No relations were found, so no qualitative judgement could be given to a certain place of the cannulas.
The adequacy of the (hemoconcentrated) volume replaced from the pump via the arterial cannula is judged by monitoring the left atrial pressure continuously during ultrafiltration.
Once again, a transvenous approach was used with arterial blood pressure monitoring and sampling via a small peripheral arterial cannula (22 gauge).
A tracheal cannula was inserted and an external jugular vein cannulated.
We experienced no trouble in inserting the cannula while, in addition, no aortic obstruction was observed when weaning any of the patients from bypass.
Deep hypothermic arrest is used in very small infants where arterial and venous cannulas would cause significant obstructive of the operative field.
Median sternotomy was performed and cannulas placed in the right atrium and ascending aorta.
Malposition of the cannulas was demonstrated by ultrasound investigation (17.1 % for the venous and in 6% for the arterial cannula).
