scholarly journals Synchronous Control with Heartbeat in a Magnetically Levitated Centrifugal Blood Pump by Estimating a Pump Flow Rate with a Radial Disturbance Observer–Validation in a Simple Mock Circulation Loop–

Author(s):  
Yui TANAKA ◽  
Tomotaka MURASHIGE ◽  
Wataru HIJIKATA
2018 ◽  
Vol 46 (4) ◽  
pp. 279-285 ◽  
Author(s):  
Maxime Leclerc ◽  
Clémence Bechade ◽  
Patrick Henri ◽  
Elie Zagdoun ◽  
Erick Cardineau ◽  
...  

We conducted a prospective study to assess the impact of the blood pump flow rate (BFR) on the dialysis dose with a low dialysate flow rate. Seventeen patients were observed for 3 short hemodialysis sessions in which only the BFR was altered (300,350 and 450 mL/min). Kt/V urea increased from 0.54 ± 0.10 to 0.58 ± 0.08 and 0.61 ± 0.09 for BFR of 300, 400 and 450 mL/min. For the same BFR variations, the reduction ratio (RR) of β2microglobulin increased from 0.40 ± 0.07 to 0.45 ± 0.06 and 0.48 ± 0.06 and the RR phosphorus increased from 0.46 ± 0.1 to 0.48 ± 0.08 and 0.49 ± 0.07. In bivariate analysis accounting for repeated observations, an increasing BFR resulted in an increase in spKt/V (0.048 per 100 mL/min increment in BPR [p < 0.05, 95% CI (0.03–0.06)]) and an increase in the RR β2m (5% per 100 mL/min increment in BPR [p < 0.05, 95% CI (0.03–0.07)]). An increasing BFR with low dialysate improves the removal of urea and β2m but with a potentially limited clinical impact.


2004 ◽  
Vol 127 (2) ◽  
pp. 254-263 ◽  
Author(s):  
Steven W. Day ◽  
James C. McDaniel

Measurements of the time-varying flow in a centrifugal blood pump operating as a left ventricular assist device (LVAD) are presented. This includes changes in both the pump flow rate as a function of the left ventricle contraction and the interaction of the rotating impeller and fixed exit volute. When operating with a pulsing ventricle, the flow rate through the LVAD varies from 0-11L∕min during each cycle of the heartbeat. Phase-averaged measurements of mean velocity and some turbulence statistics within several regions of the pump, including the inlet, blade passage, exit volute, and diffuser, are reported at 20 phases of the cardiac cycle. The transient flow fields are compared to the constant flow rate condition that was reported previously in order to investigate the transient effects within the pump. It is shown that the quasi-steady assumption is a fair treatment of the time varying flow field in all regions of this representative pump, which greatly simplifies the comprehension and modeling of this flow field. The measurements are further interpreted to identify the effects that the transient nature of the flow field will have on blood damage. Although regions of recirculation and stagnant flow exist at some phases of the cardiac cycle, there is no location where flow is stagnant during the entire heartbeat.


Author(s):  
Ahmet Onder ◽  
Rafet Yapici ◽  
Omer Incebay

The use of substitute fluid with similar rheological properties instead of blood is important due to ethical concerns and high blood volume consumption in pump performance test before clinical applications. The performance of a centrifugal blood pump with hydrodynamic journal bearing is experimentally tested using Newtonian 40% aqueous glycerin solution (GS) and non-Newtonian aqueous xanthan gum solution of 600 ppm (XGS) as working fluids. Experiments are performed at four different rotational speeds which are 2700, 3000, 3300, and 3600 rpm; experiments using GS reach between 8.5% and 37.2% higher head curve than experiments using the XGS for every rotational speed. It was observed that as the rotational speed and flow rate increase, the head curve difference between GS and XGS decreases. This result can be attributed to the friction reduction effect when using XGS in experiments at high rotation speed and high flow rate. Moreover, due to different fluid viscosities, differences in hydraulic efficiency were observed for both fluids. This study reveals that the use of Newtonian fluids as working fluids is not sufficient to determine the actual performance of a blood pump, and the performance effects of non-Newtonian fluids are remarkably important in pump performance optimizations.


2007 ◽  
Vol 24 (Supplement 39) ◽  
pp. 53
Author(s):  
R. Valero ◽  
P. Santos-Cidón ◽  
M. Net ◽  
L I. Capdevila ◽  
J C. García-Valdecasas

ASAIO Journal ◽  
1993 ◽  
Vol 39 (2) ◽  
pp. 126-131
Author(s):  
Ryuji Tominaga ◽  
Kazuhiro Kurisu ◽  
Fumio Fukumura ◽  
Atsuhiro Nakashima ◽  
Manabu Hisahara ◽  
...  

2020 ◽  
Vol 44 (6) ◽  
Author(s):  
Shaun D. Gregory ◽  
Jo P. Pauls ◽  
Eric L. Wu ◽  
Andrew Stephens ◽  
Ulrich Steinseifer ◽  
...  

1990 ◽  
Vol 73 (3A) ◽  
pp. NA-NA
Author(s):  
F H Kem ◽  
W J Greeley ◽  
R M Ungerleider ◽  
T J Quill ◽  
B. Baldwin ◽  
...  

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