Inspiratory Capacity during Exercise: Measurement, Analysis, and Interpretation

Table 2

Data derived from IC maneuvers.

Variable	Formula	Units
ΔIC	IC − ICrest	L
IC/TLC	(IC/TLC) × 100	%
IC/VC	(IC/VC) × 100	%
IRV	IC − 𝑉𝑇 or TLC − EILV	L, %TLC, %TLCpred
𝑉𝑇/IC	(𝑉𝑇/IC) × 100	%
EELV	TLC − IC	L, %TLC, %TLCpred,
	Surrogates for EELV:
	FVC − IC; VC − IC	%FVC, %FVCpred, %VC,; %VCpred
EILV	EELV + 𝑉𝑇	L, %TLC, %TLCpred, %FVC, %FVCpred, %VC, %VCpred
EFL	(𝑉FL/𝑉𝑇) × 100	%

IC: inspiratory capacity; ΔIC: change in inspiratory capacity from rest; TLC: total lung capacity; VC: vital capacity; IRV: inspiratory reserve volume; 𝑉_𝑇: tidal volume; EILV: end-inspiratory lung volume; TLC_pred: predicted total lung capacity; EELV: end-expiratory lung volume; FVC: forced vital capacity; FVC_pred: predicted forced vital capacity; VC_pred: predicted vital capacity; EFL: expiratory flow limitation; 𝑉_FL: volume of tidal breath that is flow limited on expiration (see Figure 1(a)).