline 0.05-0.1 mcg/kg/min. On arrival to ICU and after 3 and 6 h and 8:00 a.m. the next morning, mean lactate levels were 1.9 ± 09, 2.0 ± 1.2, 1.6 ± 0.8, and 1.4 ± 0.7 mmol/L (0.6-5.2 mmol/L), respectively. From arrival to ICU to 8:00 a.m. the next morning mean urine output was 3.8 ± 1.5 mL/kg/h (0.7-7.6 mL/kg/h), and mean chest drainage was 0.6 ± 0.5 mL/kg/h (0.1-2.3 mL/kg/h). Mean ICU and hospital stay were 2.7 ± 1.4 days (2-8 days) and 7.2 ± 2.2 days (4-15 days), respectively. In conclusion, normothermic high flow CPB allows pediatric and congenital heart surgery with favorable outcomes even in a new unit. The immediate post-operative period is characterized by low requirement for inotropic and respiratory support, low lactate production, adequate urine output, minimal drainage from the chest drains, short ICU, and hospital stay.

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.

Acute kidney injury and critical cardiac disease

The field of cardiac intensive care continues to advance in tandem with congenital heart surgery. The survival of patients with critical congenital heart disease is seldom in question. Consequently, the focus has now shifted to that of morbidity reduction and eventual elimination. Acute kidney injury (AKI) after cardiac surgery is associated with adverse outcomes, including prolonged intensive care and hospital stays, diminished quality of life, and increased long-term mortality. Acute kidney injury occurs frequently, complicating 30% to 40% of adult and pediatric cardiac surgeries. Patients who require dialysis are at high risk of mortality, but even minor degrees of postoperative AKI portend a significant increase in mortality and morbidity.

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.

The role of different anesthetic techniques in altering the stress response during cardiac surgery in children: a prospective, double-blinded, and randomized study

OBJECTIVES

Our goal was to evaluate the role of three anesthetic techniques in altering the stress response in children undergoing surgery for repair of congenital heart diseases utilizing cardiopulmonary bypass in the setting of fast tracking or early tracheal extubation. Furthermore, we wanted to evaluate the correlation between blunting the stress response and the perioperative clinical outcomes.

DESIGN

Prospective, randomized, double-blinded study.

SETTING

Single center from December 2008 to May of 2011.

PATIENTS

Forty-eight subjects (low-dose fentanyl plus placebo, n = 16; high-dose fentanyl plus placebo, n = 17; low-dose fentanyl plus dexmedetomidine, n = 15) were studied between ages 30 days to 3 years old who were scheduled to undergo repair for a ventricular septal defect, atrioventricular septal defect, or Tetralogy of Fallot.

METHODS

Children undergoing surgical repair of congenital heart disease were randomized to receive low-dose fentanyl (10 mcg/kg; low-dose fentanyl), high-dose fentanyl (25mcg/kg; high-dose fentanyl), or low-dose fentanyl plus dexmedetomidine (as a 1 mcg/kg loading dose followed by infusion at 0.5mcg/kg/hr until separation from cardiopulmonary bypass. In addition, patients received a volatile anesthetic agent as needed to maintain hemodynamic stability. Blood samples were tested for metabolic, hormonal and cytokine markers at baseline, after sternotomy, after the start of cardiopulmonary bypass, at the end of the procedure and at 24 hours postoperatively.

MEASUREMENTS AND MAIN RESULTS

Forty-eight subjects (low-dose fentanyl plus placebo, n = 16; high-dose fentanyl plus placebo, n = 17; low-dose fentanyl plus dexmedetomidine, n = 15) were studied. Subjects in the low-dose fentanyl plus placebo group had significantly higher levels of adrenocorticotropic hormone, cortisol, glucose, lactate, and epinephrine during the study period. The lowest levels of stress markers were seen in the high-dose fentanyl plus placebo group both over time (adrenocorticotropic hormone, p= 0.01; glucose, p = 0.007) and at individual time points (cortisol and lactate at the end of surgery, epinephrine poststernotomy; p < 0.05). Subjects in the low-dose fentanyl plus dexmedetomidine group had lower lactate levels at the end of surgery compared with the low-dose fentanyl plus placebo group (p < 0.05). Although there were no statistically significant differences in plasma cytokine levels between the three groups, the low-dose fentanyl plus placebo group had significantly higher interleukin-6:interleukin-10 ratio at 24 hours postoperatively (p < 0.0001). In addition, when compared with the low-dose fentanyl plus placebo group, the low-dose fentanyl plus dexmedetomidine group showed a lower norepinephrine level from baseline at poststernotomy, after the start of cardiopulmonary bypass, and at the end of surgery (p ≤ 0.05). Subjects in the low-dose fentanyl plus placebo group had more postoperative narcotic requirement (p = 0.004), higher prothrombin time (p ≤ 0.03), and more postoperative chest tube output (p < 0.05). Success of fast tracking was not significantly different between groups (low-dose fentanyl plus placebo 75%, high-dose fentanyl plus placebo 82%, low-dose fentanyl plus dexmedetomidine 93%; p = 0.39).

CONCLUSIONS

The use of low-dose fentanyl was associated with the greatest stress response, most coagulopathy, and highest transfusion requirement among our cohorts. Higher dose fentanyl demonstrated more favorable blunting of the stress response. When compared with low-dose fentanyl alone, the addition of dexmedetomidine improved the blunting of the stress response, while achieving better postoperative pain control.

Assessment of modified ultrafiltration hemodynamic impact by pressure recording analytical method during pediatric cardiac surgery

OBJECTIVE

Modified ultrafiltration is commonly used in pediatric cardiac surgery. Although its clinical benefits are currently debated, modified ultrafiltration has proved to improve mean arterial pressure in the first postoperative hours. Aim of our study was to measure cardiac index, stroke volume index, and mean arterial pressure modification before and after modified ultrafiltration by means of Pressure Recording Analytical Method.

DESIGN

Single-center prospective observational cohort study.

SETTING

Pediatric cardiac surgery operating room.

PATIENTS

Children below 20 kg that are included in the "pediatric" mode of Pressure Recording Analytical Method.

MEASUREMENTS AND MAIN RESULTS

Forty patients were enrolled in this study. Median age, weight, and body surface area at surgery were 3 months (interquartile range, 10 days to 3.5 yr), 5.6 (3.1-15) kg, and 0.31 (0.21-0.56), respectively. During the modified ultrafiltration procedure, a median volume of 17 mL/kg (11-25) was ultrafiltered and a median volume of 11 mL/kg (6-17) was reinfused with a median final modified ultrafiltration balance of -0.15 mL/kg (-4.0 to 0.1). By univariate analyses, there was a 10% increase in postmodified ultrafiltration mean, systolic and diastolic pressures (p = 0.01), stroke volume index (p = 0.02), and cardiac index (p = 0.001) without significant changes in heart rate, central (left and right) venous pressures, stroke volume variation, and inotropic score. By multivariate analysis, when controlling for cardiopulmonary bypass time and age at surgery, cardiac index variation was independently associated with lower preoperative body surface area (beta coefficient -5.5, p = 0.04).

CONCLUSIONS

According to Pressure Recording Analytical Method assessment, modified ultrafiltration acutely improves myocardial function, as shown by a 10% increase of systemic arterial pressure, stroke volume index, and cardiac index. This effect is more pronounced in smaller sized patients.

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.

Effect of subzero-balanced ultrafiltration on postoperative outcome of patients after cardiopulmonary bypass

OBJECTIVE

To evaluate the effect of a new ultrafiltration technique - subzero-balanced ultrafiltration technique - on early postoperative outcomes of adult patients undergoing cardiac operations with cardiopulmonary bypass.

METHODS

A total of 120 patients who required cardiopulmonary bypass for cardiac surgery were randomized into two groups, 60 in each group. Patients in the treatment group received subzero-balanced ultrafiltration during cardiopulmonary bypass, while patients in the control group received routine cardiopulmonary bypass. Postoperative outcomes, including hospital mortality and morbidity of the two groups, were analyzed.

RESULTS

Hospital mortality was 0% (0 of 60) in the treatment group versus 1.8% (1 of 60) in the control group (P=1.000). Total hospital complications was lower in the treated patients (11 of 60 [18.3%] versus 22 of 60 [36.7%], P=0.025). Duration of intubation time was shorter and transfusion volume within 24 hours postoperatively was less in patients having received subzero-balanced ultrafiltration during cardiopulmonary bypass (14.35 + or - 1.66 versus 18.64 + or - 1.57 h, P=0.036 and 1.54 + or - 1.56 versus 3.64 + or - 2.67 U/patient, P=0.032). Length of stay on the intensive care unit, duration of hospital stay, need for infusion of inotropic agent and drainage volumes within 24 h postoperatively between the two groups were comparable.

CONCLUSIONS

Subzero-balanced ultrafiltration during cardiopulmonary bypass can effectively decrease the patients' hospital morbidity and the volume of blood transfusion: it also may promote early postoperative recovery of patients. Routine application of subzero-balanced ultrafiltration during adult cardiac operations should not be necessary, but the technique should be compared to other techniques, e.g. MUF, in further studies.

Effect of modified ultrafiltration on postoperative course in neonates with complete transposition of the great arteries undergoing arterial switch operation

BACKGROUND

The purpose of the present study was to evaluate the effect of modified ultrafiltration (MUF) on neonates with transposition of the great arteries (TGA) undergoing arterial switch operation.

METHODS AND RESULTS

The current study included 36 neonates who underwent an arterial switch operation between 1998 and 2006. Arterio-venous MUF was done in 15 patients (MUF-treated group) and the other 21 patients were controls. Parameters included hematocrit, hemodynamics, pulmonary function, drain loss, leak of peritoneal fluid, length of intubation, and intensive care unit (ICU) stay. The hematocrit increased from 34+/-2% to 47+/-4% in the MUF-treated group. Blood pressure in the MUF-treated group was significantly increased without any change of central venous or left atrial pressure. Post-operative oxygenation in the MUF-treated group was greater than that of the control group (P/F ratio: 258+/-92 vs 170+/-100 mmHg, p<0.05), which did not contribute to decrease in intubation time (54+/-33 vs 52+/-29 h, p=NS). Post-operative chest drain loss and peritoneal fluid leak were comparable. The ICU stay in the MUF-treated group was significantly shorter than that in the controls (101+/-34 vs 139+/-42 h, p<0.05).

CONCLUSIONS

MUF brought improvement in blood pressure and gas exchange capacity and subsequent shorter ICU stay. MUF did not have significant impact on intubation time and capillary leak.

The benefits of continuous ultrafiltration in pediatric cardiac surgery

BACKGROUND

Systemic inflammatory response and capillary leak syndrome, caused by extracorporeal circulation, have negative effects on the function of vital organs during the postoperative period. Modified ultrafiltration (MUF) has been developed as an alternative method to reduce the detrimental effects of cardiopulmonary bypass. The aim of this prospective, randomized study is to analyze the effects of MUF in a pediatric population undergoing congenital cardiac surgery.

METHODS

Twenty-seven patients who underwent open-heart surgery at our institution were included in this prospective study. They were randomized into two groups as follows: Group I (n=14) of conventional ultrafiltration during bypass and Group II (n=13) receiving both conventional and modified ultrafiltration during and after the cessation of the bypass, respectively. The amount of prime volume, postoperative chest drain loss, transfusion requirements, hemodynamical parameters, duration of mechanical ventilatory support, and length of intensive care unit stay were compared between the two groups. During the postoperative period, the concentrations of hematological, biochemical and inflammatory parameters were also compared by analyzing the blood samples obtained at various time points.

RESULTS

MUF resulted in a significant increase in hemoglobin, hematocrit and platelet levels, and significantly reduced the amount of chest tube output and transfused blood and blood products. MUF also shortened the duration of postoperative mechanical ventilatory support, length of the intensive care unit stay and improved postoperative hemodynamical parameters. During the early postoperative hours, IL-8 is significantly reduced in patients undergoing MUF, however, the concentrations of IL-8 were similar in both groups at the end of 24 h.

CONCLUSIONS

MUF decreases the duration of mechanical ventilatory support, the length of intensive care unit stay, the need for blood transfusion and improves postoperative hemodynamics. It is associated with increased levels of hemoglobin, hematocrit and platelets. We can conclude that MUF attenuates the inflammatory response by decreasing the levels of inflammatory mediators.

Anti-inflammatory modalities: their current use in pediatric cardiac surgery in the United Kingdom and Ireland

OBJECTIVE

To determine the use of anti-inflammatory therapies in infants and children undergoing cardiac surgery in the United Kingdom and Ireland.

DESIGN

Questionnaire survey.

SUBJECTS

All centers that undertake pediatric cardiac surgery in the United Kingdom and Ireland.

RESULTS

All centers use at least one anti-inflammatory therapy, with 46% of centers using more than one. Both modified ultrafiltration (80%) and steroids (80%) are widely used as anti-inflammatory strategies. Among centers that use steroids, dose, preparation, and timing of steroid administered was highly variable. Heparin-bonded circuits and aprotinin are infrequently used as anti-inflammatory techniques.

CONCLUSION

Although anti-inflammatory interventions are believed to contribute to improved patient outcome following cardiopulmonary bypass, this survey has shown that there are still widespread variations in practice. Rather than reflecting poor clinical practice, we believe this reflects a lack of good evidence supporting clinical benefit.

Haemofiltration in newborns treated with extracorporeal membrane oxygenation: a case-comparison study

INTRODUCTION

Extracorporeal membrane oxygenation is a supportive cardiopulmonary bypass technique for patients with acute reversible cardiovascular or respiratory failure. Favourable effects of haemofiltration during cardiopulmonary bypass instigated the use of this technique in infants on extracorporeal membrane oxygenation. The current study aimed at comparing clinical outcomes of newborns on extracorporeal membrane oxygenation with and without continuous haemofiltration.

METHODS

Demographic data of newborns treated with haemofiltration during extracorporeal membrane oxygenation were compared with those of patients treated without haemofiltration in a retrospective 1:3 case-comparison study. Primary outcome parameters were time on extracorporeal membrane oxygenation, time until extubation after decannulation, mortality and potential cost reduction. Secondary outcome parameters were total and mean fluid balance, urine output in mL/kg/day, dose of vasopressors, blood products and fluid bolus infusions, serum creatinin, urea and albumin levels.

RESULTS

Fifteen patients with haemofiltration (HF group) were compared with 46 patients without haemofiltration (control group). Time on extracorporeal membrane oxygenation was significantly shorter in the HF group: 98 hours (interquartile range (IQR) = 48 to 187 hours) versus 126 hours (IQR = 24 to 403 hours) in the control group (P = 0.02). Time from decannulation until extubation was shorter as well: 2.5 days (IQR = 0 to 6.4 days) versus 4.8 days (IQR = 0 to 121.5 days; P = 0.04). The calculated cost reduction was euro5000 per extracorporeal membrane oxygenation run. There were no significant differences in mortality. Patients in the HF group needed fewer blood transfusions: 0.9 mL/kg/day (IQR = 0.2 to 2.7 mL/kg/day) versus 1.8 mL/kg/day (IQR = 0.8 to 2.9 mL/kg/day) in the control group (P< 0.001). Consequently the number of blood units used was significantly lower in the HF group (P< 0.001). There was no significant difference in inotropic support or other fluid resuscitation.

CONCLUSIONS

Adding continuous haemofiltration to the extracorporeal membrane oxygenation circuit in newborns improves outcome by significantly reducing time on extracorporeal membrane oxygenation and on mechanical ventilation, because of better fluid management and a possible reduction of capillary leakage syndrome. Fewer blood transfusions are needed. All in all, overall costs per extracorporeal membrane oxygenation run will be lower.

Modified low-flow ultrafiltration ameliorates hemodynamics and early graft function and reduces blood loss in living-donor lobar lung transplantation

BACKGROUND

This study analyzed the clinical application of modified low-flow ultrafiltration (MUF) to minimize cardiopulmonary bypass (CPB)-related adverse effects in patients undergoing living-donor lobar lung transplantation (LDLLT).

METHOD

The study enrolled 33 consecutive patients who underwent LDLLT from 1999 to 2004: 8 patients underwent conventional CPB without MUF (control group), and 15 underwent arteriovenous MUF (MUF-treated group). Hemodynamics, graft function, blood loss and blood transfusion requirements, and clinical outcomes were analyzed.

RESULTS

There was a significant increase in systolic blood pressure and a decrease in pulmonary to systemic pressure ratio in the MUF-treated group (p < 0.05). No hemodynamic changes occurred in the control group. MUF resulted in significant improvements in arterial oxygen tension/fraction of inspired oxygen ratio (PaO(2)/FiO(2;) 411 +/- 107 vs 272 +/- 107 mm Hg, p < 0.05) and the alveolar-arterial oxygen difference (a-aDO(2); 158 +/- 84 vs 315 +/- 127 mm Hg, p < 0.05) at 15 minutes after CPB. There were no differences in PaO(2)/FiO(2) and A-aDO(2) between the groups beyond 6 hours post-operatively. Post-operative blood loss and blood transfusion requirements were lower in the MUF-treated group than in the control group (p < 0.05). There were no differences in survival, duration of ventilation, intensive care unit stay, and hospital stay between the groups.

CONCLUSIONS

The low-flow MUF brought improved hemodynamics and gas exchange capacity of transplanted grafts and lowered post-operative blood loss and blood transfusion requirement. This strategy may minimize CPB-related adverse effects in patients undergoing LDLLT.

Acute kidney injury in an infant after cardiopulmonary bypass

The infant who develops acute kidney injury (AKI) after cardiopulmonary bypass (CPB) surgery presents unique challenges and opportunities to the clinician and to the investigator interested in the study of AKI pathophysiology. Infants do not have many of the comorbid conditions that confound CPB outcome studies of adults. Because the timing of the AKI event is known in this clinical setting, collaboration between cardiology intensivists, nephrologists, and perfusion technologists is essential to minimize the impact of CPB on the kidney. Early institution of ultrafiltration in the operating room and renal replacement therapy in the postoperative period may decrease the proinflammatory milieu and its resultant systemic effects. In addition, early initiation of renal replacement therapy to prevent fluid overload may result in improved infant outcomes.

Complications relating to perfusion and extracorporeal circulation associated with the treatment of patients with congenital cardiac disease: consensus definitions from the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease

The International Consortium for Evidence-Based Perfusion (www.bestpracticeperfusion.org) is a collaborative partnership of societies of perfusionists, professional medical societies, and interested clinicians, whose aim is to promote the continuous improvement of the delivery of care and outcomes for patients undergoing extracorporeal circulation. Despite the many advances made throughout the history of cardiopulmonary bypass, significant variation in practice and potential for complication remains. To help address this issue, the International Consortium for Evidence-Based Perfusion has joined the Multi-Societal Database Committee for Pediatric and Congenital Heart Disease to develop a list of complications in congenital cardiac surgery related to extracorporeal circulation conducted via cardiopulmonary bypass, extracorporeal membrane oxygenation, or mechanical circulatory support devices, which include ventricular assist devices and intra-aortic balloon pumps. Understanding and defining the complications that may occur related to extracorporeal circulation in congenital patients is requisite for assessing and subsequently improving the care provided to the patients we serve. The aim of this manuscript is to identify and define the myriad of complications directly related to the extracorporeal circulation of congenital patients.

Relationship between increased blood pressure and hematocrit during modified ultrafiltration for pediatric open heart surgery

OBJECTIVE

Modified ultrafiltration increases blood pressure after cardiopulmonary bypass in children. To investigate the cause of this hemodynamic improvement, we assessed the relationship between increased blood pressure and hematocrit.

METHODS

We retrospectively assessed 30 consecutive patients who underwent ventricular septal defect closure, and divided them into two groups: group M (modified ultrafiltration, n=15) and group C (conventional ultra-filtration, n=15). We compared the intraoperative transitions of blood pressure and hematocrit, and analyzed the correlations between blood pressure and hematocrit at 15 min after cardiopulmonary bypass (immediately after modified ultrafiltration in group M) and between the percent increases in blood pressure and hematocrit during modified ultrafiltration.

RESULTS

Although intraoperative central venous pressure and dopamine dosage were similar, in group M, increases in hematocrit (26.4% +/- 4.9% to 31.9% +/- 5.7%, P < 0.01) and systolic blood pressure (61.1 +/- 10.3 to 75.6 +/- 11.5 mmHg, P < 0.01) occurred during modified ultrafiltration. Furthermore, diastolic and mean blood pressure at 15 min after cardiopulmonary bypass (after modified ultrafiltration) were higher in group M than in group C. However, systolic, mean, and diastolic blood pressure were not correlated with increased hematocrit after modified ultrafiltration, and there was also no correlation between the percent increases in each blood pressure and hematocrit.

CONCLUSION

Modified ultrafiltration increased blood pressure and hematocrit immediately after cardiopulmonary bypass in children. However, no correlations were detected between the increases in blood pressure and hematocrit. These results indicate hemoconcentration is not the major cause of the increased blood pressure during modified ultrafiltration.