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PubMed1987

Long-term circulatory and respiratory support using two artificial ventricles and a fluorocarbon oxygenator.

Using a new heart-lung machine developed at our Institute, experiments were conducted on dogs, donkeys, and monkeys, providing complete and assisted artificial circulation, assisted oxygenation, and perfusion preservation of the heart. The new apparatus consists of two sequentially mounted artificial ventricles working in an antiphase mode; blood oxygenation is accomplished by a reusable oxygenator with a fluorocarbon preoxygenator. Experimental results indicate that clinical use of the apparatus is promising and deserves consideration. The conditions of perfusion were close to physiological conditions and provided long-term survival of the animals. Performance in left ventricular bypass was optimized by monitoring myocardial PO2 and the state of the quick-connect/cut-off assemblies.

Animals↗
PubMedDate not supplied

The evolution of counterpulsation techniques.

Assisted circulation techniques are an outgrowth of extracorporeal pump oxygenator systems developed in the mid 1950s. But the differences in physiology of total perfusions and of parital perfusions for assisting circulation delayed the clinical application of the intra-aortic balloon. The problems and risks in providing circulation assistance and the approaches used to overcome them are discussed. The various counterpulsation techniques are described and data presented to demonstrate the increased survival in patients with myocardial infarction and cardiogenic shock.

Assisted Circulation↗
PubMed1997

Pathophysiological considerations concerning uni- and biventricular mechanical cardiac assist.

Mechanical assisted circulation by the means of cardiac assist devices is a routine procedure in modern cardiac surgery and cardiology. We investigated the impact of mechanical unloading on regional myocardial "stunning" and the influence of assisted circulation on left heart and right heart failure persevered by an ultimate addition of pulmonary hypertension in experimental set ups. We found that mechanical unloading either during ischemia or in the early reperfusion phase attenuates stunning and enhances the return of synchronous heart performance. In our global dysfunction model we showed that the right heart is dispensable. Sufficient inflow to the left heart is provided unless pulmonary hypertension is present. Also additional left heart support can not overcome the deleterious situation and in select cases only additional right heart support can prevent the "low LVAD output" syndrome. We conclude that mechanical assisted circulation and mechanical unloading are beneficial in case of regional and global dysfunction persevered by pulmonary hypertension, however, the knowledge about interactions of assist systems and the circulation has to be improved in order to optimize clinical assist device performance.

Animals↗
PubMedDate not supplied

S-nitrosoglutathione preserves platelet function during in vitro ventricular assist device circulation.

Complications (severe bleeding/thromboembolism) may occur during ventricular assist device (VAD) circulation, caused mainly by platelet dysfunction from platelet activation. We hypothesized that S-nitrosoglutathione (GSNO), having platelet activity preservation properties like nitric oxide (NO), may be a titratable agent to diminish platelet activation and thus preserve platelet function. Dose-response measurement of platelet aggregation by GSNO was performed using an aggregometer. GSNO (1,000 microM) caused inhibition of collagen and ristocetin induced aggregation by approximately 50%. Next, in vitro ventricular assist device (VAD) circulation was performed (over 48 hours using human whole blood), both without (control) and with GSNO (1,000 microM), and the aggregability of perfusate was measured at 0, 0.5, 1, 3, 6, 12, 24, and 48 hours. In control VAD circuits, collagen induced platelet aggregability gradually decreased and became significantly lower after 3 hours of circulation. With GSNO, platelet function did not significantly decrease until after 12 hours. Similar results were seen for ristocetin induced aggregation; control aggregation dropped significantly after 6 hours, but not until after 24 hours with GSNO. Liquid phase measurement of total nitrogen oxides (NO(T)) confirmed added GSNO maintained high perfusate NO(T) compared with control. GSNO is effective in preserving platelet aggregation during the first 12 to 24 hours in vitro and may be effective in preserving platelet function by inhibiting platelet activation during in vivo VAD circulation.

Anti-Bacterial Agents↗
PubMed1995

Current strategy for severe heart failure with mechanical circulatory support.

In the last 10 years, 37 patients received assisted circulation or a ventricular assist device after open-heart operations at the Heart Institute of Japan. After cardiovascular surgery, 12 patients underwent venoarterial bypass (VAB), 13 had biventricular bypass (BVB), 8 had left ventricular bypass (LVB), and the remaining 4 received a left ventricular assist device (LVAD). Weaning and discharge rates of the patients by type of circulatory supports were 41.7 and 25.0% with VAB, 69.3 and 46.2% with BVB, 87.5 and 37.5% with LVB, 75.0 and 50.0% with LVAD, and 44.4 and 11.1% with PCPS, respectively. Concerning complications of postcardiotomy circulatory support, hemorrhage and ventricular arrhythmia postcardiotomy circulatory support, hemorrhage, and ventricular arrhythmia (immature weaning) decreased with low-heparinized isolated left ventricular supports (i.e., LVB, LVAD). However, profound biventricular failure, infection, and multiple organ failure remain as possible complications with any type of assisted circulation. These results suggest that early application of circulatory support and appropriate selection of the mode of support and devices used are important for successful circulatory support.

Adult↗
PubMed1993

Mechanical circulatory support for postcardiotomy ventricular failure: the Heart Institute of Japan experience 1984-1992.

In the last 9 years, 30 patients received assisted circulation or a ventricular assist device after open-heart operations at the Heart Institute of Japan. After cardiovascular surgery, 9 of those patients underwent venoarterial bypass, 10 had biventricular bypass, 7 had left ventricular bypass, and the remaining 4 received a left ventricular assist device. Of the first 15 patients, only 3 (20%) were discharged from the hospital. In contrast, 7 (46.7%) of the last 15 patients were discharged without major complications. With respect to complications, bleeding and ventricular arrhythmia (immature weaning) decreased with low-heparinized isolated left ventricular supports. However, profound biventricular failure, infection, and multiple organ failure remain as possible complications with any type of assisted circulation. These results suggest that early application of circulatory support and appropriate selection of the mode of support and devices used are important for successful circulatory support.

Adult↗
PubMed1982

Experimental and clinical ventricular bypass during acute heart failure.

Mechanical support of the failing heart in the form of bypass of the left and right ventricles by roller pumps was used in 25 dogs with model cardiogenic shock. Early application of left ventricular bypass in acute heart failure normalizes the myocardial bioenergy state and promotes reversible changes in myocardial ultrastructure as demonstrated by an increased surface area of mitochondrial cristae. On the basis of hemodynamics and morphology, we conclude that pump-aided bypass of ventricles without synchronization is a simple and effective method of circulation assistance. Mechanical support duration from 1 to 138 hours has been used in 10 patients following corrective heart surgery.

Acute Disease↗
PubMedDate not supplied

Counterpulsation in experimental cardiogenic shock with ventricular arrhythmias. The antiarrhythmic effect of morphine.

In two groups of dogs a cardiogenic shock was induced and their circulation assisted by counterpulsation. In the second group aside from the counterpulsation, 4 mgrs/Kg of morphine was administered when stable ventricular arrhythmias appeared. Morphine showed to eliminate the ventricular arrhythmias in three cases and lessened them considerably in one, permitting better assistance with a counterpulsator.

Animals↗
PubMed1975

The benefits of corticosteroids in endotoxic shock.

The experiments reported here were undertaken to study the effects of pharmacological doses of corticosteroids administered alone or in conjunction with prolonged (12-hour) assisted circulation in 22 dogs subjected to LD50-60 Escherichia coli endotoxin. The most striking findings were lengthened survival time, higher cardiac output, decreased fluid requirement, and minimal evidence of pulmonary congestion or injury in the animals treated with steroids only. Unexplained mesenteric infarction prematurely terminated the experiments in animals undergoing assisted circulation. The benefits of corticosteroids in experimentally induced endotoxic shock are clearly demonstrated in these experiments. Further studies are needed to clarify the supportive role of assisted circulation in endotoxic shock and to determine any possible advantage of hypothermia over normothermia during its course.

Animals↗
PubMed1999

Nitric oxide inhalation as a chemical assist for circulation in patients after cardiovascular surgery.

The objective of this study was to investigate whether nitric oxide (NO) inhalation might be an alternative strategy as a chemical assist for the circulation in patients showing a deterioration in oxygen delivery. Twelve adult patients whose oxygen delivery indices (DO2I) were less than 400 ml/min/m2 after cardiovascular surgery were included in this study. NO was administered via a premixing system or a side stream system at doses between 1 and 10 (5.1+/-2.4) ppm. Data obtained before and during a 120 min NO inhalation were compared using the paired Student's t-test. The increase in PaO2/FiO2 resulting from NO inhalation was significant (from 162 to 251 mm Hg). DO2I increased significantly from 326 to 417 ml/min/m2 concomitantly with significant increases in both arterial oxygen content (CaO2) and cardiac index (CI) (from 14.1 to 15.4 vol% and from 2.31 to 2.71 L/min/m2 , respectively). The increase in SvO2 during NO inhalation was significant (from 55.2 to 62.6%). Among the other hemodynamic parameters, both total pulmonary resistance and systolic pulmonary arterial pressure (SPAP) showed significant decreases during NO inhalation, but right atrial pressure did not change significantly. There was a close relationship between the baseline SPAP level (bSPAP) and the decrease in SPAP during NO inhalation (dSPAP) (r = -0.88). However, negative correlations were observed between bSPAP and percentage increase in CI (%CI) (r = -0.61) and between bSPAP and percentage increase in DO2I (%DO2I) (r = -0.48). Moreover, positive relationships were observed between dSPAP and %CI (r = 0.62) and between dSPAP and %DO2I (r = 0.45). Hemoglobin (Hb) increased significantly from 11.0 to 11.4 g/dl. There were no significant changes in Fio2, pH, PacO2, or base excess (BE) during NO inhalation. The level of methemoglobin measured during the study period remained within the normal range (0.86+/-0.23%). In conclusion, NO inhalation could be an efficient and alternative assist for the circulation in patients whose oxygen delivery deteriorates after cardiovascular surgery.

Administration, Inhalation↗
PubMedDate not supplied

[A device for complete and assisted artificial circulation].

The authors describe a system for complete and auxiliary extracorporeal circulation (EC), manufactured on the basis of elements of industrial pneumoautomatics in the form of blocks controlling venous and arterial blood flows. The venous part regulates the venous inflow volume by the feedback type mechanism; the arterial part ensures complete EC in the pulsating mode during cardiosurgical intervention and auxiliary EC in the course of heart activity recovery after cardioplegia, promoting an increase of the coronary blood flow and synchronized blood supply.

Extracorporeal Circulation↗