The feasibility of determining the time interval from left atrial appendage (LAA) flow was examined using transesophageal Doppler echocardiography. Time intervals were compared between LAA flow and mitral flow patterns during late diastole in 8 patients with mitral stenosis and in 12 controls. The start of ejection flow from the LAA was later than the initiation of mitral flow, but the termination was same in both flows, indicating the contribution of LAA ejection to the latter half of the left atrial booster pump function. The pre-ejection time and the time interval from P-wave to end-ejection correlated significantly with left atrial dimensions (r = 0.55, and r = 0.70, respectively). The pre-ejection time, duration of the ejection flow from the LAA, and duration of mitral flow in the atrial contraction phase were significantly longer in patients with mitral stenosis (126 +/- 14 msec, 131 +/- 36 msec, and 167 +/- 28 msec, respectively) than in the controls (109 +/- 13 msec, 108 +/- 15 msec, and 141 +/- 17 msec, respectively). These results indicate that electrical conduction time from the right atrium to LAA can be estimated from the LAA ejection flow, and the time is related to the left atrial size. In patients with mitral stenosis, LAA contraction may contribute to left ventricular filling in the latter half of the atrial contraction phase.

Blood Flow Velocity↗

PubMedDate not supplied

Development of an outside flow membrane oxygenator using a silicone hollow fiber.

A new membrane oxygenator was devised and assessed for performance in animal experiments. A silicone fiber membrane oxygenator, heat exchanger, and arterial blood reservoir are the components. The oxygenator is an outside flow type with minimum intrapulmonary resistance and, consequently, gas transfer is by gravity venous drainage. This device was used to conduct normothermic cardiopulmonary bypass (CPB) in 10 sheep over a period of 8 hrs (high flow group: 6 sheep, mean flow, 4.7 + 0.5 L/min; low flow group: 4 sheep, mean flow, 1 L/min). Performance was evaluated with gas transfer capacity, hematologic examination during CPB, and scanning electromicroscopic (SEM) appearance of the membrane after CPB. Blood gas was maintained with high PO2 and acceptable PCO2 levels throughout CPB. Plasma free hemoglobin was significantly low and fibrinogen was also maintained within physiologic levels. Scanning electron microscopy showed no thrombus formation on the membranes of either group. These results indicate this oxygenator to be quite adequate for gas exchange and prevention of blood cell trauma; it is also applicable to pulsatile or separating CPB because of the arterial blood reservoir.

Animals↗

PubMedDate not supplied

Collection of gingival fluid for quantitative analysis.

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Exudates and Transudates↗

PubMedDate not supplied

Evaluation of two new liquid-liquid oxygenators.

The authors devised two liquid oxygenator units in which blood is directly oxygenated with oxygenated perfluorocarbon (PFC), a substance harmless to the blood that has a high specific gravity. 1) The droplet-type oxygenator unit is composed of a blood oxygenating chamber and a PFC oxygenating chamber. Blood is oxygenated by the infusion of PFC droplets into the blood oxygenating chamber; PFC is then spontaneously separated from the blood because of a difference in specific gravity, and reoxygenated in the PFC oxygenating chamber. Experimental results obtained using mongrel dogs indicated this oxygenator to have a high efficacy of oxygenation (Qp/Qt = 0.63-0.78 with blood flow of 450-300 ml, O2 Transfer Rate = 64 ml/min with blood flow of 300 ml), and high carbon dioxide discharge (delta CO2/PaCO2 = 0.07-0.13, CO2 Transfer Rate = 11 ml/min with blood flow of 300 ml). Pathology examination showed microthrombi containing PFC in the lung and liver. 2) The disk type oxygenator unit is composed of a cylinder and 18 rotors connected to an axle. Oxygenated PFC enters into the lower part of the oxygenator and mixes with venous blood flowing above the PFC layer. The rotation of the disk in the oxygenator causes the blood and PFC to mix. Experimental results obtained using mongrel dogs showed excellent O2 exchange (Qp/Qt = 0.48-0.83, O2 Transfer Rate = 52 ml/min with blood flow of 300 ml) and CO2 removal capacity (delta CO2/PaCO2 = 0.05-0.10, CO2 Transfer Rate = 9 ml/min at blood flow rate of 300 ml/min) for 2 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Development of an air lift pump oxygenator.

The authors devised an air lift pump oxygenator, comprised of double cylinders connected together and filled with perfluorocarbon (FC-75, 3M) as an oxygen carrier. While the oxygen enters the FC-75 through the lower inlet of one cylinder, the oxygenated FC-75 is lifted by an air lift pump and circulates in the two cylinders. FC-75 adds oxygen to the blood that infuses from the lower inlet of the other cylinder. The oxygenated blood is separated from the FC-75 by gravity and infused into the subject. The size of the cylinder is 2.2 cm in internal diameter and 17 cm in effective oxygenation height. The capacity of the oxygenator is 160 ml. PO2 went from 62 mmHg to 96 mmHg and PCO2 decreased from 31 mmHg to 25 mmHg at a blood flow of 50 ml/min and an oxygen flow of 2 L/min. Maximum blood flow was 60 ml/min and the blood reserve capacity was 20 ml/min. The air lift pump oxygenator has advantages, such as simple structure, no motor, and a small priming volume.

Blood Flow Velocity↗

PubMedDate not supplied

Effects of FC43 emulsion against hyperacute rejection in rodent discordant xenotransplantation.

BACKGROUND: FC43 emulsion is one of several perfluorochemical-based artificial blood compounds developed as a red blood cell substitute. However, these compounds are not promising as red blood cell substitutes because of their immunosuppressive effects. Therefore we used FC43 emulsion as an immunosuppressive agent and not as a red blood cell substitute. METHODS: We assessed the effect of FC43 emulsion treatment on the survival of the grafted hearts in guinea pig-to-rat discordant transplantations. RESULTS: In rats treated with FC43 emulsion (5 microliters/gm body weight), rhythmic beating of the heart was maintained for 433.3 +/- 40.0 minutes, whereas the untreated heartbeat lasted for only 15.3 +/- 5.1 minutes. In the xenografted hearts treated with FC43 emulsion, no pathologic changes such as multiple coronary thromboses caused by hyperacute rejection had occurred by 300 minutes after reperfusion. CONCLUSIONS: FC43 emulsion can prolong the survival time of guinea pig heart xenografts by inhibiting thrombus formation in the xenografted heart.

Animals↗