bluuebunny/crossref_metadata_2025 huggingface dataset:
Review article : Acid-base status, hypothermia and cardiac surgery
Authors: Swain Julie A
Published: November 2007

The optimal method of pH management during hypothermia is controversial. A review of current experimental and laboratory investigations comparing different pH schemes is presented. The biochemical and metabolic consequences of keeping pH constant (pH-stat) as compared to allowing the pH to increase with hypothermia (alpha-stat) are discussed. It is concluded that, on the basis of experimental and clinical studies, the alpha-stat pH management scheme may be preferable to that of keeping pH constant throughout a wide temperature range in humans.
A modified circuit and priming procedure for neonatal ECMO
Authors: Gerstmann Dale R , Cornish J Devn
Published: November 2007

Advances in extracorporeal membrane oxygenation (ECMO) technology and equipment have allowed improvements in technique which simplify the pro cedure and increase its safety. We describe modifications to our neonatal ECMO circuit which permit use of a low priming volume (500 ml) and allow the circuit to be used in a transport setting. Major changes include the elimination of the priming reservoir, the addition of prebypass and arterial inline filters, the use of a small portable pump, and battery power backup of all components. The priming procedure has been substantially changed and its four phases are described in detail. As neonatal ECMO becomes more widely utilised, further refinements in equipment, procedure and technique can be anticipated.
Cytomegalovirus as a cause of immunosuppression following aortic valve replacement
Authors: Gould FK , Graham TR , Freeman R. , Holden MP
Published: November 2007

The postperfusion syndrome, haemolytic anaemia and thrombocytopenic purpura following open heart surgery have all been attributed to acute cytomegalovirus (CMV) infection,'-3 usually acquired from perioperative transfusions of whole blood. Increased susceptibility of bacterial infections has been described,4 but only in patients who have undergone cardiac transplantation and consequently received immunosuppressive therapy. Studies have shown that CMV can suppress cell-mediated immunity in vivo and in vitro5 and impairment of neutrophil migration has been demonstrated in CMV infected mice.6 We describe a patient with impaired polymorph function associated with an acute CMV infection following aortic valve replacement.
Normothermic blood cardioplegia reperfusion plus nifedipine after cardioplegic arrest: experimental study with a new delivery set
Authors: Noera Giorgio , Massini Carlo , Lodi Renzo , Baggio Giosuè
Published: November 2007

During the aortic crossclamping and the early period of reperfusion, the calcium metabolism plays an important role in myocardial ischaemic damage. In this study, we test the use of a calcium entry blocker (nifedipine) during the early reperfusion period after cardioplegic arrest. The experimental protocol was tested on 20 large white pigs weighing 28 ± 1 kg. All animals underwent hypothermic (28°C) cardiopulmonary bypass (CPB) and St Thomas II cold (4°C) cardioplegia was infused in a single dose (40 ml/kg of body weight) through the aortic root after aortic crossclamping (90 minutes). The animals were divided into four groups (five animals for each group): Group I-standard reperfusion after clamping the aorta; Group II-the same as Group I plus nifedipine 100 mg bolus in aortic root just prior to unclamping the aorta; Group III-reperfusion was done with warm (37°C) oxygenated blood cardioplegia via aortic root (flow rate 70 ml/min/100 gm of heart weight, St Thomas I I solution with haematocrit of 1 5% for five minutes); Group IV-the same as Group III, plus nifedipine in bolus (100 nmg) injected in aortic root prior to the cardioplegic blood reperfusion. In Groups III and IV reperfusion was performed with a new delivery set (Dideco D51 5) which allows cold crystallaoid cardioplegia to be poured into warm blood cardioplegia. Full thickness myocardial biopsies were taken before, during (90') and after (3', 5', 10' of reperfusion) the aortic crossclamping and the level of high energy phosphate (H EP) of ATP, CP, lactate and myocardial water content were measured. Global left ventricular function was evaluated measuring left atrial pressure (LAP) at constant cardiac output with a right heart preparation before cardioplegic arrest and after 30 minutes of reperfusion. The results show significant differences during reperfusion between the four groups as follows: (a) higher ATP recovery in Groups III and IV than in Groups I and II; (b) CP levels increased more significantly in Group IV than in the other groups; (c) lactate was lower in Groups I I I and IV; (d) myocardial water content increased significantly in Group I; (e) global left ventricular function showed that the heart of the animals of Groups III and IV could pump from 3-3.5 I/min. with a left atrial pressure of less than 20 mmHg in respect to the other two groups. We conclude that after prolonged aortic crossclamping, the reperfusion with warm oxygenated cardioplegic blood plus nifedipine provides better myocardial protection.
In vitro generation of C3a anaphylatoxin by an extracorporeal circuit
Authors: Loubser Paul G , Buffone Gregory J
Published: November 2007

The generation of C3a anaphylatoxin was studied during the equilibration of fresh whole blood in an extracorporeal circuit with oxygenator before institution of cardiopulmonary bypass. Twenty-seven units of whole blood were each recirculated through an extracorporeal circuit for periods up to 17 minutes Following an equilibration period of 7 ± 3.5 min, the C3a concentration increased from 563.1 ± 48.4 to 802.1 ± 73.7 ng/ml, corrected for haematocrit (p < 0.01). The increase in C3a was, however, not related to duration of equilibration time. In vivo studies by others reported higher peak levels of C3a and a correlation with duration of cardiopulmonary bypass. Our data confirm that the extracorporeal circuit is an important site of complement activation, but suggest that during cardiopulmonary bypass, other sites or mechanisms may also generate C3a.
A new ventricu lar assist device for acute cardiac failure: report of initial use for biventricular support
Authors: Diethrich Edward B , Bahadir Ilhan , Mandile Gary , Gordon Michael
Published: November 2007

A new ventricular assist device (VAD) developed by Symbion, Inc., received its initial biventricular clinical use in a 53-year-old man suffering cardiogenic shock from severe congestive heart failure secondary to cardiomyopathy and a 15-year history of coronary artery disease.

The eight-day period of biventricular support on the Symbion devices was satisfactory in spite of two complications probably unrelated to the pump. First, a neurologic deficit was noted after transition from the temporary support pumps to the Symbion pumps, ostensibly from a small air bolus entering the aortic return line. The deficit was deemed mild and reversible, and the patient showed improvement. Secondly, poor renal function secondary to prolonged hypotension associated with cardiac arrest persisted throughout the support period. All other organs, however, were well supported.

On the eighth day of support, a dramatic change in hepatic function and neurologic deterioration justified termination of support. At explant of the devices, a kink and an occluding thrombus were found at the inferior port of the right atrial outflow cannula, undoubtedly the cause of the declining hepatic status. Clots were also found adherent to both VAD chambers at the air vents, but no evidence of emboli was found at autopsy.

Redesign of the air vent sites and cannulae may be required to improve the Symbion VAD's performance.
A clinical evaluation of three modern blood oxygenators
Authors: Zadeh Barry J , Holazo Rose , Conlon Cathy , Lazenby W Douglas , Isom O Wayne , Krieger Karl H
Published: November 2007

The purpose of this study was to assess the performance of three standard oxygenators in a clinical setting. The oxygenators selected included the Bard H1700, the Bentley CM-50 and the Cobe CML. Fifty CPB procedures were performed on patients undergoing elective CABG procedures in each group and prospectively analysed. Patient related parameters were collected in three subsets: preoperative, operative and postoperative, and organized into a data base on a standard 'Clinfo' system. The groups were then compared for statistically significant differences. The three groups were similar in all demographic and patient management categories examined. Overall morbidity and mortality were not significantly different. Parameters in each of four major biocompatibility categories were found to differ significantly between the three groups. RBC and FFP use, maximum platelet decrease and maximum WBC increase were each improved in the CM L group as compared to the other two groups. The results indicate that the CML offers distinct biocompatibility advantages over the other two systems in several important blood component categories. Despite the slight user friendliness advantages of a bubbler system, we believe that the oxygenator of choice at present is the CML.
Perfiusion techniaues using VPCML in adults
Authors: latridis Evangelos K , Jenkins Columbus T
Published: November 2007

Our work has demonstrated that use of the VPCML in patients up to 70kg can have a significant effect in reducing blood usage in our surgical population. Patients are selected primarily on the basis of weight, but factors such as disease state, lean body mass and age are also considered. Our circuit emphasizes low priming volume while making provision for extra blood volume reserve capacity if required. The perfusion techniques we use with the VPCML include high blood flow rates (70-80ml/min/kg); careful attention to sweep gas flow rates throughout the perfusion; and a standard hypothermia condition of 22°C. We have found it particularly important to maintain close cooperation with the anaesthesiologist to avoid shallow anaesthesia levels during rewarming.
A clinical evaluation of the Bentley 10B and Bentley 10Plus bubble oxygenators
Authors: Pearson Derek T , Clayton Richard , Murray Alan , McArdle Brian
Published: November 2007

During clinical hypothermic cardiopulmonary bypass (CPB) in 20 adult patients, the ability of the perfusionist, using an alphastat acid-base blood gas management technique, to control blood gas values has been evaluated in the Bentley 10B and Bentley 10Plus bubble oxygenators. Superior flexibility in control of the blood gas values to within a defined target range (PaO2 20 ± 3.3 kPa, PaCO2 5.3 ± 0.6 kPa) with significantly improved control of PaO2 was demonstrated in the Bentley 10Plus when compared with the Bentley 1 0B. The percentage of values when both PaCO2 and PaO2 were within the target range was higher in the Bentley 10Plus (14%) than in the Bentley 10B (11 %). The incorporation of an Integral gas proportioning valve in the Bentley 10Plus oxygenator offers a degree of independence of control of PaO 2 and PaCO2 which is unique in a bubble oxygenator. When the two oxygenator groups were compared, the rise in plasma haemoglobin was significantly less (p<0.005) in the Bentley 10Plus but no significant differences could be demonstrated between the two groups with respect to alteration in other formed blood elements (platelets or white blood cells) or in gaseous microemboli production.
The hydraulic power outputs of pulsatile and nonpulsatile cardiopulmonary bypass pumps
Authors: Wright G.
Published: November 2007

The mean, pulsatile and total power outputs of the Centrimed centrifugal pump, the Stöckert roller pump, the Polystan flat-plate compression pump and the Keele ventricle pump were compared when loaded with an artificial circulation system. The hydraulic power in the model 'aorta' was affected by the pump output, the peripheral resistance and the model compliance, but not the pulse repetition frequency. Under similar operating conditions, the power generated by the pumps differed markedly and these differences were almost entirely due to the pulsatile content of the pressure and flow waveforms. Compared to the human heart, the Stöckert pump generated only about 12.4% as much pulsatile power, while the Polystan pump generated 82.0% and the Keele pump generated 271.9% at 4.01 min-1 and 80 strokes min-1. It is suggested that the benefits of pulsatile blood flow may be derived from the lateral transmission of energy and the promotion of tissue fluid movement. The failure of some investigators to detect these benefits may be because the pulsatile content of the pump output was insufficient.
The use of the Hemochron in assessment of heparin reversal after cardiopulmonary bypass
Authors: Hooper TL , Conroy J. , McArdle B. , Dell A. , Watson B. , Pearson DT , Kesteven PJ
Published: November 2007

The use of the Hemochron activated clotting time (ACT) for determining adequacy of reversal of heparin following cardiopulmonary bypass was evaluated in 20 patients and compared with standard laboratory tests of coagulation. The commonly used Celite ACT method proved too insensitive to have any useful predictive value in detecting or quantifying residual heparin and removal of the Celite activation rendered the test even less sensitive. In contrast, the partial thromboplastin time with kaolin (PTTK) proved to correlate well with residual heparin ( r = 0.79). It is, therefore, recommended that the use of the Hemochron following protamine administration be abandoned in favour of the PTTK.
Quantitative analysis of the effect of pulsatile flow on vascular resistance
Authors: Sohma A. , Ohga K. , Oka T. , Oda Y. , Itoh T. , Morimoto T.
Published: November 2007

'Pulsatile flow' has been reported to reduce vascular resistance. In this study, the effect of pulsatile flow was assessed quantitatively, using perfusion of canine hindlimb. The perfusion circuit consisted of roller-type pulsatile pump (Cobe Inc., Stockert pump) and bubble oxygenator (Shiley Inc., S-070/s). Each flow curve was quantified with the mean flow rate (F) and pulse power index (PPI). PPI is derived by Fourier transformation of the flow curve and represents the degree of 'pulsation'. Vascular resistance was determined during perfusion with varied flow rate and PPI. The regression formula between vascular resistance (VR) and two parameters was obtained as follows:

VR(F,PPI) = 41600x(F-1.37) -0.95+913 - PPIx{(3.99x(F-1.33)-040_0.69}

where VR is measured in mmHg. min-1.kg.ml-1; F represents ml.min-1.kg -1 (range from 2.8 to 17.1); and PPI is dimensionless (range from 2.8 to 215.7).

Using this formula, vascular resistance at a fixed flow rate and wave form can be predicted. When the flow rate is 6.27 ml.min-1.kg-1 and the PPI is 1466, (measured values under perfusion with own beating heart) the vascular resistance perfused by own beating heart is obtained. The results indicate that the pulsation of own beating heart contributes to a reduction in vascular resistance to 80%. It is also shown that the value of PPI which is necessary to reduce the vascular resistance to 80% is more than 1300 under the normal flow rate range.
Cardiopulmonary bypass technique in sheep
Authors: Noera G. , Fattori G. , Incerti Medici A. , Gatti MA
Published: November 2007

During the past two years at the University of Modena, 72 sheep underwent cardiopulmonary bypass (CPB) for various open-heart surgical procedures. An effective protocol for anaesthesia and CPB was developed in these animals. Routine barbiturate induction and maintenance anaesthesia with isofluorane and a pressure-regulated ventilator have minimized anaesthetic problems. The type of priming fluid used was the major factor in overcoming the problems associated with haemodilution effects, clotting insufficiency and postperfusion lung syndrome. Pump flows of 60ml.kg -1 bodyweight.min-1 seem to give adequate circulatory support during heart-lung bypass. A technical report and the pharmacological support protocols used successfully in 66 of the 72 animals during a two-year period are presented.
Pulmonary hypertension and platelet function
Authors: He Dingchao  , Hou Liye
Published: November 2007

Platelet number and function were measured in patients (n = 45) who underwent open-heart surgery with cardiopulmonary bypass (CPB). The study showed that platelet adhesion and aggregation were higher in the patients who suffered from congenital heart disease with pulmonary hypertension than in those in the control group, i.e. without pulmonary hypertension. Platelet number and function gradually increased in the experimental group after the operation and postoperative blood loss was greater than that in the control group. The reason for this may have been platelet hyperfunction in patients with pulmonary hypertension, which resulted in platelet destruction and severe depletion during operation. Therefore, it is difficult to achieve haemosttasis and prevent blood loss.
A safe technique for cardiopulmonary bypass in sickle cell disease
Authors: Balasundaram S. , Kassay M. , Duran Cmg
Published: November 2007

The use of exchange transfusion at the beginning of cardiopulmonary bypass (CPB) in five cases of sickle cell anaemia is described. The patient's circulating blood volume was drained into a bag through side tubing attached to the venous drainage line. Cardiopulmonary bypass was started with a prime consisting of donor packed cells, fresh frozen plasma, 25% albumin, lactated Ringer's solution, sodium bicarbonate and heparin. Moderate hypothermia, aortic crossclamping, topical hypothermia and cold crystalloid cardioplegia were used in all cases. The drained blood was spun down and the serum containing normal platelets and clotting factors was retransfused to the patient at the end of the operation. All five patients survived the procedure without complications and no homologous blood transfusion was required.
A new method for crystalloid cardioplegic oxygenation
Authors: Staffan G. , Svenmarker P. , Häggmark Sören K , Jansson K Erica
Published: November 2007

A new model of in vitro cardioplegic oxygenation was evaluated by placing Ringer's infusion bags in a pressure resistant barrel filled with pure oxygen maintaining 380mmHg. In this hyperbaric environment, oxygen gradually diffused directly through the wall of the infusion bag reaching a concentration exceeding four volumes percent after 96 hours. Decay in oxygen content was less than 1.5% after one week refrigerated at 4°C. In conclusion, the method described above offers an alternative approach to cardioplegic oxygenation, with the advantage of being safe, simple and without any extra expenditure.
In vitro and in vivo evaluations of the antithrombogenic properties of the spiral vortex pump for temporary left heart bypass
Authors: Ye Chun-Xiu , Umez Mitsuo , Nugent Allen H , Pittelkow Kay , Aitchson Fiona , Chang Victor P , Chiang Bang-Yu , Gao Xiao-Dong
Published: November 2007

From conception to realization, the design emphasis of the spiral vortex diaphragm pump has been on promoting efficient blood flow patterns in order to lower thrombogenicity. The tracer method was used to visualize flow patterns in this pump and the results were compared with those of a conventional diaphragm pump with paraxial inlet and outlet ports. During diastole, the flow through a 45° angled inlet is tangential to the axis of the pump forming a continuous vortex central along the pump axis. During systole, the vortex converges to pass through the apically located outlet. No areas of turbulence or stasis could be found, whilst in the conventional pump only random flow with recirculation could be demonstrated. Dye washout tests confirmed good washout at the periphery of this pump with no signs of stasis. However, large areas of stagnation with incomplete washout at diaphragm-housing (D-H) junctions were observed in the conventional pump. The comparative in vitro haemolysis test revealed that the level of free plasma haemoglobin was doubled in a commercially available pump compared with that of the spiral vortex pump. No thrombus formed within the pump housing after up to 50 hours of pumping in five acute animal experiments without postoperative anticoagulants. However, thrombi were found at the D-H junction of this pump due to imperfect fabrication techniques in one of the four sheep that survived 14-21 days. Neither thrombus in the pump nor infarcts in either kidneys were found in the last two sheep after 14 days of uneventful partial left heart bypass with this pump following improved fabrication methods.
Clinical experience with heparin-coated cardiopulmonary bypass circuits
Authors: Pradhan MJ , Fleming JS , Nkere UU , Arnold J. , Wildevuur ChRH , Taylor KM
Published: November 2007

The extensive area of contact between blood and synthetic surfaces during cardiopulmonary bypass results in the activation of the kallikrein, the complement and the clotting and fibrinolytic systems. This results in white cell activation and a whole body inflammatory response. Pulmonary neutrophil sequestration is also known to occur during cardiopulmonary bypass and has been associated with pulmonary damage. This has been previously demonstrated using the technique of differential neutrophil counts in simultaneous venous and left atrial samples. The efficacy of retinal fluorescein angiography as an indicator of cerebral microembolism has also been proved in previous studies. The objectives of this study were to determine whether heparin precoating with Duraflo II reduced pulmonary neutrophil sequestration, retinal microembolism and postoperative blood loss. Fourteen patients were randomized into two groups using either heparin-coated or nonheparin-coated cardiopulmonary bypass circuits. The preliminary results suggest a reduction in pulmonary neutrophil sequestration ( p> 0.05) and the generation of thrombin antithrombin complexes ( p < 0.05). Retinal microembolism was not significantly different in the two groups nor was the postoperative blood loss. Thus, heparin-coated cardiopulmonary bypass circuits do not reduce pulmonary neutrophil sequestration, retinal microembolism or postoperative blood loss.
Partial left heart bypass with centrifugal pump and limited anticoagulation during the resection of coarctation of the aorta
Authors: Everts Pam , Schönberger Jpam , Steenbrink J. , Bredée JJ
Published: November 2007

Resection of coarctation of the aorta necessitates crossclamping of the descending aorta. Despite the existence of a collateral circulation, spinal cord ischaemia and intestinal ischaemia may occur associated with a prolonged crossclamp time and distal hypoperfusion during the operation. To prevent these severe complications and to control hypertension proximal to the clamp, circulatory support may be necessary.

We performed partial left heart bypass (PLHB) with limited anticoagulation in four patients, using a centrifugal pump in orderto sustain a mean arterial blood pressure of at least 60mmHg in the distal thoracic aorta below the clamped coarctated segment. The method is practical, simple and safe. It combines features of several methods of protection of the spinal cord: adequate distal perfusion of the aorta at a desired flow rate and blood pressure, avoidance of proximal hypertension, minimal aortic and cardiac manipulation and avoidance of bleeding tendency by limited heparinization. Vasodilating drugs with their adverse effect on distal aortic pressure are not necessary in this situation.

Postoperatively, neurological sequelae orvital organ damage did not occur in our patients.
Development and current status of a new intracorporeal membrane oxygenator (IVOX)
Authors: Cox Charles S , Zwischenberger JB , Kurusz Mark
Published: November 2007

The IVOX (intravascular oxygenator) is an intracorporeal, hollow-fibre membrane oxygenator and carbon dioxide (CO2) removal device. The IVOX is surgically placed into the vena cava via a femoral or jugular venotomy. Oxygen (O2) is pulled through the hollow fibres by a vacuum pump controlled by a flow meter. There is no extracorporeal circulation of blood. Gas exchange occurs as the patient's blood flows over several hundred hollow fibres. Inlet and outlet gas conduits exit a small skin incision for inflow of O2 and outflow of CO2. Studies in sheep show that the IVOX can support approximately 30% of gas exchange requirements. The position of the IVOX in the vena cava does not affect haemodynamics or cause thromboembolic complications. It can remain in place for up to 22 days without affecting haematologic or blood chemistry parameters. The IVOX is currently undergoing clinical trials at selected medical centres in patients with acute respiratory failure.
Review articles: Cold agglutinins and hypothermic cardiopulmonary bypass
Authors: Dove Steven K , Raskin Steven A , Lawson D Scott
Published: November 2007

As hypothermic cardiopulmonary bypass has become more commonplace over the past 20 years, so has the problem of management of the patient with cold agglutinins. The perfusionist must understand the implications of the presence of cold agglutinins and formulate a plan to manage each particular patient with the cardiac surgeon.
The pattern of substrate metabolism by mammalian lung and its implication for defence against free radical oxidative damage
Authors: Datta HK , Ohri SK , Alberti Kgmm
Published: November 2007

An isolated perfused lung in situ preparation was used to study the nature of rat lung metabolism. The mammalian lung was found to metabolize reduced substrates preferentially and these were taken up in a concentration-dependent manner. The rate of lactate production accounted for approximately 50% of glucose uptake, but was nevertheless relatively minor in terms of total energy output. At a circulating lactate level of 0.4mmol there was a net release of lactate into the perfusion medium; at 2mmol and above there was a progressive increase in lactate uptake. We also demonstrate for the first time that the lung is capable of utilizing 3-hydroxybutyrate in a concentration-dependent manner. In the absence of exogenous substrate, there is a sufficient supply of endogenous substrates to maintain the mammalian lung in a viable state for up to four hours. However, unlike most other tissues, the lung contains little glycogen and triglycerides and must therefore depend on an exogenous supply of substrates over longer periods. The reliance of normally perfused lung on anaerobic metabolism may confer its protection from naturally derived products of oxidative metabolism such as oxygen-derived free radicals.
Changes in oxygen-haemoglobin affinity and myocardial function during extracorporeal perfusion in immature pigs
Authors: Willford David C , Moores William Y , Garden Richard M
Published: November 2007

An alteration in oxygen-haemoglobin affinity, as indicated by the partial pressure of oxygen at 50% haemoglobin saturation (P50), may theoretically affect oxygen delivery to the myocardium and, thus, alter myocardial tissue PO2 and possibly myocardial function. We studied the effect of changes in P50 on heart function, metabolism, and coronary sinus PO2 in 10 anaesthetized immature domestic pigs. To facilitate exchange transfusions and control of preload (left ventricular end diastolic pressure, LVEDP), afterload (mean arterial pressure), cardiac output, and heart rate, the animals were placed on right heart bypass. Stroke work (SW), myocardial oxygen consumption (MVO 2), coronary blood flow (CBF), arterial-coronary sinus O2 content difference (CaO2 -CcsO2), and P50 were measured with a control blood prime and after an exchange transfusion with blood having either a low (Group I) or high (Group II) affinity for oxygen. Results (Mean ± SEM, Control versus Test): P50 (mmHg) at 37°C and pH 7.4 increased in Group 1 (35.5 ± 0.7 versus 40.1 ± 1.2, p <0.01) and decreased in Group II (34.7 ± 1.3 versus 26.3 ± 0.5, P <0.001). At 8mmHg LVEDP, SW (gram·metres, g.m) remained constant in Group I (12.2 ± 1.1 versus 11.7 ± 0.8 g·m), but decreased (p <0.05) in Group II (11.7 ± 0.9 versus 8.6 ± 0.61 g.m). In addition, Starling curves relating SW to LVEDP between 4 and 18mmHg were uniformly depressed in Group II but not Group I. No significant change in MVO2 occurred in either group. Group II demonstrated decreased CaO2- CcsO2 (9.3 ± 0.8 versus 6.0 ± 0.3ml O2/dl, p <0.05) and increased CBF (121.6 ± 16.5 versus 188.9 ± 16.9ml/min/1 00gm, p <0.01). PcsO2 increased significantly in Group I (26.6 ± 4.2 versus 36.1 ± 2.7, P <0.02) but not Group II. In conclusion, a decrease in P50 appeared to decrease myocardial function despite a lack of change in PcsO2 or MVO2. A decrease in P50 also led to an increase in CBF. An increase in P50 did not alter function, but did increase coronary sinus and, presumably, tissue PO2.
Laboratory evaluation of the Pall LG6 leukocyte depleting arterial line filter
Authors: Gourlay T. , Fleming J. , Taylor KM
Published: November 2007

The Pall LG6 arterial line filter has been designed to remove free circulating leukocytes from the arterial line of the extracorporeal circuit employed in openheart surgery. The filter was evaluated and compared to a control filter (Pall Stat-Prime) in terms of its general blood handling characteristics, particularly with regard to the associated level of leukocyte removal. The gross air handling characteristics of the filters were also assessed together with pressure drop. It was found that the filters differed little in terms of all factors studied other than the level of leukocyte depletion. The LG6 filter was associated with substantial levels of leukocyte depletion, particularly the depletion of neutrophils. Over the 90 minute perfusion period the LG6 filter was found to be associated with a neutrophil depletion rate of around 70% while preferentially sparing lymphocytes. This compared to a 10-20% depletion rate in the control filter. This was achieved without apparently compromising the performance of the filter in terms of the other factors studied.
Changes in calcium fractions during cardiopulmonary bypass in infants and neonates
Authors: Berg Geoffrey A , Wheatley DJ , Borland William W , Dryburgh Frances J
Published: November 2007

The changes in total blood calcium fractions were investigated in 20 infants and neonates undergoing open-heart surgery for correction of congenital heart defects. On initiation of cardiopulmonary bypass (CPB), total serum calcium fell from 2.29 ± 0.05 mmol/I to 1.8 ± 0.04 mmol/I and there was a profound fall in biologically active ionized calcium from 1.26 ± 0.02 mmol/I to 0.49 ± 0.04 mmol/l. Protein-bound calcium also fell from 1.03 ± 0.07 mmol/I to 0.09 ± 0.03 mmol/l. Complexed calcium increased from 0.08 ± 0.02 mmol/I to 1.1 ± 0.05 mmol/l. The large fall in ionized calcium and increase in complexed calcium could be accounted for by the corresponding large increases in serum citrate (162.2 ± 29.8 μmol/l to 1689.8 ± 163.1 μmol/l) and serum lactate (1.27 ± 0.18 mmol/I to 7.79 ± 0.72 mmol/l). All measured fractions of calcium returned towards their pre-operative levels by the end of bypass. However, 13 of the 20 patients had less than optimal levels of ionized calcium when being weaned from bypass despite the empirical use of intravenous calcium supplements. This study demonstrates that ionized calcium can be quickly and easily measured in the peri-operative period, that there can be extremely large changes in calcium fractions during CPB in infants and neonates, and that ionized calcium can be unexpectedly low in the critical period when weaning patients from bypass. Total calcium measurements gave an inaccurate estimate of the ionized calcium fraction.
Marfan syndrome: diagnosis and replacement of the aortic arch utilizing retrograde cerebral perfusion
Authors: Ensign Robert G , Sowell Steven R , Raskin Steven A
Published: November 2007

The patient with a diagnosis of Marfan syndrome often presents to the cardiac surgical team for repair of the various cardiac and vascular abnormalities associated with the disease. One of the most complicated presentations involves an aneurysmal dilatation of the ascending and transverse aortic arch with or without involvement of the great vessels. The aortic valve may also be affected resulting in valvular insufficiency. These patients are usually in their 20s or 30s and undertaking a major surgical repair of the aortic arch exposes them to a variety of complications, which can have devastating effects. This article will review the diagnosis and pathology of the Marfan syndrome and describe the application of retrograde cerebral perfusion to lessen the chance of neurological morbidity following surgical replacement of the ascending and transverse aortic arch.
Platelet preservation during coronary bypass surgery with bubble and membrane oxygenators: effect of albumin priming
Authors: Videm Vibeke , Fosse Erik , Svennevig Jan L
Published: November 2007

Sixty-three patients admitted for routine coronary bypass operations were randomized to cardiopulmonary bypass (CPB) with a membrane oxygenator (Capiox- CA) or a bubbler (Polystan or William Harvey- WH), and in the Polystan group to prime with or without albumin (P+ or P-). Platelets were counted and blood loss from the mediastinal drains during the first 12 postoperative hours was measured. The reduction in platelet numbers from baseline to closure of the sternum was significantly larger in the P- group (121 x 109/l, median) than in the CA group (55 x 109/l) (p <0.001), with intermediate reductions in the P+ (87 x 109/l) and WH (90 x 109/l) groups. The reduced platelet loss in the P+ group compared with P- was accompanied by a significant reduction in early postoperative chest tube drainage (480 versus 728 ml). Thus, precirculation of the CPB circuit with prime containing a low dose of albumin was a simple and inexpensive means of increasing platelet function with a bubble oxygenator.
Conventional cardiopulmonary bypass in neonates. A physiological approach -10 years of experience at Marie-Lannelongue Hospital
Authors: Nicolas Françoise , Daniel Jean-Pierre , Bruniaux Jacqueline , Serraf Alain , Lacour-Gayet François , Planche Claude
Published: November 2007

There is still controversy about the optimal method of venoarterial cardiopulmonary bypass (CPB) for correction of congenital heart diseases in neonates and young infants. High rates of CPB-related morbidity and mortality are still reported.

Since 1980, conventional CPB with double caval cannulation with right-angled cannulae has been used in the high majority of neonates at Marie-Lannelongue Hospital. The extracorporeal circuit was miniaturized to be primed with a volume as small as possible. Priming (500 ml) was done with packed red cells and fresh frozen plasma. CPB was conducted at 30% haematocrit and normal ranges of flow rate, arterial pressure, systemic vascular resistances and oxygen delivery. These normal physiological parameters were also maintained during hypothermia.

During the last two years, 151 neonates below 15 days old who underwent open-heart surgery were reviewed. The overall hospital mortality was 7.24%. None of the survivors had postoperative complications related to CPB. All physiological and biological values remained within normal ranges during the postoperative course.
A guideline nomogram to control intraoperative haemodilution in cardiac surgery
Authors: Ranucci M. , Conti D.
Published: November 2007

Intraoperative blood collection prior to cardiopulmonary bypass (CPB) is a common procedure in cardiac surgery. Its aims are to obtain fresh whole blood to be infused after CPB, to use autologous blood in the prime or to avoid too high levels of haematocrit (HCT) during CPB. Calculations to determine the amount of blood to be collected are generally based on theoretical assumptions. In this paper we have set up and controlled, on a clinical basis, a nomogram to be used in order to obtain a standard pre-CPB HCT equal to 38%, using a moderately hypervolaemic haemodilution based on blood collection simultaneous with fluid replacement.

Thirty adult patients were evaluated in order to settle the nomogram; subsequently, the nomogram validity was checked on 100 adult patients. Statistical analysis revealed the good clinical usefulness of this instrument.
Clinical evaluation of the CDI™ System 400 blood gas monitor
Authors: Svenmarker Staffan , Lindholm Ronny , Häggmark Sören , Jansson Erica , Benze Sylvia
Published: November 2007

The CDI 400 blood gas monitor was evaluated by investigating its clinical performance in 30 patients undergoing cardiac surgery requiring cardiopulmonary bypass. Arterial and venous blood samples were withdrawn during stable hypothermic conditions. Reference analysis was performed on the ABL4 blood gas analyser. A total of 229 samples were included for calculations of bias and precision. Simple regression analysis was utilized to illustrate the relationship between the tested monitor and its reference. Results revealed an acceptable agreement for pH and arterial pO2 measurements. Venous pO2 bias and precision were poor (+0.76 ± 1.07 kPa). Arterial and venous pCO2 were generally overestimated (+0.5 ± 0.4 kPa and +0.2 ± 0.4 kPa). Performance given as correlation coefficients indicated a similar pattern. Slopes and intercepts deviated from the line of identity for all parameters analysed. In summary: the CDI 400 is a valid instrument in guiding the perfusionist with crucial trend information. However, its general performance implies that a reference blood gas analyser is still needed.
The hostile environment of the aging human aorta and the smaller patient- their implications for the intra-aortic balloon
Authors: Wolvek Sidney
Published: November 2007

Intra-aortic balloon counterpulsation (IABC) has been a clinical modality since 1968. In the intervening years the patient population has become older, sicker and smaller. Modern balloon design permits the insertion of balloons into this evolving patient population and the balloon is increasingly threatened by the calcific plaque of the aging aorta and by the geometry of the shorter descending thoracic aorta in the smaller patient. Balloon sizing consideration and radiographic verification of balloon position within the aorta will reduce the incidence of balloon damage during IABC.
Clinical oxygen transfer performance of the Sorin Monolyth membrane oxygenator
Authors: Fried David W. , DeBenedetto Benjamin N. , Leo Joseph J. , Mattioni Gabriel J. , Mohamed Hasratt , Zombolas Theodore L.
Published: November 2007

Oxygen transfer performance of the Sorin Monolyth membrane oxygenator was evaluated. Similar to previous oxygen transfer performance studies conducted at this institution, our purpose was sixfold: (1) to construct an oxygen transfer slope (OTS); (2) to find the maximum extrapolated oxygen transfer; (3) to calculate the oxygenator performance index (OPI); (4) to generate a shunt fraction line; (5) to determine the percentage of predicted shunt (POPS); and (6) to compare the Monolyth's performance to several previously studied membrane oxygenators. From the OTS, the maximum extrapolated oxygen transfer was 346.4 ml O2/min. This absolute value was the lowest of the four oxygenators compared. When maximum oxygen transfer was compared relative to membrane surface area, the Monolyth ranked third (157.5 ml O2/Min). The Monolyth produced a relatively narrow range for the OPI (81.64-130.47%) and had the lowest standard deviation (SD) in this group. The Monolyth exhibited higher shunt fractions over the range of clinical blood flows when compared to our three previously studied oxygenators. The range of POPS values (71.65-128.77%) was relatively narrow and the SD was the lowest of the four. We concluded from our evaluation that the Monolyth had relatively low top end oxygen transfer capabilities, but provided very consistent and predictable oxygen transfer performance.
D-901 neonatal oxygenator: a new perspective
Authors: De Somer F. , François K. , Foubert L. , Deryck Y. , De Smet D. , Vanackere M. , Van Nooten G.
Published: November 2007

Five infants with congenital heart disease were perfused with the D-901 neonatal oxygenator at the time of their cardiac surgery. The ability to reduce the prime volume below the blood volume as well as the blood handling and gas transfer characteristics were studied.

In all cases the prime volume was less than or equal to the blood volume of the patient. This resulted in a reduction in the use of homologous blood products. Due to the concept of the D-901 it was possible to adapt the tubing in such a way that a complete prime of 220 ml was obtained. The device had a maximum oxygen transfer of 45 ml/min. The maximum carbon dioxide removal was 50 ml/min at a blood gas ratio of one.

The mean platelet count post bypass decreased to 91 % of the baseline value. Mean free haemoglobin levels increased to 86 mg/100 ml at 120 minutes of bypass.

We conclude that the D-901 oxygenator opens new perspectives for perfusion in small babies in terms of priming volume and use of homologous blood products while maintaining good gas transfer characteristics. However, larger series are necessary to expand our experience with this device and its limitations.

No specific problems related to the device were encountered and all infants had an uneventful postoperative course.
Blood warms as it flows retrograde from a femoral cannulation site to the carotid artery during cardiopulmonary bypass
Authors: Dexter Franklin , Hindman Bradley J , Cutkomp Johann , Smith Tom
Published: November 2007

Hypothermia protects the brain from injury during cardiopulmonary bypass and hypothermic circulatory arrest. However, when the arterial cannula is at sites other than the ascending aorta, brain cooling before circulatory arrest may be incomplete, contributing to poor neurological outcome. The authors performed an experiment using a rabbit model of cardiopulmonary bypass with femoral arterial perfusion. Arterial perfusate and carotid artery temperatures were simultaneously measured in six rabbits undergoing cardiopulmonary bypass, three with femoral artery cannulation, and three with subclavian artery cannulation. The subclavian artery site was chosen as a surrogate for ascending aortic cannulation. Carotid blood temperature was 3.7°C to 0.3°C warmer than arterial perfusate temperature during femoral arterial perfusion. The temperature difference decreased over time (p = 0.0007). The temperature gradient was significantly less (p = 0.002) when subclavian arterial perfusion was used. Carotid blood temperature was 1.1 °C to 0.0°C warmer than arterial perfusate temperature during subclavian cannulation. The authors conclude that when femoral perfusion cooling is used, blood is warmed as it flows in a retrograde direction in the descending aorta to the carotid artery.
Isolated limb perfusion with urokinase in the treatment of extensive vascular thrombosis of the lower limbs
Authors: Kam Pca , Thompson JF , May J.
Published: November 2007

Isolated limb perfusion with urokinase was used in combination with balloon catheter embolectomy in three patients with extensive vascular thrombosis in the lower limbs after conventional methods of treatment failed to restore perfusion to the lower limb. The technique and its results are described and discussed. It is suggested that isolated limb perfusion with urokinase is safe and is worthy of further investigation in the treatment of critically ischaemic lower limbs.
Studies of the effect of Pall leucocyte filters LG6 and AV6 in an in vitro simulated extracorporeal circulatory system
Authors: Thurlow PJ , Doolan L. , Sharp R. , Sullivan M. , Smith B.
Published: November 2007

Neutrophil activation is thought to play a major role in the inflammatory response seen in reperfusion injury and similar clinical situations, i.e. extracorporeal circulation. lmpairment of neutrophil function or reduction of total numbers of neutrophils using a leucocyte filter may be beneficial in reducing the adverse clinical effects.

In this study we have investigated the effect of the Pall LG6 and control AV6 filters during simulated in vitro cardiopulmonary bypass (CPB). Various parameters were evaluated including neutrophils, total leucocytes, monocytes, lymphocytes and platelets, expression of antigens on neutrophils using a panel of leucocyte-associated monoclonal antibodies CD13, 14, 15, 45Ro, 67,11a, 11 b and L selectin. The effects of leucocyte stimulation with phorbol myristate acetate (PMA) and a leucocyte bolus from a patient with chronic myeloid leukaemia (CML) were also investigated.

We have demonstrated that the LG6 significantly reduces leucocytes, in particular neutrophils, with a modest reduction of lymphocytes, platelets and haematocrit, whereas the AV6 had no effect on leukocytes or neutrophils in the test system. In addition the LG6 was associated with a reduction in expression of all leucocyte antigens by approximately 20%; however there was no appreciable alteration of any of the antigens with AV6. Leucocyte stimulation with PMA resulted in a dramatic decrease of all cellular elements and an extra leucocyte load (using CML leucocytes) was not effectively filtered by the LG6 filter.

These studies identify the capacity of the LG6 as compared with the AV6 to deplete activated neutrophils in an in vitro simulated cardiopulmonary bypass circuit.
Carmeda surface heparinization in neonatal ECMO systems: long-term experiments in a sheep model
Authors: Palmér K. , Ehrén H. , Benz R. , Frenckner B.
Published: November 2007

The thromboresistance in three Carmeda (Stockholm, Sweden) heparin- coated neonatal ECMO systems with a runtime of 45, 56 and 96 hours, respectively, and three noncoated systems with a runtime of 12, 42 and 66 hours, respectively, were compared using a sheep model. The flow rate was 200 ml/min and the activated clotting time (ACT) was kept at approximately 120 seconds. At the end of the experiment, the heparin-coated systems only contained minimal clotting while the controls showed major clotting in the entire system. Fibrin monomers were not detected until after 24 hours in the heparin- coated group, but demonstrated within 60 minutes in the noncoated group.

It is concluded that the Carmeda heparin coating has a thromboresistant effect, and may be used to reduce the need for systemic heparinization in ECMO treatment of neonates.
The blood saving potential of vortex versus roller pump with and without aprotinin
Authors: Wahba A. , Philip A. , Bauer MF , Kaiser M. , Aebert H. , Birnbaum DE
Published: November 2007

To evaluate the potential of centrifugal blood pumps for saving blood, 120 patients scheduled for elective coronary artery bypass grafting were entered into a prospective randomized trial. A standard roller pump (group I) was compared with a centrifugal blood pump (group II) and roller pump plus aprotinin (group III). There was no significant difference between groups I and I I with respect to free haemoglobin, lactic dehydrogenase, serum bilirubin, platelet surface glycoprotein IIb-IIIa and granule membrane protein 140, chest-tube drainage, use of blood products, length of stay in intensive care, time on ventilator and postoperative mortality. Aprotinin reduced chest-tube drainage and use of blood products significantly. Three cases of graft occlusions were noted in group III. Centrifugal blood pumps offer no advantage in routine heart surgery over conventional roller pumps. Aprotinin reduces blood loss, but does not influence GP IIb-IIIa and GMP 140 expression on blood platelets.