Subglottic Secretion Drainage and Objective Outcomes

Abstract

Current guidelines recommend endotracheal tubes with subglottic secretion drainage to prevent ventilator-associated pneumonia. Subglottic secretion drainage is associated with fewer ventilator-associated pneumonia diagnoses, but it is unclear to what extent this reflects fewer invasive pneumonias versus fewer false-positive diagnoses due to less secretions and/or less microbial colonization of the oropharynx. We, therefore, undertook a systematic review and meta-analysis of the impact of subglottic secretion drainage on duration of mechanical ventilation, ICU and hospital length of stay, ventilator-associated events, mortality, antibiotic utilization, stridor, and reintubations to better understand the net benefits and limitations of this intervention. We searched Cumulative Index to Nursing and Allied Health Literature, Excerpta Medica Database, and PubMed from inception through February 22, 2015, without language restrictions. Randomized controlled trials comparing subglottic secretion drainage versus no subglottic secretion drainage in adult patients on mechanical ventilation. Eligible trials were abstracted and assessed for risk of bias by two reviewers. We identified 17 eligible trials with a total of 3,369 patients. Subglottic secretion drainage was associated with lower ventilator-associated pneumonia rates (risk ratio, 0.58; 95% CI, 0.51-0.67; I2 = 0%), but there were no significant differences between groups in duration of mechanical ventilation (weighted mean difference, -0.16 d; 95% CI, -0.64 to 0.33; I2 = 0%), ICU length of stay (weighted mean difference, +0.17 d; 95% CI, -0.62 to 0.95; I2 = 0%), hospital length of stay (weighted mean difference, -0.57 d; 95% CI, -2.44 to 1.30; I2 = 0%), ventilator-associated events (risk ratio, 0.97; 95% CI, 0.65-1.43), or mortality (risk ratio, 0.93; 95% CI, 0.84-1.03; I2 = 0%). Two studies observed significantly less antibiotic use with subglottic secretion drainage whereas a third did not. There were no significant differences between groups in stridor or reintubations. Subglottic secretion drainage is associated with lower ventilator-associated pneumonia rates but does not clearly decrease duration of mechanical ventilation, length of stay, ventilator-associated events, mortality, or antibiotic usage. Further data are required to demonstrate the benefits of subglottic secretion drainage.