At each breath, a red light on the right side of the SleepStrip should blink. If it doesn't, the patient readjusts the device until airflow from both nostrils and the mouth are reaching the sensors. The blinking light will go off in about 20-30 minutes. The patient then falls asleep and the SleepStrip will record five hours of breathing. The sensors record a signal based on the temperature of the airflow.
Inhaled air is at room temperature while exhaled air is close to body temperature.
The device can measure pauses in, or reduction to, the airflow at the mouth and nose. That pattern of breathing is analyzed by the microprocessor inside. The device is capable of measuring up to 126 total apneas and hypopneas per hour. In the morning, the red light should be blinking rapidly to indicate a successful study. If not, the test may have to be repeated.