Background: Postoperative mortality due to myocardial failure following major corrective surgery of congenital heart defects has the potential to be reduced by mechanical circulatory support systems. Evaluating of recovery of ventricular function by transthoracal and transoesophegeal echo is associated with varoius difficulties such as risk of bleeding, and lack of ultrasound window due to edema, air, and open thorax. Transfontanal and transcranial measurements of CBFV by means of dopplersonography provide non-invasive qualitative informations on cerebral hemodynamics and thereby possibly also of cardiac function.

Methods: In 7 children and infants receiving ECMO therapy after corrective surgery of congenital heart defects serial ultrasonography of the brain and measurements of CBFV in the anterior cerebral artery (ACA), internal carotid artery (ICA), and middle cerebral artery (MCA) were performed using colour duplex-dopplersonography (Sonoline CF, Siemens-Germany). The maximal systolic flow signal (Vmax) representing cardiac ejection, and the diastolic flow velocity (Ved) representing continuous ECMO flow were registered in serial studies during the therapy. The resistance index (RI) was calculated according to the formula RI=Vmax-Ved/Vmax. Hemodynamic parameters and ECMO flow were simultaneously documented.

Results: During the last14 months 7 children (age: 1 week -5 years, weight: 3,5- 19 kg, mean 9,2 kg) were enrolled in this pilot study. The mean value of ECMO duration was 8 (4-15) days. In 3 patients who successfully weaned from ECMO, RI values increased significantly during the course of ECMO therapy due to an increase in peack systolic velocity. In those 4 patients without improvement in ventricular function maximal systolic flow velocities were lower or nearly absent during the therapy.

Conclusion: In addition to the usefulness of the doppler method for evaluating an alteration in cerebral hemodynamics, serial determination of CBFV in children and infants receiving cardiac ECMO may provide an additional non-invasive method to judge arecovery of cardiac function.