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Hall A C - - 1999
Articular cartilages are exposed to significant loads in vivo, which by their effects on chondrocyte metabolism can alter the mechanical properties of the extracellular matrix. The mechanism(s) by which chondrocytes sense and respond to load are not well understood. One component of load, hydrostatic pressure, can be studied independently of ...
Undar A - - 1999
An alternate physiologic pulsatile pump (PPP) system was designed and evaluated to produce sufficient pulsatility during neonate-infant open heart surgery. This hydraulically driven pump system has a unique "dual" pumping chamber mechanism. The first chamber is placed between the venous reservoir and oxygenator and the second chamber between the oxygenator ...
Urzua J - - 1999
A simplified model for the arterial pressure control system was implemented on a personal computer using Matlab Simulink. Model responses to variations of systemic vascular resistance were comparable to those predicted by physiology. Computer simulation suggested that including this model of the internal pressure control system within the design of ...
Kawaguchi O - - 1999
PURPOSE: We analyzed the mechanism of effects of intra-aortic balloon pumping using the pressure-volume relationship and ventriculoarterial coupling in the normal and failing hearts. MATERIALS: In 12 anesthetized Holstein calves (weight, 94 +/- 8 kg), the ventricular end-systolic and arterial elastances, pressure-volume area, and external work were analyzed during steady-state ...
Tucker E A - - 1998
OBJECTIVE: To determine the acceptability and reproducibility of a novel method of measuring calf muscle pump efficiency (CMPE). If confirmed, to examine if the results had implications for the use of elastic compression stockings. EXPERIMENTAL DESIGN: A system devised to measure pressure/volume relationships in the calf during simulated ambulation and ...
Henderson D R - - 1998
We tested the hypothesis that CO2 and heat have different effects on the ventilatory pattern of grasshoppers Melanoplus differentialis. Eight grasshoppers were sealed between rostral (inspiratory) and caudal (expiratory) spiracles in separated, airtight, chambers and pressure changes were measured. Normal breathing patterns decreased pressure in the rostral chamber and increased ...
Twardowski Z J - - 1998
Blood flows and recirculations with standard and reversed direction of lines were measured by chemical (urea and creatinine) and ultrasound dilution (saline) methods in 47 chronic hemodialysis patients. Thirty-seven patients had 47 dual-lumen, central vein (CV) catheters: 32 were PermCath (Quinton Instruments Company, Seattle, WA), 6 were Access Cath (MEDCOMP, ...
Westrich G H - - 1998
We performed a crossover study to evaluate the haemodynamic effect of active dorsal to plantar flexion and seven pneumatic compression devices in ten patients who had a total knee arthroplasty. Using the Acuson 128XP/10 duplex ultrasound unit with a 5MHz linear array probe, we assessed the augmentation of peak venous ...
Brainerd E L - - 1998
The larval stage of the tiger salamander Ambystoma tigrinum is entirely aquatic, but the larvae rely on their lungs for a large proportion of their oxygen uptake. X-ray video and pressure measurements from the buccal and body cavities demonstrate that the larvae inspire using a two-stroke buccal pump and exhale ...
Polaschegg H D - - 1998
A novel method for detection of access failure has been developed. It is based on the continuous evaluation of pre-pump arterial and venous pressure in the extracorporeal circuit. Knowing the flow resistance properties of the arterial and venous branches of the extracorporeal circuit from in-vitro measurements and the height differences, ...
Miyawaki F - - 1998
The split-circulation assist device (SCAD) comprises an intra-aortic balloon pump (IABP), percutaneous cardiopulmonary support (PCPS) equipment, and two occlusion balloons that occlude the descending thoracic aorta by alternate inflation. With the SCAD, the failing heart, assisted by IABP, maintains only the upper 25-30% of the entire circulation without any interference ...
Vermette P - - 1998
The design of a nonpulsatile and pulsatile system using a centrifugal pump is presented. To induce a pulsatile flow with a centrifugal pump, an independent pneumatically driven unit provided flow patterns over a wide range of frequencies and amplitudes. The pulsatile flow was generated by the axial displacement of a ...
Araki K - - 1998
We investigated the basic characteristics of the pulsatility of motor current with an in vitro mock circuit that consists of a sac-type pulsatile pump (simulating the natural left ventricle), three reservoirs, and our mixed flow pump (MFP). There are three alternatives at the inlet of the MFP: 1) the left ...
Oshikawa M - - 1998
Our novel control strategy for a continuous flow artificial heart by detecting the total assist and sucking points based on pump pulsatility was evaluated in acute animal experiments using beagle dogs and our mixed flow pump. The pump was installed as a left ventricular (LV) bypass through a left thoracotomy. ...
Ohtsuka G - - 1998
A totally implantable centrifugal artificial heart has been developed. The plastic prototype, Gyro PI 601, passed 2 day hemodynamic tests as a functional total artificial heart, 2 week screening tests for antithrombogenicity, and 1 month system feasibility. Based on these results, a metallic prototype, Gyro PI 702, was subjected to ...
Konishi H - - 1998
Under extracorporeal membrane oxygenator (ECMO) support, it is difficult to predict recovery of cardiac function. The authors examined the rotary blood pump function curve and developed a new index of dynamic vascular impedance (DVI) for controlling the ECMO system. The cases of nine patients assisted by ECMO after cardiac surgery ...
Eremets MI - - 1998
Direct electrical transport measurements in a diamond anvil cell provide evidence for the metallization of cesium iodide (CsI) at a pressure of 115 gigapascals. A drop in the temperature dependence of the resistance was found at pressures above 180 gigapascals, indicating that the CsI was superconductive. The superconductivity changed under ...
Schneider R - - 1998
A material crossreacting with antibodies against the bufadienolide proscillaridin A and inhibiting the sodium pump was found in human blood plasma. The concentration of the material with a retention time similar to ouabain in a reversed phase HPLC correlated to systolic blood pressure and pulse pressure. Affinity purification of this ...
Reiss N - - 1998
The main limitation in the use of circulatory support in children is the lack of an adequate system with regard to size and pumping capacity. Recently, two pneumatically driven ventricular support systems with low volume chambers for use in a pediatric population became available. We have developed a hydraulic drive ...
Boschert M T - - 1998
To facilitate tumescent liposuction, a pressure infusion technique is necessary. We have devised a new technique for anesthetic solution infusion-a pressure infusion bag along with an automatic low-pressure tourniquet pump-that can generate sustained and significant volume infusion. This system is readily available, requires a minimal capital outlay, and is economically ...
Lee-Sensiba K - - 1998
The purge line is a necessary component on arterial filters, although its presence may affect the amount of flow reaching the patient as well as the pump outlet pressure in the extracorporeal circuit. In-vitro and clinical studies conducted to investigate these effects with a commonly used purge line showed that ...
Meyns B - - 1998
The purpose of this study was to test the pump performance of a miniaturized, newly developed, implantable rotary blood pump (the diagonal pump). In a series of six sheep, the pump was interposed in an atrial-aortic connection. Heart failure was induced by serial injection of glass beads into the left ...
Bierer P - - 1998
Extracorporeal circuits can cause haemolysis resulting in an increase in plasma-free haemoglobin (PFHb). High pressures and clots within the circuit have been identified as factors increasing the likelihood of haemolysis. Continuous venovenous haemodiafiltration (CVVHD) is associated with high circuit pressures as the pump-driven circuit clots over a period of time. ...
Charitos C E - - 1998
OBJECTIVE: To investigate the possible mechanisms of right and left ventricular interaction during ventricular fibrillation (VF) with mechanical maintenance of the circulation. EXPERIMENTAL DESIGN: In this experimental study, two para-aortic counterpulsation devices (PACDs) were implanted in 14 mongrel dogs. SETTING: The PACD is a spheroid, valveless, with one opening, 100 ...
Walpoth B H - - 1998
A rapid and efficient circulatory support system may save a patient in cardiogenic shock. Left heart bypass with percutaneous and trans-septal placement of the aspiration cannula simplifies the circuit and eliminates the need for an oxygenator. In this pre-clinical study we assessed left heart bypass support with a centrifugal pump ...
Nakata K - - 1998
The rotary blood pump will be an implantable left ventricular assist device (LVAD) in the near future. However, the best control method and the interrelationship between the rotary blood pump and native heart functions are unclear. An estimation was made of the native heart cardiac output from the change of ...
Mitsui N - - 1998
The influence of the Wankel type semipulsatile left ventricular assistance on hemodynamics was investigated with a computer simulation and an animal experiment. A simulation circuit was constructed to express the circulatory system. A current source was added to create a semipulsatile blood pump. The left and right ventricles were replaced ...
Tagusari O - - 1998
We have been developing centrifugal pumps for an implantable left ventricular assist device. We manufactured 2 prototype centrifugal pumps (PI, PII). These two have similar designs except for the PII having a volute casing and a large output port. To determine the differences in the hydraulic characteristics between the PI ...
Petzold T - - 1998
This paper presents a new cardiac support device for left ventricular failure which consists of two inflatable bellows positioned dorsally and ventrally to the left ventricle. The implantable multichamber pump system (IMPS) is driven by a pneumatic pump system and controlled by a microcomputer using ECG-trigger and pacemaker modules. It ...
Ferrari P - - 1998
The inhibition of the long-term pressor effect of ouabain may be useful for the therapy of essential hypertension. Here, for the first time, a selective inhibitor of the ouabain pressor effect is described. In vitro, 17beta-(3-furyl)-5beta-androstane-3beta, 14beta, 17alpha-triol (PST 2238) displaced ouabain from its binding sites on purified sodium, potassium ...
del Cañizo J F - - 1998
A computer controlled perfusion system has been developed to study the behavior of perfused kidneys in several conditions. The system is designed to perform kidney perfusions at constant pressure and low temperature (about 4 degrees C). We compared 2 types of perfusion pumps, a classical roller pump widely used in ...
Janknecht P - - 1998
On a routine sterility check, the authors found bacteria in their vitrectomy machine. Serratia marcescens was detected in the pressure receiver of a roller pump vitrectomy machine. The authors improved the machine by installing a millipore filter in front of the receiver that prevents bacteria from entering it without interfering ...
Schneider R - - 1998
In the search for endogenous cardiac glycosides, two different inhibitors of the sodium pump have been isolated from bovine adrenals. Inhibitor A with a molecular mass of 600 Da and a UV maximum at 250 nm was purified from 16 kg of bovine adrenals. The pure substance (<1 ng) inhibited ...
Tayama E - - 1997
Due to the fact that centrifugal and axial pumps do not require valves, there is a possibility of back flow when the pump speed is low. To estimate the minimum required pump speed to prevent this regurgitation, an in vitro simulation test was conducted. A pulsatile pump simulated the natural ...
Lussi A - - 1997
It was demonstrated in vitro that it is possible to achieve obturation of the root canal system with a system utilizing a reduced pressure of 15 hPa (15 mbar). The purpose of this study was to develop a procedure to reach a vacuum of at least 15 hPa within root ...
Kawahito K - - 1997
Platelets are more vulnerable to damage than erythrocytes because platelets are easily activated by contact with extracorporeal circuits and by exposure to shear forces. However, the degree of platelet damage caused by centrifugal pumps is unclear. To evaluate platelet damage in different pumping conditions, the rates of increase for specific ...
Unverdorben M - - 1997
In percutaneous balloon angioplasty the extent of trauma to the vessel as determined by slope of balloon inflation, peak pressure, and inflation time is crucial to the success of the intervention. These parameters are still not standardized and hence open to the operator. To elucidate this problem, a computer-assisted PTCA ...
DeRose J J JJ - - 1997
Cardiopulmonary bypass (CPB) causes a well described systemic inflammatory response. To avoid these potential detrimental effects, coronary artery bypass grafting (CABG) has been attempted off CPB on the beating heart. With the use of a left ventricular (LV) assist device during CABG, the heart can be made flaccid with beta-blockade, ...
Besarab A - - 1997
Access flow (QACC) is a major determinant of patency. Access recirculation (AR > 2%), normalized venous intra-access pressure (vPIA/MAP), and QACC are used to detect access dysfunction. We compared these three measures of access function (ultrasound dilution to measure AR and QACC). A total of 779 measurements were performed on ...
Ampat G - - 1997
A prospective controlled trial was carried out to compare two different fluid delivery systems used for shoulder arthroscopy. One an advanced pump system that controls both pressure and flow of fluid delivered, the other an air-driven diaphragm pump that only controls fluid pressure. Blood loss, presence of bleeding vessels and ...
Farrar D J - - 1997
As patients with left ventricular (LVAD) and biventricular assist devices are supported for increasingly long durations while awaiting heart transplantation or cardiac recovery, there is a need to facilitate greater patient mobility and ambulation. To meet these needs, the authors have developed the Thoratec TLC-II Portable VAD Driver, which is ...
Kolla S - - 1997
A novel pressure gated tidal flow extracorporeal circulation (TF ECC) device was developed, and it was hypothesized that it could provide total respiratory support in apneic adult sheep without adverse hemodynamic or cardiac effects. The circuit consisted of a single lumen cannula, computer driven tubing occluders gated by circuit pressure, ...
Inzoli F - - 1997
An experimental analysis was carried out to evaluate the effects induced by two typical extracorporeal circuits on the pressure and flow generated by a roller pump with a pulsatile module. The hydraulic behaviour of the patient was simulated by means of a mechanical mock-up system consisting of a few lumped ...
Shenkman B S - - 1997
Atrophy of skeletal muscle is a response that is considered as the most consistent under conditions of real and simulated weightlessness. Microgravity is transformed in the motor system into a number of factors, the most important of them are considered axial unloading and support unloading. The effects of support stimulus ...
Chaus N I - - 1997
The electroimpedance indicators' dilution (EIID) technique was used to study the possibility of a simultaneous separate assessment of the biological heart and LVAD performance in the position of LVB. The experimental part of the research was performed on 5 dogs; an artificial ventricle of the pulsing type (USA) with cusps ...
Ohara Y - - 1997
The hemolytic effect of the secondary vane system, the antithrombogenic structure incorporated into the back side of the impeller of the C1E3 Gyro pump, was investigated. Impellers with 0, 2, 3, and 4 secondary vanes and an additional impeller with 2 secondary channels were fabricated and incorporated into the C1E3 ...
Sueshiro M - - 1997
Working toward a completely implantable total artificial heart, we have designed an eccentric roller type total artificial heart. The actuator of this artificial heart is a drum type eccentric roller that squeezes the blood chambers. The blood chambers are made of silicone rubber and are torus in shape. The shape ...
Nishida H - - 1997
The Terumo Capiox centrifugal pump system possesses an automatic priming function in which the motor repeatedly stops and runs intermittently to eliminate air bubbles in the circuit through the micropores of the hollow-fiber membrane oxygenator. By modifying this mechanism, we have developed a pulsatile flow mode. In this mode, maximum ...
Yamada T - - 1997
We have been developing a new type of centrifugal pump for long-term use. The magnetically suspended centrifugal pump (MSCP) contains no shaft and seal so that long life expectancy is predicted. Paracorporeal left ventricular (LV) assist circulation between the left atrium and the descending aorta was instituted using sheep. The ...
Qian K X - - 1997
A permanent impeller heart that could work for years was once an idea. However, now this idea is turning into reality through the use of the magnetically suspended motor. Recently, with our implantable pulsatile impeller pump, 3 left ventricular assisted calves survived for about 2 months (62, 54, and 46 ...
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