Ask an answerable question (PICO)：
Build up a clinical question: explore the benefits of using chlorhexidine mouthwash for oral care. PICO: P: adult patients using a ventilator in intensive care unit; I: chlorhexidine mouthwash; C: oral care; O: incidence of ventilator-associated pneumonia.
The Method and Analysis of Literature Review：
This article builds up a question with PICO and use the method of hierarchical search. According to the keywords (MeSH) and their synonyms. Using OR, AND in Boolean Logic to develop strategy to search the database of Cochrane, Pubmed and CINAL. Based on meta-analysis, systematic review, and randomized controlled trial articles.
Searching results: there are 67 articles in English. We excluded the topics that are not related. Finally, four articles were reviewed. Using the Critical Appraisal Skills Programme（CASP, 2013）and Oxford Centre for Evidence- Based Medicine 2011 Levels of Evidence as the appraising tool.
Clinical Application of Evidence：
Using 7 steps of empirical knowledge translation to improve the question.The study was designed as a pre-and post-test intervention. The study was started from September 1, 2018 to September 30, 2019. The study location was the surgical intensive care unit. During the intervention, 0.12-0.2% chlorhexidine mouthwash was used to replace initial oral care.
Evaluation of Effectiveness：
Compare the infection density of ventilator-associated pneumonia pre-and post-test intervention. According to the data from the infection control center in our hospital. During April 1, 2019 to September 30, 2019, there were 3 infections in our unit. The incidence of ventilator-associated pneumonia in the test group was lower than that in the control group. In the statistical analysis, the P value (> 0.05) showed non-significant.
Conclusions and Recommendations：
This article explores whether 0.12-0.2% chlorhexidine mouthwash can reduce ventilator-associated pneumonia or not. The statistical analysis was no significant difference. The influencing factors may include the days of ventilator use, disease severity, incomplete oral care operation methods and the concentration of mouthwash not reaching the standard. In this article, the timing of chlorhexidine mouthwash intervention is mostly after intubation. But the literature recommends that prospective intubation patients should be used before intubation. In the future, we will be implemented the chlorhexidine mouthwash to the preoperative patients in general wards. It is expected to improve the quality of oral care and reduce the incidence of ventilator-associated pneumonia.