Introduction: Ventilator-associated pneumonia (VAP) is the second most common nosocomial infection overall and the most common nosocomial infection among mechanically ventilated patients in the intensive care units (ICUs). It is associated with significant morbidity and mortality. Considering the importance of prevention of VAP in patients undergoing mechanical ventilation, the aim of this study was to evaluate the critical care nurses’ knowledge of evidence-based guidelines for prevention of VAP.

 Materials & Methods: In a descriptive cross-sectional study, a total of 120 critical care nurses who worked in the ICUs of in Amol and Sari city in 2013, were evaluated. A three part self-reported questionnaire including personal information, multiple choice questions for evaluation of the nurses’ knowledge regarding evidence-based guidelines for prevention of VAP and questions about the barriers of implementing evidence-based practices regarding prevention of VAP in their wards were used for data collection. The collected data were analyzed using descriptive statistics, Pearson correlation coefficient, independent t-test, ANOVA and multiple regression analysis (adjusted) using SPSS 20 software.

 Results: The results of the present study have shown that among all of the participants, 14 (11.6%) were male and 106 (88.33%) were female, with mean±SD age of 32.45±6.11 and average work experience was 8.01±5.005 years. The lowest level of knowledge of nurses (0.5%) were about using endotracheal tubes with extra lumens for drainage of subglottic secretions and the highest level of their knowledge (92.5%) were about the appropriate position for reducing the incidence of VAP in patients undergoing mechanical ventilation. Regarding taking actions based on the evidence in the prevention of VAP, 57.5% of nurses stated that some of these actions are performed routinely in their workplace. Multivariate linear regression analysis revealed that with an increase of one year of work experience, nurse’s knowledge scores have been increased by 10%.

 Discussion & Conclusion: Considering the low level of nurses’ knowledge about evidence-based guideline in the prevention of VAP and its important role in this regard allocation of resources and educational programs regarding evidence-based practice guideline for prevention of VAP and therefore changes of caring methods in patients undergoing mechanical ventilation, can have an important role in the prevention of VAP in these patients.