Okay, what do we have so far. The pulmonary aspect of RDS is an absence of surfactant which leads to micro-atelectasis, which results in intercostal retractions because we have noncompliant lungs and a compliant chest wall. This requires positive pressure, which can save the baby, but it can result in damage to lungs, broncopulmonary dysplasia, or chronic lung disease. So, that's why we try to stop the whole process before it starts. We have already done one of those, so lets skip to some real pictures.