Clinical evaluation of the Medtronic Maxima Plus membrane oxygenator

Perfusion ◽  
1994 ◽  
Vol 9 (5) ◽  
pp. 363-372 ◽  
Author(s):  
David W Fried ◽  
Benjamin N DeBenedetto ◽  
Theodore L Zombolas ◽  
Joseph J Leo
Keyword(s):  
Pressure Drop ◽  
Surface Area ◽  
Oxygen Transfer ◽  
Membrane Surface ◽  
Transfer Performance ◽  
Membrane Oxygenator ◽  
Membrane Surface Area ◽  
Blood Flows ◽  
Priming Volume ◽  
Outside Diameter

The purpose of this study was to clinically evaluate the degree of improvement, if any, in the oxygen transfer performance of the recently released Medtronic Maxima Plus membrane oxygenator. The outside diameter of the hollow fibres was reduced, increasing the membrane surface area from 2.0 m2 to 2.3 m2 without altering the polycarbonate housing. Maximum extrapolated oxygen transfer of the Maxima Plus (444 ml O2/minute) was increased 23.68% when compared to the Maxima (359 ml O2/minute). When expressed per metre squared of membrane surface area, the Maxima Plus had an increase of 13.5 ml O2/m2/Minute (7.24%) over the Maxima. Pressure drop across the Maxima Plus was within 3.5 mmHg of the Maxima over the range of clinical blood flows indicating that the fibre bundle packing density was not significantly altered. Oxygen transfer consistency, expressed as a function of the standard deviation of oxygenator performance index values, was not significantly different for the two oxygenators. We concluded that the improvement in total oxygen transfer was due to an increase in membrane surface area as well as enhanced transfer efficiency per metre squared. We believe that the improved oxygen transfer performance was accomplished without impacting significantly upon the other attributes of the oxygenator (e.g., pressure drop, consistency, priming volume).

Clinical oxygen transfer performance of the Sorin Monolyth membrane oxygenator

Perfusion ◽  
1994 ◽  
Vol 9 (2) ◽  
pp. 119-126 ◽  
Author(s):  
David W. Fried ◽  
Benjamin N. DeBenedetto ◽  
Joseph J. Leo ◽  
Gabriel J. Mattioni ◽  
Hasratt Mohamed ◽  
...  
Keyword(s):  
Performance Studies ◽  
Oxygen Transfer ◽  
Narrow Range ◽  
Membrane Surface ◽  
Transfer Performance ◽  
Membrane Oxygenator ◽  
Membrane Surface Area ◽  
Absolute Value ◽  
Blood Flows ◽  
Membrane Oxygenators

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.

Clinical oxygen transfer comparison of the Terumo Capiox SX18 and SX25 membrane oxygenators

Perfusion ◽  
1998 ◽  
Vol 13 (2) ◽  
pp. 119-127 ◽  
Author(s):  
David W Fried ◽  
Theodore L Zombolas ◽  
Joseph J Leo ◽  
Hasratt Mohamed ◽  
Gabriel J Mattioni
Keyword(s):  
Pressure Drop ◽  
Oxygen Transfer ◽  
Membrane Surface ◽  
Shunt Fraction ◽  
Flow Rates ◽  
Membrane Surface Area ◽  
Blood Flows ◽  
Side Pressure ◽  
Membrane Oxygenators ◽  
Better Than

The purpose of this current study was to compare the Terumo Capiox SX18 (1.8 m2) with the recently released Capiox SX25 (2.5 m2). Specifically, their oxygen transfer slopes, degree of blood shunting, extrapolated maximum oxygen transfer, blood side pressure drop and oxygen transfer consistency were compared. The lower intercept value (0.209 vs 0.236) coupled with the flatter slope (0.00171 vs 0.00225) of the oxygen transfer line for the SX25 is consistent with improved oxygen transfer performance. A lower FiO2 value would be predicted for the SX25, to achieve a specific PaO2 value, when the oxygen transfer requirement is equal for both devices. Extrapolated maximum oxygen transfer for the SX25 (462.6 ml O2/min) was 36.2% higher than that for the SX18 (339.6 ml O2/min). When indexed to membrane surface area, the SX18 (188.7 ml O2/m2/min performed 2.0% better than the SX25 (185.0 ml O2/m2/min). Both the slope (3.110 vs 3.744) and the intercept (4.595 vs 6.223) of the shunt fraction line were lower for the SX25, indicating that a lower shunt fraction would be predicted for all clinical blood flow rates. The slope (23.934 vs 22.443) and intercept values (-28.388 vs -22.650) of the pressure drop lines for the two devices indicate that the blood side pressure drop, over the range of clinical blood flows, were within 2% of each other. Oxygen transfer consistency, when expressed as the standard deviation of the oxygenator performance index and the percentage of predicted shunt, was not statistically different for the two devices.

Reusable tubular membrane oxygenator for isolated organ hemoperfusion

1976 ◽  
Vol 40 (3) ◽  
pp. 476-482
Author(s):  
W. H. Waugh ◽  
T. E. Bales ◽  
H. Nihei
Keyword(s):  
Surface Area ◽  
Oxygen Transfer ◽  
Ex Vivo ◽  
Membrane Oxygenator ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Transfer Rates ◽  
Tubular Membrane ◽  
Blood Flows ◽  
Wall Compliance

A reusable tubular membrane oxygenator is described for hypotraumatic hemoperfusion of isolated organs in physiological studies. The constructed oxygenator was of approximately 0.24-m2 effective surface area and contained 450 silicone rubber capillaries of 0.51-mm nominal ID, 34.9 cm long, fixed by conical-shaped, plastic blood headers at manifolds made from Dow-Corning MDX-4–4210 silicone elastomer. During ex vivo hemoperfusions in dogs at inlet hemoglobin saturations near 67%, oxygen transfer rates of the oxygenator increased serially, from 16.6 +/- 1.7 ml/min per m2 (mean +/- SD) at blood flows of 100 ml/min to 34.1 +/- 3.8 ml/min per m2 at flows of 500 ml/min. The oxygenator was thromboresistant and of much loss priming blood volume and wall compliance than the nonresuable Travenol membrane oxygenator of 0.26-m2 effective surface area. The tubular oxygenator was easily cleaned and reassembled, with reproducible oxygen transfer rates. It should prove useful for hemoperfusion studies in organs of moderate size, such as the isolated canine kidney, stomach, and pancreas.

The macrophage capacity for phagocytosis

1992 ◽  
Vol 101 (4) ◽  
pp. 907-913 ◽  
Author(s):  
G.J. Cannon ◽  
J.A. Swanson
Keyword(s):  
Surface Area ◽  
Membrane Surface ◽  
Fc Receptors ◽  
Phagocytic Capacity ◽  
Membrane Surface Area ◽  
Murine Bone Marrow ◽  
Latex Beads ◽  
Endocytic Compartments ◽  
Frustrated Phagocytosis

Murine bone marrow-derived macrophages, which measure 13.8 +/− 2.3 microns diameter in suspension, can ingest IgG-opsonized latex beads greater than 20 microns diameter. A precise assay has allowed the determination of the phagocytic capacity, and of physiological parameters that limit that capacity. Ingestion of beads larger than 15 microns diameter required IgG-opsonization, and took 30 minutes to reach completion. Despite the dependence on Fc-receptors for phagocytosis of larger beads, cells reached their limit before all cell surface Fc-receptors were occupied. The maximal membrane surface area after frustrated phagocytosis of opsonized coverslips was similar to the membrane surface area required to engulf particles at the limiting diameter, indicating that the capacity was independent of particle shape. Vacuolation of the lysosomal compartment with sucrose, which expanded endocytic compartments, lowered the phagocytic capacity. This decrease was reversed when sucrose vacuoles were collapsed by incubation of cells with invertase. These experiments indicate that the phagocytic capacity is limited by the amount of available membrane, rather than by the availability of Fc-receptors. The capacity was also reduced by depolymerization of cytoplasmic microtubules with nocodazole. Nocodazole did not affect the area of maximal cell spreading during frustrated phagocytosis, but did alter the shape of the spread cells. Thus, microtubules may coordinate cytoplasm for engulfment of the largest particles.

scholarly journals Effect Of Surface Area Of Dialyzer Membrane On The Adequacy Of Haemodialysis

2012 ◽  
Vol 7 (2) ◽  
pp. 9-11 ◽  
Author(s):  
NS Chowdhury ◽  
FMM Islam ◽  
F Zafreen ◽  
BA Begum ◽  
N Sultana ◽  
...  
Keyword(s):  
Renal Disease ◽  
Surface Area ◽  
End Stage Renal Disease ◽  
Membrane Surface ◽  
Reduction Ratio ◽  
Urea Clearance ◽  
Membrane Surface Area ◽  
Stage Renal Disease ◽  
End Stage ◽  
Urea Reduction Ratio

Introduction: Patients with end stage renal disease require 12 hours of haemodialysis per week in three equal sessions (4 hours/day for 3 days/week). But the duration and frequency of treatment can be reduced by increasing the surface area of the dialyzer membrane. Methods: In this prospective study 40 patients of end stage renal disease receiving haemodialysis for more than six months were included to observe the effects of increment in the surface area of the dialyzer membrane on the adequacy of haemodialysis. Result: It was observed that 20 patients receiving haemodialysis on a dialyzer with membrane surface area of 1.2 m² did not have satisfactory solute clearance index. Urea reduction ratio was 45.9 ± 3.03 and fractional urea clearance (Kt/V) was 0.76 ± 0.09. On the other hand patients (20 cases) receiving haemodialysis on a dialyzer with membrane surface area of 1.3 m² had a urea reduction ratio 50.76± 5.16 and fractional urea clearance (Kt/V) 0.91 ± 0.16. All the patients of both groups received dialysis for 8 hours/week in two equal sessions (4 hours/day for 2 days/week). Statistically the increment was significant (p<0.001). Conclusion: This study reveals, adequacy of dialysis can be increased by increasing the surface area of the dialyzer membrane. So, considering the poor socioeconomic condition of Bangladesh and patients' convenience, a short duration, low cost dialysis regime can be tried by increasing the surface area of dialyzer membrane. DOI: http://dx.doi.org/10.3329/jafmc.v7i2.10387 JAFMC 2011; 7(2): 9-11

The ultrastructure of the cardiac Purkinje strand in the dog: a morphometric analysis

1983 ◽  
Vol 217 (1207) ◽  
pp. 191-213 ◽  
Keyword(s):  
Electron Microscopy ◽  
Electrical Properties ◽  
Connective Tissue ◽  
Surface Area ◽  
Series Resistance ◽  
Membrane Surface ◽  
Light And Electron Microscopy ◽  
Total Surface Area ◽  
Membrane Surface Area ◽  
Extracellular Ions

Purkinje strands from both ventricles of adult mongrel dogs were excised, and electrical properties were studied by the voltage-clamp technique. The strands were then examined with light and electron microscopy and structural properties were analysed by morphometric techniques. The canine Purkinje strand contains (by volume) about 28% myocyte and 55% dense outer connective tissue. The remainder of the volume is taken up by the inner shell of loosely packed connective tissue within 10 μm of a myocyte membrane. These volume fractions vary considerably from one strand to another. Clefts less than 10 μm wide occupy 18% of the myocyte volume and clefts less than 1 μm wide occupy 1%. The membrane surface area of the myocytes can be divided into three categories by reference to the size of the adjacent cleft. About 47.8% of the membrane surface area faces clefts wider than 1 μm, another 22.2% faces clefts between 0.1 and 1 μm wide, and the final 30% faces clefts less than 0.1 μm wide. The surface area facing the narrowest clefts (less than 0.1 μm wide) is divided between nexuses 3%, desmosomes 10%, and unspecialized membrane 17% (each figure is expressed as a percentage of the total surface area of myocyte membrane). The canine Purkinje strand has a more favourable anatomy than the sheep Purkinje strand for most physiological experiments. We expect that the complicating effects of series resistance and change in the concentration of extracellular ions will be much smaller than in sheep strands, but still not negligible.

A clinical evaluation of platelet function, haemolysis and oxygen transfer during cardiopulmonary bypass comparing the Quantum HF-6700 to the HF-5700 hollow fibre membrane oxygenator

Perfusion ◽  
2000 ◽  
Vol 15 (6) ◽  
pp. 479-484 ◽  
Author(s):  
A O Chukwuemeka ◽  
M RJ Turtle ◽  
U H Trivedi ◽  
G E Venn ◽  
D J Chambers
Keyword(s):  
Cardiopulmonary Bypass ◽  
Platelet Function ◽  
Clinical Evaluation ◽  
Oxygen Transfer ◽  
Artery Bypass ◽  
Membrane Surface ◽  
Platelet Activating Factor ◽  
Hollow Fibre ◽  
Priming Volume ◽  
First Time

The continued improvement of oxygenators is an important aspect of patient safety during cardiopulmonary bypass (CPB). The purpose of this study was to compare the Bard William Harvey HF-5700 oxygenator to the upgraded Bard Quantum HF-6700, which has recently been introduced into clinical practice. No clinical evaluation of this device has been published to date. The two oxygenators differ principally in that the Quantum has a smaller priming volume, achieved at the expense of a smaller membrane surface area which could result in sub-optimal gas exchange characteristics, increased haemolysis and increased platelet dysfunction during CPB. Twenty adult patients undergoing elective, first time coronary artery bypass grafting (CABG) were randomly assigned either to the HF-5700 ( n=10) or to the HF-6700 ( n=10) group. One patient underwent mitral valve repair in addition to CABG and was excluded from further study. There were no statistically significant differences in either preoperative or operative parameters between the two groups. Samples were obtained at the start of CPB, at 30 min, 60 min, at the end of CPB and at 1 h following termination of CPB. No significant differences between the two groups were found in oxygen transfer, haemolysis (plasma haptoglobin levels) or platelet function (a novel platelet activating factor (PAF)-induced platelet activation test) at any of the time points during CPB. It was concluded that the Quantum HF-6700 matches the HF-5700 for the parameters studied, whilst having the advantage of requiring a smaller priming volume.

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