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PubMed1979

[Prolonged peripheral arteriovenous perfusion with a membrane oxygenator].

The authors have developed the optimal method of performing prolonged veno-arterial perfusion and studied its influence on the animal organism. In 22 experiments a membrane oxygenator on the national film "Sigma" was used. It has been established that for successful performing of prolonged veno-arterial perfusion it is necessary to strictly maintain the circulating blood volume and take measures to prevent disorders in the microcirculation. The blood trauma in the membrane oxygenator with the "Sigma" film is inimal.

Animals↗
PubMed1975

[Intra-aortic balloon pumping in cardiogenic shock after cardiac surgery (author's transl)].

The results of intra-aortic balloon pumping in 7 patients with cardiogenic shock after cardiac surgery are reported. 2 patients were unresponsive to IABP, 4 patients showed initial stabilization of the circulation, but became IABP-dependent and died. One patient could be weaned from IABP, but died of uncontrollable cardiac arrhythmias. These results are discussed.

Adolescent↗
PubMed1977

Clinical and hemodynamic results of intraortic balloon counterpulsation and surgery for cardiogenic shock.

Forty-two patients with cardiogenic shock (CS) secondary to myocardial infarction were treated with intra-aortic balloon pumping (I.A.B.P.). In 14 patients C.S. was associated with ventricular septal defect (V.S.D.) and in four with mitral regurgitation (M.R.) secondary to rupture of the posterior papillary muscle. All patients were resistant to conventional medical therapy. Shock was reversed in 20 of the 24 patients in C.S. without mechanical complications. After 24 to 48 hours of I.A.B.P., cardiax index (C.I.) increased from 1.38 to 2.00 L./min./M2, systolic arterial pressure (S.A.P.) from 83 to 96 mm. Hg, urinary output (U.O.) from 10 to 56 ml. per hour, and pulmonary wedge pressure (P.W.P.) decreased from 22 to 16 mm. Hg. Three patients treated with I.A.B.P. alone survived more than 1 year; of the 13 patients who were balloon dependent, four have undergone emergency surgical procedures and two were long-term survivors. In all patients with mechanical complications, I.A.B.P. resulted in significant clinical and hemodynamic improvement. P.W.P. decreased from 19 to 15 mm. Hg, and U.O. increased from 13 to 38 ml. per hour while S.A.P. remained unchanged. In patients with V.S.D. the pulmonary/systemic flow ratio (P/S) declined from 3.5 to 2.8; in patients with M.R., "V" wave amplitude decreased by 8 mm. Hg. Emergency surgery was performed in 10 patients with V.S.D. and in three patients with M.R. and there were eight long-term survivors (13 to 27 months). It is concluded that I.A.B.P. is an effective means of supporting the circulation in C.S. Of the 42 patients with C.S. treated by combining I.A.B.P. and emergency surgery, 13(31%) were long-term survivors (20 +/- 6 months).

Adult↗
PubMed1979

A new technique to increase coronary flow. Preliminary report.

This study was planned to investigate whether part of the energy produced by cardiac contraction to propel blood toward the systemic circulation can be used to increase the coronary flow in systole. Ten devices (I-X) designed to divert laterally part of a flow column (without substantially increasing resistance to flow) were tested in a mock circulation and in nine anesthetized dogs. An increase of 11.69 +/- 1.97% (mean +/- SEM, P less than 0.005) in "coronary flow" and of 8.98 +/- 0.56% (mean +/- SEM, P less than 0.001) in coronary sinus flow were obtained with device I mounted on a stylet and placed above the "aortic valve" in the mock circulation and the dogs, respectively, without increasing the flow resistance. The results in;dicate the possibility of diverting part of the aortic flow toward the coronary arteries without increasing mean aortic pressure.

Animals↗
PubMed1979

[Effect of auxilliary orthograde perfusion on lesser circulation hemodynamics].

The causes of disorders of the venous return of blood to the heart in development of acute experimental cardiovascular insufficiency were studied. It was established that grave hemodynamic disturbances in pulmonary circulation are the consequence but not the cause of the sharp decrease of venous blood return to the heart with the development of acute cardiovascular insufficiency.

Acute Disease↗
PubMed1992

Skeletal muscle ventricles in the pulmonary circulation: up to 16 weeks' experience.

Skeletal muscle ventricles (SMVs) were constructed from the right latissimus dorsi muscle of 8 mongrel dogs. After a 3-week vascular delay period, each SMV was electrically preconditioned with 2-Hz continuous stimulation of the thoracodorsal nerve for 6 weeks. A porcine-valved conduit was then anastomosed between the right ventricle and the SMV, with a second valved conduit connecting the SMV to the main pulmonary artery. The pulmonary artery was then ligated proximal to the conduit. The SMVs were stimulated to contract in 1:2 diastolic mode with a 33-Hz burst frequency. Effective right ventricular assist was achieved in all dogs. Cardiac output increased by 22.6% (1,799 +/- 97 versus 1,467 +/- 84 mL/min; p less than 0.001), systemic systolic arterial pressure by 9.3% (90.1 +/- 3.5 versus 82.4 +/- 3.9 mm Hg; p less than 0.005), and peak pulmonary artery pressure by 31.8% (27.8 +/- 2.0 versus 21.1 +/- 1.7 mm Hg; p less than 0.001) at the initiation of this study. In 6 dogs, effective right heart assist was sustained for periods of between 1 week and 12 weeks. Two dogs survived for longer than 3 months, though with evidence of deteriorating SMV function. These results demonstrate the feasibility of providing sustained right ventricular assist using this modified "Rastelli-SMV" configuration, which obviates the limitations imposed by low right atrial preload.

Adaptation, Physiological↗
PubMedDate not supplied

[Elaboration of the structure and principles of construction of a unified system for the apparatus for artificial circulation].

A pertinet analysis and assessment of medico-technical and ergonomic characteristics, both of individual extracorporeal circulation units (ECU) and major functional components (pumps, oxygenators, etc) served as a background to suggesting a principle for establishing a unitized ECU system based on the functional (performance) and spatial (packaged) module.

Adult↗
PubMed1978

[Counterpulsation by means of a new device with a pulsatile blood flow in open heart operations (author's transl)].

A new counterpulsation method in operations on an open heart is described. Clinical experience in the use of the new device in 124 patients, which also makes it possible to produce a pulsatile flow of blood in the system of extracorporeal circulation, testifies to its effectiveness. The authors claim that the positive changes in cardiac output, diastolic and systolic pressure, and coronary circulation are among the factors which cause an improvement in the final result of the operation in patients with severe valvular diseases and ischemic heart disease.

Adult↗
PubMed1984

Pulmonary circulatory support. A quantitative comparison of four methods.

Profound right ventricular failure was produced in 16 goats by inducing ventricular fibrillation after the systemic circulation had been supported with a left atrial-aortic bypass pump. In each animal, four methods of providing pulmonary blood flow were compared quantitatively: passive flow through the pulmonary artery due to a right atrial to left atrial pressure gradient; pulmonary artery pulsation via a 40 ml intra-aortic type balloon within a 20 mm Dacron graft anastomosed to the main pulmonary artery; pulmonary artery pulsation via a 65 ml single-port, valveless, sac type pulsatile assist device; and right atrial-pulmonary arterial bypass via a valved pneumatic pulsatile pump. Average cardiac index of the 16 animals for each method was 31.1 +/- 12.9, 44.4 +/- 13.6, 64.3 +/- 16.9, and 102.0 +/- 20.7 ml/min/kg, respectively. Passive pulmonary artery flow alone provided inadequate pulmonary circulatory support. Addition of pulmonary artery pulsation via the intra-aortic balloon within a conduit increased cardiac index 13.3 ml/min/kg (43%) above passive pulmonary artery flow (p less than 0.0005); however, the cardiac index remained inadequate. Increasing pulmonary artery pulsation volume with a 65 ml sac device provided a 32.2 ml/min/kg (106%) increase in cardiac index above passive flow (p less than 0.0005) to a level that was marginally adequate. The valved right atrial-pulmonary arterial bypass pump increased cardiac index 70.9 ml/min/kg (228%) above passive pulmonary artery flow (p less than 0.0005) to a satisfactory level and is the recommended method of pulmonary circulatory support in profound right ventricular failure.

Animals↗
PubMed1991

Development of a new moving-actuator type electromechanical total artificial heart.

A new type of electromechanical total artificial heart based on a moving-actuator mechanism was developed to decrease the total pump size and to improve the fitting characteristic of the pump to atrial remnants and arterial vessels. The blood pump consists of three major parts: right and left blood sacs and a moving pump actuator between two sacs. The total weight is 810 g and the volume of the pump is 770 ml. The actuator rolls back and forth on a circular track, producing alternating blood ejection. The pump performance was evaluated in mock circulation and animal implant experiments. The pump was implanted for 100 h in a calf (approximately 100 kg) with a stable hemodynamic state until accidental (electrical short circuit) death.

Animals↗
PubMed1979

Mechanical cardiopulmonary support and artificial hearts.

The literature pertaining to the field of mechanical support of the circulation has been selective reviewed. The principal restraints to its further progress have been highlighted, and the efforts of the writer and his coworkers in certain of these sensitive areas has been commented on. The future of the materials problem, a major one, lies in study at the molecular level.

Animals↗
PubMed1990

Manipulation of external pressure as a method to assist the failing heart.

The development and state of the art in circulatory assistance using external pressure variations is reviewed. All of these techniques use the principle that by cyclic external pressure waves properly timed to the cardiac cycle, hemodynamic energy can be noninvasively transmitted to assist the circulation. Cyclic pressure waves to the lower body require that the high pressure phase occurs in diastole in order to augment cardiac output or coronary flow. In contrast, pressure waves to the chest would optimally augment cardiac output if they begin at the onset of ventricular systole. Manipulation of lung pressure by synchronized ventilation may be also utilized to augment cardiac output. The above methods are discussed in detail in the manuscript with special emphasis on the pathophysiology and mechanisms of cardiac assistance.

Animals↗
PubMed1985

Pulmonary artery balloon counterpulsation in the management of right heart failure during left heart bypass.

Pulmonary artery balloon counterpulsation was instituted in 10 pigs when right ventricular failure limited cardiac output. Global myocardial depression was produced by infusion of propranolol, and the left ventricle was fully supported by left heart bypass. A stable model of failure was achieved in six pigs. Following application of pulmonary artery balloon counterpulsation right atrial pressure decreased from 18.2 +/- 2.1 to 15.9 +/- 2.5 mm Hg (p less than 0.05). Cardiac output increased from 416 +/- 94 to 758 +/- 127 ml/min (p less than 0.001). Right ventricular stroke work increased from 0.29 +/- 0.07 to 0.65 +/- 0.12 gm X m. (p less than 0.05). There was no cardiac output before or after institution of balloon counterpulsation in four pigs studied during ventricular fibrillation or asystole. We conclude that pulmonary artery balloon counterpulsation improved cardiac output and right ventricular stroke work in a model of right ventricular failure where the pulmonary circulation was unaltered and the left ventricle supported by left heart bypass. Balloon counterpulsation was not effective during ventricular fibrillation or asystole. Pulmonary artery balloon counterpulsation should be considered when right ventricular failure limits cardiac output during left heart bypass.

Animals↗
PubMed1987

Clinical experience with bypass of the left ventricle using a roller pump.

Left ventricular bypass (LVB) using a roller pump was performed in 39 patients in the immediate postoperative period. In one group, LVB was performed as a last measure to restore cardiac function. The LVB was temporarily effective in this group, but independent circulation was restored in only 2 of 15 patients. Results were considered unsatisfactory. In a second group, LVB was used immediately when acute left ventricular insufficiency refractory to drug treatment developed. In this group, independent circulation was restored in 17 of 18 patients, demonstrating a therapeutic effect. Overall, cardiac activity was restored in 25 patients; 15 patients recovered and were released. Conditions for the recovery of patients are noted.

Adolescent↗
PubMed1993

[A case report of massive pulmonary embolism with cardiac arrest at ICU--the effect of emergency percutaneous cardiopulmonary support system].

A 27-year-old female underwent a cesarean section because of a cephalopelvic disproportion. From the night of the operation, she complained of dyspnea and became in shock, and she was transferred to our department. A pulmonary perfusion scintigraphy revealed no right pulmonary artery flow and poor left lung perfusion. We diagnosed a massive pulmonary embolism (MPE). After the scintigraphy, the blood pressure went down and the heart was arrested. Under cardiac massage, percutaneous cannulation was done via right femoral artery and vein at ICU, and she was transferred to operative room with percutaneous cardiopulmonary support (PCPS). Emergency embolectomy was carried out with complete extracorporeal circulation. Three thrombi (total weight 20 g, the longest 15 cm) were removed through a longitudinal incision in the main pulmonary artery. The postoperative course was uneventful and, 1 month after the operation she was discharged. PCPS was a highly effective method for severe MPE.

Adult↗
PubMed1985

The hemodynamic effects and mechanism of action of pulmonary artery balloon counterpulsation in the treatment of right ventricular failure during left heart bypass.

The efficacy of pulmonary artery balloon counterpulsation (PABC) was evaluated in improving right ventricular (RV) output during left heart bypass for global cardiac failure. In 13 pigs, a 40-ml balloon was positioned within a graft anastomosed to the pulmonary artery distal to the pulmonary valve, and left heart bypass was instituted from the left atrium to the carotid artery. Global myocardial failure was produced by an infusion of propranolol (range, 25 to 78 mg). In this model, RV output decreased despite volume loading to a right atrial pressure of 15 mm Hg and atrioventricular sequential pacing at 100 beats per minute. Pulmonary artery balloon counterpulsation increased both RV output (from 519 +/- 76 to 1,117 +/- 110 ml/min; p less than 0.01) and RV systolic stroke work (from 1.3 +/- 0.4 to 2.3 +/- 0.6 gm-m; p less than 0.01). Right atrial pressure decreased (from 15.5 +/- 0.9 to 10.7 +/- 1.0 mm Hg; p less than 0.01) in 8 of the pigs studied during RV failure. In 5 pigs, ventricular fibrillation occurred without a stable model of RV failure, and there was no cardiac output before or after counterpulsation. The mechanism of action of PABC was studied by placing a flow probe around a large branch of the right pulmonary artery. During RV failure, balloon inflation caused flow through the pulmonary circulation, and ventricular systole resulted in filling of the graft. During ventricular fibrillation, balloon inflation and deflation produced only a to-and-fro movement of blood in the pulmonary artery branch without net forward flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

How to produce a pulsatile flow with low haemolysis?

It is evident that a pulsatile flow is important for blood circulation because the flow pulsatility can reduce the resistance of peripheral vessels. It is difficult, however, to produce a pulsatile flow with an impeller pump, since blood damage will occur when a pulsatile flow is produced. Further investigation has revealed that the main factor for blood damage is turbulence shear, which tears the membranes of red blood cells, resulting in free release of haemoglobin into the plasma, and consequently leads to haemolysis. Therefore, the question for developing a pulsatile impeller blood pump is: how to produce a pulsatile flow with low haemolysis? The authors have successively developed a pulsatile axial pump and a pulsatile centrifugal pump. In the pulsatile axial pump, the impeller reciprocates axially and rotates simultaneously. The reciprocation is driven by a pneumatic device and the rotation by a dc motor. For a pressure of 40 mm Hg pulsatility, about 50 mm axial reciprocating amplitude of the impeller is desirable. In order to reduce the axial amplitude, the pump inlet and the impeller both have cone-shaped heads, and the gap between the impeller and the inlet pipe changes by only 2 mm, that is the impeller reciprocates up to 2 mm and a pressure pulsatility of 40 mm Hg can be produced. As the impeller rotates with a constant speed, low turbulence in the pump may be expected. In the centrifugal pulsatile pump, the impeller changes its rotating speed periodically; the turbulence is reduced by designing an impeller with twisted vanes which enable the blood flow to change its direction rather than its magnitude during the periodic change of the rotating speed. In this way, a pulsatile flow is produced and the turbulence is minimized. Compared to the axial pulsatile pump, the centrifugal pulsatile pump needs only one driver and thus has more application possibilities. The centrifugal pulsatile pump has been used in animal experiments. The pump assisted the circulation of calves for several months without harm to the blood elements and the organ functions of the experimental animal. The experiments demonstrated that the pulsatile impeller pump is the most efficient pump for assisting heart recovery, because it can produce a pulsatile flow like a diaphragm pump and has no back flow as occurs in a non-pulsatile rotary pump; the former reduces the circulatory resistance and the latter increases the diastole pressure in aorta and thus increases the perfusion of coronary arteries of the natural heart.

Animals↗