Table 2.

Stepwise Regression for Ventilation-Free and Absolute Survival: Individual Score Test Results

	Ventilation-Free Survival		Absolute Survival
	Chi-Square	P Value	Chi-Square	P Value
Age, yr	0.0556	0.8136	2.5544	0.1100
Sex	0.0458	0.8305	0.1746	0.6761
Tw Pdi, cm H2O	47.9799	<0.0001	22.3576	<0.0001
Sn Pdi, cm H2O	54.3358	<0.0001	21.3279	<0.0001
Sn Pes, cm H2O	29.6091	<0.0001	20.0359	<0.0001
SNIP, cm H2O	30.1857	<0.0001	19.7347	<0.0001
SNIP, % predicted	34.5232	<0.0001	20.1526	<0.0001
VC, % predicted	32.6306	<0.0001	16.8896	<0.0001
MIP, cm H2O	21.9363	<0.0001	15.1205	0.0001
MIP, % predicted	24.0194	<0.0001	14.3513	0.0002
Cough Pga, cm H2O	15.4459	<0.0001	16.6363	<0.0001
MEP, cm H2O	22.6263	<0.0001	19.5375	<0.0001
MEP, % predicted	30.7708	<0.0001	19.0626	<0.0001

Definition of abbreviations: Cough Pga = cough gastric pressure; MEP = maximal static expiratory mouth pressure; MIP = maximal static inspiratory mouth pressure; SNIP = sniff nasal inspiratory pressure; Sn Pdi = sniff trans-diaphragmatic pressure; Sn Pes = sniff esophageal pressure; Tw Pdi = twitch trans-diaphragmatic pressure.