Wright et al developed a formula for positioning an umbilical artery catheter in a very low birthweight infant. This is intended to reduce the overestimation common with other methods. The authors are from John Hunter Children's Hospital in New South Wales, Australia.


Patient selection: birthweight < 1,500 grams with no major cardiovascular malformations


Goal: positioning of tip at level of T6 to T10


insertion length in cm =

= (4 * (birthweight in kilograms)) + 7 cm


If an umbilical stump is present then this length must be taken into account.


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