Our respiration sensor is applied in various applications requiring respiration monitoring.
This article presents two recommended sensor positioning options, (a) thoracic and (b) abdominal (as presented in the following illustration below), both based on commonly used respiration monitoring methods. In addition, the impact of the positioning on the acquired raw signal is highlighted.
In following examples we present two sensor position options, one meausuring respiration around the thorax (position a) and one around the abdomen (position b). Note that the sensing strips of the respiration bands have been centred at the front of the thorax and abdomen.
Position A – Thoracic Respiration Monitoring
The thoracic-based method measures respiration by monitoring the changes in the thorax volume caused by the respiration mechanics (increase or decrease of the lungs’ volume).
An example signal of such an acquisition is presented in the following plot where a maximum peak-to-peak volume of 0.6V can be measured.
Position B – Abdominal Respiration Monitoring
The abdominal-based method measures respiration by monitoring the changes in volume of the abdomen caused during the respiration cycles.
An example signal of such an acquisition is presented in the following plot where a maximum peak-to-peak volume of 1.2V can be measured.
Comparison – Thoracic vs. Abdominal
It can be noted that the respiration signal acquired at the abdomen results in greater peak-to-peak amplitudes than the thoracic results, with the first being twice as high in this experiment (thoracic: 0.6V vs. abdominal: 1.2V).
A comparison is presented in the following plot figure.
Although both results provide reliable data, as the respiration cycles are visible in both, the difference in peak-to-peak amplitudes can be important in applications where artefacts can be induced, such as in high-motion activities.
In such cases, one can benefit from the advantages of greater peak-to-peak amplitudes as those are easier to extract from artefact-induced data (for example, due to the greater possibility of standing out from motion artefact-distorted baselines) to the thoracic respiration signal with smaller peak-to-peak artefacts.