scholarly journals Quantification of the distribution of blood flow pressure with postures

2012 ◽  
Vol 05 (03) ◽  
pp. 113-119
Author(s):  
Wenying Mu ◽  
Shanguang Chen ◽  
Fengyuan Zhuang ◽  
Yinghui Li ◽  
Yu Li
Keyword(s):  
Blood Flow ◽  
Flow Pressure

Numerical Study of Blood Flow Pressure Drop in Aorta Coronary Sinus Conduit

2012 ◽  
pp. 135-150
Author(s):  
Siti Aslina Hussain ◽  
Tan Hong Tat ◽  
Mohd Ismail Abdul Hamid ◽  
Norhafizah Abdullah ◽  
Azni Idris
Keyword(s):  
Blood Flow ◽  
Pressure Drop ◽  
Coronary Sinus ◽  
Numerical Study ◽  
Flow Pressure

Abolition of autoregulation of renal blood flow by acetylcholine

1964 ◽  
Vol 207 (1) ◽  
pp. 123-127 ◽  
Author(s):  
Victor E. Nahmod ◽  
Alfredo Lanari
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Run Off ◽  
Critical Closing Pressure ◽  
Flow Pressure ◽  
Renal Blood Flow Autoregulation ◽  
Autoregulatory Mechanism ◽  
Closing Pressure

In order to study the mechanism of autoregulation of renal blood flow, 36 mongrel dogs were connected in parabiosis according to the Brull method. The following determinations were made: a) flow/pressure curves in innervated and denervated kidneys and b) acetylcholine and arterenol infusion in innervated kidneys. The critical closing pressure and the "run-off" index were also determined in all cases. The results of these experiments show the existence of renal blood flow autoregulation in innervated, denervated, and arterenol-infused kidneys, and the abolition of the autoregulatory mechanism in the acetylcholine-infused kidneys. The run-off index showed a better correlation with renal resistance than with critical closing pressure.

Pulmonary blood flow, pressure and resistance following tetraethylammonium and aminophylline

1961 ◽  
Vol 200 (2) ◽  
pp. 287-291 ◽  
Author(s):  
M. Harasawa ◽  
S. Rodbard
Keyword(s):  
Blood Flow ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Systemic Blood Pressure ◽  
Arterial Blood Flow ◽  
Tetraethylammonium Chloride ◽  
Blood Flows ◽  
Arterial Blood ◽  
Pulmonary Arterial ◽  
Flow Pressure

The effects of tetraethylammonium chloride (TEAC) and aminophylline on the pulmonary vascular resistance were studied in thoracotomized dogs. Pulmonary arterial blood flow and pressure, and systemic blood pressure were measured simultaneously. Both drugs showed marked hypotensive effects on the systemic vessels. In every instance pulmonary arterial pressures and blood flows were reduced by TEAC given via the pulmonary artery and increased by aminophylline. However, the calculated pulmonary vascular resistance remained essentially unchanged in all experiments. These data challenge the concept that the pulmonary vessels respond to these drugs by active vasodilatation

scholarly journals Role of Kinins in the Control of Renal Papillary Blood Flow, Pressure Natriuresis, and Arterial Pressure

2000 ◽  
Vol 86 (5) ◽  
pp. 589-595 ◽  
Author(s):  
Jerónimo Tornel ◽  
María Isabel Madrid ◽  
Miguel García-Salom ◽  
Klaus J. Wirth ◽  
Francisco J. Fenoy
Keyword(s):  
Blood Flow ◽  
Arterial Pressure ◽  
Flow Pressure ◽  
Pressure Natriuresis

Comparison of the performance characteristics of three generations of membrane oxygenators: Univox®, Univox® Gold™ and SpiralGold™

Perfusion ◽  
1996 ◽  
Vol 11 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Philip D Beckley ◽  
Susan M Morris ◽  
James J Smith ◽  
Jerri L McNamara ◽  
Julie A Novak
Keyword(s):  
Heat Transfer ◽  
Blood Flow ◽  
Heat Exchange ◽  
Blood Flows ◽  
Heparin Coating ◽  
Baxter Healthcare ◽  
Recent Addition ◽  
Flow Pressure ◽  
The Impact

With continuous enhancement in oxygenator design, the question is raised as to how these changes actually impact the performance of the oxygenator. The recent addition of two new oxygenators by the Bentley Division of Baxter Healthcare Corporation provided us with a unique opportunity to compare the performance of each device and isolate the impact of each design change on performance. While the basic design and flow patterns have remained the same, application of the Duraflo® II treatment has produced the Univox® Gold™ and a change in the fibre-winding technique has produced the SpiralGold™. This study compared the effects of heparin coating (Univox® to Univox® Gold™) and fibre-winding (Univox® Gold™ to SpiralGold™) on gas and heat transfer and resistance to blood flow (pressure drop). Six oxygenators of each model were evaluated utilizing an in vitro single pass circuit, which first conditioned bovine blood to the Association for the Advancement of Medical Instrumentation (AAMI) venous standards. Blood flows of 4.0, 5.0, 6.0 and 7.0 I/min, FiO2 values of 1.0, 0.8 and 0.6, and gas-to-blood flow ratios of 0.5, 1.0 and 1.5 were chosen as test variables. Data generated included oxygen transfer, carbon dioxide transfer, arterial pO2, resistance to blood flow, and coefficient of heat exchange. The results indicate that the Duraflo II treatment does not have a significant effect on gas and heat transfer or resistance to blood flow. The fibre-winding technique employed with the new SpiralGold™, however, has improved significantly gas exchange and arterial PO2 when compared with the previous Univox® models. Resistance to blood flow and coefficient of heat exchange were not affected significantly by the winding technique.

Blood Flow, Pressure and Compliance in the Male Human Bladder

2002 ◽  
pp. 121-125 ◽  
Author(s):  
RICHARD T. KERSHEN ◽  
KAZEM M. AZADZOI ◽  
MIKE B. SIROKY
Keyword(s):  
Blood Flow ◽  
Human Bladder ◽  
Flow Pressure

scholarly journals Novel hemodynamic structures in the human glomerulus

2018 ◽  
Vol 315 (5) ◽  
pp. F1370-F1384 ◽  
Author(s):  
Christopher R. Neal ◽  
Kenton P. Arkill ◽  
James S. Bell ◽  
Kai B. Betteridge ◽  
David O. Bates ◽  
...  
Keyword(s):  
Blood Flow ◽  
Minimum Energy ◽  
High Capacity ◽  
Vortical Flow ◽  
Microscope Imaging ◽  
Normal Human ◽  
Flow Pressure ◽  
Electron Microscope Imaging ◽  
Human Glomerulus ◽  
Minimum Work

To investigate human glomerular structure under conditions of physiological perfusion, we have analyzed fresh and perfusion-fixed normal human glomeruli at physiological hydrostatic and oncotic pressures using serial resin section reconstruction, confocal, multiphoton, and electron microscope imaging. Afferent and efferent arterioles (21.5 ± 1.2 µm and 15.9 ± 1.2 µm diameter), recognized from vascular origins, lead into previously undescribed wider regions (43.2 ± 2.8 µm and 38.4 ± 4.9 µm diameter) we have termed vascular chambers (VCs) embedded in the mesangium of the vascular pole. Afferent VC (AVC) volume was 1.6-fold greater than efferent VC (EVC) volume. From the AVC, long nonbranching high-capacity conduit vessels ( n = 7) (Con; 15.9 ± 0.7 µm diameter) led to the glomerular edge, where branching was more frequent. Conduit vessels have fewer podocytes than filtration capillaries. VCs were confirmed in fixed and unfixed specimens with a layer of banded collagen identified in AVC walls by multiphoton and electron microscopy. Thirteen highly branched efferent first-order vessels (E1; 9.9 ± 0.4 µm diameter) converge on the EVC, draining into the efferent arteriole (15.9 ± 1.2 µm diameter). Banded collagen was scarce around EVCs. This previously undescribed branching topology does not conform to the branching of minimum energy expenditure (Murray’s law), suggesting that even distribution of pressure/flow to the filtration capillaries is more important than maintaining the minimum work required for blood flow. We propose that AVCs act as plenum manifolds possibly aided by vortical flow in distributing and balancing blood flow/pressure to conduit vessels supplying glomerular lobules. These major adaptations to glomerular capillary structure could regulate hemodynamic pressure and flow in human glomerular capillaries.

A multichannel implantable telemetry system for flow, pressure, and ECG measurements

1975 ◽  
Vol 39 (2) ◽  
pp. 318-326 ◽  
Author(s):  
T. B. Fryer ◽  
H. Sandler ◽  
S. W. Freund ◽  
E. P. McCutcheon ◽  
E. L. Carlson
Keyword(s):  
Blood Flow ◽  
Single Channel ◽  
Rechargeable Batteries ◽  
The Body ◽  
Pickup Coil ◽  
Special Design ◽  
Intact Skin ◽  
Multichannel Systems ◽  
Flow Pressure ◽  
Multiplex System

The design of telemetry systems for chronic implantation within the body have progressed from simple single-channel devices to complex multichannel systems over the last 15 yr. Although chronic measurements of temperature, ECG, and pressure have been reported with good results, measurements such as dimension and blood flow have been difficult because of heavy power requirements. The design to be described is a multiplex system that will measure up to eight individual parameters simultaneously, including blood flow. Flow is measured using an electromagnetic transducer, and by special design, the normal high power requirements of the electromagnetic technique have been reduced to a few hundred milliwatts. The system is powered by two NiCad, rechargeable batteries which are periodically recharged through the intact skin by induction at 250 kHz to an implanted pickup coil. The presently constructed units have been configured to measure ECG, two pressures, temperature and ascending aortic flow.

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