Cerebral oxygen saturation before congenital heart surgery

Background. In congenital heart disease (CHD), neurologic abnormalities sug gestive of hypoxia-ischemia are often apparent before cardiac surgery. To e valuate preoperative cerebral oxygenation, this study determined cerebral O -2 saturation (Sc-O2) in CHD and healthy children. Methods. Ninety-one CHD and 19 healthy children aged less than 7 years were studied before surgical or radiologic procedures. Arterial saturation (Sa( O2)) and Sc-O2 were measured by pulse-oximetry and near infrared cerebral o ximetry. Cerebral O-2 extraction (CEO2) was calculated (Sa(O2)-Sc-O2). Sa(O 2), Sc-O2, and CEO2 were compared among diagnoses. Multivariable regression was performed between Sc-O2 and clinical variables. Results. In healthy subjects, Sc-O2 (68% +/- 10%) and CEO2 (30% +/- 11%) we re similar to patients with ventricular septal defect, aortic coarctation, and single ventricle after Fontan operation. Sc-O2 was significantly decrea sed in patients with patent ductus arteriosus (53% +/- 8%), tetralogy of Fa llot (57% +/- 12%), hypoplastic left heart syndrome (46% +/- 8%), pulmonary atresia (38% +/- 6%), and single ventricle after aortopulmonary shunt (50% +/- 7%), or bidirectional Glenn operation (43% +/- 6%). CEO2 was significa ntly different only in patent ductus arteriosus (46% +/- 8%) and hypoplasti c left heart syndrome (38% a 12%). In multivariable regression, only Sa(O2) was related to Sc-O2 (R = 0.63, p < 0.001). Conclusions. Cerebral oxygenation in CHD varies with anatomy and arterial s aturation, and in some patients, it is very low compared with healthy subje cts. (C) 2001 by The Society of Thoracic Surgeons.