Study Of Biochemical Marker Of Brain Injury During Cardiopulmonary Bypass

Objectives:To observe the changs of biochemical marker of brain injury during cardiopulmonary bypass; Analysis the realationship between levels of these three biochemical marker(S-100βprotein, Neuron-specific enolase and Myelin base protein) and brain injury; To search sensitive biochemical marker during extracorporeal circulation.Methods: 32 consecutive patients(ASAⅡ～Ⅲ)undergoing elective cardic operations for coronary artery bypass grafting were neurologically assessed before and after the operation. Postoperative outcome of NIHSS-test at the 2nd day was classified as group A(uncomplicated), group B(confusion,agitation) and group C(disorientation). Levels of S-100βprotein, Neuron-specific enolase and Myelin base protein were evaluated in central venous blood samples drawn at these times. That is T1: before CPB; T2: CPB 30 min; T3: end CPB; T4: 1h after CPB; T5: 6h after CPB; T6: 24h after CPB. Morphine and scopolamine hydrobromide was injected at the time 1h before operation. Arteria radialis and internal jugular vein pricking were performed with local anesthesia. Anesthesia induction was induced by sufentanil, etomidate and pipecuronium bromide. than tracheal intubation and keeping PETCO2 35~45mmHg by mechanical ventilation. Anesthesia was mainted by propofol, isoflurane, sufentanil and pipecuronium bromide. In addition to the aforementioned protocol, venous blood was drown serially in 32 patients to evaluate potential short-term changes in S-100β,NSE and MBP serum levels. SPSS13.0 software was used as statistical method. Normally distributed date were expressed as mean±standard and compared with a 2-sample t-test or 1-way analysis of variance. Linear regression analysis was performed to evaluate the value of S-100β, NSE and MBP levelsand operative parameters(duration of CPB,days in ICU and neurologic outcomes).Results: No significant differences of S-100β,NSE and MBP levels were found among these three groups before operation and all the makers were normal. A Significant increase in the median serum levels of these proteins were observed during CPB ,espisilly at the 30th minutes during CPB and the 1st hour after CPB and group C was noticeable. In patients with group B/C outcomes, S-100β,NSE and MBP levels were significantly higher than those in patients with a group A outcome and than preoperative values throught the postoperative period. Levels of three proteins were significantly higher in association with group C as compared with group B outcomes. This difference was statistically significant throught the postoperative period. Elevations of S-100βin the serum levels of group A and B were observed in whom blood was serially drawn during the first 6 postoperative hours. But group C was remained significantly elevated. Reaching its highest values for NSE at the 1st hour after CPB,and the peak levels (26.40±2.25 ug/L) of NSE in group C is significantly higher than group A and B. MBP of group A and B reach its highest values at the 1st hour after CPB,and group C at the 24th hour after CPB,the peak levels is 10.41±1.65 ng/ml.The differences of MBP levels among three groups is more significantly at the 24th hour after CPB than any other time(P < 0.01)and group C is the highest. Linear regression analysis revealed a significant relation between NIHSS-test and MBP level at 30 minute of CPB( r = 0.71, P < 0.05) and at the end of CPB( r = 0.79, P < 0.05). Similar results were obtained regarding S-100β( r = 0.86, P < 0.05)and NSE ( r = 0.87, P < 0.05) levels at 1st hour after CPB; S-100βlevel ( r = 0.87, P < 0.05) at 6th hour after CPB; S-100β( r = 0.90, P < 0.05) and MBP( r = 0.87, P < 0.05) levels at 24th hour after CPB. Furthermore, there is a significant relation between S-100β( r = 0.71, P < 0.05) level and ICU at 24th hour after CPB.Conclusion: Serum levels of S-100β,NSE and MBP are reliable markers for adverse neurologic outcomes after cardiac surgery by CPB. We concluded that serum levels of MBP level at 30 minute of CPB and at the end of CPB are valid clinical predictors for adverse neurologic outcome in patients undergoing cardiac surgery. Similar results were obtained regarding S-100βand NSE levels at 1st hour after CPB; S-100βlevel at 6th hour after CPB; S-100βand MBP levels at 24th hour after CPB. Serum levels of S-100βalso might prove useful in assessing the time that stay in ICU after cardiac surgery.