In adults receiving mechanical ventilation, selective decontamination of the digestive tract reduces hospital mortality

A recent meta-analysis found that ICU patients receiving mechanical ventilation may benefit from selective decontamination of the digestive tract (SDD). Data from 30 trials and 24,034 participants contributed to the primary outcome, in-hospital mortality. Compared with standard care or placebo, SDD was associated with lower in-hospital mortality in mechanically ventilated ICU patients.

The meta-analysis was published Oct. 26, 2022, by JAMA and was summarized in the November 2022 ACP Gastroenterology Monthly. The following commentary by Naomi P. O’Grady, MD, was published in the ACP Journal Club section of the March Annals of Internal Medicine.

SDD is an infection control strategy based on the concept that many types of ICU-acquired infection can be prevented by reducing potentially pathogenic microorganisms colonizing the gut. In patients in ICUs who are receiving mechanical ventilation, this strategy may positively affect clinically relevant outcomes, including ventilator-associated pneumonia, bacteremia, and mortality. SDD can be accomplished by administering nonabsorbable, topical antimicrobial agents to the oropharynx and upper gastrointestinal tract, with or without a short course of broad-spectrum IV antibiotics.

The meta-analysis by Hammond and colleagues compared SDD with standard care in patients receiving mechanical ventilation in the ICU to determine if SDD reduced death. Using Bayesian analyses, they found a 99.3% probability that SDD was associated with a reduction in hospital mortality. However, the benefit was seen only when pooled studies included IV components of SDD. In secondary analysis, SDD reduced ventilator-associated pneumonia and ICU-acquired bacteremia. The authors used GRADE methodology to adjudicate the quality of evidence, which was moderate for mortality but very low and low for ventilator-associated pneumonia and bacteremia, respectively.

The findings support the use of SDD and did not show evidence of increased incidence of antimicrobial-resistant organisms—a concern and an obstacle to implementing SDD as standard practice in most ICUs. Notably, the review included data from regions that have very low levels of antimicrobial resistance (e.g., the Netherlands, New Zealand, Australia). It is still not clear that SDD is effective in regions with higher levels of antimicrobial resistance, although targeted studies in such settings could answer this question.