AN UPDATE ON SELECTIVE DECONTAMINATION OF THE DIGESTIVE-TRACT

Selective digestive decontamination (SDD), originally proposed for use in trauma victims, is a technique designed to prevent infections in critically ill patients. SDD consists of local applications of tobramycin, polymyxin, and amphotericin B to the buccal mucosa, the same drugs are instilled into the stomach and cefotaxime is administered in a prophylaxis program which includes comprehensive bacteriologic monitoring. SDD aims to prevent infection by eliminating colonization of mucosal surfaces by potentially pathogenic organisms and by the early treatment of infections which may be incubating as the patient is admitted. Early uncontrolled trials of SDD were highly promising and two meta-analyses indicated that SDD markedly reduced the incidence of nosocomial pneumonias and may reduce mortality by 10-15%. Recent trials have used better techniques. Most have been randomized, a few blinded, but only rarely have reliable techniques been used to diagnose pneumonias. Resistance among enterobacteriaceae has not become a major problem but resistant Gram-positive cocci, both staphylococci and enterococci, have emerged in some recent studies and portend a possibly serious problem ahead. SDD may be useful in limiting spread of resistant organisms within an intensive care unit but should not be used to replace conventional infection control procedures. Much of the reduction of infection associated with SDD can be accomplished by other, non-hazardous, means. The modest benefits of SDD do not warrant routine use.