The management of obstructive diseases of the pediatric upper airway (UA) is currently based on the evaluation of the obstruction during an endoscopy with general anesthesia. This procedure has a significant morbidity. The difficulty of quantifying UA obstruction and its impact with simple and accurate tools emphasizes the importance of evaluating new techniques. The objective of this work was to study new methods of exploration, minimally or non- invasive, of these obstructive diseases: the acoustic reflection method (ARM) and measurement of work of breathing. The ARM is based on the analysis of the reflection of a pressure wave in the UA. The work of breathing studies the load imposed on the respiratory muscles during breathing. We demonstrated that the MRA was applicable in children over 2 years, with a standardized technique. Measurements on children with cystic fibrosis and mucopolysaccharidosis were conducted, to assess the UA resistance and its evolution during the course of the disease. In younger children, when the ARM is possible, we demonstrated in infants with a Robin sequence having an increase in the work of breathing that noninvasive ventilation was able to reduce the load imposed on respiratory muscles and to improve the clinical course. Non- or minimally invasive techniques exploring the UA in children are promising because simple, safe, and potentially complementary to other more invasive tests. Their achievement is routinely possible in many cases
