Based on a pre-study sample of children undergoing minor procedures, the mean FLAAC Pain Scale score was 7.25/10. We determined that a 25% difference in the mean FLACC scores between the two groups would be clinically relevant. In various published articles a clinical significant change in pain score was noted with the use of nitrous oxide between 20% and 40%. At an alpha of .05 and a power of 80%, we estimate a sample size of 42 patients in each arm (21 patients in each of the two age ranges per arm).