<qa>  What is the primary endpoint of PSVVG?Studies in preterm infants have shown that adding volume guarantee VG to synchronized modes of ventilation is not only feasible but also advantageous for providing more constant and desirable mechanical breath size. This ideally minimizes ventilator-induced lung injury due to barotrauma and volutrauma. To date, only one recent study has investigated the relative advantages of combining VG with different modes of synchronized mechanical ventilation in clinically stable, preterm infants that were mechanically ventilated at an average age of one month. We aim to further evaluate the effects of PSVVG versus SIMVVG ventilation in very low birth weight infants within the first three to five days of life. Our hypothesis is that in very low birth weight infants requiring mechanical ventilation in the first three to five days of life, PSVVG will allow for more stable physiologic and ventilatory parameters compared to SIMVVG. The primary endpoints are a reduction in respiratory rate and average mean airway pressure in the PSVVG group compared to the SIMVVG group. 