Reassure Spot Respiration Rate Accuracy Compared to SOMNOScreen

The Reassure uses Radio Frequency (RF) waves to detect the small movements of the human body due to respiration. The reference device, the SOMNOScreen, uses chest effort bands. The Reassure is non-contact and so more comfortable and convenient for quick RR measurement, in a similar way that an Infra-Red thermometer is compared to a traditional under-the-tongue mercury thermometer.

The aim is to explore the variations in the human body that could have an effect on the radio reflection from the human torso, and thus affect the potential detection and accuracy of breathing rate. Factors that could affect non-contact RF performance are:

• High Body Mass Index (BMI) could potentially reduce the chest wall movement during breathing, or alter the nature of the breathing.
• Elderly, thin skin (ie pensioner with low BMI) may have less RF reflection.
• Female breast tissue may have an effect on detection or accuracy.

This was tested at a number of distances from the non-contact sensor and also with the subject having a thick comforter (duvet) laid across them.

The test conditions were

• Distances of 0.5 m, 1.0m and 1.5m between the subject and the RF sensor.
• Additional test condition of comforter (duvet) on the subject when the distance from subject to sensor is 1.0 m.
• Each test condition carried out twice.

The use of the comforter in one test condition is to confirm that the RR measurement by the Reassure is unaffected by the thickness of clothing or blankets being worn.

Inclusion criteria

• Greater or equal to 18 years old and less than or equal to 75 years old
• BMI within the range of greater or equal to 18 and less than or equal to 45