SERUM AND CSF LEVELS OF NEURON-SPECIFIC ENOLASE (NSE) IN CARDIAC-SURGERY WITH CARDIOPULMONARY BYPASS - A MARKER OF BRAIN INJURY

We investigated whether neuron-specific enolase (NSE) in serum or cere brospinal fluid (CSF) reflects subtle or manifest brain injury in chil dren undergoing cardiac surgery using cardiopulmonary bypass (CPB). NS E was measured in serum (s-NSE) before, and up to, 102 h after surgery in 27 children undergoing cardiac surgery with CPB. In 11 children, C SF-NSE was also measured 48 or 66 h post-surgery. As erythrocytes cont ain NSE, hemoglobin concentration in the samples was determined spectr ophotometrically at 550 nm (cut-off limit: absorbance 0.4 = 560 mg/l) in 14 children and in a further 13 children by spectroscopic multicomp onent analysis (cut-off limit 5 mu mo/l 1 = 80 mg/l). One hundred and one of 214 post-operative serum samples (47%) had to be discarded beca use of hemolysis (18% spectro-photometrically at 550 nm and 88% with s pectroscopic multicomponent analysis). On the first and second post-op erative day, the median s-NSE values were significantly higher when co mpared with samples taken after 54 h or longer (P = 0.008 and P = 0.00 2). All CSF-NSE levels were within the normal range and below the s-NS E measured in the same patient. Although in our study elevated s-NSE s eems to indicate brain injury in CPB-surgery, the low concentration of NSE in the post-operative CSF of Il children puts the neuronal origin of s-NSE in question. NSE from other non-neuronal tissues probably co ntributes to the elevated s-NSE. Additionally, normal post-operative C SF-NSE values in two children with post-operative neurological sequela e might question the predictive value of CSF-NSE with regard to brain injury. (C) 1998 Elsevier Science B.V, All rights reserved.