bluuebunny/crossref_metadata_2025_split huggingface dataset:
Air trapping ability of the Spiral Gold™ membrane oxygenator: an ex vivo study
Authors: Mueller Xavier M , Tevaearai Hendrick T , van Ness Karen , Horisberger Judith , Augstburger Monique , Burki Marco , von Segesser Ludwig K 
Published: January 2013

Despite an overall improvement in cardiopulmonary bypass (CPB) technology and materials, air emboli still occur. The latest generation membrane oxygenator from Bentley Laboratories, the SpiralGold™, was tested ex vivo for its air handling ability. The study was conducted on four calves. Bolus amounts of air of 10, 15 and 20 cm3 were each injected three times, upstream of the oxygenator and a bubble detector located directly downstream. The amount of bubbles was measured semiquantitatively on a 10 unit scale (U = one semiquantitative unit). The animals were killed 10 days after the CPB. When 10 cm3 of air was injected, no bubbles were detected. With 15 and 20 cm3, respectively, 1 ± 1.5 and 5 ± 3.3 U of bubbles were detected. Despite a total of 135 cm3 of air injected as large bolus amounts, all the animals survived without any obvious neurological deficit secondary to air bubble manipulation. In conclusion, the Spiral Gold™ oxygenator per se can reliably trap an air bolus of up to 10 cm3. This feature should be taken into account when choosing an oxygenator, as it offers an additional barrier to air bubbles in the CPB circuit.
A programme to prepare instructors for clinical teaching
Authors: Brownstein Louis , Rettie Candice S , George Catherine M 
Published: January 2013

Clinical staff perfusionists are responsible for training perfusion students to perform tasks and manage patients in the clinical setting. They are often the least prepared to assume this teaching role. To address this need, a modular programme has been developed to provide the teaching staff with instructional skills. Adult learning theory specifies that an effective learning environment addresses issues of saliency, motivation, retention and transfer. Adults have different expectations, so this programme is designed to maximize this process. The programme is comprehensive and may be used for didactic instruction as well. Derived from a model designed for physicians as teachers, five modules provide theoretical support for teaching techniques, learning tools and management techniques for giving feedback and evaluating performance. Specifically, the topics address the following subjects: managing and motivating learners; teaching medical problem solving; teaching clinical skills; giving feedback and evaluating performance. The short curriculum is based on teaching principles that apply to adult learners with diverse learning styles. While presenting techniques to use with different types of learners, the programme itself incorporates these techniques in teaching the teachers. The modules use lectures, demonstrations, role playing and video taping to challenge teachers and learners in the cognitive, psychomotor and affective domains. The success of this programme is its ability to engage each participant in the learning process.
Foetal bypass: concepts and controversies
Authors: Sistino Joseph J 
Published: January 2013

One of the most controversial and challenging surgical undertakings of the next century promises to be foetal cardiac surgery. Animal studies have been underway for several years to gain an understanding of the physiological mechanisms required to achieve this undertaking. Not since the days of crosscirculation has there been a maternal risk associated with open-heart surgery. The diagnosis of congenital heart defects with foetal ultrasound can now be made as early as 12 weeks gestation. Simple cardiac abnormalities, such as valvular stenosis or atresia, alter intracardiac flow patterns and affect normal cardiac chamber development. Without early intervention, these complex lesions often require major surgical reconstruction, beginning in the neonatal period. Foetal cardiac bypass techniques have evolved from the use of roller pumps and bubble oxygenators primed with maternal blood to the use of an axial flow pump incorporated in a right atrial to pulmonary artery or aortic shunt. Because the blood entering the right atrium is oxygenated by the placenta, an oxygenator in the bypass circuit is probably not needed. The low prime axial flow pump system avoids the dilution of the foetus with the maternal adult haemoglobin and improves the outcome. A major focus of research has concentrated on maintenance of placental blood flow with the use of vasodilators and cyclooxygenase inhibitors. Investigation with primates will be necessary to confirm the placental physiology before human operations can be performed. As the foetal bypass challenges are overcome, there is the potential for a reduction in the number of complex cardiac lesions requiring early surgical intervention in the twenty-first century.
Total extrathoracic cardiopulmonary support with kinetic assisted venous drainage: experience in 50 patients
Authors: Toomasian John M , Patrick McCarthy J 
Published: January 2013

Extrathoracic cardiopulmonary bypass is used in special situations when normal access to the right atrium and aorta is difficult or not practicable. Femero-femoral bypass using gravity drainage is effective for partial cardiopulmonary support, but cannot usually provide adequate venous drainage for full circulatory support. Kinetic assisted venous drainage (KAVD) is the process of applying a controlled suction on the venous line with a kinetic pump to augment venous drainage. KAVD has been used in 50 patients where femero-femoral bypass was selected as the mode of circulatory support. These cases included: redo-operations with significant sternal adhesions (15), minimally invasive port-access cardiac surgery (12), haemodynamic instability (10), left thoracotomy (10), and others (3). In 11 cases, a second venous catheter was added because of protocol. No appreciable increase in venous return occurred with the addition of a second drainage catheter. All patients were adequately supported and a 20-40% increase in venous return was observed once KAVD was implemented. A wide variety of different venous catheters have been used with KAVD. Optimal use relates to having a thin-walled catheter with multiple side holes, not exerting an excessive negative pressure with the pump and positioning the catheter tip at the right atrio-superior vena cava junction. Optimal catheter tip placement is enhanced by using transoesophageal echocardiography. KAVD is best regulated by measuring the siphon generated by the kinetic pump. When the inlet pressure is properly monitored and controlled, KAVD can provide adequate venous drainage to completely support the circulation on a single femoral venous cannula.
Clinical evaluation of a new generation membrane oxygenator: a prospective randomized study
Authors: Stammers Alfred H , Fristoe Lance W , Alonso Anselmo , Song Zuorui , Galbraith Timothy 
Published: January 2013

A new generation hollow-fibre membrane oxygenator (Spiral Gold™) has been introduced by Baxter Healthcare (Irvine, CA, USA). The purpose of this study was to evaluate the operational performance of this device under clinical conditions and to compare it to the Univox® Gold™ membrane oxygenator. Following institutional review board approval, and the obtainment of informed consent, 26 patients undergoing coronary artery bypass grafting were randomly assigned to either a Spiral Gold™ (Spiral) ( n = 13) or Univox® Gold™ (Univox) ( n = 13) group. Study parameters were grouped into the following categories: haematological, haemodynamic, oxygenator performance and perioperative outcomes. All patients received identical surgical, anaesthesia and postoperative care. There were no statistically significant differences in either preoperative or operative parameters between groups. During cardiopulmonary bypass, the Spiral group had a significantly lower pressure drop (26.9 ± 8.2 vs 46.7 ± 16.2 mmHg, p < 0.001). The Spiral group had significantly lower plasma free haemoglobin levels during all time periods of CPB compared to the Univox group. Heat exchange coefficients were higher during the rewarming period in the Spiral patients (0.59 ± 0.28) compared to the Univox group (0.36 ± 0.19), p = 0.06. There were no differences in oxygen transfer between groups, but ventilation gas sweep rates and FiO2 levels were statistically lower in the Spiral group at two of the three sampling time periods. The ratio of ventilating gas sweep rate to blood flow rate was lower in the Spiral group (0.56 ± 0.12) compared to the Univox group (0.74 ± 0.23), p < 0.03. The Spiral Gold™ oxygenator had superior oxygen transfer efficiency and lower haemolysis rates than the Univox® Gold™ oxygenator.
Experimental evaluation of the Dideco D903 Avant 1.7 hollow-fibre membrane oxygenator
Authors: Mueller Xavier M , Tevaearai Hendrick T , Augstburger Monique , Horisberger Judith , von Segesser L K 
Published: January 2013

Membrane oxygenators have now gained wide acceptance. A new hollow-fibre membrane oxygenator, the Dideco D903 Avant 1.7, with an optimized membrane surface (1.7 m2) and a wavy blood flow pattern, was tested for gas transfer and blood path resistance in a standardized setting with surviving animals. Three calves (mean body weight 63.29 ± 2.9 kg) were connected to cardiopulmonary bypass by jugular venous and carotid arterial cannulation, classic roller pump and the Dideco D903 oxygenator with a mean flow rate of 53 ± 0.1 ml/kg/min for 6 h. After this time, the animals were weaned from the CPB and thereafter from the ventilator. After 7 days, the animals were killed electively. Blood gas analysis was performed before bypass, after mixing (10 min) and then hourly for the 6 h of perfusion. Further samples were taken 30 min (spontaneous breathing) and 60 min after bypass (extubated). Physiological blood gas values could be maintained throughout perfusion in all animals. Mean arterial oxygen saturation varied between 99.3% and 99.7% for the arterial side of the oxygenator compared to 64.6% and 71% for the venous side. The highest mean pressure drop through the oxygenator was 54 mmHg. Postbypass blood gas analysis showed physiological values and no evidence of major lung trauma or pulmonary oedema in relation to the 6 h perfusion. The hollow-fibre membrane oxygenator, Dideco D903, offers excellent gas exchange capabilities and a low pressure drop under experimental conditions, despite reduced membrane surface area. The post mortem examination did not show any deleterious lesion.
Clinical evaluation of setting pump occlusion by the dynamic method: effect on flow
Authors: Mongero L B , Beck J R , Orr T W , Kroslowitz R M , Lee-Sensiba K , Oz M C 
Published: January 2013

Pump manufacturers recommend setting roller pump occlusion such that the level of a 100 cm column of crystalloid drops 2.5 cm/min (Sarns™, 8000 Modular Perfusion System, operator’s manual, roller pump software version 2.3L. May 1993; 2.1-2.14). Though this almost occlusive setting ensures accurate pump flow, it has been shown to cause more hemolysis than nonocclusive pumps (Noon GP, Kane LE, Feldman L et al. Reduction of blood trauma in roller pumps for long-term perfusion. World J Surg 1985; 9: 65-71). We conducted a clinical study ( n = 19) to compare the standard occlusion method with the dynamic method and to determine the accuracy of flow for the nonocclusive pump. Standard occlusion was set by clamping the pump tubing distal to the arterial line filter and timing the drop in pump outlet pressure as indicated by a pressure transducer connected to the filter. The occlusion setting, expressed in mmHg/s, was recorded for each roller at two specific points along the raceway. The pump was then set nonocclusively with the dynamic method using the Better Header™ (BH) (Circulatory Technology, Oyster Bay, NY, USA). Readings of the change in pressure in the same two selected points on the raceway were taken. The latter was repeated after discontinuation of bypass. Flow was recorded throughout the procedure from both roller pump output display and a flow meter (Model #109 Transonic, Ithaca, NY, USA). The average drop in pump outlet pressure for the standard method was 1.3 ± 4.0 (range 0-18 mmHg/s), and for the dynamic method was 38 ± 28 (range 1.2-89 mmHg/s). Off bypass, the average reading was 44 ± 38 (range 2.0-103 mmHg/s). Regression analysis indicates that patient flow, when corrected for retrograde flow by the dynamic method, equals 1.003 × revolutions per minute + 40 ml/min ( r2 = 0.964). The average error between indicated pump flow, corrected for retrograde flow, was -1% (range from -6.7 to 6.6%). We conclude that the BH allows nonocclusive settings (30 times less than our standard method) without sacrificing pump flow accuracy.
Leucocyte filtration during cardiopulmonary bypass hardly changed leucocyte counts and did not influence myeloperoxidase, complement, cytokines or platelets
Authors: Baksaas S T , Videm V , Mollnes T E , Tølløfsrud S , Hetland G , Pedersen T , Svennevig J L 
Published: January 2013

In some patients, coronary artery bypass surgery induces postoperative organ dysfunction despite an apparently adequate revascularization and good haemodynamic performance. This complication may be caused by activation of the body’s inflammatory systems on blood contact with large foreign surfaces in the extracorporeal circuit. Activated leucocytes may play an important role in organ damage, and it is conceivable that leucocyte removal by filtration may decrease the potential side-effects of cardiopulmonary bypass (CPB). The aim of the present study was to investigate possible effects of leucocyte filtration during the whole CPB period in elective coronary artery bypass surgery on biochemical and clinical parameters. Forty patients were randomized to extracorporeal circulation using a leucocyte-depleting filter (group L, n = 20) or to extracorporeal circulation with no leucocyte filter (group C, n = 20). In the leucocyte-depleted group, the mean total white blood cell counts increased from 6.3 (95% confidence interval, 5.5 - 7.0) × 109/l to 7.0 (5.7 - 8.3) × 109/l during extracorporeal circulation and in the control group from 6.3 (5.2 - 7.3) × 109/l to 8.5 (7.2 - 9.8) × 109/l. The intergroup difference was not statistically significant ( p = 0.84). A substantial increase in concentrations of interleukin-6, myeloperoxidase and complement activation products were observed in both groups without statistically significant intergroup differences. It is concluded that the leucocyte-depletion filter did not cause a significant reduction of circulating white blood cells during CPB, and there were no significant differences between the groups with respect to the inflammatory markers studied.
Haemolysis during cardiopulmonary bypass: an in vivo comparison of standard roller pumps, nonocclusive roller pumps and centrifugal pumps
Authors: Hansbro S D , Sharpe D AC , Catchpole R , Welsh K R , Munsch C M , McGoldrick J P , Kay P H 
Published: January 2013

Cardiopulmonary bypass (CPB) involves the use of either an occlusive roller pump or centrifugal pump. Damage to blood elements, including haemolysis, may arise from occlusion when using a roller pump; the appropriate degree of occlusion has not yet been determined scientifically. Centrifugal and nonocclusive roller pumps are reputed to reduce haemolysis. The objective of this study was to compare haemolysis caused by a standard roller pump with a dynamically set nonocclusive roller pump and with a centrifugal pump. We prospectively randomized 60 patients undergoing routine coronary artery surgery into three groups: standard roller pump (STD, n = 20), dynamically set roller pump (DYN, n = 20), or centrifugal pump (CEN, n = 20). The level of plasma free haemoglobin (FHb) was measured preoperatively, and the rate of formation of FHb (in mg/dl/min) was determined at the end of the ischaemic phase and at the end of CPB. Cardiotomy suction blood was isolated for the ischaemic phase and returned before the end of CPB. It was found that there were no differences between the groups in demographic or operative variables. The rate of formation of FHb at the end of the ischaemic phase was similar for all groups (STD 0.108 ± 0.10, DYN 0.117 ± 0.08, CEN 0.129 ± 0.07). At the end of CPB, after return of the cardiotomy suction blood, there was a significant (<0.001) increase in the rate of formation of FHb in all groups. The increase was similar for each of the groups (STD 0.424 ± 0.17, DYN 0.481 ± 0.20, CEN 0.471 ± 0.18). We conclude that the rates of haemolysis are similar for each of the pump types, and no benefit is conferred by the use of either a dynamically set roller pump or a centrifugal pump compared with the standard roller pump. The return of the cardiotomy suction blood to the circulation is the principal source of plasma free haemoglobin.
Enhancing liver blood flow after cardiopulmonary bypass: the effects of dopamine and dopexamine
Authors: Sharpe D AC , Mitchel I M , Kay E A , McGoldrick J P , Munsch C M , Kay P H 
Published: January 2013

Liver blood flow is reduced after cardiopulmonary bypass (CPB) and both dopamine and dopexamine are used to overcome this. This study compares the effects of these agents on liver blood flow. Thirty patients undergoing elective coronary artery bypass graft surgery were randomized into three groups ( n = 10 per group). Six hours after surgery baseline liver blood flow was determined by the percentage disappearance rate of indocyanine green measured by dichromatic auricular densitometery. Patients then received infusions of either: (1) placebo (dextrose 5%); (2) dopamine (4 μg/kg/min); (3) dopexamine (1 μg/kg/min increasing to 2 μg/kg/min). One hour after infusion, liver blood flow measurements were repeated. In the dopexamine group the infusion was increased and the measurements repeated another hour later. We found that patient-specific variables and operative details were similar for all groups. Postoperative cardiac index and heart rate were increased significantly by dopamine (cardiac index 2.82 ± 0.46 l/m/m2 vs 3.28 ± 0.67 l/m/m2: p < 0.001 and heart rate 87.5 ± 13.2 vs 96 ± 16: p < 0.05) and dopexamine at 2 μg/kg/min (cardiac index 2.71 ± 0.53 l/m/m2 vs 3.45 ± 0.67 l/m/m2: p < 0.05 and heart rate 89.0 ± 18.9 vs 107.4 ± 13.6: p < 0.001) compared to placebo (cardiac index 2.97 ± 0.8 l/m/m2 vs 3.18 ± 0.9 l/m/m2: p > 0.05 and heart rate 77.2 ± 7.4 vs 77.3 ± 8: p > 0.05) despite similar atrial and systemic arterial pressures. The disappearance rate of indocyanine green was not altered during infusion of placebo group (9.0 ± 3.2%/min vs 7.9 ± 3.0%/min: p > 0.05) or dopexamine at 1 μg/kg/min (9.7 ± 3.1%/min vs 11.2 ± 4.1%/min: p > 0.05). The disappearance rate was increased with dopamine (6.7 ± 3.7%/min vs 11.8 ± 3.0%/min: p < 0.05) and dopexamine 2 μg/kg/min (9.7 ± 3.1%/min vs 13.5 ± 3.2%/min: p < 0.05). This indicates a 76% increase in liver blood flow with dopamine and a 38% increase with dopexamine. We conclude that dopamine 4 μg/kg/min and dopexamine 2 μg/kg/min increase liver blood flow, although this may, in part, be related to an increase in cardiac output. Dopexamine shows no advantage over dopamine in enhancing liver blood flow after CPB.
Inhaled nitric oxide improves hemodynamics in patients with acute pulmonary hypertension after high-risk cardiac surgery
Authors: Beck J R , Mongero L B , Kroslowitz R M , Choudhri A F , Chen J M , DeRose J J , Argenziano M , Smerling A J , Oz M C 
Published: January 2013

Severe pulmonary hypertension and right-sided circulatory failure (RSCF) represent an increasing cause of morbidity and mortality in patients undergoing high-risk cardiac surgery. Increased pulmonary vascular resistance in the setting of cardiopulmonary bypass (CPB) may further lead to decreased blood flow across the pulmonary vascular bed; thereby decreasing left ventricular filling and cardiac output. Current management techniques for RSCF include both nonspecific vasodilator and inotropic agents (often limited by systemic hypotension) and the placement of right ventricular assist devices (associated with increased perioperative morbidity). Inhaled nitric oxide (NOi) represents a novel, specific pulmonary vasodilator that has been proven efficacious in these clinical settings. We evaluated 34 patients in 38 operations who underwent cardiac surgery at Columbia Presbyterian Medical Center, and who received NOi (20 ppm) through a modified ventilatory circuit for hemodynamically significant elevations in pulmonary vascular resistance. Nine patients underwent cardiac transplantation, three patients bilateral lung transplantation, 16 patients left ventricular assist device placement and 10 patients routine cardiac surgery. Patients receiving NOi exhibited substantial reductions in mean pulmonary artery pressure (mPAP) (34.6 ± 2.0 to 26.0 ± 1.7 mmHg, p < 0.0001), with improvements in systemic hemodynamics, mean arterial pressure (68 ± 3.1 to 75.9 ± 2.0 mmHg, p = 0.006). In five cases, patients could not be weaned from CPB until NOi was administered. Patients were maintained on NOi from 6 to 240 h postoperatively (median duration 36 h). Inhaled NO induces substantial reductions in mPAP and increases in both cardiac index and systemic blood pressure in patients displaying elevated pulmonary hemodynamics after high-risk cardiac surgery. NO is, therefore, a useful adjunct in these patients in whom acute pulmonary hypertension threatens right ventricular function and hemodynamic stability.
Optimized performance of the Abiomed BVS 5000: adjustment of the pump height based on Doppler control of the flow pattern
Authors: Lachat M , Jaggy C , Leskosek B , Jenni R , Büchi M , Zünd G , Künzli A , Vogt P , Turina M 
Published: January 2013

The Abiomed BVS 5000 is an automatic volume-driven paracorporeal pulsatile assist device providing left, right or biventricular support. The paracorporeal position allows optical adjustment of filling volumes of the device, which determines the output of the system. A procedure to adjust for maximal stable flow has not yet been established. In vitro measurements have been performed to assess the flow and pressure characteristics of the Abiomed BVS 5000 by raising the preload in 5 mmHg steps before running the system. Doppler probes were placed at the inflow and outflow lines of the pump. After setting the afterload at 80 mmHg the assist device was started. Two measurements were performed to find optimal flow (based on Doppler control and optical adjustment). (1) By Doppler control a stable flow pattern was found at a preload of 25 mmHg with a mean atrial pressure of 5 mmHg and a mean flow of 5.3 ± 0.7 l/min (mean ± standard deviation) at the inflow and outflow sites (the console flow was 4.8 ± 0.4 l/min with a frequency of 61.8 ± 2.0 l/min). (2) Optical adjustment of the pump height gave rise to a preload of 35 mmHg where we recorded a maximal atrial pressure of 107 ± 5.8 mmHg, a maximal retrograde flow of -4.3 ± 1.2 l/min at the inflow and -1.2 ± 0.4 l/min at the outflow site. The mean flow at the inflow and outflow sites was 5.1 ± 0.5 l/min (the console flow was 4.6 ± 0.3 l/min with a frequency of 59.6 ± 2.6 Hz). At an initial afterload of 60 and 40 mmHg the system showed the same qualitative behaviour, but the results were less accurate. Optical adjustment of the pump height may result in an atrioventricular valve insufficiency with undetected retrograde flow and high atrial pressures. We conclude that a Doppler flow probe must be placed at the inflow site to guarantee maximal stable flow.