Use of chlorhexidine for oral hygiene in hospitalized patients and its association with mortality: a scoping review

Hospital-acquired infections remain a significant public health challenge, particularly in intensive care units (ICUs), where critically ill patients are exposed to invasive procedures and have increased vulnerability to adverse outcomes, including mortality. Among preventive strategies, oral hygiene with chlorhexidine digluconate has been widely implemented in hospital settings, especially for mechanically ventilated patients, due to its broad antimicrobial activity and its role in reducing oral bacterial colonization and ventilator-associated pneumonia (VAP). Chlorhexidine digluconate has long been used in dentistry and hospital care in various formulations and concentrations, supported by national and international guidelines as a low-risk medication when appropriately indicated. However, emerging evidence suggests that, despite reductions in VAP incidence, chlorhexidine use may be associated with unintended adverse effects, including oral mucosal irritation, inflammatory responses, aspiration-related lung injury, and potential systemic toxicity. Several observational studies and secondary analyses have raised concerns about a possible association between chlorhexidine exposure and increased hospital mortality, particularly among critically ill and mechanically ventilated patients. The available evidence on this topic is heterogeneous, encompassing different patient populations, clinical settings, chlorhexidine concentrations, routes of administration, and study designs. In addition, findings across studies are inconsistent, contributing to ongoing clinical uncertainty and debate regarding the safety of routine chlorhexidine use for oral hygiene in hospitalized patients. Therefore, this scoping review aims to systematically map and summarize the existing literature that investigates the relationship between the use of chlorhexidine digluconate for oral hygiene and mortality outcomes in hospitalized patients. By identifying the types of evidence available, study designs employed, populations investigated, and key findings reported, this review seeks to clarify the current state of knowledge, highlight gaps in the literature, and inform future research directions and clinical decision-making regarding oral care practices in hospital environments. The expected outcomes of this scoping review include a comprehensive overview of published evidence on chlorhexidine-associated mortality, identification of methodological patterns and limitations across studies, and the recognition of areas where further high-quality research is needed to support evidence-based recommendations for oral hygiene in hospitalized and critically ill patients.