TABLE 3.

Spearman's correlation coefficients between maximal inspiratory pressure and follow-up outcomes, and between duration of mechanical ventilation and inspiratory muscle outcomes

Variable	3 months	6 months
Maximal inspiratory pressure
Diaphragm thickness	0.312*	0.273
Diaphragm thickening ratio	0.180	0.308*
6MWD	0.657**	0.622**
6MWD % predicted	0.380**	0.284*
Dyspnoea mMRC score	−0.365**	−0.379**
Borg dyspnoea	−0.097	−0.015
SGRQ	−0.349*	−0.277
Duration of mechanical ventilation
Maximal inspiratory pressure	−0.182	−0.162
Maximal inspiratory pressure, % predicted	−0.105	−0.029
Diaphragm thickness	−0.257	−0.163
Diaphragm thickening ratio	−0.106	−0.137
6MWD	−0.389**	−0.365**
6MWD % predicted	−0.427**	−0.389**
Dyspnoea mMRC score	0.424**	0.183
SGRQ	0.160	0.127

6MWD: 6-min walk distance; mMRC: modified Medical Research Council; SGRQ: St George's Respiratory Questionnaire. *: p<0.05; **: p<0.01.