Microprocessor-based pulse rate monitor

Modern biomedical instrumentation uses the technology that resulted from advances in electronics. Integrated circuit (IC) chips have replaced large systems of hard-wired electronic logic circuits and made them obsolete. Probably the most significant development in electronics is the IC chip called a microprocessor. Its capabilities make possible sophisticated instruments that can measure, compute, and display data for recurring physiological changes such as pulse rate. Because such instruments can function faster than the changes occur, information about the rate can be determined quickly, and remedial or corrective action can be implemented quickly in response to the data. This paper describes a pulse rate monitor that uses a microprocessor. It measures the occurrence rate of signals such as heart rate and respiration rate. It detects the signal rate, compares it with preset limits, and activates alarms as the limits are exceeded. The rate is measured and displayed at all times, until alarm conditions are detected. Then the display indicates the rate that caused the alarm condition. Upper and lower rate limits can be adjusted by the operator to suit the application.