TABLE 1.

Definition of ventilatory measures

Abbreviation	Parameter (Unit)	Description
Ti	Inspiratory time (msec)	The time from start to end of inspiration
Te	Expiratory time (msec)	The time from start of expiration to beginning of next inspiration
f	Breathing frequency (bpm)	The breath-by-breath rate of breathing, computed on inspiration and expiration times (Ti + Te)
TV	Tidal volume (mL)	The amount of air breathed in during inspiration
MV	Minute ventilation (mL/min)	The amount volume breathed in one minute, computed on a breath-by-breath basis (TV * f)
PIF	Peak inspiratory flow (mL/sec)	The maximum negative flow during one breath
RT	Relaxation time (msec)	The time to expire a defined percentage of tidal volume
AP (Pau)	Apneic pause	A unitless indicator of bronchoconstriction, computed as (Te/RT – 1)