Instillation of normal saline before suctioning in patients with pulmonary infections: a prospective randomized controlled trial

Abstract

OBJECTIVE: To determine the effect of instillation of normal saline before suctioning on oxygen saturation, heart rate, and blood pressure in patients with pulmonary infections. METHODS: A prospective randomized controlled trial was conducted in the surgical, medical, and burn/trauma ICUs of an academic medical center. Eighteen men and 11 women (mean age = 60 years) receiving mechanical ventilation who met the criteria for pulmonary infection were randomly assigned to 2 groups. One group had instillation of a 5-mL bolus of normal saline before suctioning; the other did not. Suctioning was done as needed during an 8-to 12-hour period. Oxygen saturation, heart rate, and blood pressure were measured noninvasively immediately before and after suctioning, at 1-minute intervals for 5 minutes after suctioning, and at 10 minutes after suctioning. RESULTS: Instillation of normal saline had an adverse effect on oxygen saturation, which worsened over time. Differences in saturation between the 2 groups were significant at 4, 5, and 10 minutes after suctioning. Differences in heart rate and blood pressure were not significant. CONCLUSION: Instillation of normal saline before suctioning has an adverse effect on oxygen saturation and should not be used routinely in patients receiving mechanical ventilation who have pulmonary infection.