Clonidine as analgesia during retinopathy of prematurity screening in preterm infants (cloROP): protocol for a randomised controlled trial

BMJ Open. 2022 Sep 22;12(9):e064251. doi: 10.1136/bmjopen-2022-064251.


Introduction: Preterm infants are at risk of negative consequences from stress and pain at the same time as they often are in need of intensive care that includes painful interventions. One of the frequent painful procedures preterm infants undergo is eye examination screening to detect early signs of ROP (retinopathy of prematurity). These examinations are both stressful and painful, and despite a multitude of research studies, no conclusive pain-relieving treatment has been demonstrated. The main aim of this trial is to investigate the analgesic effect of clonidine during ROP eye examinations.

Methods and analysis: The planned study is a multicentre randomised controlled trial with a crossover design. Infants will be recruited from two different neonatal intensive care units (NICUs) in Sweden. Infants born before gestation week 30 (and therefore eligible for ROP screening) and cared for in either of the NICUs will be eligible for inclusion in the study. The primary outcome will be Premature Infant Pain Profile-Revised score within 30 s after starting the examination. Secondary outcomes will be changes in the galvanic skin response parameters (area small peaks, area huge peaks, peaks per second and average rise time) within 30 s after starting the eye examination, together with the number and evaluation of adverse events reported within 72 hours after the examination and the examining physician's assessment of how easy the infant was to examine.

Ethics and dissemination: Approval from the Swedish Ethical Review Authority and the Swedish Medical Products Agency has been obtained for the study. Parents of eligible infants will be getting both verbal and written information about the study including that participation is voluntary. Data will be collected and treated in accordance with the European general data protection regulations. The results will be reported on group level and published in a scientific journal.

Trial registration number: (NCT04902859).EudraCT (2021-003005-21).

Keywords: neonatal intensive & critical care; paediatric ophthalmology; pain management.

Publication types

  • Clinical Trial Protocol
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analgesia*
  • Analgesics / therapeutic use
  • Clonidine / therapeutic use
  • Humans
  • Infant
  • Infant, Newborn
  • Infant, Premature
  • Infant, Premature, Diseases*
  • Multicenter Studies as Topic
  • Pain
  • Randomized Controlled Trials as Topic
  • Retinopathy of Prematurity* / diagnosis
  • Retinopathy of Prematurity* / prevention & control


  • Analgesics
  • Clonidine

Associated data