The development of a self contained device for monitoring cardiac output including a survey of related physiology and bioinstrumentation

A thermodilution method for measuring cardiac output has been proposed. The new experimental technique is described with emphasis on the early research and development. A positive change in blood heat content is induced when a .OSF capacitor is discharged through a coil of nichrome or chrome I resistance wire. This technique guarantees high reproducibility. The coil, located in the vena cava, is not expected to dangerously heat. Measurements of the coil temperature in still water show a maximum temperature change of 6T = 2.829°C. The proposed technique gives results which correlate well with actual flow (correlation coefficient r = .990). It promises to be accurate, reproducible, practical, and economical.