Early assessment of post-operative cardiac output and causes of death in the neonates with congenital heart diseases

Abstract

Objective To evaluate accurately the cardiac output, an early post-operative indicator for the cardiac function, after cardiac surgery in the neonates with congenital heart diseases and assess the risk factors for surgery, with an aim at exploring the early strategy for decressing the mortality. Methods From January 2007 to November 2007, forty-seven consec-utive neonates with complex congenital heart diseases underwent surgical correction at Shanghai Children's medical center.There were 38 boys and 9 girls with age from 3 days to 29 days [mean age (21.98 +8.15) days] and weight from 2.6 kg to 4.2 kg [ mean (3.49±0.51 ) kg]. 15 patients had delayed sternal clousure. The operations were performed with hypothermia, deep hypothermia low flow, or deep hypothermia circulatory arrest techniques. Cardiac index (CI) was derived from pulse contour analysis and calculated with the PiCCO plus system. Meanwhile, serum cardiac troponin I ( cTnl), mixed venous oxygen saturation ( SvO_2 ) and cardiopulmonary bypass (CPB) time were measured. Finally, the risk factors for surgical treatment in survivors and that associated with an increased mortality were analyzed. The association between post-operative cardiac output and the death after surgery was examined. Results Four neonates died after surgery, with a surgical mortality of 8.5%. CIvalue in the neonates [ (2.0±0.3 ) liters per minute per square meter of body surface was less than normal 2.5±0. 3. CI was associated inversely with CPB time but had a positive correlation with SvO_2. No significant difference association between CI and cTnI was observed. The value of cTnl was associated with the type of surgical procedures. Cases for which DHCA and low flow cerebral pefusion technique were used were free from neurological complications, ischemia in the lower extremities and oli-guria. The duration of cardiopulmonary bypass, urgent state of the operation and the abnormal coronary artery were associated with high mortality in the neonates after cardiac surgery. Conclusion The cardiac output of the neonates in whom cardiac pro-cedures were performed is adequate for the the oxygen supply required by the whole body though it is slightly lower than nomad after cardiac surgery. Higher mortality in the neonates during early postoperative period may be due to the complexity of the primary diseases, prolonged cardiopulmonary bypass time, residual abnormalities and severe acidosis before operation. Various techniques for CPB and that for the myocardial protection are safe and can provide an appropriate operative field. Key words: Infant,nowborn; Heart defects,congenital; Cardiac surgical procedures; Cardiac output Troponin I