Table 2.

Time and frequency domain components of RR.

Variable Name (Time Domain)	Description
Respiratory rate	Number of breaths per minute.
Inspiratory time	Time taken for inhalation.
Expiratory time	Time taken for exhalation.
Minute ventilation	Product of respiratory rate and tidal volume.
Timing ratio	Ratio of inspiration time to expiration time.
Tidal volume	Amount of inhaled air with each breath.
Variable name (Frequency domain)	Description
Mid-band spectral power	Spectral power (0.07–0.14 Hz).
High-band spectral power	Spectral power (0.15–0.50 Hz).