RESUMO
OBJECTIVES: This systematic review aimed to identify the effects of normal saline instillation before endotracheal suctioning on clinical outcomes in critically ill patients on a mechanical ventilator. RESEARCH METHODOLOGY: This review was based on the guidelines of the National Evidence-based Healthcare Collaborating Agency in Korea and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Six electronic databases were searched for relevant literature. Other sources were also searched, including the reference lists of identified reports and previous systematic reviews. After the initial literature search, a two-step retrieval process was performed to select eligible studies. Then, data were collected using a newly developed form, and the risk of bias was assessed using the checklists of the Joanna Briggs Institute. Data were analyzed using both narrative syntheses and meta-analyses. RESULTS: In total, 16 studies: 13 randomized controlled trials and three quasi-experimental studies, were included. From the narrative syntheses, instilling normal saline before endotracheal suctioning was associated with a decrease in oxygen saturation, prolonged time for oxygen saturation to recover to baseline, decreased arterial pH, increased secretion amount, reduced incidence of ventilator-associated pneumonia, increased heart rate, and increased systolic blood pressure. Meta-analyses showed a significant difference in heart rate at five minutes after suctioning but no significant differences in oxygen saturation at two and five minutes after suctioning and heart rate at two minutes after suctioning. CONCLUSION: This systematic review indicated that instilling normal saline before performing endotracheal suctioning has more harmful effects than benefits. IMPLICATIONS FOR CLINICAL PRACTICE: As recommended in the current guidelines, it is necessary to refrain from routine normal saline instillation before endotracheal suctioning.
