bluuebunny/crossref_metadata_2025 huggingface dataset:
Haemocompatibility of membrane and bubble oxygenators
Authors: Pearson D.T. , McArdle B.
Published: November 2007

During clinical hypothermic cardiopulmonary bypass (CPB), the haemocompatibility of six groups of membrane oxygenators (Cobe CML2, Shiley M2000, Maxima, Bard HF4000, Bard HF5000, Capiox E has been studied in 60 patients having open-heart surgery. A standardized anaesthetic and perfusion protocol was used, during which the abilityof the perfusionist to achieve target blood gas values (PaO2 20kPa and PaCO2 5.3kPa: alpha-stat) using inline electrodes was assessed. Haemocompatibility was evaluated by measurement of platelet numbers and function, betathromboglobulin (BTG), plasma haemoglobin, complement (C3a des Arg) and white blood cell (WBC) count pre- and post-CPB. Platelet and WBC numbers were also measured every five minutes throughout CPB.

All oxygenators allowed the perfusionist to control blood gases adequately to prescribed levels. There were only minor differences in the degree and pattern of platelet depletion, reduction in platelet aggregation, elevation of BTG and C3a des Arg observed between oxygenator groups, which did not appear to be influenced by membrane type (flat plate versus hollow fibre). The membrane oxygenator haematological data was amalgamated with that obtained in previous clinical studies using membrane and bubble oxygenators (Cobe CML, Polystan Venotherm, Harvey H 1700, Bentley BIO-10, Bentley 1 0B, Bentley 1 OPlus, Gambro 10 and Shiley S100A HED) in which a similar evaluation protocol was employed.

Comparison of the percentage change in platelet count when the pre- and post-CPB values were compared, demonstrated statistically significantly less platelet depletion (p <0.001 ) in the membrane oxygenator groups (-0.2 ± 8.3%) when compared to the bubble oxygenator groups (-21.7 ± 8.7%). A significantly lower percentage rise in BTG was also observed in the membrane oxygenator group when compared to the bubble oxygenator groups (p <0.001 ). All oxygenator groups showed elevation of both WBC count and plasma haemoglobin with a nonspecific fall in platelet aggregation over the period of bypass but no significant differences could be found between the two types of oxygenator.

Membrane oxygenators, when compared to bubble oxygenators, exhibit lower GME production and improved haemocompatibility and allow superior blood gas control. Membrane oxygenators manifestly must be the oxygenator type of choice for clinical CPB.
Peripheral tissue perfusion during coronary artery bypass grafting
Authors: Kuttila Kari , Niinikoski Juha
Published: November 2007

Central haemodynamics, peripheral tissue perfusion and blood lactate concentration were studied in eight male patients undergoing coronary artery bypass grafting, being operated upon under moderate haemodilution and systemic hypothermia. Peripheral tissue perfusion was assessed by continuous recordings of subcutaneous tissue PO2 (PscO2), skin red cell flux (RCF) and transcutaneous PO2 (PtcO2) in the upper extremity. PtcO2 index (= PtcO2/arterial PO2) was determined and finger-tip temperature (Tft) serially measured. PaO2 and PtcO2 reached maximum values during the extracorporeal circulation (ECC) at the deepest hypothermia, whereas PscO2, PtcO2 index, RCF and Tft decreased markedly during ECC, rose during rewarming and fell again towards the end of surgery. Lactate accumulated in the blood especially after coming off bypass. These data suggest that the patients develop hypoperfusion and hypoxia of the peripheral tissues during extracorporeal circulation and again at the end of operation despite seemingly adequate central haemodynamics. This is possibly caused by the cooling and vasoconstriction of the peripheral vascular bed.
Comparison of dextran 40 with albumin and Ringer's lactate as components of perfusion prime for cardiopulmonary bypass in patients undergoing myocardial revascularization
Authors: McGrath Lynn B. , Gonzalez-Lavin Lorenzo , Neary Michael J.
Published: November 2007

A major expense for the conduct of cardiopulmonary bypass in many institutions is the cost of 5% albumin. Potential advantages in using dextran 40 as the colloid component of the priming solution for cardiopulmonary bypass include decreased cost and less viscosity in the microcirculation. Possible disadvantages include bleeding and anaphylactic reactions.

From August 1985 to February 1986, 60 consecutive patients undergoing elective myocardial revascularization were prospectively randomized to receive either 5% albumin ( N = 29) or dextran 40 (N = 31) as the colloid component of the priming solution for cardiopulmonary bypass. Twenty matched patients also underwent revascularization with the prime consisting only of Ringer's lactate solution. There were no differences among the three groups for age, sex, size, crossclamp time, cardiopulmonary bypass time or number of coronary artery bypass grafts performed. In all three groups important postoperative changes were noted in platelet count, bleeding time, thrombin time, prothrombin time, fibrinogen and fibrin split products. Complement levels (C5a) were elevated in the dextran group (p = 0.03). Postoperative crystalloid (p = 0.04) and colloid (p = 0.0001 ) requirements were increased in the Ringer's lactate group and there was a significant weight gain (p = 0.0001). Colloid osmotic pressure was highest in the dextran group during (p = 0.0001) and after bypass (p = 0.001). There was no difference in clinical events and no hospital deaths.

In conclusion, we found dextran to be a safe colloid for use as prime in uncomplicated coronary artery bypass grafting patients. The cost of dextran prime was substantially less than for albumin prime. A purely crystalloid prime is discouraged because of a tendency for fluid retention.
Circulatory assistance by way of long-term cardiopulmonary bypass
Authors: Nicolas F. , Daniel J.P. , Fournier J.F. , Bruniaux J. , Binet J.P.
Published: November 2007

From 1978 to 1986, 46 patients underwent prolonged circulatory support of 5-39 hours duration, at the Centre Chirurgical Marie Lannelongue. Indication for circulatory support was decided in the immediate postoperative stage, or later in patients with major, intractable heart failure, not responsive to standard resuscitative treatment. Patient details and equipment used are described, together with the details of monitoring. Outcome was favourable in 20 to 35% of cases, depending on the severity of the underlying cardiac pathology. Circulatory support by way of cardiopulmonary bypass (CPB) proved a readily feasible and reliable procedure. The method is an effective resuscitative technique, applicable in cases of reversible underlying pathology. In extreme cases, it may constitute an intermediate step before proceeding to cardiac transplantation or total circulatory support using a mechanical device such as an artificial heart.
Haematological effects of a depth absorption arterial line filter during extracorporeal circulation
Authors: Sellman M. , Ivert T. , Blombäck M. , Semb Bkh
Published: November 2007

An arterial line filter (Swank High Flow 6000) was used during extracorporeal circulation (ECC) in 21 of 45 patients undergoing coronary artery bypass grafting, to study haematological effects. The mean age was 60 (41-69) years. All patients had obstructions of at least three coronary artery branches. Average ECC and aortic crossclamp times, drainage via chest tubes until the first day after surgery, total transfusions of blood products and haemolysis did not differ in the two groups. After 90 minutes of ECC, leukocyte counts were significantly lower in the filter group whereas haematocrit, counts of erythrocytes, lymphocytes and platelets, platelet volume, fibrinogen concentration and fibrinopeptide A were similar. Release of β-thromboglobulin and platelet factor 4 were significantly higher in the filter group. No clinically significant adverse haematological effects were observed with use of the arterial line filter, although there were indications of more pronounced platelet damage in the filter group.
Doppler ultrasound estimation of microbubbles in the arterial line during extracorporeal circulation
Authors: Sellman M. , Ivert T. , Stensved P. , Högberg M. , Semb Bkh
Published: November 2007

A pulsed Doppler ultrasound system was used to analyse microbubble intensity and size in the arterial line during extracorporeal circulation (ECC). Thirty male patients, younger than 70 (range 28-69) years, underwent isolated coronary artery bypass grafting with either a bubble oxygenator (Shiley S-100) without (group 1, n = 10) or with (group 2, n = 10) a depth adsorption arterial line filter (Swank High Flow 6000); or with a membrane oxygenator (Shiley M-2000) without a filter (group 3, n = 10). Mean ECC and aortic crossclamp times were similar in the three groups. Measurements were performed during the initial five minutes of cooling, after 30-40 minutes of ECC and after 10 minutes of rewarming. Microbubble intensity and size did not differ significantly in the three groups at the different intervals. Significantly more and larger bubbles were detected in group 1 (15-150μm) compared to group 2 (< 35μm) (p< 0.001). In group 3 only a minimal number of small bubbles (< 65μm) were observed. An arterial line filter significantly reduced the number and size of microbubbles detected in the arterial line during ECC. A membrane oxygenator was associated with a further reduction of microbubble intensity.
Vortex pumping for routine cardiac surgery: a comparative study
Authors: Wheeldon DR , Bethune DW , Gill RD
Published: November 2007

Vortex pumping has become popular for mechanical assist applications, but has only recently received serious consideration for use as the arterial pump of choice for routine open-heart surgery. We report on a prospective randomized study designed to evaluate this pump in routine use. Sixteen patients undergoing routine coronary artery surgery were randomized into two groups in which the only difference in equipment and technique was the use of a Stockert roller pump in group S and a Biomedicus vortex pump in group B. The groups were compared with respect to haematology, perioperative fluid balance, transfusion requirements, complement activation, haemolysis and microbubble transmission. The groups were reasonably well matched, with slightly longer mean bypass and ischaemic times in group S (94.8 vs 105.5 minutes and 75.7 and 83.8 minutes respectively). Group B patients showed significant improvements over group S patients with respect to preservation of platelet numbers, decreased complement activation and reduced microbubble transmission. The afterload sensitivity of the vortex pump did not present the perfusionist with any practical problems although a different technique is required for initiating and terminating bypass. We conclude that vortex pumping would seem to offer better blood handling for routine use. More extensive testing is required to establish whether or not this would be reflected in clinically measurable improved patient outcome.
Blood cell rheological changes during prolonged perfusion with membrane oxygenation (PPMO) using perfluorochemicals
Authors: Akimoto N. , Bergman P. , Liu B. , Belboul A. , AI-Khaja N. , Roberts D. , Karlsson GH , William-Olsson G.
Published: November 2007

The aim of this study was to discover the effect of the perfluorochemical FC-43 on blood cell rheology during experimental prolonged perfusion with membrane oxygenation (PPMO). Using fresh human blood from healthy donors, six experiments with FC-43 in one clinical dose of 30ml/kg, another six with a dose of 1 0ml/kg, and 16 controls were pumped for 72 hours in a perfusion system containing an oxygenator similar to an extracorporeal membrane oxygenation circuit. Blood trauma was analysed using the St George's Filtrometer by estimating blood cell filtrability, clogging particles and clogging rate; the latter two reflecting blood cell aggregability. At 72 hours the filtrability of red cells was reduced by over 95% and 7.0% in the FC-43 groups and controls respectively; the FC-43 groups showed significantly (p < 0.01) greater reductions during perfusion. Both FC-43 concentrations increased the rheological damage to white cells from the outset. The white cells showed a greater tendency to clog than the red cells, suggesting an increased aggregability during prolonged perfusion. The 30ml/kg FC-43 dose induced relatively more damage than the doses in the other groups. This study suggests that FC-43 increased blood cell damage during PPMO in a dose-related manner, and that FC-43 during PPMO should preferably be made less toxic if it is to be used routinely as a blood substitute for prolonged extracorporeal circulation.
Portable cardiopulmonary bypass for heart-lung donor transplants
Authors: Jones PE
Published: November 2007

In 1985 a portable cardiopulmonary bypass machine was devised in order that heart-lung donors from hospitals that were some distance away from our own institution could be procured. The distance of these hospitals ranged from the far north of Scotland to the Greek city of Athens. This paper will show how the portable bypass machine was developed and how it is used for the procurement of donor organs. As an offshoot of this, the device has been used for two emergency bypass procedures at noncardiac units where the transfer of the patient was impossible.
Thoracic organ preservation
Authors: Wheeldon Dereck
Published: November 2007

Clinical heart transplantation began in December 1967 when Cristiaan Barnard performed the first human to human heart transplant on a 57 year old man with ischaemic heart disease, in Cape Town. This ushered in a bout of enthusiastic heart transplantations world-wide over the subsequent few years which soon waned as the problems of acute rejection and infection became apparent to those who had embarked on this venture without fully understanding the complications.

The importance of a well functioning donor heart cannot be overemphasized. Early donor heart failure accounts for approximately 26% of the deaths of heart transplant recipients today and there is also a steep rise in acute mortality associated with storage times in excess of two hours (9.8% < 2 hours rising to 17.6% > 4 hours), although satisfactory function has been reported in a few hearts stored for up to 6 hours.1Careful selection and meticulous management of the donor, followed by optimal storage, are therefore essential to a satisfactory outcome.2

There is evidence that some of the problems of organ preservation are related to metabolic changes in the donor consequent upon brain death3-6and recent ongoing studies by our own group show some benefit from hormone replacement therapy in the donor.7

There are essentially two major approaches to the problem of organ storage; metabolic inhibition resulting in reduced substrate requirements, and the supply of metabolic requirements, or a combination of both. Although nonperfusion methods currently predominate, the simplicity of these methods are overshadowed by the short safe time interval which they allow and the variable functional quality which results. The author believes that perfusion preservation methods will predominate in the future and may also allow expansion of the donor pool bywhole donor and/or ex vivo thoracic organ resuscitation.
Heparin-coating of extracorporea circuits reduces thrombin formation in patients undergoing cardiopulmonary bypass
Authors: Gu YJ , van Oeveren W. , van der Kamp Kwhj , Akkerman C. , Boonstra PW , Wildevuur ChRH
Published: November 2007

This clinical study was performed to evaluate the inhibiting effects of heparin- coated extracorporeal circuits on thrombin formation during cardiopulmonary bypass (CPB). Thirty patients undergoing coronary artery bypass grafting were randomly divided into two groups with (Duraflo II, n=15) orwithout (control, n=15) the use of heparin-coated circuits. Standard systemic heparinization was performed in all the patients before CPB. The results showed that thrombin formation during the first phase of CPB was inhibited by heparin-coating identified by the significantly lower concentrations of thrombin-antithrombin III (TAT) complex formed in plasma in the Duraflo II group than in the control group (p <0.05). Heparin concentrations were higher in the Duraflo II group than in the control group at the end of CPB ( p <0.05). However, after release of the aortic crossclamp in the second phase of CPB, thrombin became strongly activated in both the Duraflo II and the control groups indicated by a sharp increase of TAT complex as well as fibrinopeptide A. Thus, Duraflo II heparin-coating reduces thrombin formation in the early phase of CPB, however, this beneficial effect was counteracted after aortic crossclamp release by material-independent stimuli. Therefore, adequate systemic heparinization is still required despite improved haemocompatibility of the circuits offered by heparin-coating.
Changes in plasma leucocyte elastase levels during coronary surgery and effects of steroids and nifedipine infusion
Authors: Massaut J. , Hennebert N. , Deuvaert F. , Vanderrieviere J.
Published: November 2007

Circulating concentrations of leucocyte elastase were measured in 20 adult patients undergoing cardiopulmonary bypass (CPB) with a flat-sheet membrane oxygenator. Eight patients (group I) received the calcium channel blocker, nifedipine (9μg/kg/h), during CPB and 2g methylprednisolone before CPB. Eight patients (group II) received methylprednisolone but not nifedipine infusion. Four patients (group III) received neither nifedipine nor methylprednisolone infusion. In all patients the bypass procedure was associated with elevation in elastase concentrations. Enzyme concentrations correlated with the duration of bypass (r = 0.7, p<0.01). Comparison between groups fails to demonstrate any significant effect of nifedipine infusion or methylprednisolone on elastase release. This study demonstrates moderate elastase release during CPB with a flat-sheet membrane oxygenator and fails to confirm inhibition of elastase release by nifedipine infusion during CPB.
Blood cell rheologic deterioration by complement activation during experimental prolonged perfusion with membrane oxygenation
Authors: Bergman P. , Friberg G. , Liu B. , Al-Khaja N. , Belboul A. , Heideman M. , Mellgren G. , Roberts D.
Published: November 2007

In order to understand the microcirculatory disturbances during clinical ECMO, the relation of complement activation to blood cell rheologic parameters during prolonged perfusion with membrane oxygenation was studied in 10 experiments using fresh human donor blood. The perfusion set-up was a standard ECMO circuit without a patient. Blood rheologic parameters reflecting the fluidity of blood in the microcirculation were analysed by a St George's Filtrometer. Changes in complement fractions C3a and C5a were measured by the radio-immunoassay (RIA) technique and the TCC (terminal complement complex) by ELISA technique. Samples for complement activation and blood rheological analysis were taken at 24 hours for correlation. There were strong and significant correlations between red and white cell rheologic parameters with all complement fractions. These observations indicate that complement activation plays a significant role in the deterioration of blood rheology during extracorporeal circulation. Improvements in biocompatibility and blood protection are required if this technology is to be made safer.
Transient hypercoagulability in adult patients following open-heart surgery
Authors: Horkay F. , Martin P. , Gupta NK , Satur Cmr , Walker DR
Published: November 2007

The technique of thrombelastography was used to assess whether the phenomenon of hypercoagulability (accelerated coagulation) occurred in adult patients (n = 20) undergoing consecutive open-heart surgical procedures. Standard haematological investigations (pre- and 2 hours postop) were also performed and comparisons made with thrombelastographic parameters. Thrombelastographic hypercoagulability was identified in 12/20 (60%) cases but this event was transient occurring immediately postprotamine administration, and normalizing at 2h postoperation. The standard postoperative haematological assessments routinely made 2h after operation failed to detect this phenomenon. Hypercoagulability following cardiac surgery in adult patients merits further evaluation in order that the clinical significance may be determined.
The use of the Biomedicus centrifugal pump in combination with a separate reservoir with integrated heat exchanger in aneurysms of the thoracic aorta
Authors: Maas C. , Kok R. , Segers P. , Boogaart A. , Eilander S. , Haalebos Mmp , Leicher FG , Bakhuizen R.
Published: November 2007

The surgical correction of aneurysms in the descending thoracic aorta necessitates clamping the aorta both proximal and distal to the aneurysm. The affected length can vary from a few centimetres to large portions of the upper and lower descending aorta. Clamping times can vary from a few minutes to more than one hour. No matter which technique is applied, these operations are often accompanied by excessive blood loss and the need for rapid transfusion, resulting in substantial haemodynamic fluctuations. Hypothermia may become a problem in these patients because most blood warmers are unable to warm blood adequately (>35° C) at high flow rates (>100 cc/min). This may result in clotting problems. For this reason, our clinic decided from November 1990 to integrate a reservoir with its own heat exchanger (Cobe) into our left-left bypass system. This system largely regulates transfusion during partial extracorporeal circulation (PECC). The advantages of such a system are that (1) the transfusion rate can be adapted to blood loss and is not dependent on the quality and quantity of the infusion systems; (2) blood products and other infusion liquids are filtered; and (3) the transfusion blood is warmed. In this article, we describe our experience with this application of PECC on three patients who suffered excessive blood loss during operations for large thoracic aneurysms.
In vitro evaluation of the Mera Silox-S 0.5 and 0.8 m2 silicone hollow-fibre membrane oxygenator for use in neonatal ECMO
Authors: Rais-Bahrami K. , Mikesell G. , Seale WR , Rivera O. , Hearty JP , Short BL
Published: November 2007

The Mera Silox-S is a silicone hollow-fibre membrane oxygenator made up of thousands of fibres in a clear polycarbonate housing. Being a silicone membrane it does not have the plasma leakage problem associated with conventional microporous hollow fibres when used in a long-term application. This device (Mera Senko Medical Instrument Co., Japan) is made in three sizes: 0.3, 0.5 and 0.8 m2. The performance of the 0.5 m2 and 0.8 m2 Silox-S membrane oxygenators was tested in vitro using filtered ovine blood and a customized test circuit designed to provide a continuous source of de-oxygenated, CO2-laden blood, according to the AAMI standard for oxygenator performance.

The 0.8 m2 membrane provided excellent oxygenation, with a transfer rate of 13.0-43.5 ml/min for blood flows of 200-800 ml/min. CO2 transfer over the same range of flows measured 32.3-40.8 ml/min. Flow rates of 100-500 ml/min for the 0.5 m2 membrane provided an oxygen transfer of 6.8-28.3 ml/min and would probably not be suited for the existing neonatal ECMO population. A matter of concern with both oxygenators was an increased pressure drop for blood flow through the devices. The Δ Pfor the 0.5 m2 for flows of 100-500 ml/min ranged from 155 ± 7 mmHg to 516 ± 6 mmHg. For the 0.8 m2, Δ P was 194 ± 39 mmHg to 492 ± 53 mmHg for flows of 200-800 ml/min. Overall, favourable results support further long-term evaluation for potential use in neonatal ECMO.
Review article : Malignant hyperthermia: a review for the cardiac surgical team
Authors: Stewart Todd U , Raskin Steven A
Published: November 2007

Malignant hyperthermia is an inherited skeletal muscle disorder. A malignant hyperthermia crisis is triggered by volatile anaesthetics and many drugs and has an extremely high mortality rate when not treated. This paper describes the aetiology, clinical manifestations and treatment of this disease and outlines the correct procedure for patients who are susceptible to a malignant hyperthermic crisis.
Changes in ionized calcium and related blood constituents in children after cardiopulmonary bypass
Authors: Ralston CS , Butt W.
Published: November 2007

Calcium is necessary for myocardial muscle contraction. The ionized calcium fraction in blood is the physiologically active component and can be readily measured with calcium-selective electrodes. Cardiopulmonary bypass (CPB) alters the relationship between calcium and related blood constituents, depending on the composition of the pump-prime and the quantity of blood products administered peri-operatively. Serial measurements of total and ionized serum calcium concentrations and related biochemical parameters were made in 115 consecutive children over a 24-hour period before and after CPB. Total and ionized calcium concentrations were consistently elevated in the immediate postoperative period, and though infants may, theoretically, benefit from calcium infusion after CPB, the uncritical use of calcium salts in children after cardiac surgery is not justified.
Filtration of shed mediastinal blood
Authors: Fox Mark A , Kent Andrew P , Fraser Scott R , Wilkins Karen M , Kendall Karen N
Published: November 2007

Re-infusion of shed blood carries the risk of re-infusing cellular debris. All re-infusion devices have some sort of integral filtration which is variably supple mented with a second intravenous filter. Using electron microscopy we have observed what debris is collected by secondary filtration. In 12 patients studied, nine out of 12 filters had significant amounts of cellular debris present, but not clearly related to increased rates of postoperative bleeding. Noncellular debris, silicon and strands of cellulose were also observed. Although we have not detected any clinically significant embolic phenomena from re-infusion of shed mediastinal blood, it seems prudent to include a second filter prior to re-infusion.
Clinical evaluation of heat exchangers for blood cardioplegia
Authors: Harrison DP , Munsch CM
Published: November 2007

We compared, in clinical usage, four commercially available heat exchanger systems for blood cardioplegia (BCP) delivery: Shiley BCD plus (BCD); Gish Straight Shot (Gish); Sarns Conducer (Sarns); and the Dideco D720C Helios (Dideco). Ten units of each model were evaluated during coronary artery surgery in which myocardial protection was provided by intermittent cold BCP and warm BCP reperfusion. The performance of each device was tested by (1) determination of actual cardioplegia delivery temperature and (2) by calculation of efficiency (E) of the heat exchanger. The BCD, Gish and Dideco were all able to cool BCP well below 10°C satisfactorily, but the Sarns was unable to do this consistently. During cooling E was as follows: BCD 0.78 ± 0.06; Gish 0.79 ± 0.03; Sarns 0.66 ± 0.05; Dideco 0.75 ± 0.05. During rewarming E was: BCD 0.75 ± 0.04; Gish 0.73 ± 0.06; Sarns 0.48 ± 0.05; Dideco 0.53 ± 0.09. Data are the mean ± standard error. The Sarns was significantly less efficient than all the other three devices (p < 0.05 in all cases) during cooling and less efficient than the BCD and the Gish during rewarming. We are unable to recommend the use of the Sarns in clinical practice. In addition to having acceptable performance, the BCD was the easiest and safest model to prime and to use. The BCD remains our preferred heat exchanger for BCP delivery
Differential diagnosis of suboptimal oxygenator performance
Authors: Fried David W , Zombolas Theodore L , Wilgus Michael , Mohamed Hasratt , Mattioni Gabriel
Published: November 2007

During cardiopulmonary bypass (CPB), the perfusionist must be able to differentiate between: (1) a normal oxygenator with oxygen transfer reserve; (2) a normal oxygenator without O2 transfer reserve; and (3) a failing or suboptimal oxygenator. The purpose of this paper is to report on the use of the oxygen transfer slope, as well as other evaluation techniques previously described, which aided in the differential diagnosis of suboptimal oxygenator performance. We were able to determine the presence and extent of the dysfunction, follow the progression over time, and assess the effectiveness of our intervention. As a direct result of our ability to carefully monitor the oxygenator, replacement was not necessary despite severe dysfunction.
Clinical evaluation of the LeukoGuard (LG-6) arterial line filter for routine open-heart surgery
Authors: Palanzo David A , Manley Norman J , Montesano Ralph M , Yeisley Geary L , Gordon David
Published: November 2007

Research has demonstrated that leucocyte depletion diminishes the deleterious effects that activated neutrophils have on the body following cardiopulmonary bypass (CPB). A clinical evaluation involving 36 patients (18 in each group) was conducted to compare the use of the Pall LG-6 (leucocyte-depleting) arterial line filter with the Pall EC PLUS filter for postoperative complications and lung function on routine open-heart cases. No differences were found between the groups for postoperative chest tube drainage, urine output, on bypass platelet drop, chest X-rays, blood usage and circulating elastase levels. Statistically significant differences were observed between immediately post-CPB pO 2 values and ventilator hours (EC PLUS = 13.3, LG-6 = 9.2). Many of the advantages of using leucocyte depletion that have been illustrated through experimental investigations were comparable to our clinical observations. We conclude that using the LG-6 leucocyte-depleting arterial line filter is a cost-effective method to reduce the complications known as 'postperfusion' syndrome.
Roller and centrifugal pumps compared in vitro with regard to haemolysis, granulocyte and complement activation
Authors: Moen Oddvar , Fosse Erik , Bråten Jennifer , Andersson Conny , Fagerhol Magne K. , Venge Per , Hegåsen Kolbjørn , Mollnes Tom Eirik
Published: November 2007

A Biomedicus centrifugal pump and a Polystan roller pump were compared in vitro with regard to differences in haemolysis, granulocyte and complement activation. Six circuits of tubing and oxygenators were connected to each pump. Heparinized fresh human blood was circulated for 72 hours in the systems. Blood samples were drawn at defined intervals. Haemolysis was assessed by determination of lactate dehydrogenase (LD) and potassium, and granulocyte activation by quantification of the granulocyte proteins calprotectin, lactoferrin and myeloperoxidase. Complement activation was assessed by measuring C3 activation products (C3b, iC3b and C3c), and the terminal C5b-9 complement complex (TCC). The results indicate more haemolysis and complement activation in the roller pump group, revealed by significantly higher concentrations of LD, potassium, C3 activation products and TCC. Calprotectin, lactoferrin and myeloperoxidase were all significantly increased in both groups, but the rise appeared earlier in the roller pump group. The concentrations of LD and potassium both correlated significantly with C3 activation products, indicating that complement activation may at least partly be responsible for the haemolysis.
Haematocrit measurements during cardiopulmonary bypass surgery: comparison of three stat methods with a blood cell counter
Authors: Al-Odeh Ahmed , Varga Zsolt A. , Angelini Gianni D.
Published: November 2007

Monitoring packed cell volume (PCV) is essential to safeguard oxygen delivery to the tissues during cardiopulmonary bypass (CPB). We compared the results obtained using a PCV monitor, a blood gas analyser and a microcentrifuge with those from a laboratory-based automated blood cell counter. PCV was measured in 221 samples of 40 patients undergoing open-heart surgery. The limits of agreement (mean difference ± 2 SD) was unacceptably wide when the results obtained with the PCV monitor and the blood gas analyser were compared with those of the automated blood cell counter. This was most pronounced when PCV was measured in low concentration samples. The microcentrifuge showed good limits of agreement regardless of sample concentration.

The data suggests that measurement of PCV by either continuous monitoring or by a blood gas analyser is not an accurate alternative to an established laboratory method. The microcentrifuge is the most accurate method of the ones investigated to measure haematocrit during CPB.
Surrogate tissues for detecting brain microemboli after cardiopulmonary bypass
Authors: Brown William R , Moody Dixon M , Mills Stephen A , Anderson Randy L
Published: November 2007

During cardiopulmonary bypass (CPB) microemboli lodge in the brain and other organs. Microemboli were counted in tissue samples of skin, muscle and brain from autopsy cases that had recently undergone CPB, and in skin and muscle biopsies obtained from patients before and after CPB. Unlike the brain, skin and muscle showed few microemboli.
Re-inventing the wheel: the use of autologous and fresh donor blood in cardiac surgery
Authors: Reece Ian J , Linley Gerrard H , Tolia Jitesh , Sheth Jayesh , Al Tareif Habib
Published: November 2007

From the opening of a new cardiac surgical programme in November 1992, autologous and fresh donor blood (FDB) were used rather than cold stored blood (CSB) wherever possible in patients undergoing operations involving the use of cardiopulmonary bypass (CPB).

In the first 250 consecutive patients, autologous blood was used in 168 (67.2%), fresh blood was used in 188 (75.2%). A total of 740 units of fresh blood were obtained on the day of operation (mean 3.9 ± 1.6 units per patient able to supply donors; 4.9 ± 1.7 units in the 147 who received fresh blood) and 728 units of stored blood were used (mean 3.08 ± 1.84 units per patient where fresh blood was used; 6.2 ± 2.5 units in the 114 where no fresh blood was used).

The use of autologous blood significantly reduced FDB and CSB requirements (p < 0.001), was associated with a shorter intensive care and total postoperative stay (p = 0.006 and p = 0.033 respectively), even though there were more urgent and emergency cases in this group (p = 0.009) and no significant difference in chest drainage.

Coagulopathy developed in 41 patients (16.4%) and was significantly associated with bypass time (p = 0.0001) and preoperative renal dysfunction (p = 0.005), although not with advanced age, sex, redo operation, diabetes or glucose-6-phosphate dehydrogenase deficiency. Patients with coagulopathy had significantly more transfused blood and blood products (p = 0.0001) and longer intensive care and total postoperative stays (p = 0.0001).

In terms of blood conservation, the use of autologous blood was of primary importance. Correction of renal dysfunction and keeping overall bypass time to a minimum reduced the incidence of coagulopathy and, therefore, blood use. The use of FDB in this series was not clearly associated with improved overall results, but did generate more blood than was actually used, a factor of extreme importance in situations where stored blood is always in short supply.
Pulsatile flow during cardiopulmonary bypass speeds thermal energy transfer: a possible explanation for the reduced afterdrop
Authors: Sheppard Stuart , Pierce Jmt
Published: November 2007

The instantaneous thermal energy balance and rates of thermal energy transfer during hypothermic cardiopulmonary bypass were measured for a group of patients receiving continuous flow and compared with a group receiving pulsatile flow. Cooling was more rapid and the rate of thermal energy delivery during rewarming significantly greater in the pulsatile flow group despite similar rewarming times. The final thermal energy balance at the end of cardiopulmonary bypass was larger and the period of postoperative hypothermia shorter in those receiving pulsatile flow. The greater rate of thermal energy transfer may explain the reduced afterdrop.
Comparison of the effects of centrifugal versus roller pump on the immune response in open-heart surgery
Authors: Perttilä J. , Salo M. , Peltola O.
Published: November 2007

We compared the effects of a centrifugal pump with those of a roller pump on immune responses in 26 coronary artery bypass surgery patients during cardiopulmonary bypass (CPB). The patients were randomly allocated into a (Biomedicus) centrifugal pump group and a (Stöckert) twin roller pump group. Leucocyte and differential counts; percentages of lymphocyte subpopulations (CD3-, CD4-, CD8-, CD16-, CD20- and CD25-positive lymphocytes) and monocytes (CD14); phytohaemagglutinin-, concanavalin A-, and pokeweed mitogen-induced and unstimulated proliferation of separated lymphocytes; unstimulated and pokeweed mitogen-stimulated production of IgG, IgM, or IgA; and plasma fibronectin, C-reactive protein and serum albumin concentrations were measured preoperatively, immediately before CPB, immediately before aortic declamping and on the first postoperative morning. Significant changes were seen in these variables, but no differences occurred between the groups.
In vivo testing of a pulsatile implantable impeller pump as a left ventricular assist device used in calves
Authors: Qian KX , Wang SS , Chu SH
Published: November 2007

A pulsatile implantable impeller pump was tested as a left ventricular assist device in five calves. The experiments lasted for 4-11 days. Death or termination was mainly due to respiratory complications or bleeding, irrelevant to the pump itself. As indicators of haemolysis, thrombogenesis, renal and hepatic functions, free haemoglobin( FHb), haematocrit (Hct), platelet number (Plt), lactate dehydrogenase (LDH), blood urea nitrogen (BUN), creatinine, serum glutamic oxalacetic transaminase (GOT) and total bilirubin were measured preoperatively, at the beginning of the pumping (pump on), six hours later and every day thereafter. The data indicated that the pump caused no severe blood damage or organ dysfunction. Thus, the feasibility of a pulsatile centrifugal pump was demonstrated. The pump with its driver weighs 110 g and is capable of delivering a blood flow up to 8 l/min against 100 mmHg mean pressure.
Coronary artery bypass grafting in a patient with haemophilia B
Authors: Palanzo David A , Sadr Farrokh S
Published: November 2007

Patients with coagulation disorders present the entire open-heart surgical team with an increased challenge. A patient with a known history of moderately severe Factor IX deficiency (2.4% activity) was evaluated for coronary artery disease. Cardiac catheterization revealed a 99% right coronary artery lesion, a long 99% circumflex lesion and normal left ventricular function. Sextuple coronary artery bypass grafting was performed with the aid of aprotinin and Factor IX transfusions. The patient's platelet count after cardiopulmonary bypass was 65 000/mm3, down from a preoperative level of 172 000/mm3, requiring the transfusion of six units of pooled platelets immediately postoperation. The patient was extubated five and a half hours after arriving in the Intensive Care Unit, and his chest-tube drainage after the first 24 hours was 373 ml. Other than a transient episode of atrial fibrillation on the third postoperative day, the patient had an uneventful postoperative course and was discharged on the sixth postoperative day. With the use of aproptinin and the newer monoclonal antibody-purified Factor IX concentrates that have been developed, many of the added risks of performing open-heart surgery on patients with haemophilia B are greatly reduced if not eliminated.
The haemodynamic effects of the thromboxane A2 receptor antagonist GR32191 B during cardiopulmonary bypass in the dog
Authors: Mathie RT , Fleming JS , Barrow SE , Arnold JV , Brannan JJ , Becket JM , Ritter JM , Taylor KM
Published: November 2007

This study examined whether treatment with the specific thromboxane (TX) A2 receptor antagonist GR32191 B would result in an improvement in peripheral haemodynamics during and after cardiopulmonary bypass (CPB) in anaesthetized dogs compared with animals given either saline (control) or aspirin. Following thoracotomy, heparinization and aortic cannulation, and 35 minutes before CPB, dogs received intravenously either GR32191 B (15μg/kg/min), saline (50 ml bolus) or aspirin (225 mg bolus) (n = 6 per group). Cardiac output (dye dilution), femoral artery blood flow (electromagnetic flowmeter), gastrocnemius muscle tissue perfusion (133Xe dearance), retinal blood flow (fluorescein angiography), and thromboxane biosynthesis (urinary excretion rates of TXB2 and the metabolite 2,3-dinor-TXB2) were measured before, during and after a standard 90 minute period of CPB at 2.4 l/min/m2 and 28°C. The aspirin-treated group manifested an eightfold reduction in TXB2 excretion compared with controls, indicating a decrease in TXA2 biosynthesis. There were few haemodynamic differences between the groups, though the aspirin-treated group had better maintained muscle tissue perfusion post-CPB and significantly fewer retinal microcirculatory occlusions than GR32191 B-treated animals. We conclude that specific TXA2 receptor antagonism provides no significant improvement in peripheral haemodynamics; rather aspirin provides a modest haemodynamic benefit.
Profound accidental hypothermia in the deep South: clinical experience
Authors: Tyndal Charles M , Rose Michael W , McFalls Richard E , Jacks Allen , Pinson Terry , Athanasuleas Constantine L
Published: November 2007

Accidental hypothermia resulting from exposure is generally associated with frigid regions and not with the more temperate areas of the South. However, we present clinical experience from two cases in which the victims of motor vehicle accidents were exposed to the elements for prolonged periods and became profoundly hypothermic.

The first patient was a 21-year-old male who was ejected from, and pinned under, his vehicle for approximately four hours in -15°C ambient temperature. Upon admission to the Emergency Room, the patient was unresponsive with fixed and dilated pupils and his core temperature was 25°C. After a prolonged period of cardiopulmonary resuscitation, percutaneous femoral to femoral cardiopulmonary bypass (CPB) was instituted for core rewarming. After reaching 37°C, the patient was removed from bypass. The patient was discharged from the hospital on the fourth postoperative day.

The second patient was a 40-year-old male who was ejected from his vehicle into a stream, where he was partially submerged for several hours. Although the ambient temperature was approximately 22°C, his core temperature at admission was 27°C. After a positive peritoneal lavage, the patient was taken to the Operating Room and placed on percutaneous femoral to femoral CPB for core rewarming. During rewarming, an exploratory laparotomy and a splenectomy were performed. The patient was discharged from the hospital on the seventh postoperative day.

These cases are unique in that both were trauma patients with suspected internal injuries which required the avoidance of anticoagulation. Therefore, both cases utilized a Carmeda-bonded circuit without systemic anticoagulation.
Emboli generation by the Medtronic Maxima hard shell adult venous reservoir in cardiopulmonary bypass circuits: a preliminary report
Authors: Mitchell SJ , Willcox T. , McDougal C. , Gorman DF
Published: November 2007

Increases in right common carotid artery Doppler ultrasound signals typical of emboli were found in cardiopulmonary bypass patients when the Medtronic Maxima hard-shell adult combined venous and cardiotomy reservoir was operated at reservoir blood volumes near the manufacturer;s recommended minimum of 300 ml. The signals were reduced by increasing the reservoir blood volume. Possible microembolus generation in the top- and bottom-entry versions of this reservoir was investigated using an in vitro circuit and a colour flow Doppler monitor that was interfaced with a microprocessor to count the signals. The reservoir blood volume was progressively lowered in 100 ml increments below 1000 ml, and signals were counted over five minutes at each new level. Signal counts downstream of the reservoir increased exponentially after the volume was decreased below 1000 ml in the bottom-entry version, and 700 ml in the top-entry version. Ultrasonic monitor ing, both upstream and downstream of the reservoir, showed that the source of these signals was the reservoir itself, and that recirculation of emboli around the circuit accounted for only a small proportion of the measured increase. Changes in circuit blood prime haematocrit within the range 0.11-0.31 did not alter the signal counts. However, counts were profoundly affected by exposure of the circuit to nitrous oxide via a membrane oxygena tor ; this showed that the emboli were bubbles. Bubble formation may occur where venous blood enters the reservoir as this results in a fountaining effect when the reservoir volume is low. This effect appears to have been serendipi tously reduced, but not eliminated, in the design of the top-entry version. It is
Platelet membrane receptors during short cardiopulmonary bypass - a flow cytometric study
Authors: Holada Karel , Šimák Jan , Kučera Vladimir , Rožňová Lenka , Eckschlager Tomáš
Published: November 2007

To elucidate a mechanism of platelet dysfunction during extracorporeal circulation, we performed a study on the surface expression of platelet adhesive receptors (GPlb, GPIIb-IIIa) and activation markers (GMP140, GP53) during short cardiopulmonary bypass (CPB). Ten paediatric patients, age 6-13 years, with atrial or atrioventricular septal defects were studied. The mean CPB time was 52 min (21-110 min). During CPB, a significant drop in platelet count was observed, but not below 130 x 103/μl. The expression of platelet GPlb decreased slightly during CPB and the decrease was not significant. The decrease of GPIIb-IIIa was significant, but only in samples collected either at the end of CPB (89 ± 13%, p < 0.05) or before leaving the operating room (74 ± 14%, p < 0.05). The value of surface expression of platelet activation markers (GMP140, GP53) during CPB was in the range of values for resting platelets. Our results suggest that generalized CPB-induced defects of primary haemostasis are not directly connected to circulation of activated degranulated platelets or to loss of platelet adhesive receptors GPIb-IX and GPIIb-IIIa.
Cardiopulmonary bypass support for treatment of left ventricular failure following coronary artery bypass grafting: the effects on epicardial microflow and graft flow
Authors: Yijiang Chen  , Bo Liu  , Belboul Ali
Published: November 2007

The relationship between graft blood flow, epicardial microflow and mean arterial pressure were studied to evaluate the use of repeated cardiopulmonary bypass (CPB) support for intraoperative heart failure following aorto-coronary bypass surgery.

Ten patients with unstable angina and suffering from intraoperative heart failure (group A) were compared to 22 patients with stable angina (group B). In group A, during heart failure, the mean arterial pressure fell by 41 % (29.9 ± 6.8 mmHg, p < 0.01), graft flow (GF) by 67% (9.2 ± 2.6 ml/min, p < 0.01) and epicardial microflow by 64% (19 ± 4 AU, p < 0.01). After 15-56 min of assisted CPB support, the epicardial microflow and GF were partially restored. There were significant correlations between GF, epicardial microflow and CPB time. In group B, after protamine infusion, the epicardial microflow and GF were significantly greater than group A values (66 ± 14 AU, p < 0.001 and 29 ± 9 ml/min, p < 0.001, respectively).

It is concluded that the use of temporary assisted CPB support to treat intraoperative heart failure allows the recovery of the myocardium and thereby restores the mean arterial pressure. The recovery of GF and epicardial flow occurred to a lesser extent. CPB support appeared to be suitable for about 60 min, probably because of increasing disturbance to the GF and the epicardial microcirculation.