Table 1. Baseline characteristics.

Patients’ characteristics	Cohort		p-Value a
	overall	examined
Number, [n]	346	128	-
Gestational age in weeks, median (range)	25.8 (23.0 27.9)	25.6 (23.1 27.9)	0.23
Weight in g, mean (SD)	781 (200)	752 (192)	0.15
Males	59	62	0.59
Survival beyond 28 days of life	86	88	0.70
At least one PAL during first 4 weeks of life	96	100	0.03
Two consecutive PALs during first 4 weeks of life	20	29	0.04
More than one PALs during first 4 weeks of life	40	63	< 0.01
Inotropes1 during first four weeks of life	49	66	< 0.01
Morphine2 during first four weeks of life	52	69	< 0.01
PALs in first 4 weeks of life
Total, [n]	575	277	-
Left radial artery	41	36	0.13
Right radial artery	33	35	0.47
Left ulnar artery	4	3	0.19
Right ulnar artery	3	2	0.30
Left brachial artery	2	2	0.78
Right brachial artery	2	2	0.67
Left tibial posterior artery	6	6	0.66
Right tibial posterior artery	9	14	0.02

PAL, Peripheral arterial line; SD, standard deviation

Data are presented as percentage unless otherwise indicated.

^a Student t-test for birth weight, Mann-Whitney-U for gestational age, chi-square test for all other variables.