Simultaneous measurement of erythrocyte aggregarion and oxygen saturation under in vitro pulsatile blood flow by high-frequency photoacoustics

2014 ◽  
Author(s):  
Tae-Hoon Bok ◽  
Eno Hysi ◽  
Michael C. Kolios
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
Simultaneous Measurement ◽  
High Frequency ◽  
Pulsatile Blood Flow

Gas Transport in Serpentine Microporous Tubes Under Steady and Pulsatile Blood Flow Conditions

1991 ◽  
Vol 113 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Kazuo Tanishita ◽  
Masanobu Ujihira ◽  
Akihisa Watabe ◽  
Kunio Nakano ◽  
Peter D. Richardson ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Transfer ◽  
Ex Vivo ◽  
Radius Of Curvature ◽  
Gas Transfer ◽  
Pulsatile Blood Flow ◽  
Flow Conditions ◽  
Wide Range ◽  
Exchange Unit

A serpentine gas exchange unit was built with cylindrical tubular microporous membranes featuring periodic arcs with a fixed curvature ratio (ratio of tube radius to radius of curvature) of 1/14 and circular angles between 30 and 360 deg. Oxygen transfer was measured under steady and pulsatile blood flow conditions in vitro and ex vivo to assess the design features which most effectively augment gas transfer. Under steady blood flow conditions, oxygen transfer increased with circular angles beyond 70 deg. Under pulsatile conditions, a wide range of geometrical and fluid mechanical parameters could be combined to enhance gas transfer performance, which eventually depended upon the secondary Reynolds number and the Womersley parameter.

Constant Blood Flow during Single-Needle Dialysis is Unnecessary

1993 ◽  
Vol 16 (7) ◽  
pp. 505-509 ◽  
Author(s):  
H.D. Polaschegg ◽  
R. Wojke
Keyword(s):  
Blood Flow ◽  
Vascular Access ◽  
Pulsatile Flow ◽  
Tidal Flow ◽  
Constant Flow ◽  
Pulsatile Blood Flow ◽  
Flow Rates ◽  
Flow Through ◽  
Optimal Efficiency

Single-needle (SN) dialysis employs tidal blood flow at the point of vascular access. The simplest SN systems convert this tidal flow to a pulsatile flow in the dialyser. It has been assumed that constant flow through the dialyser is necessary for optimal efficiency. Therefore SN blood circuits are designed to smooth the pulsatile flow in the dialyser to a relatively constant flow. This increases the complexity and cost of the SN system. In order to test the hypothesis that pulsatile flow results in lower clearances than constant flow, we performed measurements of clearance in vitro using pulsatile blood flow at time-averaged rates of 50-250 ml/min and tidal volumes 200-100 ml/min. These were compared with clearances using constant blood flow at the same rates. At all flow rates and at tidal volumes up to 50 ml, the clearance measurements obtained during pulsatile flow were identical to those obtained during constant flow.

scholarly journals In vitro investigation of the impact of pulsatile blood flow on the vascular architecture of decellularized porcine kidneys

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Peter R. Corridon
Keyword(s):  
Blood Flow ◽  
Blood Perfusion ◽  
Pulsatile Blood Flow ◽  
Venous Outflow ◽  
Venous Flow ◽  
Vascular Architecture ◽  
Arterial Perfusion ◽  
In Vitro Investigation ◽  
The Impact

AbstractA method was established using a scaffold-bioreactor system to examine the impact pulsatile blood flow has on the decellularized porcine kidney vascular architecture and functionality. These scaffolds were subjected to continuous arterial perfusion of whole blood at normal physiological (650 ml/min and 500 ml/min) and pathophysiological (200 ml/min) rates to examine dynamic changes in venous outflow and micro-/macrovascular structure and patency. Scaffolds subjected to normal arterial perfusion rates observed drops in venous outflow over 24 h. These reductions rose from roughly 40% after 12 h to 60% after 24 h. There were no apparent signs of clotting at the renal artery, renal vein, and ureter. In comparison, venous flow rates decreased by 80% to 100% across the 24 h in acellular scaffolds hypoperfused at a rate of 200 ml/min. These kidneys also appeared intact on the surface after perfusion. However, they presented several arterial, venous, and ureteral clots. Fluoroscopic angiography confirmed substantial alterations to normal arterial branching patterns and patency, as well as parenchymal damage. Scanning electron microscopy revealed that pulsatile blood perfusion significantly disrupted glomerular microarchitecture. This study provides new insight into circumstances that limit scaffold viability and a simplified model to analyze conditions needed to prepare more durable scaffolds for long-term transplantation.

scholarly journals Simultaneous measurement of macro- and microvascular blood flow and oxygen saturation for quantification of muscle oxygen consumption

2017 ◽  
Vol 79 (2) ◽  
pp. 846-855 ◽  
Author(s):  
Erin K. Englund ◽  
Zachary B. Rodgers ◽  
Michael C. Langham ◽  
Emile R. Mohler ◽  
Thomas F. Floyd ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Oxygen Saturation ◽  
Simultaneous Measurement ◽  
Microvascular Blood Flow ◽  
Muscle Oxygen ◽  
Muscle Oxygen Consumption

In vivo studies with an intravascular and intracardiac reflection oximeter

1962 ◽  
Vol 17 (3) ◽  
pp. 552-558 ◽  
Author(s):  
Y. Enson ◽  
W. A. Briscoe ◽  
M. L. Polanyi ◽  
A. Cournand
Keyword(s):  
Oxygen Saturation ◽  
Glass Fibers ◽  
Blood Stream ◽  
In Vivo Studies ◽  
Pulsatile Blood Flow ◽  
Cardiac Catheter ◽  
Reflected Light

An oximeter is described which employs two bundles of flexible glass fibers to conduct appropriately filtered light into, and that light diffusely reflected by the blood out of, the blood stream for the determination of oxygen saturation or dye concentration within blood flowing past the tip of either an arterial needle or a cardiac catheter which contains both bundles. The ratio of intensities of the reflected light at two wavelengths is linearly related to oxygen saturation (IRR805/ IRR660) and dye concentration (IRR900/IRR805). Data is reported in vivo and in vitro with respect to accuracy of the determinations (± 1.9%). The effect of patient-to-patient variation in hematocrit and other factors, and of pulsatile blood flow, is described. Application of the technique to physiologic study is illustrated, and theoretical aspects of reflection oximetry, as they apply to the instrument, are discussed. Submitted on November 17, 1961

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