Simulation-Based Analysis of Trial Design in Regional Anesthesia

Table 1

Input data for simulation analyses, based on published meta-analyses of nerve blocks.

Input parameter	Definition	Value	Comments
Starting trial sample size	Sample size sufficient for standard statistical techniques	30	As recommended in a prior publication [20]
Large trial sample size	90^th percentile of largest trial size included in published meta-analyses	256	Rounded up to nearest multiple of 2
Population effect size	Median absolute effect size among published meta-analyses	0.77	On a previous systematic review, median effect size for quantitative outcomes was 0.8 [21]
SD of effect size	Median of the 95% CI half-width divided by 1.96	0.27	Similar to previously published IQR of effect sizes for quantitative outcomes (0.6–1.0) [21]
Minimum effect size deemed clinically relevant	10^th percentile of the absolute effect sizes among published meta-analyses	0.11	0.10–0.34 is considered a small effect size; 0.35–0.64 is considered a medium effect size; 0.65–1.19 is considered a large effect size [22]
Number of trials needed for earliest meta-analysis	10^th percentile of the number of trials among published meta-analyses	4
Number of trials needed for next meta-analysis	SD of number of trials, among published meta-analyses	6
Number of trials needed to reach saturation of the literature	90^th percentile of the number of trials among published meta-analyses	16	On a previous systematic review, the median meta-analysis included 16 trials (IQR: 10, 28) [23]

CI, confidence interval; IQR, interquartile range; SD, standard deviation.