Model of single-sized endotracheal tube for adults

OBJECTIVE: To simulate different diameters of endotracheal tubes and to verify the fluid dynamics aspects by means of flow and resistance measurements. METHODS: Fluid dynamics software was used to calculate mean flow and airway resistance in endotracheal tube with a diameter of 6.0, 7.0, 7.5, 8.0, 9.0 and 10.0mm at normal body temperature and under constant pressure. The same measurements were taken in the fusion of the first 22cm of a 9.0mm endotracheal tube with 10.0mm diameter, and with the end part in 12cm of a 6.0mm endotracheal tube with 7.0mm diameter. RESULTS: The fusion of the first 22cm of an endotracheal tube of 10.0mm diameter with the terminal part in 12cm of an endotracheal tube of 6.0mm diameter, preserving the total length of 34cm, generated average flow and airway resistance similar to that of a conventional 7.5mm endotracheal tube. CONCLUSION: This simulation study demonstrates that a single-sized endotracheal tube may facilitate endotracheal intubation without causing increased airway resistance.