Table 1.
Grading of recommendations assessment, development and evaluation
| Certainty assessment | No. of patients | Effect | Certainty | Importance | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. of studies | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | Ultrasound | Landmark technique | Relative (95% CI) | Absolute (95% CI) | ||
| First‐attempt insertion success | ||||||||||||
| 4 | Randomised trials | Not serious | Very serious† | Not serious | Serious‡ | None | 263/396 (66.4%) | 269/411 (65.5%) | RR 1.10 (0.86–1.40) | 65 more per 1000 (from 92 fewer to 262 more) |
⨁◯◯◯ very low |
Critical |
| Insertion success | ||||||||||||
| 4 | Randomised trials | Not serious | Serious§ | Not serious | Serious‡ | None | 38/284 (13.4%) | 47/290 (16.2%) | RR 0.63 (0.22–1.80) | 60 fewer per 1000 (from 126 fewer to 130 more) |
⨁⨁◯◯ low |
Critical |
| Time to cannulation (min) | ||||||||||||
| 2 | Randomised trials | Not serious | Very serious† | Not serious | Serious‡ | None | 162 | 171 | — | MD 3.03 lower (12.73 lower to 6.67 higher) |
⨁◯◯◯ very low |
Important |
†
Heterogeneity I 2 > 80%.
‡
Wide confidence interval.
§
Heterogeneity I 2 70–80%.
CI, confidence interval; MD, mean difference; RR, risk ratio.