Priming Volume Research Articles

How intravenous nitroglycerine transit time from bag-to-bloodstream can be affected by infusion technique: a simulation study

ObjectiveTo measure the possible delays in intravenous nitroglycerine administration.MethodsThis was a simulation study of sham intravenous nitroglycerine using a standard nitroglycerine titration protocol. Variables studied were (i) common cannulae/needles, (ii)...

Atraumatic Pulsatile Leukocyte Circulation for Long-Term In Vitro Dynamic Culture and Adhesion Assays.

Low flow rate pumping of cell suspensions finds current applications in bioreactors for short-term dynamic cell culture and adhesion assays. The aim of this study was to develop an atraumatic pump and hemodynamically adapted test circuit to allow operating periods of at least several hours. A computer-controlled mini-pump (MP) was constructed based on non-occlusive local compression of an elastic tube with commercial bi-leaflet valves directing the pulsatile flow into a compliant circuit. Cell damage and activation in the system were tested with whole blood in comparison with a set with a conventional peristaltic pump (PP). Activation of circulating THP-1 monocytes was tested by measuring the expression of CD54 (ICAM-1). Additionally, monocyte-endothelial interactions were monitored using a parallel-plate flow chamber with an artificial stenosis. The system required a priming volume of only 20 mL, delivering a peak pulsatile flow of up to 35 mL/min. After 8 h, blood hemolysis was significantly lower for MP with 11 ± 3 mg/dL compared with PP with 100 ± 16 mg/dL. CD142 (tissue factor) expression on blood monocytes was 50% lower for MP. With MP, THP-1 cells could be pumped for extended periods (17 h), with no enhanced expression of CD54 permitting the long-term co-culture of THP-1 with endothelial cells and the analysis of flow pattern effects on cell adhesion. A low-damage assay setup was developed, which allows the pulsatile flow of THP-1 cells and investigation of their interaction with other cells or surfaces for extended periods of time.

Pharmacokinetics of tranexamic acid in neonates, infants, and children undergoing cardiac surgery with cardiopulmonary bypass.

Tranexamic acid (TXA) is one of the most commonly used antifibrinolytic medications in children undergoing repair of congenital heart defects. However, a pharmacokinetics analysis of TXA has never been performed in neonates or young children undergoing complex cardiac surgeries using cardiopulmonary bypass, hypothermia, circulatory arrest, and ultrafiltration. A comprehensive pharmacokinetics study was performed in this patient population. Fifty-five patients ranging from 2 days through 4 yr old were categorized into three groups: children less than 2 months old, infants 2 months to 1 yr old, and children greater than 1 yr old and weighing up to 20 kg. TXA was given as a bolus of 100 mg/kg followed by an infusion of 10 mg · kg · h throughout the surgery. A dose of 100 mg/kg was placed in the cardiopulmonary bypass prime. A total of 16 to 18 samples were obtained from all patients throughout surgery. Plasma TXA concentrations were measured by high-performance liquid chromatography and modeled under a nonlinear mixed-effects framework with a two-compartment structural model. Cardiopulmonary bypass had a statistically significant impact on all pharmacokinetic parameters. Age was a better covariate than body weight, affecting both the distribution and the elimination of TXA. However, weight performed well in some cases. Other covariates including body surface area, pump prime volume, ultrafiltrate volume, and body temperature did not improve the model. This TXA pharmacokinetic analysis is reported for the first time in neonates and young children undergoing complex cardiac surgeries with cardiopulmonary bypass. Dosing recommendations are provided as guidance for maintaining desired target concentrations.

Who is the Bad Guy in Perfusion Technologies? Priming Volume, Blood Air Interaction or Pump Type: A Prospective, Randomized Trial of Three Different Techniques

Objectives: Minimal extracorporeal circulation techniques or circuits (MECC) may reduce the side effects of conventional extracorporeal circulation (CECC). However, it is unclear how much of this reduction is caused by reducing priming volume and hemodilution or by avoiding blood-air contact and dispersion of mediastinal debris into the systemic circulation.

Mock circulation loop to investigate hemolysis in a pulsatile total artificial heart.

Hemocompatibility of blood pumps is a crucial parameter that has to be ensured prior to in vivo testing. In contrast to rotary blood pumps, a standard for testing a pulsatile total artificial heart (TAH) has not yet been established. Therefore, a new mock circulation loop was designed to investigate hemolysis in the left ventricle of the ReinHeart TAH. Its main features are a high hemocompatibility, physiological conditions, a low priming volume, and the conduction of blood through a closed tubing system. The mock circulation loop consists of a noninvasive pressure chamber, an aortic compliance chamber, and an atrium directly connected to the ventricle. As a control pump, the clinically approved Medos-HIA ventricular assist device (VAD) was used. The pumps were operated at 120 beats per minute with an aortic pressure of 120 to 80 mm Hg and a mean atrial pressure of 10 mm Hg, generating an output flow of about 5 L/min. Heparinized porcine blood was used. A series of six identical tests were performed. A test method was established that is comparable to ASTM F 1841, which is standard practice for the assessment of hemolysis in continuous-flow blood pumps. The average normalized index of hemolysis (NIH) values of the VAD and the ReinHeart TAH were 0.018 g/100 L and 0.03 g/100 L, respectively. The standard deviation of the NIH was 0.0033 for the VAD and 0.0034 for the TAH. Furthermore, a single test with a BPX-80 Bio-Pump was performed to verify that the hemolysis induced by the mock circulation loop was negligible. The performed tests showed a good reproducibility and statistical significance. The mock circulation loop and test protocol developed in this study are valid methods to investigate the hemolysis induced by a pulsatile blood pump.

Can topical administration of tranexamic acid be a good adjuvant to the intravenous route for decreasing postoperative seizure incidence? A double blinded randomized study

Background Antifibrinolytic therapy has become a mainstay in complex cardiac surgical procedures for decreasing bleeding and minimizing transfusion requirements. Tranexamic acid (TA) is an antifibrinolytic agent that can be used both systemically and topically. Current studies and case series reports mention an increased incidence of seizures after administration of high doses of TA (60-260 mg/kg body weight). Thus, we hypothesize that adding a topical dose of TA to a small dose intravenously could reduce postoperative bleeding in patients who have undergone cardiac surgery with subsequent decrease in the overall complications associated with this drug, mainly seizures. Materials and methods A total of 120 patients were randomly allocated to two groups, the intravenous TA group (group I) and the topical and intravenous TA group (group II), with 60 patients in each. Every patient in group I received an initial bolus dose of TA consisting of a bolus of 50 mg/kg body weight at the beginning and at the end of cardiopulmonary bypass (CPB), and 100 mg/100 ml priming volume was added to the priming fluid of the CPB system. In group II every patient received an initial bolus dose of TA at 30 mg/kg infused over 15 min followed by a 16 mg/kg/h infusion until chest closure with a 2 mg/kg load within the pump prime; in addition, before sternotomy closure, patients received another 2 g of TA diluted in 500 ml of warm saline (37°C), which was poured into the pericardial cavity. Results Hemoglobin concentration, hematocrit value, platelet count, international normalized ratio, bleeding time, activated partial thromboplastin time, total volume of blood loss, and total volume of blood transfused into the patients showed no significant differences between the two groups throughout the study. In contrast, prothrombin time and activated clotting time were significantly higher in group II when compared with group I at 2 h postoperatively. Seizure incidence was significantly lower in group II when compared with group I. However, the number of re-explored cases was insignificant when the two groups were compared. Conclusion Topical application of TA in addition to a small intravenous dose in patients undergoing open cardiac surgery using CPB reduces perioperative blood loss and transfusion in those patients to the same extent as sole large intravenous dose with less incidence of seizures.

Congenital Heart Defects: Early Surgical Correction and Heart Failure? Brief History

The first successful cardiac surgical procedure was performed by Robert Gross in 1938 in Boston. A 7 year-old patient underwent ligation of the ductus arteriosus [1]. In 1945, Crawford carried out the first correction for coarctation of the aorta in Sweden [2,3].Technological development that allowed for the introduction of extracorporeal circulation devices led to the beginning of open heart surgery. The first heart surgery using an extracorporeal circulation device was performed by Kirklin. Extracorporeal circulation devices had multiple negative effects on the physiology of the infant and the newborn, so that at the beginning of pediatric heart surgery, the delay of surgical correction was preferred. Initially, these devices required an extremely high priming volume that exposed the child to exanguinotransfusion. Inflammation mediators [4] caused excessive vascular permeability and tissue edema, all the more so as the age of the child was younger at the time of surgery.At first, anesthesia and intensive care for children were practically non-existent, and diagnosis was made using invasive techniques (cardiac catheterization), which most frequently generated complications. Surgical kits did not contain microsurgical instruments required for working on the fragile heart tissue of the newborn and infant. Thus, a number of palliative procedures were developed, in order to help the patient survive until the performance of surgical correction.The pathophysiology of congenital heart defects includes 3 main categories. There may be a volume load in which one or both ventricles must pump more blood than normal. This usually happens because of an increased pulmonary blood flow, as a result of a septal defect. There may be a pressure load of one or both ventricles. This can be the result of an obstruction at the outlet of the ventricle. The third possibility is cyanosis that can be secondary to a reduction in pulmonary blood flow or inadequate mixing between the two parallel circulations.Systemic pulmonary shunt reduces cyanosis by increasing pulmonary blood flow. Although from a conceptual point of view it is an easy procedure, systemic pulmonary shunt can be a challenge for the surgeon. Assessing the size of the shunt depending on the weight of the child is most important. The size of the shunt must take into consideration the subsequent development of the child, but it must not be too large in order to avoid postoperative ventricular volume overload. The Blalock-Taussig shunt was introduced by the surgeon Alfred Blalock and the cardiologist Helen Taussig [5]. The original BT shunt directly connected the sectioned subclavian artery to the right pulmonary artery and was of an adequate size to substitute for the pulmonary blood flow deficiency. In addition, this shunt had growth potential and thus, it could pathophysiologically support the patient for many years. The Waterston shunt is an anastomosis between the ascending aorta and the right pulmonary artery [6]. This shunt has the disadvantage to produce excessive pulmonary blood flow and a distortion of pulmonary arteries.The Potts shunt consists of the anastomosis of the descending aorta and the left pulmonary artery. This shunt has all the disadvantages of the Waterston shunt and in addition, it is extremely difficult to remove at the time of surgical correction.The modified BT shunt, which consists of the anastomosis of the arterial brachiocephalic trunk with the right pulmonary artery, by means of a vascular prosthesis, was introduced by deLeval [7]. This shunt was initially performed in the left subclavian artery and the left pulmonary artery through thoracotomy. It has the following advantages: it does not cause pulmonary artery distortion and pulmonary overload.High blood pressure and flow in pulmonary circulation, most frequently due to a septal defect, may lead in time to pulmonary hypertension and pulmonary vascular disease. In 1950, Muller and Dammann introduced pulmonary artery banding in order to reduce high blood pressure and flow in pulmonary circulation [8]. Like in the case of shunts, banding does not allow for an increase in diameter, so that in time, with the child’s growth, this becomes increasingly tight. It can also result in pulmonary artery distortion, so that correction and the removal of banding should be initiated as soon as possible after the regression of pulmonary hypertension.In 1950, Blalock and Hanlon introduced surgical atrial septectomy for children with transposition of the great vessels with insufficient mixing [9]. Nowadays, this septectomy is an interventional procedure performed through the rupture of the septum with a balloon catheter, according to the procedure described by Rashkind [10,11].

The Effect of Vacuum on Venous Drainage: an Experimental Evaluation on Pediatric Venous Cannulas and Tubing Systems

To observe how vacuum assisted venous drainage (VAVD) may influence the flow in a cardiopulmonary bypass circuit with different size of venous lines and cannulas. The experimental circuit was assembled to represent the cardiopulmonary bypass circuit routinely used during cardiac surgery. Wall suction was applied directly, modulated and measured into the venous reservoir. The blood flow was measured with a flow-meter positioned on the venous line. The circuit prime volume was replaced with group O date expired re-suspended red cells and Plasmalyte 148 to a hematocrit of 28% to 30%. In an open circuit with gravity siphon venous drain, angled cannulae drain more than straight ones regardless the amount of suction applied to the venous line (16 Fr straight cannula (S) drains 90 ml/min less than a 16 Fr angled (A) with a siphon gravity). The same flow can be obtained with lower cannula size and higher suction (i.e. 12 A with and -30 mmHg). Tables have been created to list how the flow varies according to the size of the cannulas, the size of the venous tubes, and the amount of suction applied to the system. Vacuum assisted venous drainage allows the use of smaller cannulae and venous lines to maintain a good venous return, which is very useful during minimally invasive approaches. The present study should be considered as a preliminary attempt to create a scientific-based starting point for a uniform the use of VAVD.

Pre-clinical Evaluation of an Adult Extracoproreal Carbon Dioxide Removal System for Pediatric Application.

IntroductionAdult extracorporeal carbon dioxide removal (ECCO2R) systems and pediatric ECMO share the common objectives of having a low blood flow rate and low priming volume while safely maintaining sufficient respiratory support. The Hemolung is a highly simplified adult ECCO2R system intended for partial respiratory support in adult patients with acute hypercapnic respiratory failure. The objective of this work was to conduct pre-clinical feasibility studies to determine if a highly efficient, active-mixing, adult ECCO2R system can safely be translated to the pediatric population.Methods14 healthy nonsedated juvenile sheep were used for acute (2 animals) and 7-day chronic (12 animals) in-vivo studies to evaluate treatment safety independently of respiratory related injuries. In all evaluations, we hypothesized that gas exchange capabilities of the Hemolung RAS in this model would be equivalent to the adult configuration performance at similar blood flows - minimum CO2 removal of 50 mL/min at a venous partial pressure of CO2 equal to 45 mmHg. Target blood flow rates were set to a minimum of 280 mL/min. Swan Ganz catheters were used under general anesthesia in the two acute subjects to evaluate blood gas status in the pulmonary artery.ResultsThe Hemolung RAS was found to have adequate gas exchange and pumping capabilities for full respiratory support for subjects weighing 3 – 25 kg. The Hemolung device was estimated to provide a partial respiratory support for subjects weighing 27 – 34 kg. The seven-day studies in juvenile sheep demonstrated that veno-venous extracorporeal support could be provided safely at low flows with no significant adverse reactions related to device operation.ConclusionThe study outcomes suggest the potential use of the Hemolung RAS in a veno-venous pediatric configuration to safely provide respiratory support utilizing a significantly less complex system than traditional pediatric ECMO.

Safety and efficacy of biocompatible perfusion strategy in a contemporary series of patients undergoing coronary artery bypass grafting - a two-center study.

ObjectiveThe profile of patients referred for coronary artery bypass grafting (CABG) is continuously changing to include older patients with multiple comorbidities. We assessed the safety and efficacy of a biocompatible perfusion strategy (BPS) in a contemporary series of patients undergoing isolated CABG.MethodsBPS consisted of a membrane oxygenator, tip-to-tip closed-system heparin-bonded cardiopulmonary bypass circuits without a cardiotomy reservoir, low systemic anticoagulation (target ACT – 250-300 sec) using heparin titration curves, low prime volume, avoidance of systemic cooling, and routine use of cell saver and anti-fibrinolytics. Data were prospectively collected using the American Society of Thoracic Surgeons National Adult Cardiac Surgery Database definitions.Results964 consecutive patients (mean age 66 ± 11 years, 83% male) undergoing CABG between 2008 and 2012 were enrolled. 30-day mortality was 1.4%. Rates of postoperative stroke, myocardial infarction, sternal infection and reoperation for bleeding were 0.9%, 1.3%, 1.9% and 4.2%, respectively. Average 24-hour chest tube drainage was 440 ± 280 ml. Blood products were used in 34% of patients (total donor exposure of 1.7 ± 4.7 units/patient). Predictors of hospital mortality in multivariable analysis were left main disease and preoperative treatment with anti-arrhythmic or immunosuppressive medications. Predictors of allogeneic blood transfusions included older age, small body surface area, female gender, increased serum creatinine, lower preoperative LVEF and hematocrit. Priority of surgery, dual antiplatelet therapy and cardiopulmonary bypass time were not predictors of adverse outcomes or blood transfusions.ConclusionsIn a contemporary cohort of patients undergoing CABG, the use of BPS is safe and effective. It is associated with excellent clinical outcomes and reduced allogeneic blood transfusions.Electronic supplementary materialThe online version of this article (doi:10.1186/s13019-014-0196-3) contains supplementary material, which is available to authorized users.

A novel small animal extracorporeal circulation model for studying pathophysiology of cardiopulmonary bypass.

Extracorporeal circulation (ECC) is indispensable for cardiac surgery. Despite the fact that ECCcauses damage to blood components and is non-physiologic, its pathophysiology has not been fully elucidated. This is because difficulty in clinical research and animal experiments keeps the knowledge insufficient. Therefore, it is desirable to have a miniature ECC model for small animals, which enables repetitive experiments, to study the mechanism of pathophysiological changes during ECC. We developed a miniature ECC system and applied it to the rat. We measured changes in hemodynamics, blood gases and hemoglobin (Hb) concentration, serum cytokines (TNF-α, IL-6, IL-10), biochemical markers (LDH, AST, ALT), and the wet-to-dry weight (W/D) ratio of the lung for assessing whether the rat ECC model is comparable to the human ECC. The ECC system consisted of a membranous oxygenator (polypropylene, 0.03 m(2)), tubing line (polyvinyl chloride), and roller pump. Priming volume of this system is only 8 ml. Rats (400-450 g) were divided into the SHAM group (n = 7) and the ECC group (n = 7). Blood samples were collected before, 60 and 120 min after initiation of ECC. During ECC, blood pressure and Hb were maintained around 80 mmHg and 10 g/dL, respectively. The levels of the inflammatory and biochemical markers and the W/D ratio were significantly elevated in the ECC group, indicating some organ damages and systemic inflammatory responses during ECC. We successfully established the ECC for the rat. This miniature ECC model could be a useful approach for studying the mechanism of pathophysiology during ECC and basic assessment of the ECC devices.

Invited Commentary

Several factors have combined in recent years to increase the use of ventricular assist devices (VADs) in children. The development of pediatric-specific devices and the progressive miniaturization of adult devices (making them amenable to implantation in smaller and smaller children) have both had a significant impact on our ability to support children with heart failure. However, significant challenges remain in providing appropriate mechanical support across the range of patient sizes and clinical conditions seen in a children’s hospital. The ability of a device to support our smallest patients is an obvious problem. However, the difficulties presented in keeping multiple rarely used devices available at a children’s hospital also include financial constraints and maintaining training and competency of staff. It is often not viable to have every device that would be potentially useful immediately available. In this context, the current case series represents an important benchmark in the design, validation, and clinical use of an adapted adult VAD in the pediatric population. Kulat and colleagues [1Kulat B. Russell H.M. Sarwark A.E. et al.Modified TandemHeart ventricular assist device for infant and pediatric circulatory support.Ann Thorac Surg. 2014; 98: 1437-1442Abstract Full Text Full Text PDF Scopus (20) Google Scholar] should be commended for designing the adaptation of the TandemHeart (CardiacAssist, Inc, Pittsburgh, PA) device, testing its properties in an animal model, and then moving on to selected clinical patients. The specifics of their series provide an important option for short-term support of smaller pediatric patients, particularly at centers already facile in the use of the TandemHeart VAD in larger patients. Their design broadens the range of patients potentially supported by the TandemHeart, allowing it to be used as the primary temporary support option for infants through adults. There are some drawbacks to this application of the TandemHeart. The bridge and connectors may result in additional turbulence, and there is the potential for thrombus formation and hemolysis. Although the TandemHeart pump has a 10-mL prime volume (versus 14-mL in the PediMag pump; Thoratec, Pleasanton, CA), this advantage may be negated by the TandemHeart’s larger tubing and the prime volume of the bridge. The hydrodynamic bearing within the TandemHeart is designed to have a 10 mL/h infusion of heparinized saline, and although this volume is insignificant in adults, it may have important consequences in infants with heart failure. Thus despite the good outcomes, this setup has not been critically compared with other support options and should be approached cautiously—especially when support is required beyond 14 days. However, as pediatric mechanical support becomes more common, this case series demonstrates one solution to the challenge of providing support across a range of patient sizes. It reinforces the fact that each center must critically evaluate available options. Evaluation should include the risks and benefits of each device and the range of support provided (both in terms of patient size and duration). However, perhaps as important is ensuring that a center can support the broadest range of patients with the most medically appropriate and cost-effective combination of devices. As Kulat and colleagues [1Kulat B. Russell H.M. Sarwark A.E. et al.Modified TandemHeart ventricular assist device for infant and pediatric circulatory support.Ann Thorac Surg. 2014; 98: 1437-1442Abstract Full Text Full Text PDF Scopus (20) Google Scholar] demonstrate, this may require innovative solutions customized to the circumstances of each center. Modified TandemHeart Ventricular Assist Device for Infant and Pediatric Circulatory SupportThe Annals of Thoracic SurgeryVol. 98Issue 4PreviewThe development of pediatric ventricular assist device (VAD) circuits with lower flow ranges for infants and small children is ongoing. We present our results with modifying a readily available adult VAD to support the pediatric population. Full-Text PDF

PS-131 Hemolysis In Neonatal Piglets Receiving Centrifugal-pump Extracorporal Respiratory Support: An In-vivo Comparative Bench Study

<h3>Background</h3> The challenge of non-cardiac, neonatal extracorporal membrane oxygenation (ECMO) is the need for miniaturised circuits, small cannulas and low flow rates. Novel small rotating pump devices with diagonal blood flow have a reduced priming volume and circuit surface area. Bench studies in different in-vitro models are encouraging. However, little data exist on hemolysis, coagulation and fibrinolysis in defined in-vivo models. <h3>Setting</h3> Twelve newborn piglets were randomly assigned to receive either veno-arterial ECMO with a novel diagonal pump system or to serve as controls. The ECMO circuit was prefilled with 70 ml packed red blood cells from adult swine. Blood was drained through 8 Fr venous and reinfused through 6 Fr arterial cannulas. ECMO was applied on 75% total cardiac output (80–100 ml/kg). The effect of the diagonal pump system on required circuit settings, heparin-use, plasma-free haemoglobin (fHb), lactatdehydrogenase and coagulation/fibsinolysis were studied. <h3>Results</h3> Mild hemolysis was diagnosed within the first hour in all ECMO-piglets [mean fHb 49.7 mg/dl [9.0; 90.3; 95% CI]. After 8 hrs on ECMO mean fHb decreased, but was still significantly higher as compared to controls (25.5 mg/dl [8.7; 42.5] vs 4.7 mg/dl [0.8; 8.6], p = 0.02). Median mean flow rate, venous inlet pressure, and revolutions per hour were 222 ml/min (197; 313, Range), -20 cm H₂O (-36; -6), and 5295 rpm (4906; 6816) respectively. Fibrin degradation products and fibrinogen levels remained normal in ECMO and control piglets throughout the study period. <h3>Conclusion</h3> The use of a novel diagonal pump system for ECMO in our in-vivo model generates a comparable amount of fHb as previously observed under in-vitro conditions.

Modified TandemHeart Ventricular Assist Device for Infant and Pediatric Circulatory Support

The development of pediatric ventricular assist device (VAD) circuits with lower flow ranges for infants and small children is ongoing. We present our results with modifying a readily available adult VAD to support the pediatric population. The TandemHeart VAD (CardiacAssist, Pittsburgh, PA) circuit was modified to include a variable restrictive recirculation shunt to permit lower flow ranges in small pediatric patients. Initial benchtop flow rates and pressures were studied. Hemolysis trials were performed using whole bovine blood to compare plasma-free hemoglobin levels between modified and unmodified VAD circuits. The modified VAD was surgically implanted in 7 piglets (6 to 14 kg) and which supported them for 4 hours. Levels of hemolysis did not increase and full hemodynamic support was achieved. The modified TandemHeart VAD with a recirculation shunt was subsequently implanted in 2 pediatric patients who were bridged to transplant successfully. Because of its simplicity, availability, low prime volume, greater patient flow range, and lower cost, the modified TandemHeart VAD with a recirculation shunt should be considered as an alternative to extracorporeal membrane oxygenation and other pulsatile VADs in children.

PO-0343 Hemolytic Characteristics Of A New Diagonal Pump For Extracorporal Respiratory Support In Neonates With Respiratory Failure

<h3>Background</h3> Neonatal extracorporal membrane oxygenation (ECMO) for pulmonary failure is characterised by small cannulas and low flow rates. Novel rotary pumps with diagonal blood flow and a reduced priming volume are now available. Bench studies in different <i>in-vitro</i> models and the short-term use for cardio-pulmonary bypass in paediatric patients are encouraging. However, little data exist on the effect of these devices on hemolysis in the defined group of neonates with respiratory failure. <h3>Design</h3> We prospectively studied circuit settings, plasma-free haemoglobin (fHb), lactatdehydrogenase and coagulation activation in neonates receiving veno-arterial ECMO due to respiratory failure with a novel diagonal pump system. <h3>Results</h3> Eight newborns (3280 g [2700; 4380, Median; Range]) received veno-arterial ECMO through 8–10Fr venous and 8Fr arterial cannulas appropriate for neck vessels. All infants were maintained on a centrifugal pump system for 4.3d (2; 7.3). Median flow rate and venous cannula pressure were 259 ml/min (215; 314), and -9 cm H2O (-50; -1) respectively. The median revolutions per minute of the pump were 4774 (4008; 6801). Mild hemolysis was detected within 24 h in all patients [median fHb 12.1 mg/dl (7.0; 70.9)] with a further increase after 48 hrs. Two patients (25%) developed disseminated intravascular coagulation and persistent moderate hemolysis. <h3>Conclusion</h3> Our <i><i>in vivo</i></i> data support previous <i><i>in vitro</i></i> studies by demonstrating that the use of a centrifugal pump on small venous and arterial cannula appears to be safe and effective for neonatal ECMO. Yet, ECMO for more than 48 hrs holds the risk for an increased hemolysis and disseminated intravascular coagulation.

Investigation of the biological effects of artificial perfusion using rat extracorporeal circulation model.

Extracorporeal circulation (ECC) is indispensable for cardiac surgery. Since difficulty in clinical research keeps the knowledge insufficient, it is desirable to have a miniature ECC system for small animals. We aimed to establish a miniature ECC system and apply the system to the rat for investigating biochemical changes. The ECC system consisted of a membranous oxygenator (polypropylene, 0.03 m(2)), tubing line (polyvinyl chloride) and roller pump. Priming volume of this system is only 15 ml. Rats were divided into the SHAM group and the ECC group. ECC pump flow was initiated and maintained at 70 ml/kg/min. We measured the serum cytokine levels of tumor necrosis factor-a, interleukin (IL)-6, and IL-10, and biochemical markers (lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase) before, 60, and 120 min after the initiation of ECC. In addition, we measured the wet-to-dry weight (W/D) ratio of the left lung tissues. During ECC, blood pressure and Hb were maintained around 80 mmHg and 10g/dl, the serum cytokine levels and biochemical markers were significantly elevated in the ECC group compared with the SHAM group. The W/D ratio increased significantly more in the ECC group compared with that in the SHAM group. These data suggest that ECC promotes organ damages and systemic inflammatory response. This rat ECC model is considered to be equivalent to the already established human ECC and useful for studying the mechanism of pathophysiological changes during artificial perfusion.

Predictive Factors for Red Blood Cell Transfusion in Children Undergoing Noncomplex Cardiac Surgery

Red blood cell (RBC) transfusion is frequently required in pediatric cardiac surgery and is associated with altered outcome and increased costs. Determining which factors predict transfusion in this context will enable clinicians to adopt strategies that will reduce the risk of RBC transfusion. This study aimed to assess predictive factors associated with RBC transfusion in children undergoing low-risk cardiac surgery with cardiopulmonary bypass (CPB). Children undergoing surgery to repair ventricular septal defect or atrioventricular septal defect from 2006 to 2011 were included in this retrospective study. Demography, preoperative laboratory testing, intraoperative data, and RBC transfusion were reviewed. Univariate and multivariate logistic regression analysis were used to define factors that were able to predict RBC transfusion. Then, we employed receiver operating characteristic analysis to design a predictive score. Among the 334 children included, 261 (78%) were transfused. Age (<18 months), priming volume of the CPB (>43 mL/kg), type of oxygenator used, minimal temperature reached during CPB (<32°C), and preoperative hematocrit (<34%) were independently associated with RBC transfusion in the studied population. A predictive score 2 or greater was the best predictor of RBC transfusion. The present study identified several factors that were significantly associated with perioperative RBC transfusion. Based on these factors, we designed a predictive score that can be used to develop a patient-based blood management program with the aim of reducing the incidence of RBC transfusion.

Minimizing the perfusion system by integration of the components. Does it affect the hematocrit drop and transfused red blood cells? A retrospective audit.

We evaluate the affect on the hematocrit (Hct) drop and the amount of transfused red blood cells (RBCs) during cardiopulmonary bypass (CPB) in adult cardiac surgery patients due to minimizing the CPB circuit by using integrated components. Two hundred and seventy-two patients were included in this retrospective audit. Patients were assigned to three cohorts: the first cohort consisted of patients operated on with a CPB circuit volume of 1630 ml in 2008; the second cohort of such patients in 2010, with 1380 ml; and the third cohort of such patients in 2011, with 1250 ml. There were no significant differences with respect to patient demographics. The priming volume was consecutively significantly reduced; (1635 ± 84 ml, 1384 ± 72 ml and 1256 ± 130 ml, p<0.0001). A trend of decreased amount of RBCs during CPB was visible (cohort 1630: 98 ± 195 ml, cohort 1380: 35 ± 151 ml and cohort 1250: 48 ± 113 ml, p=0.02). Also, the amount of RBCs during the total CPB procedure shows a decreased trend (cohort 1630: 122 ± 230 ml, cohort 1380: 52 ± 180 ml and cohort 1250: 71 ± 156 ml, p=0.04). Blood loss during CPB was significantly lower in cohorts 1380 and 1250 (1630: 922 ± 378 ml, 1380: 706 ± 347 ml and 1250: 708 ± 418 ml, p<0.0001). The volume of diuresis was significantly larger in cohort 1630 (1630: 1166 ± 800 ml, 1380: 477 ± 530 ml and 1250: 523 ± 504 ml, p<0.0001). The Hct drop at the start and end of CPB was significantly reduced comparing cohort 1630 with cohort 1250 (1630: 32 ± 7%, 1380: 30 ± 7% and 1250: 28 ± 10%, p=0.002) at the start of CPB and (1630: 31 ± 7%, 1380: 29 ± 7% and 1250: 28 ± 8%, p=0.016) at the end of CPB. The Hct values at the start and end of CPB were significantly different between the cohorts (1680: 0.23 ± 0.03 L/L - 0.22 ± 0.02 L/L, 1380: 0.25 ± 0.03 L/L - 0.25 ± 0.03 L/L and 1250: 0.25 ± 0.03 L/L- 0.25 ± 0.03 L/L, p= 0.001 and 0.0001). Minimizing our CPB circuit by using integrated components has affected the drop of Hct and the amount of transfused RBCs.

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.

THE SUCCESSFUL TREATMENT OF A PERIPHERAL VENO-VENOUS EXTRACORPOREAL MEMBRANE OXYGENATION FOR SEVERE ACUTE RESPIRATORY FAILURE IN THE EARLY PERIOD AFTER ADULT LIVER TRANSPLANTATION

Aim: of our clinical study was to present own experience of veno-venous extracorporeal membrane oxygenation (VV ECMO) for the treatment of an adult patient (female, 28 yrs, 150 cm, 35 kg) with acute respiratory distress syndrome (ARDS) in the early period after liver transplantation against satisfactory liver graft function. Materials and methods. Double-lumen cannula 22 F was placed percutaneously in the right internal jugular vein. The ext- racorporeal contour reduced in length and the polymethylpeptene oxygenator (priming volume 175 ml) were also. Results. In 1 hour after the beginning of VV ECMO, we registered the noted improvement of arterial blood gas and acid-base balance (regress of respiratory acidosis, improvement of arterial oxygenation) which allowed us to use the «protective» mode of mechanical ventilation. Improvement of gas exchange and regress of clinical and radiological manifestations of ARDS allowed for VV ECMO weaning and decannulation on day 7. The patient was discharged from ICU and then from our Centre to a homestay respectively on the 9 th and 16 th day after VV ECMO weaning with the satisfactory liver graft and lungs function. Conclusion. VV ECMO can be successfully applied to correct the life-threatening acute respiratory failure in the early period after liver transplantation.