Reduction in ventilator-associated pneumonia following the introduction of subglottic suction endotracheal tubes

Introduction

Aspiration of subglottic secretions is recommended by the American Thoracic Society, for the prevention of ventilator-associated pneumonia (VAP) [1], but has a poor implementation rate in some countries [2]. VAP is the most frequent infection in ventilated patients, occurring in up to 27% of cases [1].

Methods

We studied 993 patients from September 2005, over a 39-month period, following the introduction of our ventilation care bundle, which includes 30° head-up position, deep vein thrombosis and peptic ulcer prophylaxis, sedation holds and using chlorhexidine for mouth care. VAP is difficult to diagnose and definitions vary. Our diagnoses were made prospectively by a single consultant microbiologist using the validated Clinical Pulmonary Infection Score. After 18 months we introduced the Hi-Lo Evac/Lanz Mallinckrodt endotracheal tubes with suction applied using a 10 ml syringe 2-hourly, as our study intervention.

Results

The benchmark for European ICUs is a rate of 5% to 15% (HELICS; Hospital In Europe Link for Infection Control through Surveillance) and in America is 3 to 20 cases per 1,000 ventilator-days (NNIS; National Nosocomial Infections Surveillance System). For the 18 months following the implementation of care bundles, our VAP rate was 5.39% (25/463 patients) with an incidence of 14 cases per 1,000 ventilator-days. Following the study intervention the VAP rate fell to 1.5% (8/530 patients) and the incidence to 4.17 cases per 1,000 ventilator-days. Our cohort of patients over the period had no difference in APACHE II scores. The difference between the groups following the employment of subglottic secretion reached statistical significance with relative risk 3.57 (95% CI = 1.63 to 7.85, P < 0.001).

Conclusion

Our study confirms the benefit of subglottic secretion clearance to reduce the occurrence of VAP.