Objective To summarize and analyze the errors occurred in the Pharmacy Intravenous Admixture Services, to explore measures of risk prevention so as to ensure the safety of clinical medication.

Methods According to the "Swiss cheese model", the errors in each work link in the Pharmacy Intravenous Admixture Services of the First Affiliated Hospital of Anhui Medical University from 2019 to 2020 were retrospectively analyzed, and the corresponding prevention and improvement measures were proposed. The total number of allocated bags, the number of error bags, the frequency of errors, the frequency of risk factors, total incidence of error, the proportion of missed errors, the vulnerability coefficient, the promotion rate of risk prevention and other indicators were counted, and the occurrence of errors in the Pharmacy Intravenous Admixture Services were compared before and after improvement.

Results The total error rate and missed error ratio after improvement (January to December 2020) were 0.12‰ and 16.30%, which were significantly lower than 0.16‰ and 31.30% before improvement (January to December 2019) (χ²=5.642, 10.021; P=0.018, 0.002). After improvement, the vulnerability coefficient decreased from 0.46 to 0.19, and the promotion rate of risk prevention was 58.70%.

Conclusion "Swiss cheese model" is used to define the risk quantitative indicators such as error frequency, proportion of vulnerability error, vulnerability coefficient, promotion rate of risk prevention, comprehensively summarize and analyze the errors and error transmission in the Pharmacy Intravenous Admixture Services, and formulate and implement targeted improvement measures, which can effectively improve the risk prevention ability, reduce occurrence of errors, and effectively ensure the safe and rational drug use for patients.