Retractions in pediatrics are a sign of obstruction. Somewhere in the airway resistance is too high and can't be overcome by the negative pressure attempting to draw air in. This results in that negative pressure exerting itself against the airway itself, pulling the lungs themselves inward. In sick kids, we want to overcome this negative pressure differential with flow or pressure. Simple FiO2 doesn't reverse or overcome the actual obstruction. #Paramedicbook #paramedicsoffacebook #medicsofface