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Biomedical subjects

A Lautier

Publications and source records attributed to A Lautier.

At least 37 records · Page 2Linked to original sources
PubMed1982

A hybrid device for measurement of left ventricular heat production.

The presented hybrid system allows precise temperature measurements in various sites of the circulation, from the acquisition and preprocessing of dilution curves. From haemodynamic data and left ventricular heat production, an in situ estimate of left heart efficiency is made available. A simplifying hypothesis allows the determination of total left ventricular heat production from three data inputs: (1) the coronary sinus blood flowrate, (2) the thermal coronary veno-arterial difference, (3) the ratio of thermodilution curves areas recorded in the aortic root and the coronary sinus, following a rapid injection in the left ventricular cavity of cold isotonic glucose. Experiments were performed on anaesthetized, artificially ventilated, closed-chest dogs, into which five catheters and probes had been inserted.

Animals↗
PubMed1982

ESCA studies on heparin-like materials used for extracorporeal shunts.

Amino-acids sulfamide substituted polystyrene surfaces exhibit an heparin-like activity. Similar treatments were achieved on small diameter tubings made of polystyrene grafted on polyethylene. Electron spectroscopy for Chemical Analysis (ESCA) appeared as the suitable method for a chemical characterization of the surface (approximately 50-100 A depth) to be in contact with circulating blood. These tubings were implanted as extracorporeal shunts on dogs. The variations of local concentrations of labelled platelets, red cells and fibrinogen were recorded in situ. Depending on the conditions of preparation and implantation, a slight adhesion of platelet was observed. By using such type of materials with an improved mechanical compliance, small diameter antithrombogenic tubings could be developed, provided the chlorosulfonation prior to amino-acid grafting is mild.

Animals↗
PubMed1981

Determination of left ventricular heat production in working dog heart.

1 degree Total left ventricular heat production was reliably estimated from the coronary blood flow, the coronary arteriovenous thermal difference and the thermodilution curve areas recorded in aortic root and in coronary sinus after injection of cold glucose solution into the left ventricular cavity. The assumption was made that the distribution of a cold solution, purposely introduced into the coronary arteries, obeys the same law as the heat generated by the myocardium. 2 degrees Temperature measurements were achieved with thermistors and a linear ohmmeter. Experiments were performed on thoracotomized dogs, allowing the utilization of an ultrasonic method for determination of the entire coronary sinus blood flow diverted through a cannula positioned in the coronary sinus. The spontaneous changes in acid-base balance and hemodynamic state, which were not systematically avoided, provided a fairly large interval of variation for coronary flow and myocardial oxygen consumption. 3 degrees Within the power interval of 0.5-2.2 watts per 100 g of left ventricular weight, there was a good linear correlation between left ventricular oxygen consumption and the sum of left ventricular heat production and external pressure power. 4 degrees These results suggest that the proposed method is a valuable approach for determination of the cardiac energetics in the in situ working heart. This method permitted repeated determinations of left myocardial heat production and may lead to a practical approach for measuring the left ventricular efficiency in intact animals.

Animals↗
PubMed1975

[Correction of plasma hemoglobin measurements in calculating a hemolysis index].

A "haemolysis index" may be defined from plasma haemoglobin concentration. This is useful in evaluating the consequences of the artificial kidneys and lungs (pumps and circuitry). Measurements must be taken repeatedly, and corrections made for variations in plasma volume from standard conditions (haematocrit or total haemoglobin) to obtain meaningful comparisons. The "haemolysis index" must take into account the number of passages through the circuit.

Animals↗