Table 1

Characteristics of the total study population

Characteristics
Ultrasound group (n = 450)
Landmark group (n = 450)

Age (years)a
58.3 ± 10.3
59 ± 9.5
Gender (male/female ratio)a
0.56 ± 0.4
0.6 ± 0.4
Side of catheterisation (left/right)
222/228
218/232
Body mass index (kg/m2)a
24.1 ± 5.3
23.7 ± 5.9
Prior catheterisation
85 (18.8%)
76 (16.8%)
Limited sites for access attempts
51 (11.3%)
55 (12.2%)
Previous difficulties during catheterisation
44 (9.7%)
40 (8.8%)
Previous mechanical complication
18 (4%)
20 (4.4%)
Known vascular abnormality
4 (0.8%)
3 (0.6%)
Untreated coagulopathy
25 (5.5%)
24 (5.3%)
Skeletal deformity
15 (3.3%)
13 (2.8%)
Cannulation during cardiac arrest
31 (6.8%)
35 (7.7%)

aValues are presented as mean ± standard deviation.

Karakitsos et al. Critical Care 2006 10:R162   doi:10.1186/cc5101