Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Assisted Circulation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1995

Experimental study of physiological advantages of assist circulation using oscillated blood flow.

To estimate the effect of oscillated blood flow on hemodynamics in an awake condition, left ventricular assist circulation using oscillated blood flow was performed on 3 adult goats as chronic animal examination. A vibrating flow pump (VFP) was used for generating high-frequency oscillated flow. The blood flow rate of assisted circulation was approximately 1.0 L/min, and the driving frequency of VFP was 25 Hz. Systemic vascular resistance and arterial impedance were calculated in this study. Systemic vascular resistance during assist circulation was decreased compared with that without assistance. Oscillated blood flow may be effective in decreasing vascular resistance. Moreover, it was suggested from the study of arterial impedance that motive characteristics of the vascular wall against changing blood pressure may keep their normal reaction. Therefore, oscillated blood flow may be used for left ventricular assist circulation as concluded from the study of the characteristics of blood vessels.

Animals↗
PubMed1997

Renal circulation and cellular metabolism during left ventricular assisted circulation: comparison study of pulsatile and nonpulsatile assists.

We examined left ventricular assist during 6 h for an acute myocardial infarction model in pigs. The outflow cannula was placed in the ascending aorta and an inflow cannula in the left atrium. A pump (Pulsatile group: Zeon Medical and Nonpulsatile group: Nikkiso HPM-15) was connected to each cannula. Items measured were the regional blood flow of the cortex and the medulla in the kidney, renal arterial flow, arterial blood ketone body ratio (AKBR), lactate/pyruvic acid, BUN, creatinine and beta 2-microglobulin. After experimental study, the kidneys were removed, and a pathological study was performed. In the pulsatile assisted group, renal cortical blood flow increased but medulla blood flow decreased. On the other hand, in the nonpulsatile assisted group, both regional blood flows decreased. That means that in the pulsatile assisted group intrarenal redistribution improved, rather than in the nonpulsatile assisted group. The results of our study indicated that pulsatile assist produced superior circulation in the kidney, and the microcirculation on the cell level was superior as well in early treatment of acute left heart failure.

Animals↗
PubMedDate not supplied

[Study of the efficacy of assisted circulation control by mathematical and physical modeling methods].

The efficiency of the assisted circulation control has been studied by mathematical and physical simulation. It has been assessed by simulating a transient process within the circulation system that imitated the left ventricular failure. The control system for regulation of the assisted circulation process based on the mathematical models is shown to be capable of maintaining the main hemodynamic parameters and the left ventricular relief at the present level in heart failure.

Assisted Circulation↗
PubMed1990

[Assisted circulation by external heterotopic prosthesis as a bridge to heart transplantation].

Eleven patients aged 7 to 58 years were placed on assisted circulation with Pierce (2 cases) or Abiomed (9 cases) external prosthetic ventricles as a bridge to cardiac transplantation. The indications were terminal cardiac failure following cardiomyopathy (7 cases), decompensated ischemic heart disease (3 cases) and subacute post-transplantation rejection (1 case). The duration of the assisted circulation ranged from 24 hours to 11 days. All patients were transplanted but 3 died after transplantation (27%). The circulatory assistance was satisfactory in all patients as shown by the regression of clinical signs of low cardiac output and the normalisation of diuresis. The complications observed during assisted circulation and after cardiac transplantation were: haemorrhage (36%), infection (27%) and thromboembolism (9%). These preliminary results with a 72% post-transplantation survival rate, show that both systems are effective "bridges to cardiac transplantation". The Abiomen device is excellent value for money and relatively simple to install and represents a good compromise between the sophisticated techniques of circulatory assistance and the problems of the cost of health care.

Adolescent↗
PubMed2002

[Mechanical circulation assistance. Changes in techniques and concepts. Implication of anesthesia/resuscitation on patient management. Retrospective study on 159 cases].

Since the first case in 1987, 159 patients underwent heart mechanical assist device as a bridge to transplantation or as potential post transplanted recovery (right ventricular failure or graft failure) or in case of unsuccessful weaning of cardiopulmonary bypass. Survival rate of patients under assist device waiting either for heart transplantation or for functional recovery was 75.4%. 67.7% of them were transplanted (1 year survival rate 63%). Improvement of cardiac assist device technology and new method of intensive care allowed the observation of 6 myocardial recovery without transplantation 4 after more than 3 weeks of cardiac support. The increase in cardiac assist duration (mean duration = 103 days in 2001) because of organ shortage, led to a change in patients medical care. Unexpected interactions between cardiac treatments and anaesthetic drugs should lead anaesthetists to a better understanding of the failing heart pathophysiology. Consequently, anaesthetists well conduct appropriately anaesthesia and perioperative monitoring. Technical and conceptual evolution should allow some patient, to come back home and to fully recover without the need of transplantation.

Adolescent↗
PubMed2002

[Circulation assist in the radical operation of retro-peritoneal malignancy with the inferior vena cava thrombotic involvement].

OBJECTIVE: To discuss the key role of various mode of circulation assist in the radical operation of retro-peritoneal malignancy with the inferior vena cava thrombotic involvement. METHODS: >From the June 1999 to the March 2001, 6 patients with retro-peritoneal malignancy with thrombosis involving the inferior vena cava, were completely resected with various mode of circulation assist. RESULTS: All the patients operated have good outcomes and follow-up (1 - 20 months) except one death 1 month after operation. CONCLUSION: According to the various types of tumor thrombi, individualized and technically feasible circulation assist mode should be utilized to achieve the satisfactory outcomes.

Aged↗
PubMedDate not supplied

[Working organs of actuating devices for assisted circulation].

Business ends of operating mechanisms for assisted circulation, based on the principle of contrapulsation, must satisfy a number of requirements on which the safety and the effectiveness of their performance depend. Among these of particular importance are the working volume of the arrangement, correct conformity of the balloon and aorta diameters and also the duty cycle of the arrangement.

Assisted Circulation↗
PubMedDate not supplied

Protection of platelet glycoprotein IIb/IIIa receptor complex preserves platelet function during in vitro ventricular assisted circulation.

Platelet dysfunction probably contributes to bleeding associated with ventricular assist devices (VADs). Previous evidence suggests that VAD associated platelet dysfunction may be due to dysfunction of the platelet fibrinogen receptor. The purpose of this investigation was to test the hypothesis that selective protection of platelet fibrinogen receptor preserves platelet aggregating ability during in vitro ventricular assisted circulation. Eight in vitro nonpulsatile centrifugal VAD circuits were simulated for four days using 450 ml of fresh human whole blood. Temperature, activated clotting time, pH, PCO2, PO2, Ca2+, and glucose were maintained at physiologic values. Flow was maintained at a constant 2.0 L/min/m2. We examined whole blood platelet aggregation induced by ristocetin, collagen, and adenosine diphosphate (ADP). We added a highly specific reversible inhibitor (MK-383) of the glycoprotein (GP) IIb/IIIa receptor complex before start of circulation to the final four VAD experiments. ADP induced aggregation decreased within the first hour of circulation. Ristocetin and collagen induced aggregation decreased to negligible levels after 10 hours of circulation. With MK-383, ristocetin induced aggregation was preserved. Addition of MK-383 did not alter the decrease of ADP and collagen induced aggregation. These results suggest platelet aggregating ability is maintained with protection of the platelet fibrinogen receptor during in vitro ventricular assisted circulation.

Blood Platelets↗
PubMed1980

[Assisted circulation during coronarography: advantages and limitations. A report on 63 cases (author's transl)].

During 2588 coronarography examinations conducted over a period of 4 years, assisted circulation was employed in 63 cases to reduce the risks of the examination procedure in particularly debilitated patients. These high risk cases included 48 patients with unstable angina resistant to medical treatment and 45 cases of recent infarcts with complications. Mortality with assisted circulation was very low, in spite of the severe nature of the affections, but the authors use this technique in only a limited number of cases, mainly because of the risk of lower limb ischemia, and the possibility of using intravenous nitroglycerin and analgesia from neuroleptics for examination. For this reason the number of cases examined in this way has dropped from 4% in 1977 to 2% in 1978, though assisted circulation is still employed in certain particularly severe cases of angina, and for infarcts with complications.

Angina Pectoris↗
PubMed1966

Synchronous assisted circulation.

A summary of the work in synchronous assisted circulation undertaken at the Tufts-New England Medical Center Hospitals for the past year is presented.Counterpulsation, introduced in 1958, reduces myocardial oxygen consumption and increases coronary flow. It was applied to seven patients with terminal cardiogenic shock: one patient survived and three showed temporary improvement.The synchronous external assist makes possible control of the blood volume distribution, increases the cardiac output and decreases the pressure work of the left ventricle. The procedure does not require cannulation of the vascular system and is atraumatic.The same concept has been applied to the right ventricle using synchronous respiration.An "in-series" subcutaneously exteriorized prosthetic left ventricle, capable of long-term left ventricular assist, is under development. The device can atrialize the left ventricle. It requires no intracorporeal source of energy.This program offers hope for the development of effective temporary and long-term circulatory-assist procedures.

Aged↗
PubMed1991

Transesophageal echocardiographic evaluation in mechanically assisted circulation.

Transesophageal echocardiography (TEE) has assumed an increasing importance in cardiothoracic surgery, but its use in patients with mechanically assisted circulation is unclear. We performed TEE in 11 patients: total artificial heart (TAH) 2, right ventricular assist device (RVAD) 2, left ventricular assist device (LVAD) 6, biventricular assist device (BVAD) 1. TEE was helpful in three areas. (1) selection of the assist device (AD): evaluation of left and right ventricular function allows differentiation of left, right or biventricular failure. (2) management of patient and optimization of pump performance: in all patients, correct cannula position and pump flow could be identified. Right ventricular failure in the presence of LVAD was found to cause hemodynamic instability in 4 patients. In 1 patient with repeated RV dilation and hypotension despite RVAD, TEE allowed optimal pump settings to be determined. (3) weaning from AD: Recovery of ventricular function can be assessed prior to weaning and repeatedly monitored during weaning. TEE in TAH is limited to problems such as identification of atrial thrombus or inflow valve dysfunction. We conclude that TEE is useful in the setting of mechanically assisted circulation for AD selection, improvement of patient management, optimization of pump performance and during weaning from AD.

Assisted Circulation↗