• Title, Summary, Keyword: Pulsatile

Search Result 223, Processing Time 0.054 seconds

Development of the Pulsatile Pump System for a Perfusion Bioreactor (관류형 바이오리액터를 위한 박동 펌프 시스템 개발)

  • Kim, Hak-Jun;Kim, Sun-Hong;Chung, Ho-Yun;Yun, Won-Soo
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.28 no.4
    • /
    • pp.526-533
    • /
    • 2011
  • This research is about the pulsatile pump system utilized in the perfusion bioreactor for the in vitro human tissue culture. A pulsatile pump system which can be applied to the culture of the vascular tissues including blood vessel is developed by using the idea of human heart's blood pumping into organs as followings: culture chamber, a pressurizing device which generates laminar pulsatile flow by controlling the x-sectional area of the culture media delivering tubing, a compliance chamber which supplies the pressuring device with a constant pressure, and a peristaltic pump which circulates the culture media in a circuit ranging from the culture chamber to the compliance chamber. The developed pulsatile pump system shows that a physiology of the human heart's blood pumping including pulsatile pressure waveform of systolic-diastolic pressure is well represented. Not only time domain but also frequency domain characteristics of pulsatile pump system which are necessary for the vascular tissue culture such as pulsatile pressure waveform's shape, the frequency, and the magnitude can be easily generated and manipulated by using the proposed system.

Analysis on the Blood F1ow, Pressure and Pulsatility of a Dual Pulsatile Extracorporeal Life Support (이중 박동형 생명구조장치의 혈류, 혈압, 박동성의 분석)

  • Choi, Seong-Wook;Min, Byoung-Goo
    • Journal of Biomedical Engineering Research
    • /
    • v.28 no.5
    • /
    • pp.684-693
    • /
    • 2007
  • Previous trials for development of a pulsatile-Extracorporeal Life Support had some defects such as insufficient blood flow, high pressure at its membrane oxygenator and the high risk of blood cell damage. To solve those problems of previous pulsatile-ECLSs, we suggest dual pulsatile blood pump structure for the new pulsatile-ECLS. Two pulsatile pumps areconnected in a parallel manner and this new structure raises the inflow capacity and efficiency and it decreases the high blood pressure at membrane oxygenator. In in-vitro experiments, The Energy Equivalent Pressure Increment(EEP inc.) was 10%, and it showed that its pulsatilty was $5{\sim}10$ times higher than other commercial ECLS In in-vivo experiments, we had applied a new pulsatile-ECLS to 30 Kg pigs and a new pulsatile-ECLS couldsupport high blood flow and pulsatility above 2 L/min, 10% EEP inc.

Pulsatile Blood Flows Through a Bileaflet Mechanical Heart Valve with Different Approach Methods of Numerical Analysis : Pulsatile Flows with Fixed Leaflets and Interacted with Moving Leaflets

  • Park, Choeng-Ryul;Kim, Chang-Nyung;Kwon, Young-Joo;Lee, Jae-Won
    • Journal of Mechanical Science and Technology
    • /
    • v.17 no.7
    • /
    • pp.1073-1082
    • /
    • 2003
  • Many researchers have investigated the blood flow characteristics through bileaflet mechanical heart valves using computational fluid dynamics (CFD) models. Their numerical approach methods can be classified into three types; steady flow analysis, pulsatile flow analysis with fixed leaflets, and pulsatile flow analysis with moving leaflets. The first and second methods have been generally employed for two-dimensional and three-dimensional calculations. The pulsatile flow analysis interacted with moving leaflets has been recently introduced and tried only in two-dimensional analysis because this approach method has difficulty in considering simultaneously two physics of blood flow and leaflet behavior interacted with blood flow. In this publication, numerical calculation for pulsatile flow with moving leaflets using a fluid-structure interaction method has been performed in a three-dimensional geometry. Also, pulsatile flow with fixed leaflets has been analyzed for comparison with the case with moving leaflets. The calculated results using the fluid-structure interaction model have shown good agreements with results visualized by previous experiments. In peak systole. calculations with the two approach methods have predicted similar flow fields. However, the model with fixed leaflets has not been able to predict the flow fields during opening and closing phases. Therefore, the model with moving leaflets is rigorously required for advanced analysis of flow fields.

삼각형상 그루브 채널에서 맥동유동에 의한 열전달 향상에 관한 실험적 연구

  • 권오준;이대영;김서영;강병하;김용찬
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.13 no.10
    • /
    • pp.1009-1016
    • /
    • 2001
  • The heat transfer enhancement by pulsatile flow in a triangular grooved channel has been experimentally investigated in this study The experiment was performed in the ranges of the Reynolds number from 270 to 910, the pulsatile fraction from 0.125 to 0.75, and the Strouhal number from 0.084 to 0.665. It was measured that the heat transfer improves up to 350% compared with the steady flow case at Re=270,$\eta=0.5$, and St=0.335. The heat transfer enhancement was found to increase as the pulsatile fraction increases and the Reynolds number decreases. It was also found that the heat transfer enhancement is maximized at a specific pulsatile frequency satisfying the resonant condition. The nondimensional frequency, i.e., the Strouhal number at the resonant condition was found to increase as the Reynolds number decreases. The flow visualization revealed that the heat transfer enhancement results from the strong mixing caused by the repeating sequence of vortex formation, rotation and subsequent ejection from the grooves by the pulsatile flow.

  • PDF

Comparative Studies of Pulsatile and Nonpulsatile Blood Flow during Cardiopulmonary Bypass (박동류 및 비박동류에 의한 체외순환의 비교)

  • Sun, Kyung;Baek, Kwang-Je;Kim, Yo-Han;Kim, Chang-Young;Kim, Kwang-Taek;Kim, Hark-Jei;Kim, Hyoung-Mook
    • The Korean Journal of Thoracic and Cardiovascular Surgery
    • /
    • v.18 no.2
    • /
    • pp.182-192
    • /
    • 1985
  • [here are so many reports that pulsatile blood flow provides physiologic organ perfusions during cardiopulmonary bypass. So, we compared the recent 30 cases undergoing cardiac surgery by Cobe-Stckert pulsatile roller pump with another 30 cases by Polystan nonpulsatile roller pump. Pulsatile flow was applied during aortic-cross clamping period when synchronized to internal EKG simulator, and perfusion mode was changed to continuous nonpulsatile flow after declamping of aorta. Age, sex, weight, and disease entities were comparable and operative techniques were similar between two groups. 1. There were no differences in average ACC time, ECC time, and Operation time. 2. Postoperative artificial respiration time was 6hrs 30mins in nonpulsatile group and 4hrs 48mins in pulsatile group, and detubation time after ventilator weaning was 2hrs 44mins in nonpulsatile group and 1hrs 43mins in pulsatile group. 3. Average pulse pressure was 8mmHg in nonpulsatile group and 55mmHg in pulsatile group, and a mean arterial pressure was 66.0mmHg in nonpulsatile group and 60.7mmHg in pulsatile group. 4. Mean urine-output during ACC;ECC period was 9.717.3;9.913.2ml/kg/hr in nonpulsatile group and 14.215.0;15.817.5 in pulsatile group [p<0, 05], and thereafter progressive decrease of differences in urine output between two groups until POD 2, and lesser amounts of diuretics was needed in pulsatile group during same postoperative period. Serum BUN/Cr level showed no specific difference and urine concentration power was well preserved in both groups. 5. Plasma proteins and other Enzymes showed no differences between two groups, but serum GOT/GPT level was higher in nonpulsatile group till POD 2. 6. Serum Electrolytes showed no differences between two groups. 7. WBC, RBC, Platelet counts, Hgb and Hct were not different and Coagulogram was well preserved in both groups. 8. Plasma free Hgb level was 7.09mg% in pulsatile group compared with 3.48mg% in pulsatile group on POD 1 but was normalized on POD 2. Gross hemoglobinuria after ECC was noted in 6 cases [20%] of pulsatile group and 4 cases [13%] of nonpulsatile group. 9. In both groups, most patients were included in NYHA class III to IV [28 cases;93% in nonpulsatile group, 22 cases;73% in pulsatile group] preoperatively, and well improved to class I to 11[22 cases; 73% in nonpulsatile group, 30 cases; 100% in pulsatile group] postoperatively. There were 7 operative mortalities in nonpulsatile group only, which were 5 cases of TOF with hepatic failure, 1 case of multiple VSDs with low out-put syndrome, and 1 case of mitral valvular heart disease with cardiomyopathy. We concluded that the new, commercially available Cobe-Stckert pulsatile roller pump device was safe, simple, and reliable.

  • PDF

A NUMERICAL STUDY ON HEAT TRANSFER ENHANCEMENT BY PULSATILE FLOW IN A PLATE HEAT EXCHANGER (판형 열교환기의 맥동유동에 의한 열전달 향상에 관한 수치해석연구)

  • Lee, Myung-Sung;Hur, Nahm-Keon;Kang, Byung-Ha
    • 한국전산유체공학회:학술대회논문집
    • /
    • /
    • pp.93-96
    • /
    • 2006
  • The heat transfer enhancement by pulsatile flow in the plate heat exchanger has been investigated numerically in the present study. The numerical study was performed in the range of the mass flux from 0.04 to 0.12 kg/s. The results showed that the pulsatile flow produces resonating vortex shedding at the groove sharp edges and a strong transient vortex rotation within the grooved channels. As a result, the mixing between the trapped volume in the grooved cavity and the main stream was enhanced. Good agreements between the predictions and measured data are obtained in steady flow. And the heat transfer of pulsatile flow is about 2.4 times than steady flow when frequency is 10 Hz and the mass flux of cold side is 0.04 kg/s.

  • PDF

Simulation Study on the Efficacy of Toxin Removal by Pulsatile Flow in Blood Purification Systems that use Semipermeable Membranes

  • Lim, Ki-Moo;Shim, Eun-Bo
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.1655-1659
    • /
    • 2008
  • Using numerical models, we investigated the efficiency of toxin removal using pulsatile flow in blood purification systems that use semipermeable membranes. The model consisted of a three-compartmental mass transfer model for the inside body and a solute kinetics model for the dialyzer. The model predicted the toxin concentration inside the body during blood purification therapy, and the toxin removal efficiencies at different flow configurations were compared quantitatively. According to the simulation results, the clearances of urea and ${\beta}_2$ microglobulin (B2M) using a pulsatile pump were improved by up to 30.9% for hemofiltration, with a 2.0% higher urea clearance and 4.6% higher B2M clearance for high flux dialysis, and a 3.9% higher urea clearance and 8.2% higher B2M clearance for hemodiafiltration. These results suggest that using a pulsatile blood pump in blood purification systems with a semipermeable membrane improves the efficacy of toxin removal, especially for large molecules and hemofiltration treatment.

  • PDF

Hemodynamic Modeling of the Pulsatile Cardiac Pulmonary Perfusion for the Patient's Heart (환자의 박동형 심장의 폐순환 혈류 모델링에 대한 연구)

  • Kim, J.S.;Kim, M.S.;Choi, S.W.
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.1679-1682
    • /
    • 2008
  • Pulsatile Extracorporeal Membrane Oxygenation(ECMO) can mitigate the heart load and raise the patient's blood perfusion. But If the ECMO pulsate the blood flow during the systolic period, It can burden to the patient's heart. To avoid the heart injury, we have to consider the relation between output of ECMO, hemodynamic states and heart movement. To raise the efficacy of the pulsatile ECMO, we investigated the coronary perfusion, cardiac muscle tension and hemodynamic states during the ECMO perfusion by using the mathematical model of human blood circulatory system and ECMO. The outflow data of the pulsatile ECMO(T-PLS, Bioheartkorea, Korea) was obtained in vitro experiments. According to the phase and pumping rate of the ECMO, the heart's load and coronary perfusion could be adjusted to the proper levels. The results of the human- ECMO lumped parameter model showed that the synchronizing operation of the pulsatile ECLS can be helpful at stabilizing the patient's hemodynamic states.

  • PDF

Visualization of Three-Dimensional Pulsatile Flow in a Branching Model using the High-Resolution PIV System (고해상 PIV시스템을 이용한 분지관내3차원 맥동유동 가시화)

  • Roh, Hyung-Woon;Suh, Sang-Ho;Choi, Jin-Yong
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.765-768
    • /
    • 2003
  • The objective of the present study was to visualize the pulsatile flow field in a branching model by using the high-resolution PIV system. A bifurcated flow system was built for the experiments in the pulsatile flow. Harvard pulsatile pump was used to generate the pulsatile velocity waveforms. Conifer powder as the tracing particles was added to water to visualize the flow fields. Two consecutive particle images at several cross sections of the flow filed were captured by the CCD cameras ($1K{\ast}1K$ and $640{\ast}480$). The results after the image processing clearly showed the recirculation zones and the formation of the paired secondary flows from the distal to the apex in the bifurcated model. The results also indicated that the flow velocities in the inner wall moved faster than those in the outer wall due to the inertial force effects and the helical motions generated in the branch flows as the flow proceeded toward the outer wall. While the PIV images from the $1K{\ast}1K$ camera were closer to the simulation results thantheimagesfromthe640${\ast}$480camera,bothresultsofthePIVexperimentsusingthetwocamerasgenerallyagreed quitewellwiththeresultsfromthenumericalsimulation.

  • PDF

Flow Visualization of Pulsatile Flow in a Branching Tube using the PIV System and Numerical Analysis (PIV와 수치해석을 이용한 분지관내 맥동유동의 가시화)

  • Roh, Hyung-Woon;Suh, Sang-Ho;Yoo, Sang-Sin
    • Proceedings of the KSME Conference
    • /
    • /
    • pp.535-540
    • /
    • 2000
  • The objective of the present study is to visualize the pulsatile flow fields by using three-dimensional computer simulation and the PIV system. A closed flow loop system was built for the steady and unsteady experiments. The Harvard pulsatile pump was used to generate the pulsatile pressure and velocity waveforms. Conifer powder as the tracing particles was added to water to visualize the flow field. Two consecutive particle images were captured by a CCD camera for the image processing. The cross-correlation method in combination with the moving searching area algorithm was applied for the image processing of the flow visualization. The pulsatile flow fields were visualized effectively by the PIV system in conjunction with the applied algorithm. The range validation and the area interpolation methods were used to obtain the final velocity vectors with high accuracy. The finite volume predictions were used to analyze three-dimensional flow patterns in the bifurcation model. The results of the PIV experiment and the computer simulation are in good agreement and the results show the recirculation zones and formation of the paired secondary flow distal to the apex of the bifurcated model. The results also show that the branch flow is pushed strongly to the inner wall due to the inertial force effect and helical motions are generated as the flow proceeds toward the outer wall.

  • PDF