To establish the possible advantages of ultrashort acting barbiturates administered in continuous infusion as the only sedative agent for mechanically ventilated patients, sodium thiopental was given to 30 subjects for periods ranging from 2–14 days. Plasma levels were maintained at approximately 15 μg/ml, using both laboratory determinations and clinical judgment. This technique proved effective for patients requiring either controlled ventilation or intermittent mandatory ventilation. None of the hemodynamic and respiratory variables studied was significantly altered during the infusion, with the exception of decreased heart rates. In view of these results, the technique is considered both expedient and safe for prolonged sedation of patients requiring ventilatory support.