In a review of the literature on differential lung ventilation (DLV) the average mortality was found to be 47%. The major cause of death (66%) was infection. The effect of a novel infection prevention regimen on the colonisation and infection rate of the respiratory tract and on outcome was studied in polytrauma patients. Nineteen patients who presented with asymmetric pulmonary contusion were treated with DLV (103 +/- 72 h) and conventional mechanical ventilation (CMV) (16 +/- 10 days). They were treated with selective decontamination of the digestive tract with topical non-absorbable antibiotics in combination with systemic antibiotic prophylaxis starting immediately after admission. In one patient colonisation of the respiratory tract was found with Staphylococcus aureus. This disappeared after continued systemic antibiotic prophylaxis. Colonisation with hospital-acquired Gram-negative bacteria or yeasts was not observed. No patient developed pneumonia throughout the period on conventional mechanical ventilation or on DLV. One patient died from cerebral injury. It is concluded that prolonged endobronchial intubation for DLV can be used without increased risk for pneumonia with this antibiotic regimen and that the very low mortality in this study may be attributed to the prevention of infectious complications.