Futagawa K, et al. - The effects of size, shape, and partial compression of the nasotracheal tube (NTT) on airway resistance have not been investigated, therefore, researchers conducted this study to determine the values of airway resistance with partial compression of preformed NTTs of various sizes. Findings demonstrated that pressure losses through NTTs were in inverse proportion to the tubes’ internal diameters (IDs). It was observed that greater pressure losses due to slip joints, acute bending, and partial compression of the NTT were obvious in small NTTs. As per observations, pressure losses through NTTs vs standard tubes, especially in small NTTs, could increase the work of breathing to a greater extent; intranasal compression further increased the pressure loss.