Oral care with chlorhexidine was used to be considered an effective way to prevent ventilator-associated pneumonia (VAP). However, recent evidence revealed that oral care with chlorhexidine may associate with higher mortality and increasing risks of acute respiratory distress syndrome due to the aspiration of chlorhexidine. In addition, the majority of relevant studies in the past have only focused on cardiothoracic intensive care unit (ICU) or post-operation patients. Thus, whether this is effective and safe for medical ICU patients remains unclear.

Ventilator-associated pneumonia (VAP) is one of the most common hospital-acquired infections in the ICU, associated with an increased hospital stay, increased cost of treatment, prolonged ventilator days, and increased morbidity and mortality rates (Divatia et al, 2019). The overall incidence of VAP was around 12% in Asia and nearly 8% in Taiwan in the past 30 years (Bonell et al, 2019), with a mortality rate that may exceed 45% for those receiving mechanical ventilation (Feng et al, 2019). Therefore, the prevention of VAP is a key part of managing patients undergoing mechanical ventilation.

Oral decolonization by mouthwash using a chlorhexidine-contained solution was suggested by accumulated evidence in preventing VAP (Dai et al, 2022). However, controversial opinions existed from a few different points of view. First of all, Klompas et al (2014) conducted a meta-analysis that showed the effectiveness of chlorhexidine (CHG) oral care in preventing VAP was limited only to cardiac surgery patients (Klomopas et al, 2014). Second, recent evidence showed a possibility of unfavored outcomes related to the use of CHG mouthwash by increased mortality either in the ICU (Price et al, 2014) or the general ward (Deschepper et al, 2018). Last but not least, the subjectiveness of the diagnostic criteria of VAP had led to the discussion on the credibility of the outcome in relevant studies (Skrupky et al, 2016). Therefore, the US Centers for Disease Control and the National Healthcare Safety Network have proposed alternative diagnostic criteria for the ventilator-associated event (VAE) as alternation (Peña-López et al, 2022).

The objective of this study was to examine the effectiveness of oral care with 0.12% CHG in MICU patients for the prevention of ventilator-associated events.

Inclusion Criteria:

• patients aged over 20 years old
• admitted to MICU
• an oral endotracheal tube inserted under mechanically ventilated

Exclusion Criteria:

• an endotracheal tube inserted over 24 hours before enrollment
• intubated because of trauma, burn, operation, or neurological disease
• already suffered from oral ulcers before intubation
• known history of allergic reaction to CHG
• use of ECMO