ECMO-/ECLS

relatively inefficient because of the high resistance associated with the long
cannula required to reach the right atrium. A femoral cannula placed into the
inferior vena cava does not usually provide adequate extracorporeal blood flow.
In children under 5 years of age the femoral vein is too small to function as the
primary drainage site; therefore, the iliac vein should be considered the second
choice of access in young children.[ 7 ] Umbilical venous drainage may rarely be
used to augment venous drainage, but the contribution of the umbilical vein flow
is considered minimal.[ 8 ] A proximal venous drainage cannula (PVDC) may be
placed into the proximal internal jugular vein to enhance venous drainage to the
extracorporeal circuit, and may decrease intracranial pressure.[ 9 ]
The size of the reinfusion cannula is less critical than that of the venous
cannula, although it must be large enough to tolerate the predicted blood flow
rate at levels of total support without generating a pressure proximal to the
membrane lung of > 350 mmHg.[ 4 ] Infusion cannulas typically have a single end
hole while venous drainage cannulas have additional side holes. The first choice
for placement of a cannula into the arterial circulation is the carotid artery in all
age groups since it provides easy access to the aortic arch. Few complications
have been associated with carotid artery cannulation and ligation in newborns,
children and adults. The second choice for arterial access is the axillary or
femoral artery in those patients over 5 years of age who require gas exchange
support and the femoral artery in those with isolated cardiac dysfunction.
Disadvantages associated with use of the axillary and femoral arterial access
sites are that the femoral artery does not provide easy access to the aortic arch