Isolated Organs

This model is useful in the study of the pathophysiology of myocardial ischemia, reperfusion, and vascular resistance.

The Langendorff preparation consists of a retrograde system which perfuses the coronary vascular system of an isolated heart via the aorta with blood (by donor rat) or other oxygenated fluid (such as Krebs-Henseleit) from a reservoir to study coronary flow during cardiac activity. Models are maintained at constant mean pressure (controlled by a balloon placed in the left ventricle) or constant mean flow (using an in-line flowprobe inserted into the perfusion line).

Transonic Systems' research flowmeters operate inline (flow through) flowprobes for high resolution volume flow measurements in extracorporeal circuits. Ultrasonic transit time flowprobes can measure blood, buffer solutions and other non-aerated liquids used in perfused organ studies. A dual channel or dual module flowmeter will operate two 1N flowprobes to simultaneously measure aortic flow and venous return for cardiac output.

• Direct volumetric flow measurement
• High resolution and sensitivity for low flow conditions
• Exceptional electrical and zero baseline stability
• Measures blood, saline & other non-aerated liquids

Variations to the Langendorff preparation are made so the left ventricle performs pressure-volume work for the study of myocardial performance. Retrograde perfusion through the aortic cannula is reversed when the heart resumes contractions and antegrade perfusion is established via a cannula into the pulmonary vein or left atrium to produce a work-performing heart. Aortic flow plus coronary sinus effluent equals cardiac output. Flow in the aortic cannula and venous cannula can be accurately measured with inline flowprobes. Coronary flow can be collected and weighed or be derived from aortic flow and venous return. Other cardiac parameters can be calculated from the pressure-flow relationships: heart rate, contractility, stroke volume and stroke work.