Embleton developed equations for using the foot and crown-rump length to estimate the length of a nasotracheal tube in a neonate. The authors are from the Royal Victoria Infirmary and the Royal Shrewsbury Hospital in England.



(1) foot length in cm

(2) crown rump length (CRL) in cm


nasotracheal tube length in cm =

= (1.06 * (foot length)) + 2.44


nasotracehal tube length in cm =

= (0.30 * (crown rump length in cm)) + 0.22


An additional 0.5 cm is added to the tube length if it is sutured to a tape.


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