Mc Donnell, MD, MB, C., Pehora, MN, C. and Crawford, MBBS, M.W. 2012. PCA-derived factors that may be predictive of postoperative pain in pediatric patients: A possible role for the PCA ratio. Journal of Opioid Management. 8, 1 (Jan. 2012), 39–44. DOI:https://doi.org/10.5055/jom.2012.0094.