Effect of the type of cardiopulmonary bypass pump flow on postoperative cognitive function in patients undergoing isolated coronary artery surgery

Pulsatile flow, generated by a pump during cardiopulmonary bypass, has been accepted as more physiological in coronary artery bypass grafting surgery (CABG). Therefore, we aimed to investigate the effects of pulsatile and nonpulsatile flow on postoperative cognitive function and to review relationship with the biomarkers S100ß and neuron-specific enolase (NSE). Patients who underwent isolated CABG were included this prospective, randomized, double-blind study, which was performed between March 2010 and December 2010. Patients were divided into two groups: pulsatile (Group I, n=20) and nonpulsatile (Group II, n=20) flow. Blood samples were collected 1 day before surgery and in the sixth postoperative hour for the analysis of S100ß and NSE. In addition, Mini-Mental State Examination (MMSE) was performed during preoperative period and on third postoperative day. Outcomes were determination of effects of pump flow type on cognitive function and relationships with concentrations of S100ß and NSE. Forty patients were included. No differences were observed between the groups with respect to complications, mortality, S100ß (Group I: 1.9±0.2 µ/L; Group II: 2.0±0.2 µ/L), NSE (Group I: 12.5±0.8 µ/L; Group II: 12.4±0.7 µ/L), MMSE scores [Group I: 25 (23-27); Group II: 25 (23-27)], and postoperative cognitive dysfunction (POCD) (p>0.05). No correlation was observed between MMSE scores and concentrations of S100ß (r=-0.032) and NSE (r=-0.423) (p>0.05). There was no difference between types of pump flow for POCD and no relationship between cognitive dysfunction and S100ß and NSE concentrations. Pump flow type does not affect NSE concentrations.