Effect of Fentanyl and Morphine on Gallbladder Dimensions in Newborns Admitted to the Neonatal Intensive Care Unit: A Randomized Double-Blinded Clinical Trial

Background: The effect of fentanyl and morphine, two most frequently used drugs for premedication in general anesthesia, on gallbladder of newborns, has not been sufficiently investigated. Intubation and mechanical ventilation in a neonatal respiratory distress syndrome are stressful procedures, in which these two drugs are used to reduce stress and pain. We studied the effect of these drugs on neonatal bile system during these procedures Objectives: The present study aimed at determining the effect of fentanyl and morphine on gallbladder dimensions among newborns admitted to the neonatal intensive care unit (NICU). Methods: Thirty-two newborns with the gestational age between 26 and 38 weeks, undergoing intubation and mechanical ventilation, were selected for this randomized, double-blinded, clinical trial study. They were randomly divided into two groups; group 1 received morphine and group 2 received fentanyl. Gallbladder measurements ( width, depth, length and volume) were compared between the two groups by ultrasound evaluation. The data were collected between Nov 2012 and Oct 2013 at the NICU of the Children's hospital in Bandar Abbas, Iran. Results: There were no significant differences between the two groups in the evaluated parameters when demographic variables were compared. We found statistically differences between width, depth and volume of the newborns' gallbladders. However, there was no significant differences with regard to gallbladder length (P = 0.19). Conclusions: Morphine caused gallbladder dilatation more than fentanyl. However, it should be considered that total parenteral nutrition (TPN) which is common in NICU leads to gallbladder dilatation. Therefore, it seems that fentanyl could be considered as a preferred short-term analgesic with less adverse effects than morphine. A larger study is needed to confirm these results.