2 mg | 5 mg | 8 mg | P values | |
Imaging time (s) | 28.7±28.6 | 30.1±30.2 | 30.4±27.2 | 0.890 |
Needling time (min) | 5.7±2.3 | 5.8±2.3 | 6.2±2.5 | 0.272 |
Performance time (min) | 6.2±2.3 | 6.3±2.4 | 6.7±2.6 | 0.258 |
Onset time (min) | 18.6±6.5 | 18.2±6.2 | 18.9±6.2 | 0.711 |
Total anesthesia-related time (min) | 24.6±7.3 | 24.4±6.8 | 25.5±6.7 | 0.483 |
Blocks with a minimal composite score of 14 points | 115 (96.6) | 111 (92.5) | 117 (97.5) | 0.134 |
Surgical anesthesia | 118 (99.2) | 115 (95.8) | 117 (97.5) | 0.540 |
Operator’s experience level (expert/trainee) | 23/96 | 27/93 | 24/96 | 0.919 |
Number of passes | 2 (1–5) | 2 (1–4) | 2 (1–6) | 0.994 |
Block-related pain (scale 0–10) | 1 (0–6) | 1 (0–8) | 1 (0–7) | 0.841 |
Duration of motor block (hours) (95% CI) | 14.9±4.5 (14.1 to 15.8) | 16.1±4.9 (15.1 to 17.1) | 15.3±4.5 (14.5 to 16.1) | 0.148 |
Duration of sensory block (hours) (95% CI) | 16.6±4.6 (15.7 to 17.5) | 18.0±5.0 (17.0 to 19.0) | 17.3±4.8 (16.4 to 18.2) | 0.102 |
Duration of postoperative analgesia (hours) (95% CI) | 20.0±5.7 (18.9 to 21.1) | 22.7±6.0 (21.6 to 23.9) | 22.0±7.4 (20.6 to 23.4) | 0.006* |
Vascular puncture | 6 (5.0) | 4 (3.3) | 3 (2.5) | 0.308 |
Paresthesia | 4 (3.4) | 3 (2.5) | 1 (0.8) | 0.200 |
Continuous variables are presented as mean±SD; categorical variables are presented as count (percentage). Ordinal variables (number of passes, block-related pain scores) are presented as median (range). Onset and total anesthesia-related times are calculated only for patients with a minimal composite score of 14 points at 30 min.
*Statistically significant difference: 5 mg vs 2 mg (p=0.006).