Automation of the Harvard Apparatus Pulsatile Blood Pump

2012 ◽  
Vol 6 (4) ◽  
Author(s):  
Charles E. Taylor ◽  
Zachary W. Dziczkowski ◽  
Gerald E. Miller
Keyword(s):  
Heart Rate ◽  
Stroke Volume ◽  
Mechanical Design ◽  
Blood Pump ◽  
Cardiac Assist ◽  
Usb Communication ◽  
And Performance ◽  
Vitro Analysis ◽  
Pulsatile Blood Pump

Producing accurate physiological circulatory conditions in vitro is integral to the evaluation of cardiac assist technologies. The ability to simulate cardiac function, normal or pathological, is dependent on the capabilities of the pump deployed for this purpose. Presented is a reference standard for this in vitro analysis, with automation features targeted for robust bench-top testing. Cardiac performance is typically described in terms of stroke volume, heart rate, and percent systole. Respectively, these three settings prescribe the volume of fluid ejected, the rate of pumping, and the percentage of the pumping cycle spent in ejection. A pump that provides settings for each of these parameters and precise repeatability allows for accurate construction of simulation conditions. These capabilities are present in the commercially available Harvard Apparatus 1423 pulsatile blood pump. Modifications have been made to this particular model that allow for the automation of its function and real-time performance determination. Discussed in this publication is the design and performance of a modified 1423 pump that employs universal serial bus (USB) communication in the control of its stroke volume, heart rate, and percent systole. The percent systole is denoted as the phase ratio on the hardware. Utilization of an embedded microcontroller (MCU) allows for not only the digital communication via a computer terminal, but process control of the subsystems maintaining each parameter. Care was taken to preserve the mechanical design employed by Harvard Apparatus; the modifications were not invasive to the mechanical driveline of the pump. Electromechanical design characterization was performed in Simulink® using the following Simscape™ block sets: Simscape™ Foundation Library, SimElectronics®, and SimMechanics™. This provided an accurate model of the systems during the design process, which assisted in the deployment of the process controllers with minimal prototype construction. Communication with the MCU is achieved with American Standard Code for Information Interchange (ASCII) commands delivered through a LabVIEW VI interface. Continuous readbacks on fill/ejection rate, pump rate (HR), percent systole (PS), and stroke volume (SV) are possible with these modifications. The deployed upgrade allows for complete automation of the Harvard Apparatus 1423 pulsatile blood pump, with the capability to run sequences of conditions without the need for manual intervention.

Experimental Analysis of Pulsatile Flow Through Elastic Collapsible Tubes: Application to Cardiac Assist Device

1990 ◽  
Vol 112 (1) ◽  
pp. 75-79 ◽  
Author(s):  
O. Lichtenstein ◽  
U. Dinnar
Keyword(s):  
Systemic Circulation ◽  
Aortic Pressure ◽  
Assist Device ◽  
Cardiac Assist ◽  
Cardiac Assist Device ◽  
Non Invasive ◽  
Failing Heart ◽  
In Series ◽  
Vitro Analysis

This study presents a simulated analysis of Phased Compression Cardiac Assist Device (PCCAD) and evaluation of its applicability as a non-invasive temporary assist for a failing heart. The new technique is based on the chest pump mechanism for blood flow augmentation during external massage by phased compression of the abdominal and thoracic cavities. A semi-closed hydraulic system to simulate the systemic circulation was constructed; the system includes a left ventricle which functions according to the Starling principle and a pneumatic system which controls the pressures applied to the thoracic and abdominal cavities, in complete synchronization with the beating normal or failing heart. The possibility of manipulating the three pumps in series (venous, heart, and arterial) has been checked, and the principal parameters which effect the efficiency of the PCCAD were evaluated. This in-vitro analysis shows the high potential of a non-invasive temporary cardiac assist device. It points to the necessary measures one has to take in order to achieve good synchronization and to interfere externally with the augmentation of cardiac output or with the augmentation of root aortic pressure.

The importance of nervous and humoral mechanisms in the control of cardiac performance in the Atlantic cod Gadus morhua at rest and during non-exhaustive exercise

1988 ◽  
Vol 137 (1) ◽  
pp. 287-301 ◽  
Author(s):  
M. Axelsson
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Gadus Morhua ◽  
Positive Inotropic Effect ◽  
Atlantic Cod ◽  
Inotropic Effect ◽  
Response Curves

The nervous regulation of heart rate and stroke volume in the Atlantic cod Gadus morhua was investigated both in vivo, during rest and exercise, and in vitro. The cholinergic and adrenergic influences on the heart were estimated in experiments with injections of atropine and sotalol. At rest the cholinergic and adrenergic tonus on the heart were 38% and 21%, respectively (ratio 1.81:1). At the end of an exercise period, the cholinergic tonus had decreased to 15% but the adrenergic tonus had increased to 28% (ratio 0.54:1). The results suggest that variation of the cholinergic tonus on the heart is a major factor in the regulation of the heart rate. In one group of fish, cardiac output was also measured, allowing calculation of stroke volume. Cardiac output increased significantly during exercise, and this effect persisted in the presence of both atropine and sotalol, although the increase in heart rate was reduced or abolished. The persisting increase in cardiac output during exercise is due to an increase in stroke volume, reflecting a Starling relationship. In the presence of the adrenergic neurone-blocking agent bretylium, a positive inotropic effect on isolated, paced atrial and ventricular strips was observed. In the atrial preparations the effect persisted after 24 h. The effect was prevented by pretreatment with sotalol or cocaine, but potentiated by phentolamine pretreatment. This shows that bretylium exerts its neurone-blocking action after being taken up into the adrenergic nerves, and suggests that the positive inotropic effect of bretylium observed in vivo is due to release of endogenous catecholamines. The concentration-response curves for adrenaline on isolated spontaneously beating atrial preparations showed that the concentrations of catecholamines necessary to produce appreciable effects on the heart are higher than the concentrations found in cod plasma during ‘stress’ situations (handling and exhaustive swimming).

Solanum macrocarpon Leaf Extracts Reduced Blood Pressure and Heart Rate After Oral Administration to Spontaneously Hypertensive Rats

2019 ◽  
Vol 17 (3) ◽  
pp. 282-290 ◽  
Author(s):  
Olayinka A. Oluwagunwa ◽  
Adeola M. Alashi ◽  
Rotimi E. Aluko
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Leaf Extracts ◽  
Spontaneously Hypertensive ◽  
Vitro Analysis ◽  
Gallic Acid Equivalent ◽  
In Vitro Analysis

The aim of this work was to determine the ability of polyphenol-enriched aqueous vegetable leaf extracts to ameliorate blood pressure and heart rate dysfunctions in spontaneously hypertensive rats (SHRs). Solanum macrocarpon (SM), a common edible vegetable leaf in West Africa was cultivated using varying levels (0-80 kg/ha) of urea that was applied at planting (T1) or 2 weeks after planting (T2). In vitro analysis showed that total polyphenolic compounds varied from 489.87 ± 5.66 to 513.56 ± 1.42 mg gallic acid equivalent/g dry wt of extract. Rutin, caffeic acid and myricetin were the major polyphenols quantified in the extracts. All the extracts inhibited in vitro activities of renin and angiotensin converting enzyme to varying extents. Two extracts (SM40T1 and SM80T2) were orally administered to SHRs at 100 or 500 mg/kg body wt. Results showed that systolic blood pressure was reduced to a similar level by SM40T1 (10.8 mmHg) and SM80T2 (10.5 mmHg) for the 100 mg/kg body wt dose; the 500 mg/kg body wt dose produced similar values. Diastolic blood pressure and heart rate were also depressed by the two extracts with similar effects observed for both doses. We conclude that the leaf extracts could serve as potential ingredients to formulate antihypertensive functional foods and nutraceuticals.

Dynamic Hemodynamic Energy Loss in Normal and Stenosed Aortic Valves

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Choon-Hwai Yap ◽  
Lakshmi P. Dasi ◽  
Ajit P. Yoganathan
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Energy Dissipation ◽  
Stroke Volume ◽  
Momentum Equation ◽  
Navier Stokes ◽  
Hydrodynamic Characteristics ◽  
Clinical Tool ◽  
Heart Rates

Aortic valve (AV) stenosis, if untreated, leads to heart failure. From a mechanics standpoint, heart failure can be interpreted as the failure of the heart to generate sufficient power to overcome energy losses in the circulation. Thus, energy efficiency-based measures for evaluating AV performance and disease severity have the advantage of being a direct measure of the contribution of the AV hydrodynamic characteristics toward heart failure. We present a new method for computing the rate of energy dissipation as a function of systolic time, by modifying the Navier–Stokes momentum equation. This method preserves the dynamic term of the Navier–Stokes momentum equation, and allows the investigation of the trend of the rate of energy dissipation over time. This method is applied to a series of in vitro experiments, where a trimmed porcine valve is exposed to various conditions: varying stroke volumes (50 ml to 90 ml) at the fixed heart rate; varying heart rates (60–80 beats/min) at fixed stroke volume; and varying stenosis levels (normal, mild stenosis, moderate stenosis). The results are: (1) energy dissipation waveform has a distinctive pattern of being skewed toward late systole, due to flow instabilities during deceleration phases; (2) increasing heart rate and stroke volume increases energy dissipation, but the normalized shape of the energy dissipation waveform is preserved across heart rates and stroke volumes; (3) increasing stenosis level increases energy dissipation, and also alters the normalized shape of the energy dissipation waveform. Since stenosis produces a signature energy dissipation waveform shape, dynamic energy dissipation analysis can potentially be extended into a clinical tool for AV evaluation.

scholarly journals In vitro study of flow propagation velocity as it relates to stroke volume and heart rate

2003 ◽  
Vol 41 (6) ◽  
pp. 419
Author(s):  
Donald Stevens ◽  
Mark Trinh ◽  
Ikuo Hashimoto ◽  
Aarti Hejmadi ◽  
Xiaokui Li ◽  
...  
Keyword(s):  
Heart Rate ◽  
Stroke Volume ◽  
Propagation Velocity ◽  
In Vitro Study ◽  
Vitro Study ◽  
Flow Propagation Velocity ◽  
Flow Propagation

A Compact Centrifugal Blood Pump for Extracorporeal Circulation: Design and Performance

1987 ◽  
Vol 109 (3) ◽  
pp. 272-278 ◽  
Author(s):  
Shinobu Tanaka ◽  
Shuzo Yamamoto ◽  
Ken-ichi Yamakoshi ◽  
Akira Kamiya
Keyword(s):  
Thrombus Formation ◽  
Animal Experiments ◽  
Left Ventricular ◽  
Blood Pump ◽  
Assisted Circulation ◽  
In Vitro Tests ◽  
Outer Diameter ◽  
Centrifugal Blood Pump ◽  
And Performance

A new compact centrifugal blood pump driven by a miniature DC servomotor has been designed for use for short-term extra corporeal and cardiac-assisted circulation. The impeller of the pump was connected directly to the motor by using a simple-gear coupling. The shaft for the impeller was sealed from blood by both a V-ring and a seal bearing. Either pulsatile or nonpusatile flow was produced by controlling the current supply to the motor. The pump characteristics and the degree of hemolysis were evaluated with regard to the configuration of the impeller with a 38-mm outer diameter in vitro tests; the impeller having the blade angles at the inlet of 20 deg and at the outlet of 50 deg was the most appropriate as a blood pump. The performance in an operation, hemolysis and thrombus formation in the pump were assessed by a left ventricular bypass experiment in dogs. It was suggested by this study that this prototype pump appears promising for use not only in animal experiments but also in clinical application.

A hemodynamic comparison of young and older endurance athletes during exercise

1985 ◽  
Vol 58 (6) ◽  
pp. 2041-2046 ◽  
Author(s):  
J. M. Hagberg ◽  
W. K. Allen ◽  
D. R. Seals ◽  
B. F. Hurley ◽  
A. A. Ehsani ◽  
...  
Keyword(s):  
Heart Rate ◽  
Stroke Volume ◽  
Vascular Resistance ◽  
Age Groups ◽  
Maximal Heart Rate ◽  
Master Athletes ◽  
Older Athletes ◽  
Submaximal Work ◽  
And Performance ◽  
Sedentary Subjects

This study assessed the hemodynamic responses to exercise of master athletes (56 +/- 5 yr of age) who placed in the top 10% of their age groups in local 10-km competitive events, competitive young runners (26 +/- 3 yr), young runners matched in training and performance to the master athletes (25 +/- 3 yr), and healthy older sedentary subjects (58 +/- 5 yr). The maximal O2 consumption (VO2max) of the master athletes was 9 and 19% lower than that of the matched young and competitive young runners, respectively. When compared at the same relative submaximal work rates, these three groups had similar stroke volumes and arteriovenous O2 (aVO2) differences, though the master athletes had lower VO2, cardiac output, and heart rate, and higher vascular resistance. The older sedentary group had a lower stroke volume, aVO2 difference, and higher vascular resistance than the master athletes. Maximal stroke volume and estimated aVO2 difference were the same in the three groups of athletes; the lower maximal heart rate of the master athletes appears to account for their lower VO2max. The older sedentary subjects' VO2max was 47% lower than that of the master athletes; this difference was almost equally the result of a lower stroke volume and a lower a-VO2 difference. Thus these older athletes did not exhibit the decline in maximum stroke volume and aVO2 difference that occurs with aging in sedentary individuals; they also appear to have retained a greater peripheral vasodilatory response than their sedentary peers.

Comprehensive multilevel in vivo and in vitro analysis of heart rate fluctuations in mice by ECG telemetry and electrophysiology

2015 ◽  
Vol 11 (1) ◽  
pp. 61-86 ◽  
Author(s):  
Stefanie Fenske ◽  
Rasmus Pröbstle ◽  
Franziska Auer ◽  
Sami Hassan ◽  
Vanessa Marks ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Fluctuations ◽  
Vitro Analysis ◽  
In Vitro Analysis

The native structure of the eukaryotic ribosome

1983 ◽  
Vol 41 ◽  
pp. 432-433
Author(s):  
R.A. Milligan ◽  
P.N.T. Unwin
Keyword(s):  
Ribosomal Proteins ◽  
Crystal Form ◽  
Native Structure ◽  
X Ray Diffraction ◽  
Eukaryotic Ribosome ◽  
Vitro Analysis ◽  
In Vitro Analysis ◽  
Resolution Structure ◽  
Stable Unit

A detailed understanding of the mechanism of protein synthesis will ultimately depend on knowledge of the native structure of the ribosome. Towards this end we have investigated the low resolution structure of the eukaryotic ribosome embedded in frozen buffer, making use of a system in which the ribosomes crystallize naturally.The ribosomes in the cells of early chicken embryos form crystalline arrays when the embryos are cooled at 4°C. We have developed methods to isolate the stable unit of these arrays, the ribosome tetramer, and have determined conditions for the growth of two-dimensional crystals in vitro, Analysis of the proteins in the crystals by 2-D gel electrophoresis demonstrates the presence of all ribosomal proteins normally found in polysomes. There are in addition, four proteins which may facilitate crystallization. The crystals are built from two oppositely facing P4 layers and the predominant crystal form, accounting for >80% of the crystals, has the tetragonal space group P4212, X-ray diffraction of crystal pellets demonstrates that crystalline order extends to ~ 60Å.

Sign in / Sign up

Export Citation Format

Share Document