Background
Medline's 2022 transition to automated indexing has had a profound impact on the precision, accuracy and completeness of MeSH headings applied to records, and consequently, on the findability and usability of publications. Health science librarians must adapt accordingly. We will document the rise of automated indexing in Medline, and briefly touch on its present-day growing pains.

Methods
We searched the usual places: MEDLINE and EMBASE (both via Ovid), the Web of Science Core Collection, CINAHL and LISA (Library and Information Science Abstracts; both via EBSCO), and went on to hand-search key journals, track citations, and peruse a wide range of grey literature.
We are guided by Arksey and O’Malley’s 2005 framework, with updates from Levac et al (2010) and the 2020 JBI Guidelines. Our protocol was deposited on the Open Science Framework (OSF) in November 2024 https://osf.io/g4q8u/.
Aggregated data will be thematically coded and presented as conceptual maps. We anticipate the impetus, benefits, and shortcomings of automated indexing as themes.

Results
We will present a chronology of the development and deployment of automated indexing vis-a-vis Medline. We will make recommendations for future research on the impact of automated indexing in Medline and other health science databases, and discuss gaps identified in our review of publications.

Discussion
Beyond the history of automated indexing, we will explore its impacts on the accuracy and completeness of Medline records, and the downstream impacts on librarian practices.