How does the respiration sensor work and what kind of values does it measure?
The NeXus respiration sensor employs a unique mechanism to monitor breathing patterns. It utilizes a magnet alongside a hall sensor, which is designed to detect the presence of a magnetic field.
This setup measures the degree to which the sensor's attached band stretches. The primary data obtained from this method reflects the expansion that occurs with each breath, directly linked to the movement of the chest belt. Specifically, the sensor generates raw data indicative of chest expansion levels, which is subsequently processed to calculate the respiration rate. This rate, expressed in breaths per minute (BPM), is derived from analyzing the raw sensor outputs. It's important to note that the placement of the chest belt can vary with each use, leading to fluctuations in absolute data readings.
Consequently, direct volume measurements of inhalation and exhalation are not achievable with this sensor. Factors such as patient size can further influence the signal's variance, as larger patients may exhibit smaller relative changes in body circumference during breathing. This variability underscores the reason raw or absolute respiration values are not comparable across different sessions or individuals. However, the calculated respiration rates remain a reliable metric for comparative analysis.