Does selective decontamination of the digestive tract reduce death risk for adults on mechanical ventilation?

Selective decontamination of the digestive tract (SDD) is a preventive strategy where antibiotics are applied to the mouth and stomach, and sometimes given intravenously, to reduce infections in critically ill patients on mechanical ventilation. The key question is whether this approach lowers the risk of death. Based on the most comprehensive evidence available, SDD appears to reduce hospital mortality, though the benefit is modest and some studies show no effect.

What the research says

A 2025 updated meta-analysis of 32 randomized trials involving over 27,000 patients found that SDD reduced the relative risk of hospital death by about 9% compared to standard care (relative risk 0.91; 95% credible interval 0.82 to 0.99), with a 99.2% probability that SDD is beneficial ¹. This analysis included a large 2022 trial from Australia and Canada that, on its own, did not show a statistically significant mortality benefit ⁴¹⁰. However, when combined with all prior trials, the overall evidence favors SDD. A separate 2022 meta-analysis (also including 32 trials) reported similar findings ⁹. Notably, in patients with acute brain injuries, a post-hoc analysis of the 2022 trial found SDD reduced in-hospital mortality from 38% to 32.3% ¹¹. While SDD's effect on mortality is supported, other aspects of care—such as sedation protocols, nutrition, and weaning strategies—also influence outcomes for ventilated patients ⁷⁸⁶.

What to ask your doctor

• Would SDD be appropriate for my condition or my loved one's condition in the ICU?
• What are the potential risks of SDD, such as promoting antibiotic resistance?
• How does SDD compare with other infection prevention strategies used in this ICU?
• Is the mortality benefit of SDD considered clinically meaningful in my situation?
• Are there any specific patient groups (e.g., those with brain injuries) where SDD is more or less effective?