BackgroundCare bundles have proven to be effective in improving clinical outcomes. It is not known which strategies are the most effective to implement care bundles. A systematic review was conducted to determine the strategies used to implement care bundles in adult intensive care units and to assess the effects of these strategies when implementing bundles.MethodsThe databases MEDLINE/PubMed, Ovid/Embase, CINAHL and CENTRAL were searched for eligible studies until January 31, 2015. Studies with (non)randomised designs on central line, ventilator or sepsis bundles were included if implementation strategies and bundle compliance were reported. Methodological quality was assessed by using the Downs and Black checklist. Data extraction and quality assessments were independently performed by two reviewers.ResultsIn total, 1533 records were screened and 47 studies were finally included. In 49 %, pre/post designs were used, 38 % prospective cohorts, and the remaining studies used retrospective designs (6 %), interrupted time series (4 %) and longitudinal designs (2 %). The methodological quality was classified as ‘fair’ in 77 %, and the remaining as ‘good’ (13 %) and ‘poor’ (11 %). The most frequently used strategies were education (86 %), reminders (71 %) and audit and feedback (63 %). Our results show that compliance is influenced by multiple factors, i.e. types and numbers of elements varied and different compliance measurements were reported. Furthermore, compliance was calculated within different time frames. Also, detailed information about compliance, such as numerators and denominators, was not reported. Therefore, recalculation of consistent monthly compliance levels was not possible.ConclusionsThe three most frequently used strategies were education, reminders and audit and feedback. We conclude that the heterogeneity among the included studies was high due to the variety in study designs, number and types of elements and types of compliance measurements. Due to the heterogeneity of the data and the poor quality of the studies, conclusions about which strategy results in the highest levels of bundle compliance could not be determined. We strongly recommend that studies in quality improvement should be reported in a formalised way in order to be able to compare research findings. It is imperative that authors follow the standards for quality improvement reporting excellence (SQUIRE) guidelines whenever they report quality improvement studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13012-015-0306-1) contains supplementary material, which is available to authorized users.