“…Vocal cord markings vary among ETT manufacturers [ 18 , 19 , 20 , 21 ] and package inserts have provided no guidance to the caregivers on the proper use of such markings; both of these factors contribute to user uncertainty and error in accurate ETT placement [ 8 ]. Improving safety standards for ETT design should be based on neonatal airway dimensions [ 17 , 18 , 19 , 22 , 23 ] but such measurements have been scarce and discrepant between studies, particularly those comparing living preterm neonates and deceased fetuses [ 5 , 23 , 24 , 25 , 26 ]; there is evidence that postmortem tracheal length is significantly shorter than that in the living, dynamic state [ 27 ]. Due to insufficient evidence on the relative efficacy of various ETT markings from different manufacturers, the International Organization for Standardization (ISO) has not standardized these markings [ 28 ].…”