Systematic literature study of trachea and bronchus morphology in children and adults

Understanding the dimensions of the lower airway is critical for performing respiratory surgery, selecting and designing appropriate airway equipment, and removing aspirated foreign bodies via bronchoscopy, anaesthesia, and radiography. The purpose of this study was to analyse the trachea and bronchus morphologically in children and adults, as well as to standardise the data for these structures' measurements. Various databases were reviewed for studies on lower airway dimensions. The criteria for inclusion and exclusion were established. Finally, it was agreed to look into 28 studies that took place between 1984 and 2021. The length of the trachea, its anterior-posterior (AP) and transverse dimensions, the lengths and transverse diameters of the right and left major bronchus, and the subcarinal angle were also investigated in the study. In studies where measurements were performed with different methods and procedures. It was revealed that age and gender were effective in the difference in lower respiratory tract dimensions. The mean values of all parameters were greater in adults than in children, the AP diameter of the trachea in adults was greater than the transverse diameter. In children, it was observed that the transverse diameter was larger than the AP diameter on average, the left main bronchus was longer than the right main bronchus, and the transverse diameter was smaller than the right main bronchus in most of the studies. The articles reviewed for this study revealed that measurements were done using a variety of different procedures and approaches, and the resulting data were inconsistent and could not be standardized. The data collected will be beneficial both conceptually and clinically; we believe that additional comparison research involving children and adults in bigger groups are necessary.