bluuebunny/crossref_metadata_2025 huggingface dataset:
Acetate Hemodialysis Does Not Increase the Frequency of Arrhythmia in Hemodialysis Patients
Authors: Kayatas Mansur , Ertürk Arif , Muderrisoglu Haldun , Emin Korkmaz  , Nurhan Özdemir
Published: March 2003

It is the goal of this section to publish material that provides information regarding specific issues, aspects of artificial organ application, approach, philosophy, suggestions, and/or thoughts for the future.

Arrhythmia is one of the most important causes of mortality in patients on hemodialysis and may develop due to cardiovascular diseases or fluid‐electrolyte or acid‐base abnormalities. Previous studies have shown that acetate hemodialysis (AHD) increased the frequency of arrythmia. To evaluate the frequency and the causes of arrhythmias during AHD, we studied 33 randomly selected patients (25 male and 8 female, mean age of 45 ± 18 years) who were under AHD (4 h, 3 times/week, mean duration of HD of 38 ± 29 months) with the same Cuprophan membranes. All patients underwent a detailed echocardiographic evaluation during the interdialytic period. Twenty‐four hours of Holter monitoring was performed starting from the onset of HD. Twelve lead electrocardiography (ECG) was obtained, and venous and arterial blood samples were drawn for serum electrolytes, pH, and arterial blood gas measurements before and after HD. Serum magnesium and potassium levels dropped after AHD (from 2.3 ± 0.5 to 1.9 ± 0.3 mEq/L and from 5 ± 0.7 to 3.4 ± 0.4 mEq/L respectively, p < 0.001); on the other hand serum pH, bicarbonate, sodium, and calcium levels were normalized. Electrocardiographic evaluation revealed significant lengthening of the QTc interval (from 433 ± 42 to 464 ± 43 ms, p < 0.001), which was thought to be related to the decrease in serum magnesium and potassium levels. The frequencies of ventricular premature contractions (VPCs) were not different during AHD and the interdialytic period (8 ± 9.1 to 6.5 ± 11 contractions/h, p > 0.05). This was also true for supraventricular premature contractions (SVPCs) and supraventricular tachycardia (SVT). Nonsustained ventricular tachycardia was observed in 2 patients during HD and in 1 patient in the interdialytic period. No relation was established between the echocardiographic findings and the frequency of arrhythmia. In our ambulatory electrocardiographic study, the frequencies of VPCs and SVPCs observed during the interdialytic period were only positively correlated with age (r = 0.54, p = 0.013 and r = 0.50, p = 0.010, respectively). No relation was found between the frequency of arrhythmia and the gender of the patients; duration of HD; etiology of kidney disease; or serum Na, K, Ca, iCa, Mg, bicarbonate, or pH levels (p > 0.05). In conclusion, the application of AHD does not increase the frequency of arrhythmia in HD patients as had been shown in previous studies.
Complement Activation as a Cause of Transient Hypotension During Plasmapheresis
Authors: Shiga Yusei , Fujihara Kazuo , Onodera Hiroshi , Nagata Tetsuya , Itoyama Yasuto
Published: March 2003

Hypotension is one of the most common adverse effect of plasmapheresis (PP) and often is attributed to hypovolemia due to extracorporeal circulation and the vasovagal reflex. Complements are activated during PP, and the activated complements are strong anaphylatoxins and potent vasodilators. Therefore, we studied the relationship between the transient hypotension and the plasma levels of activated complements during and after PP in 8 sessions of 7 patients using the Plasmafro OP‐08 as a plasma separator. Five of the patients underwent immunoadsorption PP using the IM‐TR 350 or IM‐PH 350 as the adsorption column. The other underwent double filtration PP using the Evaflux 4A as a second filter. In 4 of 8 sessions, patients experienced transient hypotension with significantly elevated plasma levels of activated complements C3a and C5a. In contrast, patients without hypotension showed no increases in C3a and C5a values during PP. In this report, we emphasize the critical role of activated complements for hypotension during PP.
The Effects of Serum from Patients with Acute Liver Failure on the Growth and Metabolism of Hep G2 Cells
Authors: Shi  , Gaylor  , Cousins  , Plevris  , Hayes  , Grant
Published: March 2003

In many bioartificial liver systems currently being designed and evaluated for use in fulminant hepatic failure, direct contact is required between the patient's blood and the liver cells in the device. The efficacy of such devices will be influenced by the interaction of fulminant hepatic failure (FHF) patient serum with the cells. We have found that FHF serum inhibits the growth rate and the synthesis of DNA, RNA, and protein; disturbs glutathione homeostasis; and induces morphological changes in cultured human Hep G2 cells. These interactions should influence the design of bioartificial liver devices based on proliferating cell lines and indicate the requirement to pretreat FHF patient plasma to reduce the toxin load.
Evaluation of Platelet Adhesion and Activation on Materials for an Implantable Centrifugal Blood Pump
Authors: Takami Yoshiyuki , Yamane Shingo , Makinouchi Kenzo , Niimi Yoshinari , Sueoka Akinori , Nosé Yukihiko
Published: March 2003

A totally implantable centrifugal artificial heart has been developed in which a pivot bearing supported centrifugal pump is used as a blood pump. The following have been adopted as blood contacting materials in our pump: titanium alloy (Ti‐6Al‐4V) for the housing and impeller, alumina ceramic (Al2O3) for the male pivots, and ultrahigh molecular weight polyethylene (PE) for the female pivots. Greater antithrombogenicity is required for an implantable blood pump. To examine the thrombogenicity of these materials, we evaluated in vitro platelet adhesion and activation, which may play key roles in thrombogenesis on foreign surfaces. Ti‐6Al‐4V, Al2O3, and PE were compared with polycarbonate (PC), silicone carbide (SiC), and pure titanium (pTi). Platelet adhesion was assessed using monoclonal antibody (CD61) directed against glycoprotein IIIa. Platelet activation was evaluated by measuring P‐selectin (GMP‐140) released from irreversibly activated platelets. Each material with a surface area of 16.6 cm2 was incubated with 2.5 ml of plasma or 2.5 ml of heparinized fresh whole blood for 3 h at 37°C. The optical density (OD) at a wavelength of 450 nm for CD61 was 0.93 ± 0.35 in PC, 0.34 ± 0.13 in PE, 0.27 ± 0.13 in pTi, 0.26 ± 0.01 in Al2O3, 0.21 ± 0.04 in SiC, and 0.12 ± 0.12 in Ti‐6Al‐4V. The GMP‐140 levels of the tested materials were not significantly different from the control value (45.9 ± 7.2 ng/ml). These results indicate that Al2O3, PE, and Ti‐6Al‐4V, which are incorporated into our implantable centrifugal pump, have satisfactory antithrombogenic properties in terms of platelet adhesion. However, platelet activation by any material was not observed under the static condition in this study.
Nitric Oxide Inhalation as a Chemical Assist for Circulation in Patients After Cardiovascular Surgery
Authors: Kumon Keiji , Yahagi Naoki , Imanaka Hideaki , Takeuchi Muneyuki , Miyano Hiroshi , Ohashi Yoko
Published: March 2003

The objective of this study was to investigate whether nitric oxide (NO) inhalation might be an alternative strategy as a chemical assist for the circulation in patients showing a deterioration in oxygen delivery. Twelve adult patients whose oxygen delivery indices (D O2I) were less than 400 ml/min/m2 after cardiovascular surgery were included in this study. NO was administered via a premixing system or a side stream system at doses between 1 and 10 (5.1 ± 2.4) ppm. Data obtained before and during a 120 min NO inhalation were compared using the paired Student's t‐test. The increase in Pa
O2/Fi
O2 resulting from NO inhalation was significant (from 162 to 251 mm Hg). D
O2I increased significantly from 326 to 417 ml/min/m2 concomitantly with significant increases in both arterial oxygen content (Ca
O2) and cardiac index (CI) (from 14.1 to 15.4 vol% and from 2.31 to 2.71 L/min/m2, respectively). The increase in S
VO2 during NO inhalation was significant (from 55.2 to 62.6%). Among the other hemodynamic parameters, both total pulmonary resistance and systolic pulmonary arterial pressure (SPAP) showed significant decreases during NO inhalation, but right atrial pressure did not change significantly. There was a close relationship between the baseline SPAP level (bSPAP) and the decrease in SPAP during NO inhalation (dSPAP) (r = −0.88). However, negative correlations were observed between bSPAP and percentage increase in CI (%CI) (r = −0.61) and between bSPAP and percentage increase in D
O2I (% D
O2I) (r = −0.48). Moreover, positive relationships were observed between dSPAP and %CI (r = 0.62) and between dSPAP and %D
O2I (r = 0.45). Hemoglobin (Hb) increased significantly from 11.0 to 11.4 g/dl. There were no significant changes in Fi
O2, pH, Pa
CO2, or base excess (BE) during NO inhalation. The level of methemoglobin measured during the study period remained within the normal range (0.86 ± 0.23%). In conclusion, NO inhalation could be an efficient and alternative assist for the circulation in patients whose oxygen delivery deteriorates after cardiovascular surgery.
Hemodynamic and Mechanical Performance of Arterial Grafts Assessed by Numerical Simulation: A Design Oriented Study
Authors: Cavalcanti Silvio , Tura Andrea
Published: March 2003

The hemodynamic and mechanical characteristics of an end‐to‐end implanted prosthesis for a small artery were theoretically investigated. The changes in the main physical and geometrical properties of the prosthesis were simulated by means of a numerical model of arterial hemodynamics. Variation in the pressure‐radius curve due to changes in lumen size, wall thickness, elasticity, and tapering were considered. The effects of such changes on pressure, flow, and wall stresses during the cardiac cycle were evaluated. To avoid superimposing the effects, only 1 of the graft properties was varied with respect to a reference condition in each simulation. A prosthesis with a reduced lumen size (20%) was subjected to higher shear stress, which was dangerously doubled. Wall thickening (200%) primarily determined decreased circumferential stress (300%) and increased wall shear stress (48%) because it caused a reduction of the graft lumen size. The time averages of flow and pressure over the cardiac cycle were not significantly influenced by the simulated changes, being imposed primarily by the proximal and distal circulations.
Thrombogenicity of Deflated Intraaortic Balloon: Impact of Heparin Coating
Authors: Mueller Xavier M. , Tevaearai Hendrick T. , Hayoz Daniel , Von Segesser Ludwig K.
Published: March 2003

In a calf model, 3 standard and 3 heparin coated intraaortic balloons (IAB) were inserted and left deflated in the descending aorta during 20 min to simulate balloon rupture. At the end of the experiment, the IAB were examined, and 3 samples of each were collected for scanning electron microscopy (SEM) analysis. None of the heparin coated IAB showed any sign of clot or deposit whereas all 3 standard IAB exhibited clots. SEM revealed no deposit on the heparin coated samples while 8 of the 9 standard samples disclosed deposits (p < 0.001). Morphometrically, 16.1 ± 21.4% of the surfaces of the standard samples were covered with deposits whereas all the heparin coated samples were free (p = 0.004). The presence of clots on every standard IAB supports the hypothesis that other than local factors of the insertion site can play a role in the vascular complications of IAB. The absence of clots and deposits on the heparin coated IAB suggests a promising role of such devices in circumventing the tendency of clot formation on deflated balloons while avoiding the drawback of systemic anticoagulation.
The Effect of Sintered β‐Dicalcium Pyrophosphate Particle Size on Newborn Wistar Rat Osteoblasts
Authors: Sun Jui‐Sheng , Tsuang Yang‐Hwei , Liao Chun‐Jen , Liu Hwa‐Chang , Hang Yi‐Shiong , Lin Feng‐Huei
Published: March 2003

During recent years, sintered dicalcium phosphate (SDCP) has been shown to be an effective artificial bone filler for repairing bone defects. The goal of this study was to elucidate the effect of SDCP particle size on osteoblasts. Osteoblasts were mixed and cultured with various sized SDCP particles (0.5–3.0, 37–63, 177–250, and 420–841 μm) for 1 h, 3 h, 1 day, 3 days, and 7 days and then analyzed. The results show that the adding of smaller sized SDCP particles (0.5–3.0 and 37–63 μm) into osteoblast culture can significantly affect the cell counts of osteoblasts. The secretion of transforming growth factor‐β1, alkaline phosphatase, and prostaglandin E2in culture medium increased significantly. The changes were most significant and persisted longer in smaller particle groups. Small sintered dicalcium phosphate particles can inhibit the proliferation of the osteoblasts. The inhibitory effects of the smaller sized SDCP particles on the osteoblasts were mediated by the promotion of osteoblast differentiation and the increased synthesis of prostaglandin E2.
Multifunctional Implantable Nerve Stimulator for Cardiac Assistance by Skeletal Muscle
Authors: Lanmüller Hermann , Sauermann Stefan , Unger Ewald , Schnetz Guntram , Mayr Winfried , Bijak Manfred , Girsch Werner
Published: March 2003

Different methods are used, clinically and experimentally, to assist severely impaired heart function by means of skeletal muscle. The efficiency of these methods is restricted by skeletal muscle losing strength after transpositioning and during conditioning and not being sufficiently resistant to fatigue. This is mainly due to the nonphysiological activation of the nerves by electrical stimulation. We have developed a battery operated, ECG triggered multichannel implant that is capable of implementing various advanced stimulation techniques. The stimulator can activate 2 skeletal muscles via the motor nerves. It allows for application of multichannel stimulation methods, i.e., carousel stimulation and sequential stimulation, as well as the programming of optimized pulse trains. Synchronization delay and burst duration can be automatically and dynamically adapted to the heart rate. The multichannel stimulator is hermetically sealed in a titanium case. Its calculated life span on the basis of the integrated battery is 3–5 years, depending on the programmed stimulation parameters. The implant dimensions are 65 × 17 mm (diameter × height), and it weighs 93 g. The implant has been tested in vitro as well as in vivo.
New Easy to Install Nerve Cuff Electrode Using Shape Memory Alloy Armature
Authors: Crampon Marie‐Agathe , Sawan Mohamad , Brailovski Vladimir , Trochu François
Published: March 2003

This paper presents an easy to install nerve cuff electrode dedicated to functional electrical stimulation (FES). In this new device, a shape memory alloy (SMA) armature is used to perform the closing of the electrode. This technique makes the electrode installation around the nerve much easier, quicker, and safer. Both remarkable mechanical properties of SMA materials, namely, shape memory effect and superelasticity, can be used to obtain the desired mode of electrode closing. The fabrication procedure of the new electrode is described. It does not require any expensive or complex techniques. Bipolar and tripolar electrodes have been manufactured with an inner diameter of 1.6 mm and a cuff wall thickness of 0.8 mm. These electrodes are to be used for FES of the bladder in spinal cord injured patients. Acute studies in dogs are being carried out to validate the device and the implantation procedure.
Analysis of Optimal Design Configurations for a Multiple Disk Centrifugal Blood Pump
Authors: Miller Gerald E. , Fink Rainer
Published: March 2003

A multiple disk centrifugal pump was analyzed as a blood pump for use in cardiac assistance or as a bridge to transplant device. The original configuration consisted of 6 parallel disks with 0.016 inch spacing between disks. This pump suffered from a degradation of flow with increasing afterload. A study was conducted to analyze flow performance as a function of afterload, preload, and motor speed. Configurations were examined including 4, 5, and 6 disks each with spacings of 0.15, 0.20, and 0.25 inches. Flow rates were examined for variations in afterload from 60–130 mm Hg, in preload from 0–20 mm Hg and for motor speeds of 1,250, 1,500, and 1,750 rpm. Analyses of afterload effects were intended to determine those configurations that produced less flow degradation with increasing afterload. Analyses of motor speed effects were intended to determine any configurations that produced greater flow increases with increasing motor speed. A hemolysis study was also performed. Both plasma free hemoglobin and the index of hemolysis were compared to data reported for other centrifugal blood flow devices. Results indicated that a 5 disk configuration with a 0.15 inch spacing produced optimal flow results with minimal degradation at higher afterloads. No optimal configuration based upon motor speed was indicated. Preload effects on pump performance were minimal. Hemolysis results indicated minimal blood damage with levels below those of many other centrifugal blood pump designs.
Feasibility of a Tiny Gyro Centrifugal Pump as an Implantable Ventricular Assist Device
Authors: Yoshikawa Masaharu , Nakata Kin‐ichi , Ohtsuka Goro , Takano Tamaki , Glueck Julia , Fujisawa Akira , Makinouchi Kenzo , Yokokawa Michihiro , Nosé Yukihiko
Published: March 2003

The Gyro pumps were developed for long‐term circulatory support. The first generation Gyro pump (C1E3) achieved 1 month paracorporeal circulatory support in chronic animal experiments; the second generation (PI702) implantable ventricular assist device (VAD) was successful for over 6 months. The objective of the next generation Gyro pump is for use as a long‐term totally implantable VAD and for pediatric circulatory support. This tiny Gyro pump (KP101) was fabricated with the same design concept as the other Gyro pumps. The possibility of an implantable VAD was determined after performance and hemolysis test results were compared to those of the other Gyro pumps. The pump housing and impeller were fabricated from polycarbonate with an impeller diameter of 35 mm. The diameter and height of the pump housings are 52.3 mm and 29.9 mm, respectively. At this time, a DC brushless motor drives the KP101, which is the same as that for the C1E3. The pump performance was measured in 37% glycerin water at 37°C. Hemolysis tests were performed utilizing a compact mock loop filled with fresh bovine blood in a left ventricular assist device (LVAD) condition at 37°C. The KP101 achieved the LVAD conditions of 5 L/min and 100 mm Hg at 2,900 rpm; generated 10 L/min against 100 mm Hg at 3,200 rpm; 3 L/min against 90 mm Hg at 2,600 rpm; and 2 L/min against 80 mm Hg at 2,400 rpm. In addition, the pump efficiency during this experiment was 12.5%. The other Gyro pumps, that is, the C1E3, PI601, and PI701, in an LVAD condition require 1,600, 2,000, and 2,000 rpm, respectively. The KP101 produced a normalized index of hemolysis (NIH) value of 0.005 g/100 L. With regard to the NIH, the other Gyro pumps, namely the C1E3, PI601, and PI701 demonstrated 0.0007, 0.0028, and 0.004 g/100 L, respectively. The KP101 produced an acceptable pressure flow curve for a VAD. The NIH value was higher than that of other Gyro pumps, but is in an acceptable range.
Termination of Extracorporeal Membrane Oxygenation for Cardiac Support
Authors: Steinhorn David M.
Published: March 2003

Abstract: The determination of when to stop extracorporeal membrane oxygenation (ECMO) rests upon demonstration of the return of adequate cardiac function to support vital organs and permit subsequent recovery. In general, patients with myocardial stun will recover function within several days. Factors that limit recovery include elevated end diastolic pressures leading to marginal myocardial perfusion, ongoing organ damage, massive anasarca, or progressive deterioration in lung function. Following a trial of slow weaning of ECMO support to condition the heart to take over the entire system flow requirements, decannulation can be accomplished in a standard fashion. When weaning is not successful and additional time does not lead to adequate recovery of cardiac function, physicians and nurses must be prepare to realistically advise families regarding such options as cardiac transplantation or withdrawal of support. It is critically important to provide an open and nonjudgmental environment for families to make these difficult decisions. The greatest difficulties involve ethical and emotional decisions that need to be made in a timely fashion to prevent undo burden on the patient when further ECMO support is futile.
Surgical Aspects of Pediatric Cardiac Extracorporeal Membrane Oxygenation
Authors: Wollenek Gregor , Czerny Martin , Golej Johann
Published: March 2003

Abstract: Because children with severe myocardial dysfunction have limited therapeutic options, mechanical support of a failing heart is a matter of great interest. In the setting of cardiogenic shock or severe low cardiac output and hypoperfusion, extracorporeal membrane oxygenation (ECMO) can produce decisive improvements. The criteria for successful treatment include appropriate patient selection, improved surgical techniques and experience, higher recognition and anticipation of complications, and minimized delay in initiation of ECMO. Because the need for mechanical circulatory support may arise pre‐, intra‐, and postoperatively, every pediatric cardiac surgeon must be familiar with the principles and the surgical aspects of ECMO.
The Pumping Oxygenator: Design Criteria and First In Vitro Results
Authors: Fiore Gianfranco Beniamino , Costantino Maria Laura , Fumero Roberto , Montevecchi Franco Maria
Published: March 2003

Abstract: A new project is presented, the pumping oxygenator, functionally integrating pulsatile pumping and blood oxygenation in a single device. Solid, semipermeable silicone membranes allow gas exchange and simultaneously transfer energy from pressurized gas to blood thanks to their distensibility and to inlet and outlet 1‐way valves. Two small‐sized (1 m2 exchange surface area) prototypes were designed, constructed, hydraulically characterized, and subjected to gas transfer evaluation tests. Blood flow rates (Qb) up to 1,250 ml/min were obtained with 30 mm Hg static preload and 130 mm Hg afterload with 0.7 m upstream and 2.1 m downstream 3/8 inch pipes. Physiological oxygen transfer (V
o2 = 5 ml/dl, ml of transferred O2/dl of treated blood) was delivered at Qb < 900 ml/min, about 4 ml/dl at Qb = 1,250 ml/min. V
o2 also was significantly increased by increasing percent systolic time. CO2 transfer decreased regularly with increasing Qb from V
co2 = 4.8 ml/dl at Qb = 400 ml/min to V
co2 = 2.1 ml/dl at Qb = 1,250 ml/min. The results confirm the possibility of integrating oxygenation and pulsatile pumping. The pumping oxygenator represents a promising project deserving further improvements.
Effect of Hemodialysis on Plasma Nitric Oxide Levels
Authors: Hon Wei‐Min , Lee Jon‐Choon , Lee Kang‐Hoe
Published: March 2003

Abstract: Nitric oxide (NO) is produced in excess in various pathological states, including sepsis and hepatic cirrhosis, and appears to be related to inflammatory status. In uremia, one would expect the levels of NO to increase. We aimed to determine whether hemodialysis (HD) would remove NO from the systemic circulation of uremic patients. Blood was collected before, after, and 1 day after HD from 12 uremic patients. Plasma nitrite and nitrate (NOx−) levels were measured by colorimetric Greiss reaction and cGMP was measured by an enzyme immunoassay kit. Our study demonstrated that uremic patients have high plasma NO levels, and HD led to a significant drop in plasma NOx− level (63 ± 15% reduction). The level rose back to the pre‐HD level on the following day. Plasma cGMP in the patients also decreased significantly after HD (27 ± 14% reduction). In conclusion, we hypothesized that HD might be a possible approach for the removal of excess NO in pathological conditions such as sepsis and hepatic cirrhosis.
Continuous Renal Replacement Therapy and Charcoal Plasmaperfusion in Treatment of Amanita Mushroom Poisoning
Authors: Splendiani Giorgio , Zazzaro Dario , Di Pietrantonio Pietro , Delfino Leone
Published: March 2003

Abstract: Hemoperfusion has been used in the treatment of mushroom poisoning for many years. The aim of this study was to study the efficacy of charcoal plasmaperfusion (CPP) and continuous renal replacement therapy (CRRT) in 2 patients severely poisoned by the amanita mushroom. Both patients arrived at the ICU from another hospital with a diagnosis of amanita phalloides mushroom poisoning. The patients were precociously treated with CRRT for 20 h and CPP for 3 h every day. The treatments were effected for 3 and 5 days, respectively. Both patients recovered completely and were discharged asyntomatic after 7 and 10 days.
Control Strategy for Biventricular Assistance with Mixed‐Flow Pumps
Authors: Endo George , Araki Kenji , Oshikawa Mitsuo , Kojima Kazushi , Saitoh Tomokazu , Nakamura Kunihide , Onitsuka Toshio
Published: March 2003

Abstract: A left ventricular assist device (LVAD) is an effective method to rescue severe heart failure. Although some require a biventricular assist, the control method for the biventricular assist device (BVAD) with a rotary pump is rarely shown. The objective of this study was to investigate the strategy for controlling BVAD with rotary pumps by in vivo studies. Using 5 piglets, we set a BVAD through a left thoracotomy and made global ischemia for 30 min by clamping the base of the ascending aorta. After unclamping, the analysis of pumping performance acted for 6 h reperfusion. We set the target flow of the LVAD and set the right ventricular assist device (RVAD) speed limit as less than when the atrial collapse occurs. To detect the ventricular collapse without any specific sensor, we calculated the index of current amplitude from motor current waveform and simultaneous mean current value. In all cases, over 6 h of observation was performed, and the RVAD was weaned almost automatically.
Low Power Laser Protects Human Erythrocytes In an In Vitro Model of Artificial Heart‐Lung Machines
Authors: Itoh Takashi , Murakami Hironobu , Orihashi Kazumasa , Sueda Taijiro , Kusumoto Yoshisuke , Kakehashi Masayuki , Matsuura Yuichiro
Published: March 2003

Abstract: The protective effect of the low power helium‐neon (He‐Ne) laser against the damage of human erythrocytes in whole blood was examined in a perfusion model using an artificial heart‐lung machine. Preserved human whole blood was diluted and perfused in 2 closed circuits with a double roller pump. The laser irradiated one of the circuits (laser group), and none the other (control group). In the laser group, erythrocyte deformability and erythrocyte adenosine triphosphate (ATP) levels were significantly higher, and free hemoglobin levels were significantly lower than those in the control group. Subsequent morphological findings by means of scanning electron microscope were consistent with these results. Low power He‐Ne laser protected human erythrocytes in the preserved diluted whole blood from the damage caused by experimental artificial heart‐lung machines. The clinical application of low power laser treatment for extracorporeal circulation is suggested.
Improvement of Metabolic Performance of Cultured Hepatocytes by High Oxygen Tension in the Atmosphere
Authors: Yanagi Kennichi , Ohshima Norio
Published: March 2003

Abstract: Maintaining metabolic functions of cultured hepatocytes at higher levels is an essential requirement for the development of a bioartificial liver. We investigated the effect of oxygen tension (10–40%) of the medium on immobilization efficiency and metabolic functions of cultured hepatocytes obtained from a rat for up to 4 days. Immobilization efficiencies of cultures in 10% oxygen showed a significantly lower value from those for the other conditions. The ammonium metabolic rate and the albumin secretion rate were significantly improved with an increase of dissolved oxygen tension for up to 2 days. These values remained similar in the later stage of the culture. The urea secretion rate showed similar values in all conditions. In conclusion, higher oxygen tension improved immobilization efficiency and metabolic functions of cultured rat hepatocytes in the earlier stage of culture for up to 2 days.
Systemic Effects of Hyperthermic Isolated Lower Limb Perfusion with Carboplatin and Interferon‐β
Authors: Tominaga Ryuji , Nakano Toshihide , Shibata Satoko , Siraishi Kimihiro , Nagae Shounosuke , Nakayama Juichirou , Yasui Hisataka
Published: March 2003

Abstract: The changes in systemic circulation during hyperthermic isolated lower limb perfusion with carboplatin and interferon‐β were investigated in 19 patients with malignant melanoma. The cardiac output (CO) increased significantly (p < 0.01) from 3.81 ± 0.22 L/min before the procedure to 5.30 ± 0.49 L/min 1 h after hyperthermic perfusion. The double product (mean arterial pressure × heart rate) also increased significantly (p < 0.01) from 5,145 ± 372 mm Hg/min to 6,760 ± 486 mm Hg/min. In some patients, it increased to more than twice the control value. These changes were accompanied by an increase in body temperature, presumably caused by the systemic leakage of both warmed blood and interferon‐β. Blood chemistry data demonstrated no significant changes in the liver or renal function. However, the serum CPK level increased markedly on the first postoperative day, and persisted for 1 week, thus suggesting that some muscle damage occurred during the procedure. There was no operative death or severe complications. From these data, we concluded that hyperthermic isolated limb perfusion with interferon‐β is a relatively safe therapeutic method for malignant melanoma of the extremities. However, care should be taken in patients with ischemic heart disease who may suffer a heart attack due to the rapid increase in cardiac work during the procedure.
Artificial Organs and Vanishing Boundaries
Authors: Malchesky Paul S.
Published: March 2003

Abstract: With the first clinical use of the artificial kidney over 5 decades ago, we entered into a new era of medicine—that of substitutive and replacement therapy. Yet it took nearly another 15 years until chronic treatment was possible and nearly another 15 years until widespread treatment was possible due to government support. The history of development and clinical use of other artificial organ technologies such as the artificial heart and heart valves, the artificial lung, artificial blood, joint replacements, the artificial liver, the artificial pancreas, immunologic, metabolic, and neurologic support, neurocontrol, and tissue substitutes have followed similar long development paths. Despite their relatively long time to be put into clinical use, the contributions of artificial organ technologies to the betterment of mankind have been unquestionably a major success. For example, modern day surgery would not be possible without heart‐lung support, and the technologies for heart support have led to the development of various minimally invasive technologies. The powerful impact that artificial organ technologies presently has on our lives is seen through the statistic that in the U.S.A. nearly 1 in 10 persons is living with an implanted medical device. With the aging of our population and the improvements in technologies, these numbers will only increase.
Tissue‐Engineered Product: Allogeneic Cultured Dermal Substitute Composed of Spongy Collagen with Fibroblasts
Authors: Kuroyanagi Yoshimitsu , Yamada Naoto , Yamashita Rie , Uchinuma Eiju
Published: March 2003

Abstract: Recently, various types of allogeneic skin substitutes including cultured epidermal substitute (CES), cultured dermal substitute (CDS), and cultured skin substitute (CSS), which are composed of keratinocytes and/or fibroblasts as the cellular component(s), have been used as biological wound dressings. In our study, the allogeneic CDS was prepared by plating fibroblasts on a spongy collagen. The clinical evaluation was conducted using fresh or cryopreserved allogeneic CDS. In 145 of our clinical cases, 95% (138/145) of various wounds were evaluated as achieving good or excellent results, including 96% (22/23) of deep dermal burns (DDB) and dermal burns (DB), 100% (53/53) of partial‐thickness donor wounds, 91% (21/23) of traumatic skin defects, 100% (5/5) of pressure ulcers, 82% (9/11) of chronic skin ulcers, 100% (6/6) of coverage for debrided DB, and 92% (22/24) of coverage for autologous meshed graft. The results obtained in our study suggest that the allogeneic CDS is able to provide an effective therapy for patients with partial and/or full‐thickness skin defects.
Heparin‐Coated Extracorporeal Circulation with Full and Low Dose Heparinization: Comparison of Thrombin Related Coagulatory Effects
Authors: Mirow Nikolas , Brinkmann Thomas , Minami Kazutomo , Tenderich Gero , Kleesiek Knut , Körfer Reiner
Published: March 2003

Abstract: Thrombin related coagulatory effects of a heparin‐coated cardiopulmonary bypass system combined with full and low dose systemic heparinization were investigated in a prospective, randomized study in coronary bypass surgery patients. One hundred nineteen patients were divided into 3 groups. Group A (n = 39) had a standard uncoated extracorporeal circulation (ECC) set, and systemic heparin was administered in an initial dose of 400 IU/kg body weight. During ECC activated clotting time (ACT) was maintained at ≥480 s. Group B (n = 42) had the same ECC set completely coated with low molecular weight heparin. Intravenous heparin was given in the same dose as in Group A, and ACT was kept at the same level. Group C (n = 38) had the same coated ECC set as Group B, but intravenous heparin was reduced to 150 IU/kg, and during ECC, ACT was set to be ≥240 s. The same ECC components were used in all 3 groups including roller pumps, coronary suction, and an open cardiotomy reservoir. Thrombin generation as indicated by F1/F2 was significantly elevated at an ECC duration >60 min if heparin‐coated ECC combined with low dose systemic heparinization was employed. Complexed thrombin (TAT) was significantly elevated after administration of protamine. Release of D‐dimers indicating fibrinolysis was not significantly different between groups. Signs of clinical thromboembolism, i.e., postoperative neurological deficit, occurred in 2 patients in Group A and 1 patient in Group C. We conclude that heparin‐coated extracorporeal circulation combined with reduced systemic heparinization intraoperatively leads to significantly increased thrombin generation, but not to increased fibrinolysis.
Effects of Ultrafiltration, Dialysis, and Temperature on Gas Exchange During Hemodiafiltration: A Laboratory Experiment
Authors: Ruzicka Jiri , Novak Ivan , Rokyta Richard , Matejovic Martin , Hadravsky Milan , Nalos Marek , Sramek Vladimir
Published: March 2003

Abstract: To study gas exchange in the filter during continuous venovenous hemodiafiltration (CVVHDF), an air‐tight heated mixing chamber with adjustable CO2 supply was constructed and connected to a CVVHDF monitor. Bicarbonate‐free crystalloid (Part 1) and packed red blood cell (Part 2) solutions were circulated at 150 ml · min−1. Gas exchange expressed as pre‐postfilter difference in CO2 and O2 contents was measured at different CVVHDF settings and temperatures of circulating and dialysis solutions. Ultrafiltration was most efficacious for CO2 removal (at 1,000 ml · h−1 ultrafiltration CO2 losses reached 13% of prefilter CO2 content). Addition of dialysis (1,000 ml · h−1) increased CO2 loss to 17% and at maximal parameters (filtration 3,000 ml · h−1, dialysis 2,500 ml · h−1), the loss of CO2 amounted to 35% of prefilter content. Temperature changes of circulating and/or dialysis fluids had no significant impact on CO2 losses. The O2 exchange during CVVHDF was negligible. Currently used CVVHDF is only marginally effective in CO2 removal. Higher volume ultrafiltration combined with dialysis can be expected to reach clinical significance.
Neonatal and Pediatric Extracorporeal Membrane Oxygenation Using Nonocclusive Blood Pumps: The Vienna Experience
Authors: Trittenwein G. , Golej J. , Burda G. , Hermon M. , Marx M. , Wollenek G. , Pansi H. , Trittenwein H. , Pollak A.
Published: March 2003

Abstract: Neonatal and pediatric extracorporeal membrane oxygenation (ECMO) is carried out commonly using occlusive blood pumps. Centrifugal pumps provide simple and safe technology for transportation on ECMO. The assistence respiratoire extra corporelle (AREC) system enables single needle venovenous ECMO for infants. We report on our experience with neonatal and pediatric ECMO treatments using nonocclusive blood pumps. One‐hundred forty‐six ECMO treatments were performed for cardiac, neonatal, and pediatric indications in 54, 19, and 27% of cases. Centrifugal pumps were used in 99, and the AREC system in 42 cases. Hospital mortality was estimated retrospectively and influence of type of pump, type of ECMO belonging to indication group, and lactate at ECMO installation were estimated. Irreversible organ failure leading to ECMO termination was investigated within groups of indications. Survival (recent 50 ECMO treatments) was 80, 70, 43, and 30% after meconium aspiration syndrome, acute respiratory distress syndrome, cardiac surgery, and prolonged resuscitation. Lactate exceeding 100 mg/dl at ECMO installation predicted significantly worse outcome. Cerebral damage was the main reason for ECMO termination in all but persistent circulatory failure in the cardiac group. Myocardial recovery resulted in all except 2 cardiac cases. Nonocclusive blood pumps can be used safely in neonatal and pediatric ECMO. Early installation may improve outcome markedly. In cardiac cases results of surgery should be thouroughly investigated on the table before ECMO installation to prevent hopeless ECMO treatments.
Initial Management of Severe Hemorrhage with an Oxygen‐Carrying Hypertonic Saline Solution
Authors: De Figueiredo Luiz Francisco Poli , Cruz Ruy Jorge , Neto Antonio Capone , Yada‐Langui Margareth Maçae , E Silva Mauricio Rocha
Published: March 2003

Abstract: We tested the hypothesis that the combination of polymerized bovine hemoglobin (PBHg) with hypertonic saline may be beneficial for the initial management of hemorrhagic shock in 22 mongrel dogs (15 ± 1 kg) bled to a mean arterial pressure (MAP) of 40 mm Hg in 5 min and maintained at this level for 45 min (shed blood volume ∼50 ml/kg). Animals were treated with a 4 ml/kg bolus over 4 min of one of the following fluids: whole blood, 7.5% NaCl (HS), 13 g/dl of PBHg, or 7.5% NaCl combined with polymerized bovine hemoglobin (HS‐PBHg). No additional intervention was performed, and the animals were followed for 60 min after treatment. PBHg and HS‐PBHg produced a sustained, significant increase in MAP. Cardiac output was transiently increased only after HS and HS‐PBHg. A partial increase in superior mesenteric artery blood flow was observed, particularly after HS‐PBHg. We concluded that small volumes of PBHg alone restore MAP, but not blood flow. The combination of PBHg with hypertonic saline provides improvements in cardiac output and mesenteric blood flow, suggesting a potential benefit for the initial management of major blood loss.
Clinical Experience with Heart Valve Homografts in Brazil
Authors: Da Costa Francisco Diniz Affonso , Da Costa Marise Brenner Affonso , Da Costa Iseu Affonso , Poffo Robinson , Sardeto Evandro Antônio , Matte Everson
Published: March 2003

Abstract: The purpose of this paper is to describe the development and progress of the first heart valve homograft bank in Brazil as well as to report the 5‐year clinical results. The bank was started in 1995 and employs modern techniques of cryopreservation. Organ procurement increased from 11 hearts in 1995 to 138 hearts in 2000. In the beginning of the experience, only 2 hospitals were using these valves, but this increased to 18 centers in 2000. Clinical experience at the major center includes 117 cases of the Ross procedure, 62 aortic homograft implantations, and 18 cases of mitral homografts. Five‐year survival after the Ross procedure was 99.1%, and survival free from any kind of complication was 88.8%. No patients are on anticoagulants, and the incidence of thromboembolism was null. We conclude that auto‐ and homografts are probably the best alternative to aortic valve replacement for young patients in developing countries.
The Molecular Adsorbents Recycling System as a Liver Support System Based on Albumin Dialysis: A Summary of Preclinical Investigations, Prospective, Randomized, Controlled Clinical Trial, and Clinical Experience from 19 Centers
Authors: Stange Jan , Hassanein Tarek I. , Mehta Ravindra , Mitzner Steffen R. , Bartlett Robert H.
Published: March 2003

Abstract: Artificial liver support aims to prolong survival time of patients with liver failure by detoxification. Albumin as a molecular adsorbent in dialysis solution is capable of attracting even tightly albumin‐bound toxins from blood into the dialysate if a specific dialysis membrane is used and if the albumin's binding sites are on‐line‐purified by a sorbent/dialysis‐based recycling system (i.e., molecular adsorbents recycling system, or MARS). The MARS technology has been shown to remove water‐soluble and albumin‐bound toxins and to provide renal support in case of renal failure. Fourteen centers have reported that MARS treatment improved mental status of patients with liver failure and hepatic encephalopathy. In treating liver failure and cholestasis, MARS was associated with hemodynamic stabilization, improvement of hepatic and kidney function, and disappearance of pruritus. In hepatic failure and hepatorenal syndrome, a prospective, randomized, controlled trial of MARS treatment was able to prolong survival time significantly. MARS has been used in 26 patients with acute liver failure or primary graft dysfunction. Nineteen centers reporting on 103 patients have shown that MARS treatment is safe, easy to handle, feasible, and effective.
In Vitro Investigation of Opening Behavior and Hydrodynamics of Bileaflet Valves in the Mitral Position
Authors: Feng Zhonggang , Nakamura Takao , Fujimoto Tetsuo , Umezu Mitsuo
Published: March 2003

Abstract: The performance of four 25 mm bileaflet valves of different designs was evaluated in the mitral position of our own pulse simulator. With the aid of a high‐speed video camera, it was demonstrated that both the St. Jude Medical (SJM) valve (Hemodynamic Plus [HP] Series, St. Jude Medical, Inc., St. Paul, MN, U.S.A.) and the CM valve (CarboMedics, Inc., Austin, TX, U.S.A.) were able to open fully and that the CM valve fluttered much more vigorously at the fully open position than did the SJM HP valve. Conversely, neither the ATS valve (ATS Medical, Inc., Minneapolis, MN, U.S.A.) nor the On‐X valve (Medical Carbon Research Institute, Austin, TX, U.S.A.) exhibited movement to a fully open configuration. The overall average opening angles of the ATS and the On‐X, on 3, 4, and 5 L/min flow rate for a heart rate of 70 bpm and 5, 6, and 7 L/min for 100 bpm, were 74.8 degrees and 81.6 degrees, respectively, whereas their design opening angles were 85 degrees and 90 degrees. Pressure drops across the CM and the ATS were consistently higher than those of the On‐X and the SJM HP. Closing volumes for all the valves were below 8% for a heart rate of 70 bpm. This in vitro investigation yielded the following conclusions: The ATS and On‐X valves are not able to open fully in the mitral position, but this does not impair their normal function; both a larger orifice diameter and a large opening angle can decrease the pressure drop; in general, the On‐X valve achieves its design goals in this experiment (i.e., it produces a lower pressure drop and lower closing volume by virtue of its large orifice and high‐profile design); however, the hinge flow in the non‐fully open state should be investigated further.
Comparison of Coagulation Activity Tests In Vitro for Selected Biomaterials
Authors: Van Oeveren W. , Haan J. , Lagerman P. , Schoen P.
Published: March 2003

Abstract: Testing of coagulation induced by external communicating medical devices is an International Standardisation Organization (ISO) requirement for products exposed to human blood. Four categories of tests are indicated by ISO 10993/4: a clotting test (partial thromboplastin time; PTT), thrombin generation, fibrinogen deposition, or measurement of coagulation split products. We evaluated the specificity of these tests on various polymers and found only thrombin generation and fibrinogen binding sensitive and reproducible tests while thrombin generation correlated best with the classical PTT. The thrombin generation assay is therefore the method of choice for testing coagulation induced by biomaterials and medical devices.
RheoSorb: A Specific Adsorber for Fibrinogen Elimination in Clinical Situations with Impaired Rheology
Authors: Koll R.A. , Klinkmann J. , Richter W.O.
Published: March 2003

Abstract: A functional microcirculation is crucial for the normal function of an organism. In many physiophathological situations, impaired microcirculation may contribute to the development or progress of diseases. Microcirculation is closely interrelated with blood and especially plasma rheology. Thus, improvement of plasma viscosity has beneficial effects on rheology, microcirculation, and the related tissue microenvironment. However, at best tools that only have a minor influence on plasma viscosity exist so far. Fibrinogen is known to be the major contributor to plasma viscosity, making it an interesting target for therapeutic intervention. An adsorber specific for fibrinogen was developed on the basis of the TheraSorb technology. The TheraSorb technology (PlasmaSelect AG, Teterow, Germany) allows the selective removal of components from human blood plasma by means of an affinity chromatography column. A ligand specific for a defined plasma component is coupled to a solid matrix (sepharose) thus binding and eliminating the target molecule from plasma. Using a fibrinogen specific pentapeptide as ligand, selective removal of fibrinogen, fibrin, and degradation products, containing the target sequence of these molecules, can be obtained. The LIFE‐18, a state‐of‐the‐art integrated plasma therapy instrument, is used to perform the treatment. The procedure improves plasma and whole blood viscosity in a dose dependent manner as shown in Phase 1 and 2 clinical trials. This article describes the first clinical experience in patients with diabetic foot syndrome and provides an outlook for further clinical and scientific investigations related to this promising new procedure.
Functional Electrical Stimulation‐Induced Surface Muscle Stiffness Captured by Computer‐Controlled Tonometry
Authors: Rafolt Dietmar , Gallasch Eugen , Fend Martin , Bijak Manfred , Lanmüller Hermann , Mayr Winfried
Published: March 2003

Abstract: A new tonometric test system to assess surface stiffness over relaxed and activated calf muscles was developed. The mechanical arrangement consists of a skin indentor driven by a torque motor (galvo‐drive) that is rigidly connected to an ankle dynamometer. The indentation depth is measured by a displacement transducer. Software routines for cyclic indentation (recording of stiffness curves), static indentation (sensing of twitch responses), and vibration (skin resonance) were implemented. A visual interface is used to capture surface stiffness during target contractions and during controlled relaxation. For functional electrical stimulation (FES) applications, the software includes a pulse train synthesizer to generate arbitrary stimulation test patterns. The system's performance was tested in FES and voluntary contraction procedures.