The effects of oral rinse with 0.2% and 2% chlorhexidine on oropharyngeal colonization and ventilator associated pneumonia in adults' intensive care units

Highlights

• This study showed 2% chlorhexidine is effective in reducing VAP.

• Oral care protocol used in study improved oral care.

• The frequency of oropharyngeal colonization decreased.

Abstract

Background

Ventilator Associated Pneumonia (VAP) is the most common nosocomial infection in Intensive Care Units (ICUs) which increases the length of ICU stay, duration of mechanical ventilation, and mortality. The present study used an oral care protocol and compared the effects of two different concentrations of chlorhexidine on reduction of oropharyngeal colonization and VAP.

Materials and methods

This study was performed on 114 patients from trauma, surgery, neurosurgery, and general ICUs randomly allocated to two groups under oral care with 0.2% and 2% chlorhexidine solution. A multidisciplinary team approved the oral care protocol. Data was collected using a demographic information form, APACHE IV form, Beck oral assessment scale, mucosal-plaque assessment scale, and oropharyngeal swab culture.

Results

The results showed a significant reduction in VAP (p = 0.007) and oropharyngeal colonization (p = 0.007) in the group under oral care with 2% chlorhexidine solution compared with the other group. However, no significant difference was found between the two groups in terms of oropharyngeal adverse effects (p = 0.361).

Conclusion

Oral decontamination with 2% compared to 0.2% chlorhexidine is a more effective method in the prevention of VAP and reduction of oropharyngeal colonization (especially gram-positive).

Introduction

Ventilator Associated Pneumonia (VAP) is a subgroup of hospital-acquired pneumonia that occurs in patients under mechanical ventilation through an endotracheal tube or tracheostomy for at least 48–72 h [1]. This type of pneumonia occurs in 9–27% of patients in Intensive Care Units (ICUs) [2], [3]. In the United States, the cost of VAP is $2 billion annual and approximately $30000–40,000 per case [4]. The mortality rate of this infection ranges from 20 to 70% [3], [5]. VAP increases the duration of mechanical ventilation and of hospital stay [6]. It is also responsible for 50% of the antibiotics prescribed in ICUs [6], [7]. Yet, VAP is preventable [7].

The most important mechanism in the development of VAP is continuous micro-aspiration of oropharyngeal colonization into the lower respiratory tract. Twenty-four hours after a patient's admission to the ICU, normal oropharyngeal flora changes into gram-negative pathogens, which increases dental plaque. Plaques are suitable environments for the growth and accumulation of pathogens [8], [9]. In addition, the tracheal tube may operate as a conduit for oral cavity pathogens to the lungs. Several studies have also shown a relationship between dental plaque colonization and respiratory pathogens [10]. Fortunately, the incidence of VAP is reduced by identifying the risk factors and improving prevention methods. Recently, the mortality rate of VAP has been estimated at about 9–13% [7].

The Center for Disease Control and Prevention (CDC) and Institute for Healthcare Improvement (IHI) have introduced recommendations, as the VAP bundle, that include daily oral care with chlorhexidine [11], [12]. Oral care is a basic and special nursing care that helps create comfort for patients and prevent VAP [13], [14] and generally includes mechanical and pharmacological interventions. In this regard, common antiseptics are saline, chlorhexidine, and povidone iodine. Chlorhexidine is a broad spectrum antiseptic agent (gram-positive, gram-negative, and yeast) which is easy to use, safe, and cost-effective. Additionally, chlorhexidine's slow release properties maintain antimicrobial activity up to 12 h [15], [16]. Thus, it is known as an effective drug in controlling dental plaque and inflammation [17], [18]. Chlorhexidine has been studied at various concentrations (0.12%, 0.2%, 0.5%, 1%, and 2%) and forms [2], [19]. A large number of studies have confirmed that oral care with chlorhexidine reduces the incidence of VAP [20], [21], but there is no consensus on the best concentration of chlorhexidine, the frequency of its use, or oral care techniques [4]. Concentrations of 0.12% and 0.2% have shown conflicting results with respect to reduction of the incidence of VAP, but 2% chlorhexidine has been associated with a significant decrease in the incidence of VAP [2], [19]. The use of 0.2% chlorhexidine is also common in ICUs, but only a few studies have been conducted on 2% chlorhexidine. Therefore, the present study aimed to compare the effects of two different concentrations of chlorhexidine on reducing oropharyngeal colonization and the incidence of VAP.