Measurement of cerebral-oxygenation status when commencing cardiopulmonary bypass in pediatric open-heart surgery

We hypothesize that there is a difference in the cerebral-oxygenation status between cyanotic and non-cyanotic congenital heart disease when commencing a crystalloid-primed cardiopulmonary bypass (CPB). We tested this hypothesis by using near-infrared spectroscopy (NIRS).

Group 1 consisted of ten patients with non-cyanotic congenital heart diseases, including atrial septal (n=4) and ventricular septal defects (n=6), while group 2 consisted of ten patients with cyanotic congenital heart diseases, including tetralogy of Fallot (n=7) and univentricular heart (n=3). Changes in cerebral-oxygenated, deoxygenated and total hemoglobin concentrations were measured by NIRS just before and every minute for the first 10 min after commencing CPB. Arterial blood analysis was performed at those same time times.

NIRS showed a rapid fall and plateauing of cerebral-oxygenated, deoxygenated and total hemoglobin in group 1. However, although group 2 showed a rapid fall and plateauing of cerebral-oxygenated hemoglobin, a rapid fall and continuous gradual decrease in cerebral-deoxygenated and total hemoglobin were also seen. Cerebral-deoxygenated and total hemoglobin decreased more markedly in group 2 than in group 1 (P<0.001, 0.01, respectively).

NIRS revealed that the cerebral-oxygenated hemoglobin could be maintained at a similar level at the beginning of CPB in both groups. However, it showed a different distribution of cerebral-deoxygenated and total hemoglobin between the groups. An inadequate cerebral-oxygenation status may occur in the early phase of CPB in patients with cyanotic congenital heart diseases.