Table 1. Patient characteristics.

	DNTP Group (n = 128)	Palpation Group (n = 128)	P value
Age, years	72 (68, 78)	74 (69, 78)	0.32
Sex, female	85 (66.4)	82 (64.1)	0.69
BMI, kg m-2	24.0 ± 4.0	23.8 ± 3.5	0.75
ASA (I/II/III)	8/89/31 (6.3/69.5/24.2)	8/95/25 (6.3/74.2/19.5)	0.66
Hypertension, n	86 (67.2)	92 (71.9)	0.42
Diabetes mellitus, n	37 (28.9)	32 (25.0)	0.48
Hypercholesterolemia, n	35 (27.3)	37 (28.9)	0.78
Peripheral vascular disease, n	28 (21.9)	18 (14.1)	0.10
History of smoking, n	13 (10.2)	8 (6.3)	0.26
Diameter of the RA, mm	2.3 ± 0.4	2.3 ± 0.5	0.70
Depth of the RA, mm	2.6 (2.0, 3.6)	2.6 (2.0, 3.4)	0.63
SBPstart, mmHg	120.0 ± 22.3	119.7 ± 21.4	0.91
HRstart, bpm	77 (65.0, 84.8)	75.5 (65.3, 88.8)	0.31

Values are presented as number (percentage, %), mean ± standard deviation or median (first, third quartiles).

DNTP, dynamic needle tip positioning; BMI, body mass index; ASA, American Society of Anesthesiologist physical status classification; n, number; RA, radial artery; SBPstart, systolic blood pressure at the start of the procedure; HRstart, heart rate at the start of the procedure; bpm, beats per minute.