Subglottic Secretion Drainage and Objective Outcomes: A Systematic Review and Meta-Analysis

Objective: 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. Data Sources: We searched Cumulative Index to Nursing and Allied Health Literature, Excerpta Medica Database, and PubMed from inception through February 22, 2015, without language restrictions. Study Selection: Randomized controlled trials comparing subglottic secretion drainage versus no subglottic secretion drainage in adult patients on mechanical ventilation. Data Extraction: Eligible trials were abstracted and assessed for risk of bias by two reviewers. Data Synthesis: 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; I-2 = 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; I-2 = 0%), ICU length of stay (weighted mean difference, +0.17 d; 95% CI, -0.62 to 0.95; I-2 = 0%), hospital length of stay (weighted mean difference, -0.57 d; 95% CI, -2.44 to 1.30; I-2 = 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; I-2 = 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. Conclusions: 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.