High airway pressure may be injurious to lung parenchyma, but lowering airway pressure using conventional mechanical ventilation necessitates lowering tidal volume (VT). Intubated patients in the surgical intensive care unit (SICU) were randomly assigned to group 1 (VT = 12 ml/kg, n = 56) or group 2 (VT = 6 ml/kg, n = 47). Variables recorded included acute physiology and chronic health evaluation (APACHE II) score, mean peak airway pressure (MPAP), mean PaO2/FIO2, incidence of pulmonary infectious complications (PIC), duration of intubation (DOI), and duration of SICU stay (DOS). Results in the table are means +/- SE. (table; see text) The incidence of pulmonary infection tended to be lower and DOI and DOS tended to be shorter for nonneurosurgical and noncardiac surgical patients randomized to low VT, suggesting that morbidity may be decreased. The use of low VT was associated with a statistically significant but clinically irrelevant decrease in oxygenation. The routine use of low VT appeared to be safe in a selected population of patients in the SICU.