The objective of this systematic review is to determine the extent and quality of evidence for use of different types of locking fluids to prevent central venous access device complications in adult critical care patients. Specifically, rates of catheter-related bloodstream infection, colonization, and occlusion were considered. All types of devices were included in the review: central venous catheters, peripherally- inserted central catheters and hemodialysis catheters. Eligibility criteria. Papers had to include adult (>18 years old) critical care patients, be experimental trials, conducted in North America and Europe, and published in peer-reviewed journals from 2010 onwards. Information sources. A search of Medline and EMBASE databases was performed. The search is current as of November 28th, 2022. Risk of bias. The Cochrane Risk of Bias 2 and the Risk of Bias In Non-Randomized Studies of Intervention tools were used to assess the risk of bias in included studies. Included studies. A total of 240 paper titles and abstracts underwent review, of these seven studies met the final criteria for quality appraisal. A total of three studies earned a low risk of bias quality appraisal. Limitations of evidence. Due to heterogeneity of types of locking fluids investigated and small number of studies identified, meta-analysis of results was not possible. Interpretation. Out of all fluids investigated, only citrate 46.7% was found to statistically reduce central venous access device complication rates. This systematic review has also identified a gap in the literature regarding studies of locking fluids that are adequately powered in this patient population. Future research should include investigations and use of novel locking fluids with more effective properties against complications. It is imperative that future studies are adequately powered, randomized controlled trials in this patient population to facilitate optimal evidence-based care.