RESUMEN
Thrombectomy is a routine or common practice for treating organized portal vein thrombosis (PVT) during liver transplantation. However, this procedure is often performed in a blinded fashion and can result in insufficient thrombectomy or devastating consequences such as injury to the retropancreatic portal vein where prompt repair is very difficult. To overcome these drawbacks for blind thrombectomy, we herein describe a new technique that makes complex thrombectomy safe and easy under direct ultrasound vision. This procedure is readily available and highly reproducible and can be used as the standard procedure for treating extensive PVT.
Asunto(s)
Trasplante de Hígado/métodos , Vena Porta/diagnóstico por imagen , Trombectomía/métodos , Ultrasonografía Intervencional/métodos , Trombosis de la Vena/cirugía , Humanos , Donadores Vivos , Masculino , Persona de Mediana Edad , Vena Porta/patología , Vena Porta/cirugía , Trombectomía/instrumentaciónRESUMEN
A high-density convergent plasma sputtering device has been developed for a liquid metal target, using an unheated glass plate. The convergent magnetic field lines, which are produced by an external solenoid coil and a permanent magnet positioned behind the liquid metal target, effectively transport high-density plasmas near the target. In this study, a liquid gallium target was sputtered with nitrogen plasmas, without additive gas required for depositing gallium nitride films on the unheated substrates. The deposition rate of the GaN film was estimated at â¼13 nm/min at a gas pressure of 0.2 Pa. A strong diffraction peak was observed along the GaN (002) axis, with the use of an unheated glass plate and a target-substrate distance of â¼45 mm.
Asunto(s)
Enfermedad Veno-Oclusiva Hepática/diagnóstico por imagen , Enfermedad Veno-Oclusiva Hepática/cirugía , Trasplante de Hígado , Complicaciones del Embarazo/diagnóstico por imagen , Complicaciones del Embarazo/cirugía , Adulto , Femenino , Venas Hepáticas/diagnóstico por imagen , Venas Hepáticas/patología , Enfermedad Veno-Oclusiva Hepática/patología , Humanos , Embarazo , Complicaciones del Embarazo/patología , Tomografía Computarizada por Rayos X , Vena Cava Inferior , Adulto JovenRESUMEN
Transplant-associated thrombotic microangiopathy (TA-TMA) is a rare but severe complication after liver transplantation. In contrast to other thrombotic microangiopathies, treatment for TA-TMA has yet to be clarified. A 52-year-old male patient with liver cirrhosis due to hepatitis C underwent split liver transplantation from a deceased donor. His clinical course was without complication until 4 days after transplantation, when he experienced impaired consciousness, hemolytic anemia with fragmented erythrocytes, and marked thrombocytopenia. TA-TMA was diagnosed, and recombinant thrombomodulin was administered for 4 days. The patient's clinical symptoms and laboratory data rapidly improved. He has been followed up for 6 months and has not shown any complications. The pathogenesis of TA-TMA is endothelial damage in the vasculature. Recombinant thrombomodulin, an endothelial cell-protecting agent, is a promising new therapeutic choice for TA-TMA after liver transplantation.
Asunto(s)
Trasplante de Hígado/efectos adversos , Trombomodulina/uso terapéutico , Microangiopatías Trombóticas/tratamiento farmacológico , Microangiopatías Trombóticas/etiología , Hepatitis C/complicaciones , Humanos , Cirrosis Hepática/cirugía , Cirrosis Hepática/virología , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: Sarcopenia is an independent predictor of death after living-donor liver transplantation (LDLT). However, the ability of the Asian Working Group for Sarcopenia criteria for sarcopenia (defined as reduced skeletal muscle mass plus low muscle strength) to predict surgical outcomes in patients who have undergone LDLT has not been determined. METHODS: This study prospectively enrolled 366 patients who underwent LDLT at Kyushu University Hospital. Skeletal muscle area (determined by computed tomography), hand-grip strength, and gait speed were measured in 102 patients before LDLT. We investigated the relationship between sarcopenia and surgical outcomes after LDLT performed in three time periods. RESULTS: The number of patients with lower skeletal muscle area has increased to 52.9% in recent years. The incidence of sarcopenia according to the Asian Working Group for Sarcopenia criteria was 23.5% (24/102). Patients with sarcopenia (defined by skeletal muscle area and functional parameters) had significantly lower skeletal muscle area and weaker hand-grip strength than did those without sarcopenia. Compared with non-sarcopenic patients, patients with sarcopenia also had significantly worse liver function, greater estimated blood loss, greater incidence of postoperative complications of Clavien-Dindo grade IV or greater (including amount of ascites on postoperative day 14, total bilirubin on postoperative day 14, and postoperative sepsis), and longer postoperative hospital stay. Multiple logistic regression analysis revealed sarcopenia as a significant predictor of 6-month mortality. CONCLUSIONS: The combination of skeletal muscle mass and function can predict surgical outcomes in LDLT patients.
Asunto(s)
Fuerza de la Mano , Trasplante de Hígado/efectos adversos , Músculo Esquelético/fisiopatología , Complicaciones Posoperatorias/mortalidad , Sarcopenia/mortalidad , Velocidad al Caminar , Anciano , Femenino , Humanos , Incidencia , Trasplante de Hígado/métodos , Donadores Vivos , Masculino , Persona de Mediana Edad , Fuerza Muscular/fisiología , Complicaciones Posoperatorias/etiología , Periodo Posoperatorio , Estudios Prospectivos , Sarcopenia/etiología , Sarcopenia/fisiopatología , Tomografía Computarizada por Rayos XRESUMEN
Although Roux-en Y hepaticojejunostomy was previously recommended for the biliary reconstruction in liver transplantation for primary sclerosing cholangitis (PSC), some recent reports showed no difference in the graft survival between Roux-en Y and duct-to-duct anastomosis in deceased-donor liver transplantation. On the other hand, considering the risk of recurrence and the short length of the bile duct of the graft, duct-to-duct biliary anastomosis has never been reported in a patient undergoing living-donor liver transplantation (LDLT) for PSC. A 45 year-old male underwent LDLT using a left-lobe graft donated from his brother. Cholangiography showed no lesion in his common bile duct and duct-to-duct anastomosis was chosen for him. Fifteen months later, he suffered cholangitis due to PSC recurrence and endoscopic retrograde cholangiography was performed. The stents were inserted into his B2 and B3, and he remains well. Because of the ability to easily manage biliary complication, duct-to-duct biliary reconstruction may become the first choice in LDLT for PSC without common bile duct lesions.
Asunto(s)
Procedimientos Quirúrgicos del Sistema Biliar/métodos , Colangitis Esclerosante/cirugía , Trasplante de Hígado/métodos , Anastomosis Quirúrgica/métodos , Conductos Biliares/cirugía , Supervivencia de Injerto , Humanos , Donadores Vivos , Masculino , Persona de Mediana Edad , Recurrencia , Reoperación/métodos , StentsRESUMEN
Reconstruction of multiple venous orifices of a right lobe graft is a time-consuming and troublesome procedure in right lobe living-donor liver transplantation. In the current study, we present a new venous reconstruction technique for a right lobe graft with multiple and complex hepatic vein (HV) orifices, in which procurement of the recipient's left portal vein was performed in situ to keep the anhepatic period to a minimum. All of the HV orifices were reconstructed together at the back table, while maintaining patency of the recipient's systemic and splanchnic circulation. A homologous vein graft and veno-venous bypass were not necessary. All HVs were patent during the follow-up and the patient was free from complications. In conclusion, the present technique is readily available for reconstruction of complex and multiple HV tributaries, while avoiding a long anhepatic time and the use of veno-venous bypass.
Asunto(s)
Venas Hepáticas/cirugía , Cirrosis Hepática Alcohólica/cirugía , Trasplante de Hígado/métodos , Vena Porta/trasplante , Femenino , Humanos , Hígado/irrigación sanguínea , Donadores Vivos , Masculino , Persona de Mediana Edad , Procedimientos de Cirugía Plástica/métodos , Circulación Esplácnica , Esposos , Procedimientos Quirúrgicos Vasculares/métodosRESUMEN
A flat type, segmented multi-loop antenna was developed in the Tokai Helicon Device, built for producing high-density helicon plasma, with a diameter of 20 cm and an axial length of 100 cm. This antenna, composed of azimuthally splitting segments located on four different radial positions, i.e., r = 2.8, 4.8, 6.8, and 8.8 cm, can excite the azimuthal mode number m of 0, ±1, and ±2 by a proper choice of antenna feeder parts just on the rear side of the antenna. Power dependencies of the electron density ne were investigated with a radio frequency (rf) power less than 3 kW (excitation frequency ranged from 8 to 20 MHz) by the use of various types of antenna segments, and n(e) up to ~5 × 10(12) cm(-3) was obtained after the density jump from inductively coupled plasma to helicon discharges. Radial density profiles of m = 0 and ±1 modes with low and high rf powers were measured. For the cases of these modes after the density jump, the excited mode structures derived from the magnetic probe measurements were consistent with those expected from theory on helicon waves excited in the plasma.
RESUMEN
The standard therapy against hepatitis C virus (HCV) recurrence postliver transplantation includes interferon (IFN)α and ribavirin. IFNL4 ss469415590 polymorphism has been reported as a novel predictor of the response to IFN therapy for chronic HCV infection. We examined the impact of IFNL4 polymorphism on the responsiveness to IFN therapy after liver transplantation. Tissue specimens were collected from 80 HCV-infected recipients and 78 liver donors, and their IFNL4 ss469415590 genotype, hepatic IFNL4 and interferon-stimulated genes' mRNA expression levels were examined. The association of the polymorphism and expression levels in terms of the IFN therapy response to HCV recurrence was analysed. Most individuals who had rs8099917 risk alleles also had ss469415590 risk alleles (R(2) = 0.9). Sustained virological response (SVR) rates were higher in both liver graft recipients and transplants with ss469415590 TT/TT alleles than in those with the risk ΔG allele (P = 0.003 and P = 0.005, respectively). In recipients with ss469415590 TT/TT, IFNL4 TT mRNA levels showed no significant differences between livers of patients who responded to therapy and those who did not (P = 0.4). In recipients with the risk ΔG allele, IFNL4 ΔG mRNA expression levels were significantly lower in SVR patients than in non-SVR patients (P = 0.02). Hepatic interferon stimulable genes and IFNL4 mRNA expression were correlated. Our findings suggest that analysing the ss469415590 genotype and IFNL4 ΔG expression provides a novel prediction strategy for the possible response to IFN therapy after liver transplantation.
Asunto(s)
Antivirales/uso terapéutico , Hepatitis C/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Interleucinas/genética , Trasplante de Hígado , Polietilenglicoles/uso terapéutico , Polimorfismo Genético , Receptores de Trasplantes , Adulto , Anciano , Femenino , Perfilación de la Expresión Génica , Genotipo , Hepatitis C/genética , Humanos , Interferón alfa-2 , Donadores Vivos , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple , Proteínas Recombinantes/uso terapéutico , Recurrencia , Ribavirina/uso terapéutico , Resultado del Tratamiento , Adulto JovenRESUMEN
A method for characteristic impedance monitoring (CIM) is developed for anomaly detection during plasma processing. Advantages of the method include high-sensitivity and real-time monitoring, as well as structural simplicity to install the measurement system in the mass production equipment. To obtain real-time monitoring without time delay, our CIM system consists of a directional coupler and a newly developed vector processing system instead of the conventional high voltage and current probes. The system can measure the time variations of characteristic and load impedances even while the plasma is generated.
RESUMEN
BACKGROUND AND AIMS: This study was conducted to clarify the effects of age on human liver regeneration. PATIENTS AND METHODS: Thirty major hepatectomies, equal to or more than two segmentectomies for hepatocellular carcinoma, were performed. Ages ranged from 37 to 85 years and five octogenarians were included. The early regenerative index was defined: (liver volume after 7 days after hepatectomy - estimated remnant liver volume before hepatectomy)/estimated remnant liver volume, using three-dimensional computed tomographic volumetry. Farnesoid X receptor and forkhead box m1 expression in the liver, which has been reported to age-related decrease of liver regeneration in animal model, were examined using real-time polymerase chain reaction. The patients were divided into two groups: low early regenerative index (n = 15), early regenerative index less than 55% and high early regenerative index (n = 15), early regenerative index equal to or more than 55%. RESULTS: The mean early regenerative index was 57%. Age (R (2) = 0.274, P = 0.003) and estimated blood loss (R (2) = 0.134, P = 0.0466) were inversely correlated with the early regenerative index, and the expression of farnesoid X receptor and forkhead box m1 was not. The incidence of post-hepatectomy liver failure in the low early regenerative index group was higher than that in the high early regenerative index group (P = 0.0421). CONCLUSIONS: Age and intraoperative blood loss are inversely correlated with early liver regeneration in humans. In elderly patients, massive blood loss should be avoided in view of liver regeneration.
Asunto(s)
Carcinoma Hepatocelular/cirugía , Hepatectomía , Neoplasias Hepáticas/cirugía , Regeneración Hepática/fisiología , Adulto , Factores de Edad , Anciano , Biomarcadores/metabolismo , Femenino , Proteína Forkhead Box M1 , Factores de Transcripción Forkhead/metabolismo , Humanos , Hígado/metabolismo , Hígado/fisiología , Hígado/cirugía , Masculino , Persona de Mediana Edad , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores Citoplasmáticos y Nucleares/metabolismo , Estudios RetrospectivosRESUMEN
The Gyro centrifugal pump developed as a totally implantable artificial heart was designed with a free impeller, in which the rotational shaft (male bearing) of the impeller was completely separated from the female bearing. For this type of pump, it is very important to keep the proper magnet balance (impeller-magnet and actuator-magnet) in order to prevent thrombus formation and/or bearing wear. When the magnet balance is not proper, the impeller is jerked down into the bottom bearing. On the other hand, if magnet balance is proper, the impeller lifted off the bottom of the pump housing within a certain range of pumping conditions. In this study, this floating phenomenon was investigated in detail. The floating phenomenon was proved by observation of the impeller behavior using a transparent acrylic pump. The impeller floating phenomenon was mapped on a pump performance curve. The impeller floating phenomenon is affected by the magnet-magnet coupling distance and rotational speed of the impeller. In order to keep the proper magnet balance and to maintain the impeller floating phenomenon at the driving condition of right and left pump, the magnet-magnet coupling distance was altered by a spacer which was installed between the pump and actuator. It became clear that the same pump could handle different conditions (right and left ventricular assist), by just changing the thickness of the spacer. When magnet balance is proper, the floating impeller phenomenon occurs automatically in response to the impeller rev. It is called "the dynamic RPM suspension".
Asunto(s)
Diseño de Equipo , Corazón Auxiliar , Centrifugación/instrumentación , Hemólisis , Magnetismo/instrumentación , Trombosis/prevención & controlRESUMEN
OBJECTIVE: The purpose of this study was to compare the proton-density (PD)-weighted fast spin-echo (FSE) and fast-recovery FSE (FRFSE) sequences for the evaluation of the anatomical structures of the knee. METHOD: 24 healthy volunteers who underwent MRI by both sagittal PD-weighted FSE and FRFSE sequences were evaluated. The signal-to-noise ratio, contrast-to-noise ratio (CNR) and anatomical detail visualisation were compared for the two techniques. RESULTS: The mean CNRs and reader ratings for both readers were significantly higher for the PD-weighted FRFSE images than for the PD-weighted FSE images in the cartilages/the femorotibial joint effusion and the cruciate ligaments/the effusion around the cruciate ligaments; however, the mean CNRs and reader ratings for both readers were significantly higher for the PD-weighted FSE sequences than for the PD-weighted FRFSE sequences in the cartilages/the menisci and the cruciate ligaments. CONCLUSIONS: The main advantages of the PD-weighted FRFSE sequence are the increase in contrast between fluid and non-fluid tissues and the time saved by using the procedure. However, in the absence of joint effusion, the PD-weighted FRFSE sequence generates a poorer contrast between the cartilage and meniscus, the cruciate ligaments and fat of the intercondylar fossa.
Asunto(s)
Cartílago Articular/anatomía & histología , Articulación de la Rodilla/anatomía & histología , Rodilla/anatomía & histología , Imagen por Resonancia Magnética/métodos , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Protones , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
IL28B genetic polymorphism is related to interferon-sensitivity in chronic hepatitis C, but the significance of grafts carrying different genotypes from recipients is still unclear in liver transplantation. A 51-year-old Japanese male carrying a minor genotype underwent dual liver transplantation for liver cirrhosis due to hepatitis C virus (HCV). The left lobe graft carried a major genotype, and the right a minor genotype. He achieved virological response during the course of pegylated-interferon and ribavirin therapy against recurrent hepatitis C for 2 years, but HCV relapsed immediately at the end of the therapy. Two years after antiviral therapy, liver biopsy was performed from each graft. The specimens showed A1F0 in the left lobe graft and A2F2 in the right. Moreover, quantitative polymerase chain reaction was performed using RNA extracted from each specimen to see there was no HCV RNA in the left lobe whereas there was in the right. This case provides clear evidence that IL28B genetic variants determine interferon sensitivity in recurrent hepatitis C following liver transplantation, which could result in new strategies for donor selection or for posttransplant antiviral therapy to HCV positive recipients.
Asunto(s)
Variación Genética , Hepatitis C/genética , Interleucinas/genética , Trasplante de Hígado/efectos adversos , Secuencia de Bases , Cartilla de ADN , Humanos , Interferones , Masculino , Persona de Mediana Edad , Recurrencia , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
We performed endoscopic carpal tunnel release in four hands in three patients suffering from radial dysplasia due to thalidomide embryopathy. Carpal canal pressure measurements results confirmed the diagnoses. All operations were successfully performed and resulted in no complications. Tingling sensation and sensory disturbances of the hands subsided.
Asunto(s)
Síndrome del Túnel Carpiano/complicaciones , Deformidades Congénitas de la Mano/complicaciones , Radio (Anatomía)/anomalías , Talidomida/efectos adversos , Anomalías Inducidas por Medicamentos , Adulto , Síndrome del Túnel Carpiano/cirugía , Endoscopía , Femenino , Deformidades Congénitas de la Mano/inducido químicamente , Humanos , Masculino , Músculo Esquelético/anomalías , TeratógenosRESUMEN
Continuous flow blood pumps, such as axial flow and centrifugal pumps, have been gaining interest as circulatory devices for total artificial hearts (TAHs) and a biventricular assist device (BVAD) because of their smaller size and simpler structure compared to pulsatile pumps. However, continuous flow pumps are more prone to suction of the left ventricle than pulsatile pumps are. Sudden increases in flow rate to meet changes in physiological demand, especially in the left pump, often cause ventricle suction. In this study, a control algorithm to prevent suction from occurring in the left ventricle by controlling the rotational speed of the right pump, instead of reducing the cardiac output of the left pump, was developed and investigated. The method was tested in acute animal experiments with calves. The results indicate that this proposed method is capable of preventing suction and could simultaneously maintain circulatory control. A key advantage of this control system is that flow rates can be maximized while avoiding ventricle suction conditions particularly when the circulatory system is unstable such as in a the first few days after operation.
RESUMEN
OBJECTIVE: The Baylor Gyro BVAD is under development with the final goal of establishing a totally implantable biventricular assist system (BVAD). The aim of this study was to evaluate the safety, reliability, and effectiveness of the device in a long-term in vivo model. METHODS: The BVAD was implanted into eight calves for longer than 4 weeks in a biventricular bypass fashion, with the native heart remaining. Pump performance was assessed with the system's digital data acquisition unit. Postoperatively, anticoagulation was maintained with i.v. heparin perfusion (ACT< or = 250 sec) gradually replaced by coumadin. Treadmill exercise tests were performed daily following a 10-day reconvalescence period after surgery. RESULTS: The animals were kept alive for 37-90 days. The pumps yielded average flows of 5.3 +/- 1.1 l/min and 4.9 +/- 0.7 l/min for the LVAD and RVAD, respectively. Power consumption was 8.2 +/- 2.7 W and 9.6 +/- 4.7 W at 1935 +/- 123 rpm and 2015 +/- 365 rpm, respectively. All cases exhibited low hemolysis; renal and liver function were kept normal throughout the experiments. The animals demonstrated no thromboembolic neurological symptoms and tolerated moderate treadmill exercise. CONCLUSION: The Baylor Gyro BVAD demonstrated effective and reliable in vivo performance with acceptable biocompatibility. Based on these studies, we conclude that the system will be suitable as a long-term totally implantable BVAD for uses intended for longer than two years.
Asunto(s)
Diseño de Equipo/instrumentación , Corazón Auxiliar , Implantación de Prótesis , Animales , Biomarcadores/sangre , Gasto Cardíaco/fisiología , Bovinos , Creatinina/sangre , Seguridad de Equipos/instrumentación , Prueba de Esfuerzo , Fibrina/metabolismo , Frecuencia Cardíaca/fisiología , Ventrículos Cardíacos/cirugía , Implantes Experimentales , Modelos Animales , Modelos Cardiovasculares , Contracción Miocárdica/fisiología , Complicaciones Posoperatorias/etiología , Valores de Referencia , Flujo Sanguíneo Regional/fisiología , Resultado del Tratamiento , Función VentricularRESUMEN
The Gyro centrifugal pump, developed as a totally implantable artificial heart, was designed with a free impeller in which the rotational shaft (male bearing) of the impeller was completely separated from the female bearing. For this type of pump, it is very important to keep the proper magnet balance (impeller-magnet and actuator-magnet balance) to prevent thrombus formation or bearing wear. When the magnet balance is not proper, the impeller is jerked down into the bottom bearing. On the other hand, if magnet balance is proper, the impeller is lifted off the bottom of the pump housing within a certain range of pumping conditions. In this study, this floating phenomenon was investigated in detail. The floating phenomenon was proven by observation of the impeller behavior by means of a transparent acrylic pump. The impeller floating phenomenon was mapped on a pump performance curve. The impeller floating phenomenon is affected by the magnet-magnet coupling distance and the rotational speed of the impeller. To keep the proper magnet balance and to maintain the impeller floating phenomenon at the driving conditions of right and left pumps, the magnet-magnet coupling distance was altered by a spacer that was installed between the pump and actuator. It became clear that the same pump could handle different conditions (right and left ventricular assist) by changing the thickness of the spacer. When magnet balance is proper, the floating impeller phenomenon occurs automatically in response to the impeller revolution. This is called "the dynamic revolutions per minute suspension."
Asunto(s)
Corazón Artificial , Magnetismo/instrumentación , Centrifugación , Diseño de Equipo , Humanos , Técnicas In Vitro , Modelos Cardiovasculares , Flujo PulsátilRESUMEN
In this study, the association of the Pro12Ala peroxisome proliferator-activated receptor gamma2 (PPARgamma2) polymorphism with atherosclerosis was examined in a Japanese Type 2 diabetic population. PPARgamma has been identified as a key regulator of adipogenesis. Recently, some studies reported that the Pro12Ala polymorphism was associated with resistance to Type 2 diabetes. It is well-known that Type 2 diabetes is closely related with disorder of lipid metabolism as well as impaired glucose homeostasis, resulting in atherosclerosis. We aimed to evaluate the association between carriers of the Pro12Ala PPARgamma2 mutation and clinical profiles concerning atherosclerosis besides plasma glucose and lipid concentrations. Screening for the mutation was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method among 154 Type 2 diabetic patients. The homozygotes of the Pro12 allele were 143 (93%), the heterozygotes of the Pro12 and Ala12 allele were 11 (7%) and the homozygote of the Ala12 allele was not detected. The group with the Ala12 allele had a significantly lower value of carotid artery intima-media thickness (IMT) than that without it, although there was no difference between two groups in sex, age or other clinical variables we examined. The Pro12Ala PPARgamma2 polymorphism may be associated with carotid artery IMT values in Type 2 diabetes mellitus.
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Alanina , Arterias Carótidas/fisiología , Polimorfismo de Nucleótido Simple/genética , Prolina , Receptores Citoplasmáticos y Nucleares/genética , Factores de Transcripción/genética , Túnica Íntima/fisiología , Túnica Media/fisiología , Adulto , Anciano , Arteriosclerosis/epidemiología , Secuencia de Bases , Índice de Masa Corporal , ADN/sangre , ADN/genética , Cartilla de ADN , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/fisiopatología , Humanos , Japón , Persona de Mediana EdadRESUMEN
We proposed and developed a practical and effective servo control system for rotary blood pumps. A rotary blood pump for assisting the failing natural heart should be operated only in physiologically acceptable conditions. The operation of a rotary blood pump is based on the rotational speed of the impeller and pressure head. If the pump flow and the pressure head are set within an acceptable range, the driving condition is deemed normal condition, and this control system maintains the preset operating point by applying proportional and detective control (PD control). If the pump flow or pressure head is outside the acceptable range, the driving condition is determined to be abnormal condition, and this system operates the pump in a recovery fashion. If the driving condition is kept under abnormal conditions of sudden decrease of the flow, the condition is termed a suction condition. The controller releases the pump from the suction condition and later returns it to the normal condition. In this study, we evaluated these servo control modes of the centrifugal pump and confirmed whether the performance of this proposed operating point control system was practical.