Measurement of cardiac output in man with a U.S. $150 plethysmograph.

It has been found possible to adapt a simple battery-operated plethysmograph costing U.S.$150 for the measurement of cardiac output. Although the method is certainly less convenient and possibly less accurate than the computerized impedance cardiographs(costing $23 000) now often used in the United States, it provides a useful measurement of changes in cardiac output over a period of time. In developing countries, it can be recommended for the repeated assessment or monitoring of patients during surgery, in Critical Care Units and in the evaluation of patients during circulatory stress tests (AU)