The effect of enteral synbiotics on the incidence of ventilator-associated pneumonia in mechanically ventilated critically ill patients

Introduction

Ventilator-associated pneumonia (VAP) affects between 8% and 28% [1] of mechanically ventilated patients. A novel way of reducing the incidence of VAP may be the use of enteral synbiotics. Synbiotics may reduce VAP directly (reducing pathogenic organisms in the proximal gut) or indirectly (improving host immunity) [2].

Objective

To determine the effect of enteral Synbiotic 2000 FORTE^® (a mixture of lactic acid bacteria and fibre) on the incidence of VAP in critically ill patients.

Design

A prospective, randomised, double-blind, placebo-controlled trial in the 14-bed general ICU of a UK university hospital.

Participants

Mechanically ventilated, enterally fed, critically ill patients were recruited over a 13-month period.

Methods

Patients were enterally fed as per the ICU protocol and were randomly assigned to receive either synbiotic 2000 FORTE^® (twice a day) or a cellulose-based placebo, throughout the ICU stay. Oropharyngeal swabs were obtained on days 0, 4 and 7.

Measurements and results

The treatment group (n = 130) was well matched with the placebo group (n = 129) for age (median 53 and 50 years) and APACHE II score (median 17 for both). Oropharyngeal microbial flora and colonization rates were unaffected by synbiotics. The overall incidence of VAP was lower than anticipated (11.2%) and no statistical difference was demonstrated between synbiotic or placebo in the incidence of VAP (9% and 13%, P = 0.31), VAP rate per 1000 ventilator-days (13 and 14.6, P = 0.73) or hospital mortality (27% and 33%, P = 0.32), respectively.

Conclusion

The incidence of VAP and mortality were not significantly decreased by the administration of Synbiotic 2000 FORTE^®. These preliminary data indicate that synbiotics are unlikely to be harmful, although trends to benefit suggest a larger multicentre study may be warranted.