A New Automatic Cardiac Output Control Algorithm for Moving Actuator Total Artificial Heart by Motor Current Waveform Analysis

1996 ◽  
Vol 19 (3) ◽  
pp. 189-196 ◽  
Author(s):  
W.W. Choi ◽  
H.C. Kim ◽  
B.G. Min
Keyword(s):  
Cardiac Output ◽  
Artificial Heart ◽  
Control Algorithm ◽  
Total Artificial Heart ◽  
Waveform Analysis ◽  
Right Atrial ◽  
Current Waveform ◽  
Output Control ◽  
Mock Circulatory System ◽  
Motor Current

A new automatic cardiac output control algorithm for an implantable electromechanical total artificial heart (TAH) was developed based on the analysis of motor current waveform without using any transducer. The basic control requirements of an artificial heart can be described in terms of three features: preload sensitivity, afterload insensivity, and balanced ventricular output. In previous studies, transducers were used to acquire information on the hemodynamic states for automatic cardiac output control. However, such a control system has reliability problems with the sensors. We proposed a novel sensorless automatic cardiac output control algorithm (ACOCA) providing adequate cardiac output to the time-varying physiological demand without causing right atrial collapse, which is one of the critical problems in an active filling device. In vitro tests were performed on a mock circulatory system to assess the performance of the developed algorithm and the results show that the new algorithm satisfied the basic control requirements of the cardiac output response.

Cardiac Output Requirements and Maximum Dimensions for a Neonate Total Artificial Heart

1991 ◽  
Vol 14 (11) ◽  
pp. 707-715 ◽  
Author(s):  
E. Koppert ◽  
G.M. Pantalos ◽  
R. Tieleman ◽  
P. Swier ◽  
G.L. Burns
Keyword(s):  
Cardiac Output ◽  
Artificial Heart ◽  
Total Artificial Heart ◽  
Limiting Factors ◽  
Valvular Regurgitation ◽  
Left Heart ◽  
Hypoplastic Left Heart ◽  
Term Neonates ◽  
Left Heart Syndrome ◽  
First Time

Two equally important issues need to be addressed during the early stages of the design of an implantable total artificial heart (TAH): proper anatomical fit and cardiac output capacity. As part of a first-time feasibility study to develop a neonate-size TAH, two studies were conducted to establish useful anatomical and physiological standards. The first (Study A) was conducted to determine the maximum dimensions of a neonate-size TAH. Twelve preserved hearts from full-term neonates with the hypoplastic left heart syndrome were examined. A second study (Study B) was designed to determine the acceptable minimum stroke volume compatible with minimum neonate cardiac output requirements. This study was based on a combination of: a) reported cardiac output studies in healthy term neonates, and term neonates with heart failure, b) body weight range, and c) limiting factors of TAH technology, e.g., valvular regurgitation and leveling off of the maximum cardiac output value at a specific heart rate and filling pressure. The proposed neonatal standards for TAH technology are presented.

Remifentanil Induces Systemic Arterial Vasodilation in Humans with a Total Artificial Heart

2004 ◽  
Vol 100 (3) ◽  
pp. 602-607 ◽  
Author(s):  
Alexandre Ouattara ◽  
Gilles Boccara ◽  
Uwe Köckler ◽  
Patrick Lecomte ◽  
Pascal Leprince ◽  
...  
Keyword(s):  
Artificial Heart ◽  
Recovery Period ◽  
Invasive Procedure ◽  
Systemic Arterial Pressure ◽  
Early Postoperative Period ◽  
Total Artificial Heart ◽  
Right Atrial ◽  
Vascular Effects ◽  
Hemodynamic Variables ◽  
Left And Right

Background To assess intrinsic vascular effects of remifentanil, increased concentrations were infused in critically ill patients with a total artificial heart. Methods In the early postoperative period after implantation of a total artificial heart, nine ventilated patients requiring short general anesthesia were included in this study. After anesthesia was induced with 0.3 mg/kg intravenous etomidate, the artificial heart settings were modified to render cardiac output "preload-independent." While maintenance of anesthesia was ensured by a continuous infusion of etomidate, increased concentrations of remifentanil (from 0.1 to 1 microg x kg(-1) x min(-1)) were infused in steps of 5 min under hemodynamic monitoring, including left and right atrial pressures, systemic and pulmonary arterial pressures, and left and right cardiac indices. The invasive procedure was started under the highest concentration of remifentanil tolerated by the patient. Infusion of remifentanil was stopped at the end of the invasive procedure, while etomidate infusion was maintained. New hemodynamic measurements were performed at the end of the 12-min recovery period. Results Remifentanil produced a dose-dependent and significant decrease in systemic arterial pressure and vascular resistances (n = 9) from a concentration of 0.25 microg x kg(-1) x min(-1). No significant changes were observed on pulmonary vascular resistances (n = 6). Neither right (n = 9) nor left (n = 6) atrial pressures were affected by remifentanil infusion. Hemodynamic variables returned to baseline value over the 12-min recovery period. Conclusions In humans with a total artificial heart, remifentanil induces a systemic arterial vasodilation without significant effect on the capacitance vessels.

Physiological control of a total artificial heart: conductance- and  arterial pressure-based control

1998 ◽  
Vol 84 (3) ◽  
pp. 868-876 ◽  
Author(s):  
Y. Abe ◽  
T. Chinzei ◽  
K. Mabuchi ◽  
A. J. Snyder ◽  
T. Isoyama ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Arterial Pressure ◽  
Artificial Heart ◽  
Control Method ◽  
Venous Hypertension ◽  
Activity Level ◽  
Total Artificial Heart ◽  
Physiological Control ◽  
The Stability ◽  
Control Equation

To obtain a physiological response by a total artificial heart (TAH), while eliminating the hemodynamic abnormalities commonly observed with its use, we proposed the use of a conductance- and arterial pressure-based method (1/R control) to determine TAH cardiac output. In this study, we endeavored to make use of a variable more closely tied to central nervous system (CNS) efferents, systemic conductance, to provide the CNS with more direct control over the output of the TAH. The control equation that calculates the target cardiac output of the TAH was constructed on the basis of measurement of blood pressures and TAH flow. The 1/R control method was tested in TAH-recipient goats with an automatic method by using a microcomputer. In 1/R control animals, the typical TAH pathologies, such as mild arterial hypertension and substantial systemic venous hypertension, did not occur. Cardiac output varied according to daily activity level and exercise in a manner similar to that observed in natural heart goats. These results indicate that we have determined a control method for the TAH that avoids hemodynamic abnormalities exhibited by other TAH control systems and that exhibits physiological responses to exercise and daily activities under the conditions tested. The stability of the control and the complete lack of inappropriate excursions in cardiac output is suggestive of CNS involvement in stabilizing the system.

Switch from Assist Device to Total Artificial Heart to Improve Cardiac Output

2009 ◽  
Vol 57 (01) ◽  
pp. 52-53 ◽  
Author(s):  
J. Sindermann ◽  
A. Hoffmeier ◽  
T. Tjan ◽  
H. Scheld
Keyword(s):  
Cardiac Output ◽  
Artificial Heart ◽  
Total Artificial Heart ◽  
Assist Device
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