Effect of the Green Cross method on patient safety culture in a postanaesthesia care unit: a longitudinal quasi-experimental study.

Background: Hospitals should adopt multiple methods to monitor incidents for a comprehensive review of the types of incidents that occur. Contrary to traditional incident reporting systems, the Green Cross (GC) method is a simple visual method to recognise incidents based on teamwork and safety briefings. Its longitudinal effect on patient safety culture has not been previously assessed. This study aimed to explore whether the implementation of the GC method in a postanaesthesia care unit changed nurses' perceptions of different factors associated with patient safety culture over 4 years.

Methods: A longitudinal quasi-experimental pre-post intervention design with a comparison group was used. The intervention unit and the comparison group, which consisted of nurses, were recruited from the surgical department of a Norwegian university hospital. The intervention unit implemented the GC method in February 2019. Both groups responded to the staff survey before and then annually between 2019 and 2022 on the factors 'work engagement', 'teamwork climate' and 'safety climate'. The data were analysed using logistic regression models.

Results: Within the intervention unit, relative to the changes in the comparison group, the results indicated significant large positive changes in all factor scores in 2019, no changes in 2020, significant large positive changes in 'work engagement' and 'safety climate' scores in 2021 and a significant medium positive change in 'work engagement' in 2022. At baseline, the comparison group had a significantly lower score in 'safety climate' than the intervention unit, but no significant baseline differences were found between the groups regarding 'work engagement' and 'teamwork climate'.

Conclusion: The results suggest that the GC method had a positive effect on the nurses' perception of factors associated with patient safety culture over a period of 4 years. The positive effect was completely sustained in 'work engagement' but was somewhat less persistent in 'teamwork climate' and 'safety climate'.