When the unexpected happens: intracardiac ECMO venous cannula kinking.
A term newborn with a right-sided CDH and severe pulmonary hypertension
with systemic hypotension required veno-arterial ECMO. Despite
appropriate cannulas size, high drainage pressure exceeding 60 mmHg was
needed to maintain an ECMO flow at 120 ml/kg/min. Pericardial tamponade
and misplacement of the venous cannula within the azygos vein were
detected. Open thorax surgery was performed, and the cannula was
repositioned. Postoperative X-rays showed an anomalous tip position of
the cannula, suggesting the kinking inside the right atrium (Fig. 1).
Reintervention was needed to restore the cannula. Cannula problems
complicate about 12.8% of all neonatal respiratory ECMO. Both cannula
malposition and kinking can affect the proper functioning of the ECMO
support, and they should be carefully ruled out anytime suboptimal
venous drainage and insufficient ECMO flow are experienced.
Nevertheless, their diagnosis can be challenging, and both X-ray and
echocardiography are essential tools. In particular, incidental azygos
vein cannulation represents a possible rare ECMO complication in
right-sided CDH and should always be kept in mind in this specific
population. The decision to reposition or replace the cannula is
mandatory, although not risk-free, in case of inadequate venous drainage
or case of possible cardiac or vessel perforation.