Variability in opioid conversion calculators in critically ill children transitioned from fentanyl to hydromorphone

PURPOSE: Opioid conversion calculators (OCCs) are used to convert between opioids. The purpose of this study was to describe the variability in OCC results in critically ill children transitioned from fentanyl to hydromorphone infusions. METHODS: This was a descriptive, retrospective study. Seventeen OCCs were identified and grouped into 6 groups (groups 1-6) based on the equianalgesic conversions. The OCCs were used to calculate the hydromorphone rate in critically ill children (<18 years) converted from fentanyl to hydromorphone. Information from a previous study on children stabilized on hydromorphone (defined as the first 24-hour period with no change in the hydromorphone rates, <3 hydromorphone boluses administered, and 80% of State Behavior Scale scores between 0 and -1) were utilized. The primary objective was to compare the median hydromorphone rates calculated using the 17 OCCs. The secondary objective was to compare the percent variability of the OCC-calculated hydromorphone rates to the stabilization rate. RESULTS: Seventeen OCCs were applied to data on 28 children with a median age and hydromorphone rate of 2.4 years and 0.08 mg/kg/h, respectively. The median hydromorphone rate calculated using the 17 OCCs ranged from 0.06 to 0.12 mg/kg/h. Group 3 and group 6 OCCs resulted in a calculated hydromorphone rate that was higher than the stabilization rate in 96% and 75% of patients, respectively. Use of group 4 and group 5 OCCs resulted in a calculated hydromorphone rate that was lower than the stabilization rate in 64% and 75% of patients, respectively. CONCLUSION: Given the considerable variability of OCCs, caution should be used when applying OCCs to critically ill children.