. Author manuscript; available in PMC: 2017 Jul 11.

Published in final edited form as: Am J Crit Care. 2017 May;26(3):210–220. doi: 10.4037/ajcc2017468

Table 6.

Correlations among covariates of interest (models 3 and 4)

Variable	Study day	Weaning trial	VAS-A score	Age	Ventilator days before enrollment	ICU days before enrollment	Sedative dose frequency	Sedation intensity score	Fraction of inspired oxygen	Tracheostomy
Study day	—	0.02	−0.03	−0.04	−0.06^a	−0.07^a	−0.18^a	−0.17^a	−0.11^a	0.45^a

Weaning trial	0.02	—	−0.02	0.04	0.06^b	0.09^a	−0.06^b	−0.10^a	−0.12^a	−0.10^a

VAS-A score	−0.03	−0.02	—	0.13^a	−0.04	−0.05	0.08^b	0.08^b	−0.01	−0.04

Age	−0.04	0.04	−0.13^a	—	−0.19^a	−0.13^a	−0.10^a	−0.11^a	−0.06^a	−0.16^a

Ventilator days before enrollment	−0.06^a	0.06^b	−0.04	−0.19^a	—	0.88^a	−0.15^a	−0.09^a	−0.10^a	0.38^a
ICU days before enrollment	−0.07^a	0.09^a	−0.046	−0.13^a	0.88^a	—	−0.128^a	−0.04	−0.15^a	0.41^a
Sedative dose frequency	−0.18^a	−0.06^b	0.08^b	0.10^a	−0.15^a	−0.13^a	—	0.82^a	0.07^b	−0.30^a
Sedation intensity score	−0.17^a	−0.10^a	0.08^b	−0.11^a	−0.09^a	−0.04	0.82^a	—	0.01	−0.25^a
Fraction of inspired oxygen	−0.11^a	−0.12^a	−0.01	−0.06^a	−0.10^a	−0.15^a	0.07^b	0.01	—	−0.12^a
Tracheostomy	0.45^a	0.10^a	−0.04	−0.16^a	0.38^a	−0.41^a	−0.30^a	−0.25^a	−0.12^a	—

Abbreviations: ICU, intensive care unit; VAS-A, visual analog scale for anxiety.

P < .01.

P < .05.