Table 1.

Overview of sEMG Index Tests and Its Assessment Ability of Respiratory Mechanics and Respiratory Sensation.

Study	(Sample Size) & Population	Intervention & Design	Muscle: EMG Index Test	Reference Standard	Target Response
					Respiratory Mechanics (Loading/Unloading)	Respiratory Sensation (Dyspnea)
Brochard et al. (1989)	(N = 8) subjects with RF & PMV	4 levels of MV support (PSV 0 – 15 cmH2o), prospective cohort	SCM: EMGMAX	RR, VT, VE, Pdi, Edi, ΔPes - ΔV, ${\dot{\text{V}}}_{{\text{O}}_{\text{2}}}$, & diaphragm H/L frequency ratio	+	N/A
Imsand et al. (1994)	(N = 5) subjects with RF	3 levels of MV support (During SIMV-PSV mode: Low, medium & high), prospective cohort	SCM: EMGMAX & EMGTi	RR, VT, VE, PTP, Edi, ΔPes - ΔV, diaphragmatic EMGTi and TIe, & P0.1	+	N/A
Tassaux et al. (2002)	(N = 10) subjects with RF	Equal levels of MV support (during SIMV-PS & ASV modes), prospective cohort	SCM: EMGAUC	RR, VT, VE, & P0.1	+	N/A
Schmidt et al. (2013)	(N = 12) subjects with RF	2 low & 2 high levels Of MV support (PSV 6–12 ml/kg), prospective cohort	Para, scalene & ala-nasi: EMGMAX, EMG/min & EMGAUC	RR, Vt, PVA & VAS-dyspnea	+	+
Cecchini et al. (2014)	(N = 12) subjects with RF & PMV	7 levels of MV support (during PSV & NAVA 7–20 cmH2O), prospective cohort	Scalene & ala-nasi: EMGAUC	RR, VT, Edi & ${\text{P}}_{{\text{ETCO}}_{\text{2}}}$	+	N/A
Walterspacher et al. (2016)	(N = 9) subjects with RF & PMV	PCV & PSV at different body position, prospective cohort	Para: EMGMAX	RR, Borg scale & diaphragmatic sEMG	N/A	+
Bellani et al. (2018)	(N = 14) subjects with RF	3 levels MV support (during PSV changing by 4 cmH2O), prospective cohort	Para & SCM: EMGMAX, EMG/min & EMGMEAN	Pmus, Edi & diaphragmatic sEMG	N/A	N/A

N/A, data not available, + responsive; PSV, pressure support ventilation; SIMV, synchronized intermittent mandatory ventilation; ASV, adaptive synchronized ventilation; NAVA, neurally adjusted ventilatory assist; PCV, pressure control ventilation; COPD, chronic obstructive pulmonary disease; RF, respiratory failure; PMV, prolonged mechanical ventilation; SCM, sternocleidomastoid; para, parasternal; EMG_MAX, maximum EMG activity; EMG_AUC, EMG area under the curve; EMG/min, EMG activity per minute; EMG_MIN, minimum EMG activity; EMG_MEAN, mean EMG activity; EMG_MAX-MIN, maximum-minimum EMG activity; Pdi, trans-diaphragmatic pressure; Edi, electrical activity of the diaphragm; RR, respiratory rate; V_T, tidal volume; ${\dot{\text{V}}}_{\text{E}}$, minute ventilation; ${\dot{\text{V}}}_{{\text{O}}_{\text{2}}}$, oxygen uptake; P_0.1, occlusion pressure at 1 milliseconds; PTP, pressure time product; ΔPes −ΔV, esophageal pressure – volume curve; EMG_Ti, duration of electrical activity; TI_e mechanical duration of inspiratory effort; H/L, high/low; VAS, visual analogue scale; PVA, patient-ventilator asynchrony; Pmus, inspiratory muscle pressure; ${\text{P}}_{{\text{ETCO}}_{\text{2}}}$, end tidal carbon dioxide.