The safety, efficacy, and outcome of long-term patient-triggered synchronized assisted ventilation in infants (SAVI) was studied in very low birthweight infants (450 to 1250 g) with uncomplicated respiratory failure. Synchronization was accomplished by modified thoracic impedance technology using standard neonatal cardiorespiratory monitors with the output of the ventilation synchronizer triggering the exhalation solenoid of a standard neonatal respirator. In this nonrandomized study, the technique was found to be safe and reliable without any episodes of technical failure or adverse effects. The results indicated that in comparison with infants receiving conventional ventilation, infants receiving SAVI required (1) shorter duration of ventilation, (2) decreased duration of oxygen therapy, and (3) decreased progression of intraventricular hemorrhage to greater than or equal to grade III. Decreased duration of ventilation was statistically significant in infants weighing less than 850 g (P less than .02). These beneficial trends were ratified during a 3-year period in a total of 110 cases.