Marjon Borgert

123 Implementation of care bundles in ICUs standardised de nitions and measurements of the study outcomes were interpreted di erently between the participating ICUs. This resulted in di erences in collecting data and therefore, data between ICUs were not fully comparable. 78 The variety in compliance rates could be in uenced by other factors. Bundle compliance is often monitored by using checklists (Supplementary File 3). 79 Besides auditing compliance, checklists are useful tools to standardise care processes, comparable to care bundles, and to improve the reliability of care to ensure patients receive all evidence-based interventions needed. 79 Although the use of checklists is promising, it is known that they are underused and barriers exist to use them which negatively in uences the reliability of care. 79,80 Thus, there could be a discrepancy between actual delivered care and the use of checklists, resulting in lower compliance rates, while the care was actually performed. Another example is that, compliance of a new intervention could be negatively in uenced when related to the habits and positive beliefs regarding the ‘old’ intervention even when the new intervention is based on robust science. 27 Furthermore, one study showed that lack of monitoring compliance was the reason for non-compliance. 50 Complementary, the frequency of monitoring compliance has resulted in positive e ects on bundle compliance rates. 81 Monitoring data, e.g. on compliance and/or infection rates, results in increased awareness and encourage ICU sta to be compliant with the care bundle. Although desirable, it can be challenging to achieve and maintain levels of bundle compliance of more than 95%. 4,9 In order to sustain the success of implementation, change of the organisational culture into a safety culture is required. 9,82 Creating a culture of safety includes the change of behaviour or attitudes of hospital sta to openly discuss about patient safety-related issues and to learn from mistakes without blaming. 13 Creating a culture of safety is necessary to enhance the adoption of care bundles, which subsequently contributes to redesign care processes and improve team work and communication between professionals. 4,9 Implementation of quality improvement projects does not have to give the same positive ndings when reproduced in other hospitals. One example is the Keystone project in Michigan which showed a sharp decline in the central line infection rates in ICUs. 9 Many of the components of this project were replicated in ICUs in the UK which also showed a reduction in infection rates. However, these positive ndings were not only due to the multifaceted interventions of the programme used, but were part of a secular trend. Secular trends are not often measured in quality improvements 83,84 , i.e. studies about implementing quality initiatives are often part of larger hospital or