bluuebunny/crossref_metadata_2025 huggingface dataset:
Preclinical evaluation of the Kyocera Gyro centrifugal blood pump for cardiopulmonary bypass
Authors: Takami Yoshiyuki , Ohara Yasuhisa , Otsuka Goro , Nakazawa Tadashi , Nosé Yukihiko
Published: January 2013

The Kyocera Gyro pump has been developed as a completely seal-less centrifugal pump to overcome the problems of the conventional centrifugal pumps. The Gyro pump is a double pivot bearing-supported centrifugal pump with several specific design features, including its eccentric inlet port. We investigated the feasibility of the Gyro pump for cardiopulmonary bypass (CPB) in a bovine model, comparing it with the BioMedicus pump (BP-80). Ten healthy calves (5: Gyro pump, 5: BP-80) underwent 6 h of mildly hypothermic CPB at approximately 33°C. Both pumps provided more than 50 ml/kg/min without any incidents. The haemodynamics of both groups remained stable within the normal range. All haematology and biochemistry data demonstrated no significant differences between the two groups. However, values of plasma-free haemoglobin and lactate dehydrogenase were less throughout the experiments of the Gyro pump than those of the BP-80. To obtain flow equivalent to that of the BP-80, the Gyro pump needed less rotational speeds than the BP-80 (2749.7 ± 233.3 versus 3170.6 ±300.8 rpm, p < 0.05). Less rotational speed in addition to the difference in operating principle may contribute to less blood damage during the CPB of the Gyro pump. After pumping for CPB, no leakage or thrombus formation was observed in either pump. The present study indicated that the Kyocera Gyro pump can be applied as a centrifugal pump for CPB with the same performance as the BP-80 and with relatively less haemolysis than the BP-80.
Altered activation of the L-arginine nitric oxide pathway during and after cardiopulmonary bypass
Authors: Duke Trevor , South Mike , Stewart Alastair
Published: January 2013

The serum concentrations of nitrogen oxides, the stable metabolites of nitric oxide, were measured in 61 children during and after cardiopulmonary bypass (CPB) for surgery of congenital heart disease. Overall, there was a small reduction in serum nitrogen oxide concentrations during CPB, from a median of 27.5 (interquartile range 16.6-55.7) to 26.4 (15.3-40.6) μmol/l, followed by an increase in the following 24 h to 33.1 (21.3-46.7) μmol/l. The largest postoperative increases in nitrogen oxides occurred in children who developed renal impairment, or were treated with nitrovasodilators. There was no relationship between changes in serum nitrogen oxides intraoperatively and early changes in pulmonary vascular resistance, and a weak positive relationship between changes in serum nitrogen oxides and early postoperative changes in cardiac index ( r2 = 0.09, p = 0.04). We found no evidence for increased activation of the L-arginine nitric oxide pathway during CPB; and the reduction in nitric oxide metabolites that occurred during CPB were of doubtful significance to pulmonary or systemic haemodynamic changes in the postoperative period.
Assessment of left ventricular compliance during heart preservation
Authors: Larson Douglas F , Gatewood Lance B , Bowers Mark , Sethi Gulshan , Copeland Jack G
Published: January 2013

There is critical need for a greater number of donor hearts for transplantation. The demand can be relieved, in part, by an extension of preservation time. This necessitates new methods of preservation and development of means to assess the functional condition of the preserved heart. We report a heart-preservation system designed for long-term preservation support and discuss issues specifically related to extended heart preservation. This article presents methodology to assess ventricular compliance and to quantify coronary flow distribution during the use of microperfusion preservation. Ventricular adenosine triphosphate (ATP) concentrations are directly related to the immediate post-preservation function: however, direct measurement of ATP is not clinically available. Based on the premise that ventricular compliance relates directly to the ventricular ATP concentrations, we performed sequential ventricular compliance measurements using a simple left ventricular balloon during a 24 h preservation period. A porcine heart model was employed using a continuous, hypothermic, antegrade, microperfusion system for 24 h and measurements were made at specific intervals during the preservation time. The compliance measurements were ascertained by pressure-volume curves using a flaccid balloon inserted into the left ventricle through the mitral valve. In addition, to assess microvascular function during the preservation interval, regional coronary flow measurements were performed using a microsphere technique. We report that after 12 h of preservation there was a twofold reduction in ventricular compliance which decreased further by fivefold at 18 h. In contrast, there was a time-dependent decrease in left ventricular coronary flow, especially with the left-ventricular subendocardial region significantly decreasing by 50 % at 12 h. In conclusion, a simple ventricular-compliance balloon provided a direct measurement of ventricular compliance of the preserved heart which may provide an indirect estimate of the ventricular high-energy phosphates of the preserved heart prior to transplantation.
Effects of flow types in cardiopulmonary bypass on gastric intramucosal pH
Authors: Hamulu Ahmet , Atay Yüksel , Ya'gdi Tahir , Dışçıgıl Berent , Bakalim Tamer , Büket Suat , Bilkay Önol
Published: January 2013

The aim of this study was to determine the relationship between splanchnic perfusion and oxygen consumption, and flow types in cardiopulmonary bypass (CPB), by measuring gastric intramucosal pH. Twenty patients undergoing elective open-heart surgery were prospectively randomized to receive either pulsatile or nonpulsatile flow during CPB. Gastric intramucosal pH was measured using gastric tonometry. A flowmeter was used to measure the inferior caval vein flow. A catheter was inserted through the femoral vein to sample blood from the iliac vein. Systemic vascular resistance index, gastric intramucosal pH, inferior caval vein flow and arterial, inferior vena caval and iliac venous blood gases were recorded at different times. Gastric intramucosal pH decreased in all patients; only in the nonpulsatile group was this decrease statistically significant. After 45 min of CPB, the pH was 7.37 ± 0.03 compared with the prebypass value of 7.48 ± 0.04 ( p = 0.00016). After weaning from CPB, the pH was 7.358 ± 0.02 compared with the prebypass value ( p = 0.000037). At 2 h post-operatively the pH was 7.416 ± 0.025 ( p = 0.02). Systemic vascular resistance index rose in all patients during bypass in both groups. These changes did not have any statistical significances and after weaning from bypass returned to prebypass levels. We conclude that nonpulsatile flow in CPB is associated with reduced gastric intramucosal pH and the measurement of intramucosal pH during open-heart surgery provides important information about splanchnic perfusion.
Can an oxygenator design potentially contribute to air embolism in cardiopulmonary bypass? A novel method for the determination of the air removal capabilities of neonatal membrane oxygenators
Authors: De Somer F , Dierickx P , Dujardin D , Verdonck P , Van Nooten G
Published: January 2013

At present, air handling of a membrane oxygenator is generally studied by using an ultrasonic sound bubble counter. However, this is not a quantitative method and it does not give any information on where air was entrapped in the oxygenator and if it eventually was removed through the membrane for gas exchange. The study presented here gives a novel technique for the determination of the air-handling characteristics of a membrane oxygenator. The study aimed at defining not only the amount of air released by the oxygenator, but also the amount of air trapped within the oxygenator and/or removed through the gas exchange membrane. Two neonatal membrane oxygenators without the use of an arterial filter were investigated: the Polystan Microsafe and the Dideco Lilliput. Although the air trap function of both oxygenators when challenged with a bolus of air was similar, the Microsafe obtained this effect mainly by capturing the air in the heat exchanger compartment while the Lilliput did remove a large amount of air through the membrane. In conclusion, the difference in trap function was most striking during continuous infusion of air. Immediate contact with a microporous membrane, avoidance of high velocities within the oxygenator, pressure drop, transit time and construction of the fibre mat all contribute to the air-handling characteristics of a membrane oxygenator.
Changes in leucocyte counts and soluble intercellular adhesion molecule-1 and E-selectin during cardiopulmonary bypass in children
Authors: Williams Hilary J , Rebuck Naomi , Elliott Martin J , Finn Adam
Published: January 2013

A consequence of cardiopulmonary bypass (CPB) in young children is postoperative capillary leak and associated pulmonary dysfunction. Neutrophils sequester in the lungs and may contribute to functional endothelial damage. The endothelial adhesion molecules, E-selectin and intercellular adhesion molecule-1 (ICAM-1), mediate sequential steps in adhesion by binding to leucocyte ligands. Circulating forms of these proteins have been identified. We studied changes in the plasma concentrations of soluble E-selectin and soluble ICAM-1 using fixed phase immunoassays, and associated leucocyte counts in 10 paediatric patients undergoing CPB. Concentrations of soluble L-selectin and soluble ICAM-1 consistently fell during CPB from preoperative levels of 89 ± 17 ng/ml (mean ± 2SEM) and 218 + 61 ng/ml, respectively, to 39 ± 7 ng/ml and 84 ± 24 ng/ml, respectively at the beginning of maximum hypothermia. The haemodilution that occurred during CPB largely explained this fall, but not the more marked decrease in white cell counts that also occurred over this period (6.7 ± 1.1 to 1.7 ± 0.5 × 109/l) which may reflect increased leucocyte sequestration. By 24 h postoperatively, levels of both soluble adhesion molecules approached preoperative concentrations, as did lymphocyte counts. In marked contrast, neutrophil counts rose appreciably towards the end of CPB, and continued to rise to a maximum of 10.9 ± 3.1 ×109/l during the immediate postoperative period and remained at these elevated levels 24 h later. Major consistent changes in circulating leucocyte numbers which occur early in cardiopulmonary bypass may reflect changes in adhesion to the endothelium and consequent sequestration. Alterations in the levels of soluble adhesion proteins may influence these processes.
Plasma adrenomedullin level after cardiopulmonary bypass
Authors: Komai Hiroyoshi , Naito Yasuaki , Fujiwara Keiichi , Noguchi Yasuzo , Nishimura Yoshiharu
Published: January 2013

Adrenomedullin is an intrinsic vasodilator which is metabolized mainly in the pulmonary circulation. We measured plasma levels of adrenomedullin in children with congenital cyanotic heart disease (CY group, n = 6), children with high pulmonary blood flow due to congenital heart disease (PH group, n = 8), and in adults with mitral valve disease (MV group, n = 7) before and 3 h after cardiopulmonary bypass (CPB). Before CPB, the adrenomedullin level was the highest in the MV group, possibly due to chronic heart failure. Three hours after CPB, the plasma adrenomedullin level (pg/ml) increased to 1712.7 ± 498.4 in the CY group, 167.6 ± 26.4 in the PH group, and 1404.3 ± 313.7 in the MV group, the level in the PH group being significantly lower than the rest. In the PH group, there was a statistically significant negative correlation between the mean pulmonary arterial pressure at the preoperative catheter study, and the adrenomedullin level 3 h after CPB. These results illustrate that the adrenomedullin level increased after CPB, but that the increase was less marked in the PH group, implying that where the pulmonary vasculature was damaged most, this results in increased vasoconstriction.
Interleukin-8 mRNA expression in circulating leucocytes during cardiopulmonary bypass
Authors: John Alison E , Galea Joseph , Francis Sheila E , Holt Cathy M , Finn Adam
Published: January 2013

Interleukin-8 (IL-8) is found in patients following cardiopulmonary bypass (CPB). It may contribute to microvascular injury by activating neutrophils. We examined IL-8 mRNA expression in leucocytes in bypass. IL-8 mRNA levels were measured by Northern analysis and densitometry of isolated mononuclear leucocytes and neutrophils from blood samples taken before, during, and 2 and 48 h after CPB. Plasma IL-8 was measured at each time-point by immunoassay. A strong signal for IL-8 mRNA was detected in neutrophils in five of five and, more weakly, in mononuclear leucocytes of three of five patients studied. The signal peaked consistently during, and fell following bypass, usually to undetectable levels by 48 h. There was always a detectable signal in neutrophils preoperatively. Plasma IL-8 increased from undetectable prebypass levels and peaked later (2 h postbypass) in four of five patients. In the other patient, the cytokine remained detectable throughout.

These data demonstrate that IL-8 transcription occurs in leucocytes before and during CPB, but suggest that much of the IL-8 detectable in plasma following bypass may derive, not from these leucocytes, but from other cell types. The release of some IL-8 by neutrophils could lead to local positive feedback in neutrophil recruitment and associated endothelial injury.
A novel leucocyte-depleting filter for use in continuous venovenous haemofiltration: preliminary in vitro studies
Authors: Gant V A , May J , Treacher D F , Morris K , Berrill K
Published: January 2013

Multiple organ failure (MOF) secondary to circulatory shock, sepsis, or trauma was first described over 20 years ago. Despite much research effort and clinical trials of biological response modifiers, MOF continues to be the leading cause of death in both medical and surgical intensive care units (ICU). MOF is associated with widespread cellular and humoral systemic inflammatory responses which, in turn, are linked with inadequate tissue perfusion to vital organs and the inappropriate accumulation of activated neutrophils, resulting in microcirculatory injury. Much evidence suggests that such activated neutrophils cause vascular damage by adhering to the endothelium and releasing a variety of highly reactive and toxic moieties; these may subsequently produce endothelial injury and compromised organ function. We reasoned that a clinical device designed to remove such cells in a controlled fashion from the circulation of patients with MOF by means of using a continuous venovenous circuit might be beneficial. We report the leucocyte depletion performance of a novel filter medium as a first step towards the production of a clinical device, and show specific depletion of phagocytes relative to other formed elements in the blood.
Acute phase and opsonin response in cardiac surgery patients: influence of underlying cardiac disease
Authors: Welters I , Menges T , Ballesteros M , Sablotzki A , Görlach G , Hempelmann G
Published: January 2013

Cardiopulmonary bypass (CPB) leads to an activation of plasma cascade systems, complement activation, and an acute phase response. To evaluate the influence of the underlying cardiac disease on the activation pattern of these systems, we compared inflammatory changes in coronary artery bypass grafting (CABG) patients with patients undergoing aortic valve replacement.

We investigated changes of the acute phase proteins α1-proteinase inhibitor and fibrinogen, the unspecific opsonin fibronectin, and the complement components C3c and C4 induced by extracorporeal circulation in 12 patients undergoing aortic valve replacement and in 12 patients undergoing CABG.

Concentrations of C3c and C4 decreased in both groups after the onset of CPB and C4 concentration remained below post-induction levels up to 24 h after onset of CPB ( p = 0.04). Fibronectin levels dropped immediately before the onset of CPB ( p = 0.01), reaching the lowest values after 20 min of extracorporeal circulation. Fibrinogen and α1-proteinase inhibitor levels after induction of anaesthesia were significantly higher in the CABG group and remained higher throughout the entire study period ( p < 0.001). As an indicator of a postoperative acute phase response, concentrations of both proteins rose in the postoperative period above post-induction levels ( p < 0.02).

It can be concluded that, based on pre-existing differences of acute phase protein concentrations, the CPB-induced inflammatory response takes place at a higher level in CABG patients. A different level in acute phase and opsonin response in patients suffering from coronary artery sclerosis may contribute to infectious complications in the postoperative period.
In vitro evaluation of new surface coatings for extracorporeal circulation
Authors: Baksaas Svein T , Videm Vibeke , Fosse Erik , Karlsen Harald , Pedersen Thore , Mollnes Tom E , Hagve Tor A , Svennevig Jan L
Published: January 2013

Cardiopulmonary bypass (CPB) exposes blood to large, foreign surfaces. This exposure may activate the cellular and humoral inflammatory systems, resulting in inflammatory reactions and organ dysfunction. Coating the inner surfaces of the bypass circuit may help alleviate these side-effects. The objective of this study was to determine the influence of two new surface treatments on blood cell and complement activation.

Oxygenator and tubing sets coated with synthetic polymers ( n = 7) or heparin ( n = 7) were compared to uncoated sets ( n = 7) in an in vitro model of CPB. The circuits were run at 4 l/min and recirculated for 120 min. The inflammatory response was assessed at regular intervals by platelet counts, and activation of complement, leucocytes and platelets.

We found that the median platelet counts decreased from 127 to 122 × 109/l (not significant, NS) in the synthetic polymer sets, from 96 to 88 × 109/l (NS) in the heparin-coated sets, and from 93 to 54 × 109/l ( p < 0.01) in the uncoated sets after 2 h of recirculation. There were significant differences in platelet counts between the coated sets and the uncoated set at end of experiments ( p < 0.05). Beta-thromboglobulin (BTG) concentrations increased in the synthetic polymer sets from 166 to 352 ng/ml ( p < 0.01), in the heparin coated sets from 336 to 1168 ng/ml ( p < 0.01), and in the uncoated sets from 301 to 3149 ng/ml ( p < 0.01) after 2 h of recirculation. The differences in BTG at termination of the experiments were significant among all three sets ( p < 0.05). Myeloperoxidase (MPO) concentrations in the synthetic polymer sets increased from 63 to 86 μg/l ( p < 0.01), in the heparin-coated sets from 90 to 208 μg/l ( p < 0.01), and in the uncoated sets from 122 to 513 μg/l ( p < 0.01) after 2 h of recirculation. The differences in MPO at termination of the experiments were significant among all three groups ( p < 0.01). There were no significant differences at termination of the experiments among the three sets regarding complement activation as measured by C3 activation products and the terminal complement complex.

We conclude that in the current in vitro model of a CPB circuit, the synthetic polymer coating and the heparin coating caused significantly less platelet loss and granulocyte and platelet activation than the uncoated surface ( p < 0.05). The synthetic polymer coating caused significantly less granulocyte and platelet activation than the heparin coating ( p < 0.05). There was moderate complement activation within each group, but no significant differences among the three groups.
Lipid peroxidation during initiation of extracorporeal membrane oxygenation after hypoxia in endotoxemic rabbits
Authors: Trittenwein Gerhard , Rotta Alexandre T , Gunnarsson Björn , Steinhorn David M
Published: January 2013

Initiation of extracorporeal membrane oxygenation (ECMO) in septic children with severe respiratory failure often improves oxygenation but not pulmonary function. The factors affecting pulmonary function following onset of ECMO are not completely understood, but are thought to involve injury mediated, in part, by reactive oxygen species. We hypothesized that induction of ECMO using 100% oxygen as the sweep gas through the oxygenator would increase lipid peroxidation in endotoxin-primed animals after severe hypoxia. We further speculated that provision of oxygenated blood to the pulmonary circulation via venovenous ECMO would promote a greater degree of oxidative damage to the lung as compared to venoarterial ECMO.

Eighteen New Zealand White rabbits were assigned to a control group (control) or two intervention groups subjected to 60 min of venoarterial or venovenous ECMO. ECMO was initiated following an intravenous challenge with 0.5 mg/kg of E. coli endotoxin and a period of global hypoxia leading to an arterial pH of 6.99 ± 0.09, PaCO2 of 103 ± 31 mmHg and PaO2 of 27 ± 5 mmHg. Malondialdehyde (MDA), a marker of lipid peroxidation, was measured in lung tissue homogenates and in arterial plasma.

Lung tissue MDA demonstrated a strong trend towards an increase in the venoarterial group (1884 ± 945 nmol/g protein) and in the venovenous group (1905 ± 758 nmol/g protein) in comparison to the control group (644 ± 71 nmol/g protein) ( p = 0.1; significance at 95% in Scheffe test). Lung tissue MDA in the venovenous group had a significant correlation with mean PaO2 during ECMO by regression analysis ( r2 = 0.678, p = 0.044). The change in blood MDA concentration between pre-ECMO and post-ECMO values was greater in the venovenous group (pre 1.62 ± 0.61 versus post 5.12 ± 0.2.07 μmol/l, p = 0.043) compared with that seen in the venoarterial group (pre 1.46 ± 0.38 versus post 3.9 ± 0.93 μmol/l).

Our data support the hypothesis that initiation of ECMO with a circuit gas oxygen concentration of 100% after global hypoxia enhances oxidative damage to lipids in endotoxin-challenged animals. During venovenous ECMO this finding is dependent on PaO2.
Investigation of the phenomenon of electrostatic compromise of a plastic fiber heat exchanger
Authors: Elgas R J
Published: January 2013

The use of a new generation of blood oxygenator design using plastic fibers for the heat exchange material is growing. The benefits of a plastic heat exchange material are improved biocompatibility and performance over some of the traditional metals used.

During the initial period of clinical use of one of these new oxygenators, there were reports of four blood-to-water leaks. No patient complications were associated with these leaks, but the product was withdrawn from the market. After a thorough evaluation, the cause of the leaks was found to be an electrostatic discharge that occurred within the heat exchanger during priming of the extracorporeal circuit.

It was found that an electrostatic potential between the blood path and the water path of the heat exchanger is generated as the prime solution is recirculated by a roller pump with polyvinyl chloride (PVC) pumphead tubing. The magnitude of the potential generated was found to vary with the make and model of the roller pump. If this voltage exceeds the dielectric strength of the fiber, a discharge through the wall of a single heat exchange fiber will occur and produce a hole.

Several solutions to this problem of roller pumps generating an electrostatic charge when used with PVC pumphead tubing were identified. Centrifugal blood pumps and roller pumps using silicone rubber pumphead tubing were found to generate no significant electrostatic potential between the blood path and the water path. Another solution, a charge equalization line (CEL), was designed to provide a conductive path for the charge to equilibrate across the fiber wall. The CEL can be either external or internal to the oxygenator.

Each of these solutions was validated and the product has been reintroduced for clinical use.
Albumin in the cardiopulmonary bypass prime: how little is enough?
Authors: Palanzo David A , Zarro Debra L , Montesano Ralph M , Manley Norman J
Published: January 2013

Previous studies have demonstrated high transoxygenator pressures with noncoated hollow-fiber membrane oxygenators. These reports have been associated with dramatic platelet count drops during cardiopulmonary bypass (CPB). It has also been shown that adding human albumin to the prime of the bypass circuit reduces, if not eliminates, these problems. This study was conducted to determine what is the smallest amount of albumin added to the prime that will still display its protective effects. Eighty patients undergoing nonemergency open-heart surgery were randomly divided into four groups. Groups I and II received the Sarns Turbo 440 oxygenator with 0.0375 g of albumin/100 ml of prime and 0.125 g of albumin/100 ml of prime, respectively, added to the pump prime. Groups III and IV received the Medtronic Maxima-PRF oxygenator with 0.0375 g of albumin/100 ml of prime and 0.125 g of albumin/100 ml of prime, respectively, added to the pump prime. Pre-CPB, on CPB (15-20 min after the initiation of bypass) and warming hemoglobin, hematocrit and platelet counts were drawn on all patients. Net platelet count drop, which accounted for hemodilutional effects, was calculated for all specimens and compared to previous results obtained from the test oxygenators without albumin in the prime. The net platelet count drops for the study groups were as follows:

• Sarns oxygenator with no albumin in the prime = 11.8 ± 12.5%;

• Sarns oxygenator with 0.0375 g of albumin/100 ml prime = -3.7 ± 10.8%;

• Sarns oxygenator with 0.125 g of albumin/100 ml prime = -2.0 ± 12.6%;

• Medtronic oxygenator with no albumin in the prime = 20.1 ± 14.5%;

• Medtronic oxygenator with 0.0375 g albumin/100 ml prime = -6.9 ± 8.7%; and

• Medtronic oxygenator with 0.125 g albumin/100 ml prime = -14.0 ± 12.4%.

Our results illustrate that adding as little as 0.0375 g albumin/100 ml prime (3 ml of 25% solution/2000 ml of prime) to the pump prime illicits the beneficial effects of surface coating on platelet loss during CPB.
Nucleated red blood cells after cardiopulmonary bypass in infants and children: is there a relationship to the systemic inflammatory response syndrome?
Authors: Frey Bernhard , Duke Trevor , Horton Stephen B
Published: January 2013

In a retrospective case control study we aimed to evaluate whether infants and children with nucleated red blood cells (NRBCs) in their peripheral blood smears after cardiopulmonary bypass (CPB) had longer bypass times than controls without NRBCs. On review of a 3-year period, 58 children with NRBCs after CPB (and without NRBCs prior to CPB) were identified (cases). A random sample of 100 children without NRBCs after CPB over the same period served as controls. The median age (range) of the children with NRBCs and without NRBCs was 0.6 years (2 days to 20 years) and 1.4 years (2 days to 16 years), respectively ( p = 0.03). The children with NRBCs had a significantly longer bypass time than the controls (mean, standard deviation (SD): 114 min, 50 vs 79 min, 46 min; p < 0.0001). For the patients with postoperative polychromasia alone, the mean CPB time (111 min, SD 46 min) was also significantly longer than the respective time in the controls ( p < 0.001). Markers of organ dysfunction (renal failure, use of inotropic support, time of endotracheal intubation, stay in intensive care unit and stay in hospital) were significantly more frequent/longer in the NRBC group. Post-CPB release of NRBCs is associated with longer CPB time. This alteration may be part of the CPB-related systemic inflammatory response syndrome.
Retrospective analysis of effect of low-dose aprotinin priming on allogeneic blood transfusion in repeated cardiac operations
Authors: Miyashita Tetsuya , Hayashi Yukio , Ohnishi Yoshihiko , Kuro Masakazu
Published: January 2013

The objective of this retrospective study was to investigate efficacy of low-dose aprotinin priming therapy on the requirement of allogeneic transfusion and to identify risk factors for allogeneic transfusion in patients undergoing repeated cardiac operations.

The present study includes a critical review of 124 consecutive charts of patients undergoing elective repeat cardiac surgery. We examined the effect of low-dose aprotinin priming therapy on blood loss, amounts of mediastinal drainage following intensive care unit (ICU) administration and the number of units of blood products given during the perioperative period.

The rate of nonallogeneic transfusion was not affected by low-dose aprotinin priming therapy, although aprotinin reduced the amount of allogeneic transfusion and the amount of mediastinal drainage 12 h following ICU admission.

In conclusion, low-dose aprotinin priming therapy is effective in reducing blood loss and the amount of allogeneic transfusion. However, it failed to improve the rate of cardiac reoperations without allogeneic blood transfusion.
Nitric oxide donors attenuate increase in pressure drop across membrane oxygenators
Authors: De Somer F , Foubert L , Schacht E , Van Nooten G
Published: January 2013

We have evaluated the effect of nitric oxide (NO) on the pressure drop across a membrane oxygenator in one in vitro model and two in vivo models (using four dogs and five pigs). In all the experiments sodium nitroprusside (SNP) was used as a NO source, whereas gaseous NO was only used in the in vitro model. The drugs were given when the pressure drop or resistance across the device increased to at least twice the baseline values.

In the in vitro model, both SNP and gaseous NO decreased the pressure drop to 75% of its peak value after 10 min and to 67% after 20 min. In the dog model, resistance decreased from 390 to 153 mmHg/l/min after 5 min and to 85 mmHg/l/min after 20 min for a baseline value of 75 mmHg/l/min.

The initial resistance across the membrane oxygenator in the pig model increased from 6.6 ± 1.3 to 74 ± 38 mmHg/l/min. An infusion of 10 μg/kg/min SNP reduced the resistance to 16 ± 5 mmHg/l/min.
Transient electroencephalographic suppression with initiation of cardiopulmonary bypass in pigs: blood versus nonblood priming
Authors: Conroy Brendan P , Lin Cheng Y , Jenkins Larry W , DeWitt Douglas S , Johnston William E
Published: January 2013

Electroencephalographic (EEG) changes have been reported with cardiopulmonary bypass (CPB). We tested whether the type of priming solution (blood versus nonblood) affected the EEG. Twenty-six anesthetized pigs (29.5 ± 1.6 kg) were cannulated for CPB primed with 1 liter plasmalyte and 500 ml 6% hetastarch (nonblood prime). EEG signals were recorded during the initiation of normothermic CPB. Three minutes later, animals were weaned from CPB and allowed to stabilize. CPB was reinstituted using the animals’ hemodiluted blood as prime. We found that with nonblood prime, abrupt and marked EEG suppression lasting 12.6 ± 0.7 s was found in all animals, followed by gradual resumption of baseline EEG activity. In contrast, CPB with blood prime caused no detectable EEG changes. We conclude that severe reductions in EEG activity occur after initiating CPB with nonblood prime; these reductions are not seen when using blood prime. The cause of EEG suppression is unknown, but may represent transient impairment of oxygen delivery to the brain caused by nonblood perfusion.
Impact of a remote pump head on neonatal priming volumes
Authors: Horisberger J , Jegger D , Boone Y , Seigneul I , Pierrel N , Hurni M , Corno A F , von Segesser L K
Published: January 2013

Reduction of priming volumes of the cardiopulmonary bypass (CPB) circuit in neonatal cardiac surgery to decrease haemodilution and blood transfusion requirements can be achieved with the use of neonatal low prime oxygenators and smaller diameter tubing. We have further reduced our prime volume with the use of a custom-designed arm allowing for remote positioning of a double-headed roller pump. This arm enables the double pump to be placed alongside the main heart-lung machine close to the operating table, and to position the pump inlet and outlet tubing immediately at the reservoir outlet and oxygenator inlet, respectively, therefore reducing tubing lengths. Priming volumes of four cases using this configuration were compared to four cases using our standard neonatal bypass setup. Results showed a 29% decrease in priming volume and a 58% reduction in blood utilization during CPB. This reduction in priming volume is clinically significant as it lowers the ratio of priming volume to patient blood volume and reduces homologous blood requirements.
Leucocyte-depleted cardioplegia does not reduce reperfusion injury in hypothermic coronary artery bypass surgery
Authors: Browning P G , Pullan M , Jackson M , Rashid A
Published: January 2013

This study investigated the effects of leucocyte-depleted cardioplegia on postreperfusion oxidative stress and myocardial injury in elective hypothermic coronary artery bypass surgery. Forty patients were randomized to receive either cardioplegia with leucocytes depleted by an in-line Pall BC1B filter, or blood cardioplegia without leucocyte depletion. Transmyocardial oxidative stress was assessed by oxidized glutathione measurements in samples taken simultaneously from the coronary sinus and aortic root, and myocardial injury by postoperative CKMB and troponin-T measurements. The BC1B filters reduced numbers of cardioplegia leucocytes by a mean of 90.7%. Both patient groups demonstrated significant increases ( p < 0.001) in transcardiac oxidized glutathione gradients after crossclamp release. No significant differences were found between the groups for postreperfusion oxidized glutathione gradients, postoperative levels of CKMB or troponin-T, or in the frequency of perioperative and postoperative complications. These results suggest that leucocyte-depleted cardioplegia does not significantly improve myocardial protection in patients undergoing elective coronary artery bypass surgery.
Laboratory testing of femoral venous cannulae: effect of size, position and negative pressure on flow
Authors: Kurusz Mark , Deyo Donald J , Sholar Alina D , Tao Weike , Zwischenberger Joseph B
Published: January 2013

Femoral venous cannulae (17-28 French) were tested to compare flows obtained by their placement in a simulated inferior vena cava (IVC) or right atrium (RA) and by varying drainage pressures using gravity siphon drainage or a centrifugal pump in the venous line. The circuit consisted of conventional tubing and equipment including a segment of thin-walled latex tubing to simulate the IVC connected to a flexible reservoir to simulate the RA. The test fluid was a 40% glycerin solution. Flow was measured at height differentials of 30-60 cm (cannula-to-inlet of hard-shell venous reservoir) and with a -10 to -80 mmHg negative pressure created by the centrifugal pump. A roller pump returned the test fluid to a flexible bag to maintain a filling pressure of 0-1 mmHg. Flow increased modestly with an increasing height differential. When negative pressure was applied with the centrifugal pump, flow increased 10% and 18% (IVC and RA positions, respectively) compared to gravity siphon drainage conditions. There also was a tendency for flow to plateau or cease when the centrifugal pump was used at higher levels of negative pressure or when larger cannulae were used. We conclude: (1) position of smaller cannulae in the RA yield better flows than when the cannulae are larger and placed in the IVC; (2) smaller-sized cannulae are capable of achieving higher flows when the centrifugal pump is used; (3) cannulae must be properly positioned to achieve maximum flow; (4) the centrifugal pump will augment flow, but should be regulated to avoid extreme negative pressures; and (5) cannula design has no demonstrable effect on flow.
Double valve replacement in a patient with anticardiolipin antibody syndrome
Authors: Myers Gerard J , Hirsch Gregory M
Published: January 2013

Cardiopulmonary bypass (CPB) was used during the replacement of the aortic and mitral valves in a 43-year-old female patient. The case was complicated by the presence of a rare hypercoagulable condition called anticardiolipin (antiphospholipid) antibody syndrome. The course of bypass was uneventful and the patient was released from the intensive care unit on the first postoperative day. CPB in the presence of anticardiolipin antibodies is an unusual situation that requires diligent hematological monitoring. Since 1989 there have been only 14 reported cases of these antibodies and cardiopulmonary bypass. Eight of these have involved valve replacements.
A literature review of cardiopulmonary bypass models for rats
Authors: Ballaux Philippe KEW , Gourlay Terence , Ratnatunga Chandi P , Taylor Kenneth M
Published: January 2013

Cardiopulmonary bypass (CPB) has improved a great deal since its first applications in the early 1950s. If improvements are to be continued, a preclinical model of CPB for small animals is desirable, mainly because of convenience of equipment and low costs. We review the different models of CPB for rats that have been designed, discuss their characteristics and points where improvements may be made. We give suggestions and requirements for a new up-to-date model that could be a useful tool in continued research on the pathophysiology and therapeutic strategies of CPB.
Tubing failure during prolonged roller pump use: a laboratory study
Authors: Peek Giles J , Wong Kim , Morrison Colin , Killer Hilliary M , Firmin Richard K
Published: January 2013

Little is known about the mechanical forces acting on extracorporeal circuit tubing with prolonged roller pump use during extracorporeal membrane oxygenation (ECMO). We examined the time to tubing rupture of three different materials during actual roller pump use, mean and standard deviation (SD) (SD shown in parentheses): Tygon® (control) 243.7 h (175.4); LVA 121 h (14.3); and SRT 6.6 h (2.1). Failure times for both LVA and SRT were significantly different from the control (paired t-test, p = 0.02 and p < 0.001, respectively). The minimum failure times for Tygon and LVA were 99 and 101 h, respectively. We then examined Tygon under conditions of pure compression, demonstrating that even after 3.67 million compression cycles at full occlusion crack formation did not occur. If the tubing was over-occluded, cracks appeared within 24 h. Scanning electron microscopy of Tygon, which has been used during clinical ECMO, and the failure pattern during destruction testing demonstrate that shear stress and compression coexist during clinical ECMO. Use of under-occlusive pump settings could improve tubing life.
Survival Analysis for Economic Evaluations Alongside Clinical Trials—Extrapolation with Patient-Level Data
Authors: Latimer Nicholas R.
Published: January 2013

Background. In health technology assessments (HTAs) of interventions that affect survival, it is essential to accurately estimate the survival benefit associated with the new treatment. Generally, trial data must be extrapolated, and many models are available for this purpose. The choice of extrapolation model is critical because different models can lead to very different cost-effectiveness results. A failure to systematically justify the chosen model creates the possibility of bias and inconsistency between HTAs. Objective. To demonstrate the limitations and inconsistencies associated with the survival analysis component of HTAs and to propose a process guide that will help exclude these from future analyses. Methods. We reviewed the survival analysis component of 45 HTAs undertaken for the National Institute for Health and Clinical Excellence (NICE) in the cancer disease area. We drew upon our findings to identify common limitations and to develop a process guide. Results. The chosen survival models were not systematically justified in any of the HTAs reviewed. The range of models considered was usually insufficient, and the rationale for the chosen model was universally limited: In particular, the plausibility of the extrapolated portion of fitted survival curves was very rarely explicitly considered. Limitations. We do not seek to describe and review all methods available for performing survival analysis—several approaches exist that are not mentioned in this article. Instead we seek to analyze methods commonly used in HTAs and limitations associated with their application. Conclusions. Survival analysis has not been conducted systematically in HTAs. A systematic approach such as the one proposed here is required to reduce the possibility of bias in cost-effectiveness results and inconsistency between technology assessments.
Dialogue on Middle East Biological, Nuclear, and Chemical Weapons Disarmament
Authors: Taylor N. A. J. , Camilleri Joseph A. , Hamel-Green Michael
Published: January 2013

Negotiations on the establishment of a Middle East zone free of biological, nuclear, and chemical weapons and their means of delivery are now at a critical phase after more than three decades of prenegotiations. This article examines the factors that have impeded negotiations in order to identify the key actors whose mutually reinforcing efforts are essential to its establishment. We argue that current efforts to negotiate a zone free of nuclear weapons and other weapons of mass destruction and their delivery systems (WMDFZ) in the Middle East can learn much from the successful negotiation of other nuclear weapons free zones (NWFZs). Nevertheless, the circumstances in the Middle East are unique and require a more holistic approach. Success here will depend largely on a multidimensional perspective that brings together the energies and insights of a range of state and nonstate actors, not least civil society in the Middle East, where confidence and trust building is too complex and demanding a task to be seen as the preserve of political and geostrategic calculation. Enabling the societies and polities of the region to identify areas of mistrust and misunderstanding across strategic, political, but also cultural and religious divides in order to open up possibilities for dialogue and mutual respect holds the key to creating a favorable negotiating environment.
Subject, action and polis
Authors: Häkli Jouni , Kallio Kirsi Pauliina
Published: January 2013

In this paper, we develop tools for understanding political agency and political events as they unfold contextually in everyday life. We discuss alternative understandings of the subject so as to grasp the scope of the subject’s autonomy as the ground for political subjectivity. We conceive of political agency in terms of subjectivity related to subject positions offered in the flux of everyday life. To bring together political subject and action, we conceptualize the topological settings of political agency in terms of polis. To illustrate the analytical potential of our approach, we analyse a sequence in a movie by Ingmar Bergman.
On timing ability in Australian managed funds
Authors: In Francis , Kim Sangbae , Ji Philip I
Published: January 2013

This paper investigates the timing abilities of Australian managed fund managers. To examine timing abilities, the cross-sectional bootstrap approach is adopted to determine whether timing ability is due to skill or luck. Based on three alternative timing measures, we find that top-ranked Australian fund managers have genuine timing abilities. In addition, the poor timing ability with bottom-ranked funds is not likely to be due to luck either, implying that the market exposure of some Australian managed funds is mistakenly adjusted when the stock market improves.
Growth and accounting choice
Authors: Dichev Ilia D , Li Feng
Published: January 2013

We investigate for a positive relation between growth and the aggressiveness of accounting choices. The motivation is that this relation is an unexamined and very general implication from most existing theories and types of accounting choice. Note that the firms’ decision to use aggressive choices is determined by the joint presence of two factors: specific incentives to increase earnings such as maximizing compensation and also the ability to increase earnings. Growth captures the ability to increase income because an “aggressive” accounting choice will only increase earnings for growing firms and will have no effect or even decrease earnings for no-growth or negative growth firms. Thus, a ranking on growth can be potentially used as a powerful large-sample lens that summarizes the economic importance of many disparate accounting theories and settings of aggressive choice. The empirical tests use a sample of 260,000 observations over the last 50 years and a wide set of nine accounting choices to provide a comprehensive investigation of the hypothesized relation. Our main finding is that there is essentially no reliable relation between growth and aggressive accounting choice. A number of specifications and sensitivity analyses confirm this main finding. In additional tests unrelated to the growth argument, we find no reliable positive correlation between the aggressiveness of individual accounting choices, which implies that companies make no concerted efforts to increase income over the available set of accounting choices. Finally, changes in accounting choice are rare, which implies that accounting choice is a blunt and unwieldy instrument for most aggressive earnings objectives. The conclusion is that visible and long-term accounting choices are seldom used for achieving income-increasing objectives.
Results of Arthroscopic Repair of Partial- or Full-Thickness Longitudinal Medial Meniscal Tears by Single or Double Vertical Sutures Using the Inside-Out Technique
Authors: Haklar Ugur , Donmez Ferdi , Basaran Serdar Hakan , Canbora Mehmet Kerem
Published: January 2013

Background:

Although numerous studies have assessed arthroscopic repair of meniscal tears, no study has described the repair of partial- or full-thickness longitudinal medial meniscal tears using single or double vertical sutures.

Purpose:

To present the intermediate-term results of medial meniscal tears repaired with single or double vertical sutures.

Study Design:

Case series; Level of evidence, 4.

Methods:

The authors evaluated the results of 112 longitudinal medial meniscal tears treated with inside-out single or double vertical sutures, with or without anterior cruciate ligament (ACL) reconstruction, based on the clinical resolution of symptoms, the Lysholm knee scoring scale, and the Tegner activity scale. Re-examination was also performed by magnetic resonance imaging after the repair. The length of the tears was evaluated arthroscopically. Eighty-five tears of 112 were >2 cm in length, and 27 were tears ≤2 cm. Eighty-nine (79.4%) of the 112 repairs were performed in conjunction with ACL reconstructions, and the remaining 23 (20.6%) repairs were performed in ACL-intact knees. The tear type of the menisci in our study was full thickness in 66 (58.9%) cases and partial thickness in 46 (41.1%) cases. Double vertical sutures were used for full-thickness tears, and single vertical sutures were used for partial-thickness tears.

Results:

The cases were evaluated after a mean follow-up duration of 49.3 months (range, 12-88 months). Clinical and radiological examination results determined that 99 (88.4%) meniscal repairs had healed, and the remaining 13 cases (10.6%) were considered to be failures. The healing rate of the full-thickness group was 80.3%, while in the partial-thickness group, the rate was 100%. The mean Lysholm score improved significantly from a preoperative value of 63.8 to a postoperative value of 89.5 ( P < .001). The mean Tegner activity score was 3.3 preoperatively and 6.7 postoperatively ( P < .001). Logistic regression analysis found that concurrent ACL reconstruction, tear length, and smoking as factors had a significant effect on meniscal healing.

Conclusion:

Single or double vertical sutures using the inside-out technique provide a high rate of healing in longitudinal medial meniscal tears.