Selective digestive decontamination (SDD) is the most extensively studied m
ethod for the prevention of infection in patients in intensive care units (
ICUs). Despite 27 prospective randomized studies and six meta-analyses, rou
tine use of SDD is still controversial. In this review, we summarize the av
ailable scientific information on effectiveness of SDD in ICU patients. The
effects of SDD have been studied in different combinations of the concept,
using different antibiotics. Comparison of the individual studies, therefo
re, is difficult. In most studies, SDD resulted in significant reductions i
n the number of diagnoses of ventilator-associated pneumonia. However, inci
dences of ventilator-associated pneumonia in control groups ranged from 5%
to 85%. Moreover, these reductions in incidences of ventilator-associated p
neumonia in individual studies were not associated with improved patient su
rvival, reductions of duration of ventilation or ICU stay, or reductions in
antibiotic use. The numbers of patients studied are too small to determine
effects on patient survival. Although two meta-analyses suggested a 20% mo
rtality reduction when using the full concept of SDD (topical and systemic
prophylaxis) these results should be interpreted with caution. Formal cost-
benefit analyses of SDD have not been performed. SDD is associated with the
selection of microorganisms that are intrinsically resistant to the antibi
otics used. However, the studies are too small and too short to investigate
whether SDD will lead to development of antibiotic resistance. As long as
the benefits of SDD (better patient survival, reduction in antibiotic use o
r improved cost-effectiveness) have not been firmly established, the routin
e use of SDD for mechanically ventilated patients is not advised.