A Case Study Evaluating the Efficacy of an Ad Hoc Hospital Collection Device for Fentanyl in Infant Oral Fluid

Abstract

Neonatal drug exposure is currently assessed using meconium, urine, blood, hair, or umbilical cord tissue/blood. Due to the invasiveness, challenges, and limitations of collection, and/or analytical difficulties of these matrices, oral fluid may be a more desirable matrix in diagnosing opioid exposure and risk for opioid withdrawal in neonatal abstinence syndrome. Traditional oral fluid collection devices are not viable options as they are too large for neonates' mouths and may contain chemicals on the collection pad. Unstimulated and stimulated infant oral fluid samples have been used for therapeutic drug monitoring as an alternative matrix to blood. The objective of this study was to assess the viability of a simple oral fluid collection system using a sterile foam-tipped swab rinsed in phosphate-buffered saline. Two infants were administered fentanyl for post-operative pain relief while hospitalized in the Neonatal Intensive Care Units at the Children's Hospital of Richmond of Virginia Commonwealth University. Oral fluid samples were collected at 16 h, 2 days, and/or 7 days following the start of intravenous infusion of fentanyl. Samples were analyzed by ultra-high-pressure liquid chromatography-tandem mass spectrometry for fentanyl and norfentanyl after solid-phase extraction. In one of the three samples tested, fentanyl and norfentanyl were detected at concentrations of 28 and 78 ng/mL, respectively. Based on the infusion rate, the theoretical oral fluid fentanyl concentration at steady state was calculated to be 33 ng/mL.