Should All ICU Patients Receive Systemic Digestive Decontamination?

Selective digestive decontamination (SDD) has been proposed as a strategy for pneumonia prevention in ICU patients that has been reported to reduce both ICU-acquired infection rates, and mortality. Numerous studies over the past 25 years have been conducted, with mixed results, but meta-analysis has supported a survival benefit to this application of prophylactic antibiotics to the oropharynx and stomach, particularly when combined with a short-course (4 days) of systemic antibiotics. Recently 4 prospective studies have reported a mortality benefit from using the SDD approach. In spite of these possible benefits, widespread use of SDD in all ICU patients should not be encouraged. In many studies, the benefits have applied only to selected populations such as surgical and trauma patients, with less benefit to medical patients. In addition, those at the extremes of disease severity (mild or severely ill) may not benefit. The major concern with use of SDD is that it probably needs to be used in all patients in a given ICU, and this widespread use has been shown in some studies to promote the emergence of resistant bacteria, particularly gram-positives such as MRSA. This is likely to be an even greater problem in ICU's with a high baseline rate of resistance. SDD has also been reported to lead to an increased rate of hospital-acquired infections in patients after they leave the ICU. In addition, there remain questions about whether a similar benefit could be obtained with only oral decontamination, even done with antiseptics and not antibiotics. Finally, many ICU's are employing non-antibiotic VAP prevention strategies, which have been successful, especially when bundled together, and it is uncertain if SDD adds incremental benefit to these efforts.