Comparison of two different extracorporeal circuits on cerebral embolization during cardiopulmonary bypass in children.

OBJECTIVE

To compare the effect of two different extracorporeal circuits on the counts of high-intensity transient signals (HITS) during pediatric cardiopulmonary bypass (CPB).

METHODS

Transcranial Doppler was used to detect HITS associated with extracorporeal sources during the period of aortic crossclamping in the middle cerebral artery of children undergoing CPB. Based on body size, children were assigned one of two extracorporeal circuits (A or B). Circuit A included a D-705 oxygenator and associated reservoir, and circuit B included a Lilliput oxygenator and reservoir. Patients were further classified into two groups according to the complexity of surgical repair: single simple lesions or multiple complex lesions.

RESULTS

We studied 109 pediatric patients. Surgery for multiple complex lesions was associated with longer periods of aortic crossclamping and CPB (p < 0.0001). The median count of extracorporeal HITS was 12 (25th, 75th percentiles: 3, 51). The type of extracorporeal circuit (p = 0.012) and the complexity of surgical repair (p < 0.0001) had an effect on the HITS counts. The use of circuit A was associated with higher HITS counts during surgery for multiple complex lesions compared to single simple lesions (p < 0.0001). Conversely, no differences were found with the use of circuit B between these two surgical groups (p > 0.25). During surgery for multiple complex lesions, patients treated with circuit A showed higher HITS counts than those with circuit B (p < 0.01), but there were no circuit-related differences in HITS counts (p = 0.30) during single simple lesions.

CONCLUSION

Variations in the design characteristics of extracorporeal circuits can increase cerebral emboli during CPB in children. This may be related to the reduced ability of some circuits to remove emboli during long periods of CPB for complex congenital heart-surgery.