Indian Journal of Science and Technology

Abstract

Objectives: This paper highlights on the development of a simple electronic circuit based low-cost, noninvasive and portable apnea detector for patient care monitoring system. Methods/Statistical Analysis: Apnea indicates the cessation of breathing. In this study, thermistor sensitivity method has been implemented in designing the apnea detector. The resistance of a thermistor changes significantly with temperature. The change of temperature between inhaled and exhaled air (during respiration process) is sensed by the thermistor and corresponding change of thermistor resistance is measured in terms of electrical signal with the help of additional active and passive circuit elements. Findings: The resistance of the thermistor changed by 7 Ohm with increase of temperature of 1 degree centigrade. When the apnea detector is switched on and no exhaled breath is incident on the thermistor, the buzzer associated with the device gives sound to indicate the condition of apnea or absence of breathing. The output voltage of the circuit is found to be 8 Volts at this condition. However, if a subject exhales upon the thermistor, the sound of the buzzers stops to indicate the presence of breathing. During this condition, the output voltage is less than 8 Volts and found to vary from subject to subject. Application/Improvements: The designed apnea detector, being a low-cost and portable device can be implemented in patient care monitoring system.

Keywords: Apnea, Apnea Detector, Health Care System, Patient Care Monitoring System, Respiratory Activity