Table 1.

List of respiratory metrics implemented in BreathMetrics and their respective calculations

Metric	Calculation
Breathing rate	1/average time between inhale onsets
Inter-breath interval	Average time between inhale onsets
Inhale and exhale volumes	Sum of airflow between breath onset and offset
Tidal volume (average volume of air displaced per breath)	Average inhale volume + average exhale volume
Minute ventilation (volume of air displaced each minute)	(Breathing rate × average tidal volume)/1 min
Duty cycle (proportion of breath that is inhaled)	Average inhale duration/average interbreath interval
Coefficient of variation of duty cycle	SD of inhale duration/average inhale duration
Coefficient of variation of breathing rate	SD of difference between inhale onsets/average difference between inhale onsets
Coefficient of variation of breath volumes	SD of breath volumes/average breath volume