Fifteen premature neonates of between 1-2 kilograms' current weight, with gestational age at birth between 24-34 weeks, and receiving non-invasive ventilation will be enrolled in the study after consent is obtained. The infants will be ventilated using NIV NAVA and NIPPV applied in random order for 15 minutes each while using respiratory inductance plethysmography to measure thoracoabdominal asynchrony as an estimate of work of breathing.