To Örebro University

Background: Numerous clinical studies have aimed at reducing pain in newborn infants. Little is known about whether the outcome measures are valid for the specific type of pain or group of infants included. 

Aim: To evaluate the reporting of pain assessments used in published trials.

Methods: A systematic search up to January 2019 was performed in Embase, PubMed, PsycInfo, Cinahl, Cochrane Library, Scopus and Luxid. Randomized and quasi-randomized clinical trials were included. Title and abstract screening followed by full text screening were performed by two independent researchers. Data extraction and quality assessment were also performed by two researchers independently.

Results: The search retrieved 3715 articles. 342 studies with a total of 16210 infants were included. 90% of the studies concerned procedural pain where the most frequently used pain scales were PIPP or PIPP-R followed by NIPS For ongoing or post-operative pain COMFORT and NFCS were mostly used. We observed a wide variation of pain scales and found numerous studies where pain scales were used that were not validated for the studied population or type of pain. 

Conclusion: This is the first scoping review reporting systematically how neonatal pain scales are used in clinical trials. There are a few validated pain assessment scales used in most clinical studies. It is crucial to choose an appropriate scale, validated for the type of pain and population of infants included in the study. The inappropriate use of pain scales raises serious concerns on ethical conduct of research and waste of resources.