Measuring the heart´s output

Measurement of the heart´s flow output can be of particular value in the diagnosis and treatment of patients with cardiac disorders. One technique applicable to such patients is the thermal-dilution method, which involves measurement of a small temperature change in the bloodstream resulting from injection of a bolus of cool liquid upstream of the observation point. Simple analogue-computing techniques can provide a direct reading of cardiac output, and rapid serial measurements are obtainable.