Chronic pulmonary damage, induced by mechanical ventilation, represents a major morbidity risk for low birth weight infants. Lung overexpansion by high tidal volumes has been recognized as a contributory factor. In currently used ventilation modes, the inbuilt flow sensor and the gadget for closed endotracheal suction increase the dead space significantly. This apparative dead space is commonly combated by high tidal volumes. A recently inaugurated alternative consists in flushing the anatomical dead space with fresh gas – which is split off the regular ventilation circuit – bypassing the apparative dead space. Such a flow partition system was compared with conventional ventilation in 17 preterm infants weighing < 2000 g. Ventilation requirements were significantly lowered in all patients. Mean minute volumes could be reduced by 40.6% (P < 0.001), while mean arterial partial pressures of carbon dioxide fell from 54.3 (± 10.74) mmHg to 47.4 (± 3.80) mmHg (P = 0.009) on average. We conclude that the dead space decrease by split flow signs responsible for the reduced ventilation requirements, and would expect correspondingly less pulmonary injury. Specialized flow sensor calibration will be required for routine usage.