Table 5.

Analysis of contributing factors for the differences in submax norepinephrine level between both groups

Contributing factors	Simple regression			Multiple regression (backward variable selection P < 0.05)
	Regression coefficient	95% confidence interval	P value	Regression coefficient	95% confidence interval
Submax D-Respiratory frequency	0.063	(0.014, 0.112)	0.015
Submax D-Heart rate (beats/minute)	0.025	(0.010, 0.040)	0.003
Submax D-Arterial pH	−10.853	(−18.328, −3.374)	0.008
Submax D-Minute ventilation (L/minute)	0.057	(0.020, 0.094)	0.005	0.057	(0.020, 0.094)
Submax D-Oxygen uptake (mL/minute)	0.002	(0.000, 0.004)	0.023
Submax D-Carbon dioxide production (mL/minute)	0.002	(0.000, 0.0003)	0.012

Abbreviation: D, difference.