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 After the termination of CPB, blood was withdrawn through the aortic cannula and passed through a hemoconcentrator attached to the blood cardioplegia set and returned to the patient through the venous cannula.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.

Blood Conservation and Hemostasis Management in Pediatric Cardiac Surgery

Pediatric cardiac surgery is associated with significant perioperative blood loss needing blood product transfusion. Transfusion carries serious risks and implications on clinical outcomes in this vulnerable population. The need for transfusion is higher in children and is attributed to several factors including immaturity of the hemostatic system, hemodilution from the CPB circuit, excessive activation of the hemostatic system, and preoperative anticoagulant drugs. Other patient characteristics such as smaller relative size of the patient, higher metabolic and oxygen requirements make successful blood transfusion management extremely challenging in this population and require meticulous planning and multidisciplinary teamwork. In this narrative review we aim to summarize risks and complications associated with blood transfusion in pediatric cardiac surgery and also to summarize perioperative coagulation management and blood conservation strategies.

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.

Antenatal and Perioperative Mechanisms of Global Neurological Injury in Congenital Heart Disease

Congenital heart defects (CHD) is one of the most common types of birth defects. Thanks to advances in surgical techniques and intensive care, the majority of children with severe forms of CHD survive into adulthood. However, this increase in survival comes with a cost. CHD survivors have neurological functioning at the bottom of the normal range. A large spectrum of central nervous system dysmaturation leads to the deficits seen in critical CHD. The heart develops early during gestation, and CHD has a profound effect on fetal brain development for the remainder of gestation. Term infants with critical CHD are born with an immature brain, which is highly susceptible to hypoxic-ischemic injuries. Perioperative blood flow disturbances due to the CHD and the use of cardiopulmonary bypass or circulatory arrest during surgery cause additional neurological injuries. Innate patient factors, such as genetic syndromes and preterm birth, and postoperative complications play a larger role in neurological injury than perioperative factors. Strategies to reduce the disability burden in critical CHD survivors are urgently needed.

Comparison of two cardiopulmonary bypass strategies with a miniaturized tubing system: a propensity score-based analysis

INTRODUCTION

The existing cardiopulmonary bypass tubing system has already been significantly improved in our hospital by reducing the priming volume; thus, we further employed a new cardiopulmonary bypass strategy in children based on a miniaturized cardiopulmonary bypass circuit. We aimed to compare the effectiveness of new and conventional strategies by analyzing the outcomes after congenital heart surgery.

METHODS

We performed a database analysis of all patients undergoing congenital heart surgery with cardiopulmonary bypass at Shenzhen Children's Hospital from 1 May 2015 to 30 June 2017. Propensity score matching was used to adjust for significant covariates, and multivariable regression models and stratified analysis were used to assess the association of cardiopulmonary bypass strategy with outcomes.

RESULTS

Of 925 total patients, 55.35% were in the conventional strategy group and 44.65% were in the new strategy group. After propensity score matching, there were 610 patients in total, with 305 patients in each group. In the multivariable regression models, the cardiopulmonary bypass strategy was not significantly associated with successful early extubation (p > 0.05), reintubation (p > 0.05), or nasal continuous positive airway pressure (p > 0.05) rates. The new strategy group had fewer hospital stays (p = 0.04) and intensive care unit stays (p < 0.05) compared with patients who underwent conventional strategy. The difference remained statistically significant (p < 0.05) when The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category was <3.

CONCLUSION

The implementation of a new cardiopulmonary bypass strategy, with selective ultrafiltration based on a miniaturized cardiopulmonary bypass circuit system, was safe and effective for children who underwent congenital heart surgery in a Chinese hospital. The new cardiopulmonary bypass strategy was associated with fewer hospital and intensive care unit stays.

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.

A Table Mounted Cardiopulmonary Bypass System for Pediatric Cardiac Surgery

Systemic inflammatory response and hemodilution are prominent factors associated with cardiopulmonary bypass and result in increased morbidity and mortality in children. Miniaturized systems have evolved to decrease such effects and restrict use of blood products, especially in the neonatal population. We have developed a table mounted cardiopulmonary bypass system that allows closer proximity of the system to the patient with consequent decrease in priming volumes, hemodilution, and its associated effects, and contributes to development into an ideally bloodless surgical approach.

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.

Splitting blood and blood product packaging reduces donor exposure for patients undergoing cardiopulmonary bypass

BACKGROUND

Cardiopulmonary bypass for congenital heart surgery requires packed red cells (PRBC) and fresh frozen plasma (FFP) to be available, both for priming of the circuit as well as to replace blood loss. This study examines the hypothesis that splitting one unit of packed red blood cells and one unit of fresh frozen plasma into two half units reduces blood product exposure and wastage in the Operating Room.

METHODS

Beginning August 2013, the blood bank at Children's National Medical Center began splitting one unit of packed red blood cells (PRBC) and one unit of fresh frozen plasma (FFP) for patients undergoing cardiopulmonary bypass (CPB). The 283 patients who utilized CPB during calendar year 2013 were divided into 2 study groups: before the split and after the split. The principal endpoints were blood product usage and donor exposure intra-operatively and within 72 hours post-operatively.

RESULTS

There was a significant decrease in median total donor exposures for FFP and cryoprecipitate from 5 to 4 per case (p = 0.007, Mann-Whitney U-test). However, there was no difference in the volume of blood and blood products used; in fact, there was a significant increase in the amount of FFP that was wasted with the switch to splitting the unit of FFP.

CONCLUSIONS

We found that modification of blood product packaging can decrease donor exposure. Future investigation is needed as to how to modify packaging to minimize wastage.

Outcomes of cardiac surgery in patients weighing <2.5 kg: affect of patient-dependent and -independent variables

OBJECTIVE

A recent Society of Thoracic Surgeons database study showed that low weight (<2.5 kg) at surgery was associated with high operative mortality (16%). We sought to assess the outcomes after cardiac repair in patients weighing <2.5 kg versus 2.5 to 4.5 kg in an institution with a dedicated neonatal cardiac program and to determine the potential role played by prematurity, the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) risk categories, uni/biventricular pathway, and surgical timing.

METHODS

We analyzed the outcomes (hospital mortality, early reintervention, postoperative length of stay, mortality [at the last follow-up point]) in patients weighing <2.5 kg at surgery (n = 146; group 1) and 2.5 to 4.5 kg (n = 622; group 2), who had undergone open or closed cardiac repairs from January 2006 to December 2012 at our institution. The statistical analysis was stratified by prematurity, STAT risk category, uni/biventricular pathway, and usual versus delayed surgical timing. Univariate versus multivariate risk analysis was performed. The mean follow-up was 21.6 ± 25.6 months.

RESULTS

Hospital mortality in group 1 was 10.9% (n = 16) versus 4.8% (n = 30) in group 2 (P = .007). The postoperative length of stay and early unplanned reintervention rate were similar between the 2 groups. Late mortality in group 1 was 0.7% (n = 1). In group 1, early outcomes were independent of the STAT risk category, uni/biventricular pathway, or surgical timing compared with group 2. A lower gestational age at birth was an independent risk factor for early mortality in group 1.

CONCLUSIONS

A dedicated multidisciplinary neonatal cardiac program can yield good outcomes for neonates and infants weighing <2.5 kg independently of the STAT risk category and uni/biventricular pathway. A lower gestational age at birth was an independent risk factor for hospital mortality.

Recent Advances in Pediatric Cardiopulmonary Bypass

There have been numerous recent advances geared specifically toward the practice of pediatric cardiopulmonary bypass (CPB). These advances include the development of the first oxygenator intended solely for the neonatal CPB patient; pediatric oxygenators with low prime volumes and surface areas, which allow flows up to 2 L/min; pediatric oxygenators with integrated arterial filters; and miniature ultrafiltration (UF) devices, which allow for high rates of ultrafiltrate removal. When used in combination with heart lung machines with mast-mounted pumps, these advances can result in significant decreases in CPB circuit surface areas and prime volumes. This may attenuate CPB-associated hemodilution and decrease or eliminate the need for homologous red blood cells during or after CPB. In addition to these equipment-related advances, changes in myocardial protection strategies and the technique of modified UF as it relates to these advances are discussed.

Five-year experience with mini-volume priming in infants ≤5 kg: safety of significantly smaller transfusion volumes

Reducing the cardiopulmonary bypass (CPB) priming volume in congenital cardiac surgery is important because it is associated with fewer transfusions. This retrospective study was designed to compare safety and transfusion volumes between the mini-volume priming (MP) and conventional priming (CP) methods. Between 2007 and 2012, congenital heart surgery using CPB was performed on 480 infants (≤5 kg): the MP method was used in 331 infants (MP group, 69.0%), and the CP method was used in 149 infants (CP group, 31.0%). In the MP group, narrow-caliber (3/16″) tubing was used, and the pump heads were vertically aligned to shorten the tubing lengths. The smallest possible oxygenators and hemofilters were used, and vacuum drainage was applied. Ultrafiltration was vigorously applied during CPB to avoid excessive hemodilution. The mean age and body weight of the patients were 48 ± 41 (0-306) days and 3.8 ± 0.8 (1.3-5.0) kg, respectively. The total priming and transfusion volumes during CPB were lower in the MP group than in the CP group (141 ± 24 mL vs. 292 ± 50 mL, P < 0.001, and 82 ± 40 mL vs. 162 ± 82 mL, P < 0.001, respectively). In the MP group, the smallest priming volume was 110 mL. However, there was no significant difference in the lowest hematocrit level during CPB between the two groups (22 ± 3% vs. 22 ± 3%, P = 0.724). The incidence of postoperative neurological complications was not significantly different between the MP and CP groups (1.8% vs. 2.7%, P = 0.509). After adjustment for the Risk Adjustment for Congenital Heart Surgery category, body surface area, and age, MP was not an independent risk factor of postoperative neurological complications or early mortality (P = 0.213 and P = 0.467, respectively). The MP method reduced the priming volume to approximately 140 mL without increasing the risk of morbidity or mortality in infants ≤5 kg. The total transfusion volume during CPB was reduced by 50% without compromising hematocrit levels. We recommend the use of mini-volume priming, which is a safe and effective method for reducing transfusion volumes.

A clinical evaluation of the Maquet Quadrox-i Neonatal oxygenator with integrated arterial filter

High-performance, low-prime-volume oxygenators for the pediatric patient population have become a growing market among manufacturers. In the summer of 2011, our institution clinically evaluated the performance of the newly released Maquet Quadrox-i Neonatal oxygenator with integrated arterial filter. The static priming volume, including the integrated arterial filter, is 40 ml and the maximum rated blood flow is 1.5 liters per minute (LPM). The device was used on seven pediatric patients, ranging from 3.2 to 14 kg, undergoing various congenital heart defect repairs. Data were collected to calculate gas transfer, trans-oxygenator pressure drop, and heat exchange performance. The mean cardiopulmonary bypass time was 85 minutes and the mean cross-clamp time was 56 minutes. The average oxygen transfer was 34.3 ± 22.8 ml/O2/min and increased with both blood flow and FiO2. The average carbon dioxide transfer was 22.3 ± 17.8 ml/min and increased with both blood flow and gas sweep to blood flow ratio. The average trans-oxygenator pressure drop per blood flow was 53.3 ± 15.5 mmHg/L/min and increased with flow. The average heat exchanger performance factor was 47.6 ± 11.6% and decreased with flow. The heat exchange performance factor at maximum observed clinical flow, 1.42 LPM, was 36.4%. During this evaluation, the Maquet Quadrox-i Neonatal oxygenator adequately performed within its operational flow in the clinical setting.

Prolonged warm ischemia for transfusion-free arterial switch and ventricular septal defect surgery in a 4.5-Kg baby

Blood-free pediatric surgery is increasingly used for surgical correction of simple cardiopathies. Herein, we describe a complex cardiopathy, arterial switch operation and ventricular septal defect, with pre-operative thrombocytopenia in a 4.5 Kg baby treated with warm surgery and intermittent warm blood microplegia without any blood product. Bypass time was 89 min and aortic cross-clamp time 61 min. The maximal length of warm ischemia (time between microplegia injections) was 42 minutes. The postoperative course was uneventful. The patient was weaned off the ventilator after 7 hours, was discharged from the ICU on day 2 and was discharged from the hospital on day 7. The two main factors involved in this result were high pre-operative hemoglobin level and bypass technique with small prime volume, microplegia and warm perfusion. However, the success of this challenging case is also the result of teamwork and of rigorous patient care.

Use of a miniaturized cardiopulmonary bypass circuit in neonates and infants is associated with fewer blood product transfusions

Miniaturized bypass circuits, including the Kids D100 oxygenator and the D130 arterial filter, were specially designed to reduce blood transfusions in small infants undergoing cardiac surgery. This study compared the number of blood product transfusions and short-term outcome between patients younger than 1 year undergoing cardiac surgery with a conventional and a miniaturized bypass circuit, after controlling for baseline characteristics and surgical complexity by 1:1 matching. Adjusted odds ratios (ORs) and 95% confidence intervals for exposure to transfusions and to any additional transfusion were estimated from binary and polytomous regression models. Of the 804 patients enrolled retrospectively, 246 were analyzed after matching. The use of the miniaturized circuit required a lower priming volume, 265.5 vs. 432.4 mL, p < 0.001, fewer packed red blood cell (PRBC) transfusions, 1.4 vs. 2.0 U, p < 0.001, and fewer platelet transfusions on the day of surgery, 57.7% vs. 76.4%, p < 0.001. After adjustment for the use of antifibrinolytics, the ultrafiltration rate, and the year of surgery, the use of the miniaturized circuit was independently related to a reduced risk of additional PRBC transfusions, OR 0.04 (0.01, 0.13), and exposure to platelet transfusions, OR 0.78 (0.63, 0.96). Short-term outcome was similar.

Blood transfusion in pediatric cardiac surgery

The aim of the study is to measure the volume of homologous blood needed for one pediatric patient during his hospital stay. Over a 4-month period, all the patients operated upon with a blood prime or requiring blood transfusion during their hospital stay were included in this study.The cardiopulmonary bypass protocol associates a miniaturized bypass circuit, vacuum-assisted venous drainage, and microplegia. The volume of each blood product opened is known and the volume of blood product remaining, following the last transfusion, is measured. Data collected areas follows: patient weight; hemoglobin level before surgery,during bypass, and in intensive care after the last transfusion;time to extubation; and degree of inotropic support.Forty-six patients weighing 5.1 1.5 kg were included in this study. Cardiopulmonary bypass priming volume was 100 mL for patients up to 3.5 kg, 120 mL for patients between 3.6 and 7.5 kg, and 160 mL for patients between 7.6 and 8.6 kg. The volume of blood transfusion was 271 112 mL, hemoglobin level before surgery was 10.3 1.7 g/dL, hemoglobin level during surgery was 11.0 1.5 g/dL, and hemoglobin level after the last transfusion was 12.3 2.4 g/dL. Time to extubation was 12 3.3 h, and inotropic support was enoximone in 37 patients,whereas 6 patients needed enoximone and epinephrine.No patient needed reexploration for bleeding and one patient received a platelet transfusion.The mean blood transfusion volume was equivalent to 60% of the patient’s total blood volume (estimated to be 80 mL/kg).

Perioperative blood conservation strategies in pediatric patients undergoing open-heart surgery: impact of non-autologous blood transfusion and surface-coated extracorporeal circuits

BACKGROUND

The aim of this study was to explore the relative clinical and biomaterial effects of blood transfusions (Tx) and novel low-prime, surface-coated circuitry on perioperative outcome in a pediatric population undergoing cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

Over a 12-month period, 80 patients weighing >10 kg undergoing ventricular septal defect (VSD) repair with CPB were prospectively randomized into two groups according to the type of CBP circuit used, then each randomized group was enrolled into two groups again, according to the need for transfusion (N=20): Group 1- Tx-free procedures on low-prime, surface-coated extracorporeal circuitry (FX05, Terumo); Group 2- procedures requiring Tx on coated circuitry; Group 3- Tx-free procedures with standard uncoated circuitry (D902, Sorin); Group 4 (Control)- procedures requiring Tx on uncoated circuitry. Blood samples were collected at baseline (T1), at the end of the CPB (T2) and 24 h (T3) postoperatively. rSO(2) desaturation risk score >6000 (Invos, Somanetics) was calculated by multiplying rSO(2) <50% by time.

RESULTS

IL-6 levels (pg/ml) were significantly lower in Groups 1 and 3 versus control at T2 (13±4; 17±5 versus 33±8; p<0.05). CD11b/CD18 levels (%) were significantly lower in Group 1 (12±4) versus control (25±8) at T2 (p<0.05). Respiratory support time (h) was significantly less in Group 1 (11.4±6) versus control (19.8±7) (p<0.05). rSO(2) desaturation risk >6000 (%) was 15.7±9 in Group 1 and 26.8±11 in control (p<0.05).

CONCLUSION

Allogenic Tx amplifies the CPB-related inflammatory response. It is feasible to do congenital procedures safely without Tx for patients weighing >10 kg by using combined blood management strategies.

Coagulation considerations for infants and children undergoing cardiopulmonary bypass

Cardiac surgery involving cardiopulmonary bypass imposes a significant pathophysiologic burden on patients. Pediatric patients are especially predisposed to the adverse effects of surgery and bypass on the coagulation system, with resultant bleeding, transfusion, and poor outcomes. These risks accrue to pediatric patients in inverse proportion to their weight and are attributable to hematologic immaturity, coagulation defects associated with congenital heart disease, bypass equipment, and the nature of congenital heart surgery. Standard anticoagulation does not completely inhibit thrombin generation, and continuous consumption of coagulation factor continues throughout bypass. Conventional measurements of anticoagulation during bypass poorly reflect this incomplete anticoagulation, and alternate methods may improve anticoagulant therapy. Emerging therapies for blocking the effects of bypass on the coagulation system hold promise for decreasing bleeding and related complications, and improving outcomes in congenital heart surgery.

Mediastinitis in pediatric cardiac surgery: Prevention, diagnosis and treatment

In spite of advances in the management of mediastinitis following sternotomy, mediastinitis is still associated with significant morbidity. The prognosis is much better in pediatric surgery compared to adult surgery, but the prolonged hospital stays with intravenous therapy and frequent required dressing changes that occur with several therapeutic approaches are poorly tolerated. Prevention includes nasal decontamination, skin preparation, antibioprophylaxis and air filtration in the operating theater. The expertise of the surgical team is an additional factor that is difficult to assess precisely. Diagnosis is often very simple, being made on the basis of a septic state with wound modification, while retrosternal puncture and CT scan are rarely useful. Treatment of mediastinitis following sternotomy is always a combination of surgical debridement and antibiotic therapy. Continued use of numerous surgical techniques demonstrates that there is no consensus and the best treatment has yet to be determined. However, we suggest that a primary sternal closure is the best surgical option for pediatric patients. We propose a simple technique with high-vacuum Redon's catheter drainage that allows early mobilization and short term antibiotherapy, which thus decreases physiological and psychological trauma for patients and families. We have demonstrated the efficiency of this technique, which is also cost-effective by decreasing intensive care and hospital stay durations, in a large group of patients.

Specific requirements for bloodless cardiopulmonary bypass in neonates and infants; a review

A miniaturized cardiopulmonary bypass circuit enables the safe performance, in selected pediatric patients, of bloodless open heart surgery. As the latest survival rates in neonatal and infant cardiac surgery have become satisfactory, investigators have concentrated upon the improvement of existing procedures. Institutional guidelines and multidisciplinary efforts undertaken in the pre- and postoperative periods are of great importance, concerning bloodless CPB and should be seriously pursued by all involved caregivers.

This review reflects upon the selective, most relevant requirements for success of asanguinous neonatal and infant CPB: acceptable level of hemodilution during the CPB, patient preoperative hematocrit value and volume of CPB circuit. We present an assessment of practical measures that were also adapted in our institution to achieve an asanguinous CPB for neonatal and infant patients.

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.

Cardiopulmonary bypass and edema: physiology and pathophysiology

Edema is a common morbidity following cardiopulmonary bypass (CPB) and can result in injury to many organs, including the heart, lungs, and brain. Generalized edema is also common and can lead to increased post-operative hospital stay and other morbidities. Pediatric patients are more susceptible to post-CPB edema and the consequences are more severe for this population. Hemodilution and systemic inflammatory responses are two suspected causes of CPB-related edema; however, the mechanisms involved are far from understood. Also, the common strategies to improve edema have not been completely successful and there is a need for new strategies at maintaining a fluid balance of patients as close to physiological as possible, especially for pediatric patients. An integrative approach to understanding edema is necessary as the forces involved in fluid homeostasis are dynamic and interdependent. Therefore, this review will focus on the physiology of fluid homeostasis and the pathologies of fluid shifts during CPB which lead to general edema as well as tissue-specific edema.