A Novel Injection System for Hypovolemic Patients

2006 ◽  
Author(s):  
Simone P. Ercolani ◽  
Paolo Conti ◽  
Lucio Banetta
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Heart Valves ◽  
Venous Pressure ◽  
Vena Cava ◽  
Maximum Flow ◽  
Injection System ◽  
Constant Flow Rate ◽  
Experimental Apparatus

The aim of this paper is to test a new infusion system prototype which is intended to recover the normal venous return and lost blood quantity in hypovolemic patients. For this purpose a bolus of fluid is injected at a high speed in the vena cava, accelerating and dragging the stagnating flow upstream the catheter. In order to improve the effects of the injection and to avoid damage to heart valves, the injection is synchronized with the heart cycle and should be controlled by the electrocardiogram track of the patient in such a way that the maximum flow rate injected occurs when the tricuspid valve is open. An in-vitro experimental apparatus — simulating the vena cava and its environment — has been built and used to measure velocity and pressure fields in the vena cava during the high velocity injection. In a first embodiment, the experimental apparatus consists of two reservoirs arranged, respectively, upstream and downstream a Starling Resistor, but at different heights. A constant flow rate inside the vena cava is maintained, thus simulating the diastolic phase of the heart. In a second embodiment of the experimental apparatus, two electrical valves, arranged downstream the Starling Resistor, generate an oscillating pressure wave along the vena cava, thus simulating the human central venous pressure. By varying the flow rate inside the vena cava and the opening rate of the valves, it has been possible to evaluate the dragging effect of the new injection system and the mechanical behavior of the vena cava during both continuous and pulsating infusion.

A prototype paediatric venous cannula with shape change in situ

Perfusion ◽  
2003 ◽  
Vol 18 (1) ◽  
pp. 61-65 ◽  
Author(s):  
David Jegger ◽  
Antonio F Corno ◽  
Antonio Mucciolo ◽  
Giuseppe Mucciolo ◽  
Yves Boone ◽  
...  
Keyword(s):  
Flow Rate ◽  
Shape Change ◽  
Venous Pressure ◽  
Flow Characteristics ◽  
Maximum Flow ◽  
Venous Drainage ◽  
Vessel Diameter ◽  
Single Stage ◽  
Set Up

During cardiopulmonary bypass (CPB), venous drainage may be impeded due to small vessel and cannula size or chattering, thus, blood return to the heart-lung machine is reduced. We designed a self-expandable prototype cannula, which is able to maintain the vein open and overcome this problem and analysed its performance capability. This prototype and several other cannulae were tested using an access vessel diameter of 7 mm. An in vitro circuit was set up with a 10 mm penrose latex tube simulating the patient’s vein placed between the patient preload reservoir and the cannula, encasing the cannula’s inlet(s). Maximum flow rate was determined for passive venous drainage (PVD) at preloads (P) of 2 and 4 mmHg. We compared these results to three classic single-stage venous cannulae: basket tip, thoracic drain and percutaneous tip. By comparing the other cannulae to the prototype, under PVD conditions and a central venous pressure (CVP) of 2 mmHg, the prototype cannula’s flow rate (1.329 /0.04 L/min) outperformed the basket type (the best performing comparator) (1.029 /0.08 L/min) by 23% (p B /0.005). When the preload was increased to 4 mmHg under PVD conditions, the same trend was noted with the prototype cannula (1.659 /0.05 L/min), outperforming the basket cannula’s value (1.269 /0.05 L/min) by 24% (p B /0.001). This new cannula design provides superior flow characteristics, under all test conditions, compared to the classic single-stage venous cannulae used for paediatric CPB surgery.

A New Expandable Cannula to Increase Venous Return during Peripheral Access Cardiopulmonary Bypass Surgery

2002 ◽  
Vol 25 (2) ◽  
pp. 136-140 ◽  
Author(s):  
D. Jegger ◽  
X. Mueller ◽  
G. Mucciolo ◽  
A. Mucciolo ◽  
Y. Boone ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Flow Rate ◽  
Heart Surgery ◽  
Open Heart Surgery ◽  
Vena Cava ◽  
Maximum Flow ◽  
Venous Drainage ◽  
Set Up

Peripheral cannulation for cardiopulmonary bypass (CPB) is of prime interest in minimally invasive open heart surgery. As CPB is initiated with percutaneous cannulae, venous drainage is impeded due to smaller vessel and cannula size. A new cannula was developed which can change shape in situ and therefore may improve venous drainage. An in vitro circuit was set-up with a penrose latex tubing placed between the preload reservoir and the cannula, encasing the cannula's inlet and simulating the vena cava. The preload (P) was stabilised at 2 and at 5mmHg respectively. The maximum flow rate was determined for 4 conditions: passive venous drainage (PVD) and assisted venous drainage (AVD) using a centrifugal pump at the 2 preload settings. We compared the results of the prototype cannula to classical femoral venous cannulae: basket 28Fr, a thoracic 28Fr and a percutaneous 27Fr. Under PVD conditions and a CVP of 2mmHg, the prototype cannula's flow rate outperformed the next best cannula by 14% (p=0.0002) and 13% under AVD conditions (p=0.0001). Under PVD conditions and a CVP of 5mmHg, the prototype cannula outperformed the percutaneous cannula by 19% (p=0.0001) and 14% under AVD conditions (p=0.0002). The new cannula outperforms the classical percutaneous venous cannulae during all of the four conditions tested in vitro.

Maximum Flow Rates Possible During Power Injection Through Currently Available PICCs: An In-Vitro Study

2004 ◽  
Vol 9 (3) ◽  
pp. 150-154
Author(s):  
Ari I. Salis ◽  
Anthony Eclavea ◽  
Matthew S. Johnson ◽  
Nilesh H. Patel ◽  
Debie G. Wong ◽  
...  
Keyword(s):  
Flow Rate ◽  
Superior Vena ◽  
Vena Cava ◽  
In Vitro Study ◽  
Maximum Flow ◽  
Intravenous Contrast ◽  
Flow Rates ◽  
Wide Range ◽  
Polyurethane Catheters

ABSTRACT Purpose Currently available 4 French and 5 French PICCs were investigated to evaluate their possible application for contrast injection using power injectors. The study was performed using an in-vitro model to demonstrate the feasibility of using PICCs for contrast enhanced studies. Materials and Methods An evaluation of 24 catheter versions consisting of 4 French single lumen and 5 French dual lumen PICCs from 13 different manufacturers was conducted. Six of the catheter types were silicone and 18 catheter types were polyurethane. Ten catheters of each type were evaluated with five at full length and five trimmed to 40cm. Using a silicone-based simulated superior vena cava model, the catheters were infused with 50cc of intravenous contrast at each flow rate increment. Catheters were tested at increasing flow rates from 0.5cc/second to 5cc/second in 0.5cc/second increments using a Percupump CT injector. Catheters that failed to rupture were then infused at 1 cc/second increments at flow rates from 5cc/second to 17cc/second using a MedRad Mark VTM power injector. Tolerated and bursting pressures were recorded. Results Polyurethane catheters ruptured at flow rates between 4–15.4cc/second, with one catheter not rupturing at the maximum flow rate (l7cc/second). Silicone catheters ruptured at flow rates between 0.5–3.5cc/second. Average rupture locations by type and length were at the extension leg/hub connection area on 5 of the PICCs, on the extension legs on 21 of the PICCs, on the catheter/hub connection on 4 PICCs, and on the proximal catheter on 16 of the PICCs. Conclusion The low burst rates at which all silicone catheters ruptured suggest those catheters are not able to withstand typical flow rates used for CTA. Conversely, although a wide range of discrepancy is found in the polyurethane catheter burst pressures, many polyurethane catheters can tolerate relatively high flow rates without rupture. This suggests that they may be safely used for CTA with appropriate precautions and protocols in place.

The Application of PIV in the Study of Impeller-Diffuser Interaction in Centrifugal Fan: Part I — Impeller-Vaneless Diffuser Interaction

2001 ◽  
Author(s):  
Tarek Mekhail ◽  
Zhang Li ◽  
Du Zhaohui ◽  
Willem Jansen ◽  
Chen Hanping
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
High Speed ◽  
Maximum Flow ◽  
Image Processing Technique ◽  
High Speed Photography ◽  
Centrifugal Fan ◽  
Performance Measurements ◽  
Vaneless Diffuser ◽  
Unstable Flow

Abstract The PIV (Particle Image Velocimetry) technology is a brand-new technique of measuring velocity. It started in the 1980’s with the development of high-speed photography and the image processing technique of computers. This article deals with PIV applied to the study of unsteady impeller-vaneless diffuser interaction in centrifugal fen. Experiments were carried out at The Turbomachinery Laboratory of Shanghai Jiaotong University. The test rig consists of a centrifugal, shrouded impeller, diffuser and volute casing all made of plexiglass. A series of performance measurements were carried out at different speeds and different vaneless diffuser widths. PIV measurements were applied to measure the unsteady flow at the exit part of the impeller and the inlet part of the diffuser for the case of the same width vaneless diffuser. The absolute flow field is measured at medium flow rate and at maximum flow rate. It is informative to capture the whole flow field at the same instant of time, and it might be more revealing to observe the unstable flow in real time.

Vertical Mixed Jet Behavior of Orifice Nozzle

2014 ◽  
Vol 1070-1072 ◽  
pp. 1978-1981
Author(s):  
Lu Peng ◽  
Dong Jun Kim ◽  
Hei Cheon Yang
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Water Tank ◽  
Entrainment Ratio ◽  
Penetration Length ◽  
Air Compressor ◽  
Primary Fluid ◽  
Experimental Apparatus ◽  
Jet Behavior ◽  
Transfer Behavior

The objective of this study is to experimentally investigate the mixed jet and oxygen transfer behavior of a vertical orifice nozzle. The experimental apparatus consisted of an electric motor-pump, an orifice nozzle, a circulation water tank, an air compressor, a high speed camera unit and controlling or measuring accessories. The entrainment ratio was calculated using the measured primary fluid flow rate and suction air flow rate with primary flow pressure. The visualization image of vertically injected air and mixed jet issuing from the orifice nozzle was analyzed qualitatively. As the air compressor pressure increases, the penetration length of mixed jet decreases and the mass ratio and dissolved oxygen concentration increase.

scholarly journals Analisis Performance Sumur X Menggunakan Metode Standing Dari Data Pressure Build Up Testing

2016 ◽  
Vol 5 (2) ◽  
pp. 57-61
Author(s):  
Novrianti Novrianti
Keyword(s):  
Flow Rate ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Well Test ◽  
Time Data ◽  
Constant Flow Rate ◽  
Optimal Flow ◽  
Production Wells ◽  
Inflow Performance

The number of production wells refers to the performance of the well, which is shown in the graph of inflow performance relationship (IPR). Reservoir characteristics influence on performance of the well, type of welltest and methods that be used in the determination of IPR. By using the IPR curves, maximum flow rate and the optimal flow rate of the well will be known. Pressure Build Up test is used to know performance and a maximum flow rate of the X well. Well test conducted for 15 hours. The well produced at a constant flow rate than close the wellhead. The Pressure data and time data obtained from the well test. The result of Pressure build-up testing analysis among permeability, skin and flow efficiency. After analyzing the Pressure build-up testing permeability obtained 190 mD, skin + 1,68 and 0,83 flow efficiency. Based on the value of flow efficiency Standing method is the most appropriate method is used to analyze the productivity of X well. Standing appropriate method for wells with skin ≠ 0 and flow efficiency ≠ 1. The maximum flow rate of the X well using Standing Method on the 0,83 flow efficiency was 13,91 MMSCFD

A Method to Measure the Station of Artificial Mechanical Heart Valves

2013 ◽  
Vol 683 ◽  
pp. 712-715
Author(s):  
Feng Zhou ◽  
Liang Liang Wu ◽  
Yuan Yuan Cui ◽  
Ying Chen ◽  
Jie Yang ◽  
...  
Keyword(s):  
High Speed ◽  
Heart Valves ◽  
Ultrasonic Method ◽  
High Speed Photography ◽  
In Vitro Experiments ◽  
In Vivo Experiments ◽  
Artificial Heart Valves ◽  
Economic Injury

The experiments of artificial heart valves were divided into in vivo and in vitro experiments; in vivo experiments provide accurate experimental parameters serving in vitro research. Simulation experiment used in vitro usually goes like this, firstly design a similar model or prototype phenomenon, then analysis the model working out the regular parameters related to the process, ruled out the possibility of impact on the study of individual exist in vivo experiment. In vitro experiments are likely designed; performance can be simplified and prominently concerned about contents, even designed some extreme conditions to test. A number of means related to fluid experimental measurement are included, such as the Particle Image Velocimetry（PIV）[1], Dual Catheter Method [2]，and ultrasonic method[3] and so on. However, these methods have different kinds of limitations, for example the Dual Catheter Method cannot be used as a routine determination for clinic due to its destructiveness, and PIV test requires expensive equipment. This study was designed by the image processing technology of high-speed photography aiming at the production of a reliable, simple, economic, injury-free and non-contact measurement method.

In Vitro Determination of the Curvatures and Bending Strains Acting on the Leaflets of Polyurethane Trileaflet Heart Valves During Leaflet Motion

1995 ◽  
Vol 209 (4) ◽  
pp. 243-253 ◽  
Author(s):  
J Corden ◽  
T David ◽  
J Fisher
Keyword(s):  
High Speed ◽  
Heart Valves ◽  
Video Camera ◽  
Casting Technique ◽  
Modes Of Failure ◽  
Bending Strain ◽  
High Speed Video Camera ◽  
Valve Opening ◽  
Valve Operation

Leaflet tears originating from the free leaflet edge and calcification around the commissural region are common modes of failure exhibited by explanted bioprosthetic trileaflet heart valves. These may be a result of the cyclic bending and high levels of curvature that affect the leaflets within these areas during normal valve operation. These high leves of curvature occur in a short time period (approximately 20 ms) during rapid leaflet opening and to a lesser degree during leaflet closure. The curvatures that occur at the free leaflet edge of two designs of polyurethane trileaflet heart valve were determined in vitro at various stages during a cardiac cycle using a high-speed video camera (1000 frames/s). Significant deformations at the free leaflet edge were observed and bending radii as low as 0.55 ± 0.125 mm (mean ± standard deviation) were present during leaflet opening, 0.76 ± 0.24 mm during leaflet closure and 1.01 ± 0.27 mm while the valve was fully open during peak systole. The values of curvature were used to determine the values of bending strain and bending stress acting at the free leaflet edge using thin shell bending theory. The calculated values of bending strain were a maximum during the leaflet flexure associated with valve opening. These high levels of bending strain, which occur for short periods of time, are likely to be an important determinant of the valve's durability. It has been shown that the method of manufacture significantly influenced the level of bending strain in the valve leaflets. Valves manufactured using a dip-casting technique resulted in open leaflet bending strains up to 31 per cent lower than valves manufactured from solvent-cast sheets of polyurethane.

Digital Feed-Forward Control of Gas Mixture With High-Speed Valve Switching

2018 ◽  
Author(s):  
Christopher R. Martin ◽  
Todd D. Batzel
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Gas Flow ◽  
Pulse Width Modulation ◽  
Modulation Scheme ◽  
Switching Frequency ◽  
Gas Mixture ◽  
Constant Flow Rate ◽  
Feed Forward Control ◽  
Flow Rate Control

To address a need for digital gas mixture control, this paper presents a valve design for digital gas flow rate control without a feedback measurement. This design uses a transonic nozzle to regulate a constant flow rate with partial pressure recovery and a pulse-width modulation scheme to actuate flow rate without needing precise location of a throttle body. Experimental results from a prototype are presented showing linear variation of flow with respect to duty cycle and switching frequency consistent with the valve’s theory of operation. Outliers are especially prominant as frequency is varied, and are believed to be due to acoustic effects in the supply line.

scholarly journals Developing the Tissue Engineered Heart Valve – a Descriptive Hemodynamic and Ultrasound in Vitro Characterization Study of Heart Valves in a Bioreactor

2021 ◽  
Vol 31 (3) ◽  
pp. 555-563
Author(s):  
Ionela MOVILEANU ◽  
◽  
Dan Octavian NISTOR ◽  
Leslie SIERAD ◽  
Klara BRINZANIUC ◽  
...  
Keyword(s):  
Heart Valve ◽  
High Speed ◽  
Heart Valves ◽  
Normal Function ◽  
Pressure Gradients ◽  
Functional Area ◽  
In Vitro Characterization ◽  
Hemodynamic Characteristics ◽  
Tissue Engineered Heart Valve

The inherent limitations of current heart valve substitutes create the premise for the Tissue Engineered Heart Valve (TEHV), considered the perfect substitute. We aimed to compare in vitro hemodynamic performances of our TEHV, the conventional prosthetic valve and similar porcine valves, by ultrasonography and geometry resulting in six valve models analysis. In a bioreactor, pulmonary and aortic physiology were replicated thus hemodynamic characteristics were tested. Using ultrasound, transvalvular pressure gradients and flow were measured and used to calculate their valvular functional area (VFA) and using a high-speed camera, the geometric peak opening area (GOA) was assessed. The obtained results were normalized to the diameter of the biological prosthesis in order to increase the measurement’s accuracy. The ultrasound revealed normal function of all valves and physiologic transvalvular pressure gradients. The TEHV scaffold revealed absence of laceration or dehiscence, and performances in accordance with the control prostheses. The GOA was facile to obtain and the normalized values proved to be greater than the calculated functional area in all analyzed cases and the peak opening areas resulted lesser for the aortic conditions for all six used valves prototypes. To our knowledge, this is the first study to use bioreactors, for in vitro evaluation of heart valves.

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