Impact of chlorhexidine mouthwash prophylaxis on probable ventilator-associated pneumonia in a surgical intensive care unit

BACKGROUND: Prevention of ventilator-associated pneumonia is a healthcare goal. Although data is inconsistent, some studies suggest that oral chlorhexidine may decrease rates of pneumonia in mechanically-ventilated patients. We sought to assess the rate of pneumonia in the Surgical Intensive Care Unit (SICU) pre and post implementation of routine chlorhexidine mouthwash prophylaxis. MATERIALS AND METHODS: A retrospective cohort study was conducted, including patients between 1/1/2009 and 12/31/2009 who did not receive chlorhexidine mouthwash compared to patients that received prophylactic chlorhexidine mouthwash between 3/1/2010 and 2/28/2011. The primary outcome of the study was rate of probable ventilator-associated pneumonia (VAP) for the pre-chlorhexidine implementation cohort compared to post-implementation, using the 2013 Center for Disease Control definitions. Mechanically ventilated patients with respiratory cultures were screened for inclusion in the study. Secondary endpoints included duration of mechanical ventilation, in-hospital mortality, ICU and hospital length of stay. Statistical analysis was conducted by Fisher's exact test for nominal data and Mann-Whitney U test for continuous data. RESULTS: A total of 1780 mechanically ventilated patients in the pre-chlorhexidine group and 1854 in the post-chlorhexidine group were screened for inclusion. Of the 601 mechanically ventilated patients that were further evaluated for inclusion; 158 patients (26.3%) had positive cultures and were included in the study (94 pre-group and 64 post-group). The rate of probable VAP was significantly decreased in the post-group compared to the pre-group (1.85% pre vs 0.81% post, P = 0.0082). CONCLUSION: Use of chlorhexidine mouthwash prophylaxis may reduce rates of probable VAP. Further study is warranted.