Table 4 Success rate of the first attempt in the ultrasound-assisted group versus conventional puncture group
| Â | ultrasound-assisted group | Conventional puncture group | P-value |
|---|---|---|---|
Total(n) | 72 | 72 | Â |
Success on first attempt (n) | 45 | 27 | 0.017 |
%(95% CI) | 61.4(50.7, 73.3) | 38.6(26.3, 48.7) | Â |
Rate difference, %(95% CI) | 24.5(8.6, 40.4) | – |  |
Relative risk, (95% CI) | 1.547(1.072, 2.235) | 0.640(0.436, 0.939) | Â |
Cyanosis(n) | 36 | 36 | Â |
Success on first attempt (n) | 24 | 12 | 0.035 |
%(95% CI) | 66.7(51.3, 82.1) | 33.3(17.9, 48.7) | Â |
Rate difference, %(95% CI) | 33.3(11.6, 55.1) | – |  |
Relative risk, (95% CI) | 1.714(1.042, 2.820) | 0.545(0.293, 1.017) | Â |
Acyanosis(n) | 36 | 36 | Â |
Success on first attempt (n) | 21 | 15 | 0.194 |
%(95% CI) | 57.6(42.2, 74.4) | 42.4(25.6, 57.8) | Â |
Rate difference, %(95% CI) | 16.7(−6.1, 39.4) | – |  |
Relative risk, (95% CI) | 1.413(0.823, 2.428) | 0.716(0.432, 1.187) | Â |