Effect Of Propfol On Postoperative Cognitive Function In Valve Replacement Patients

Objective To investigate the effects of propofol on postoperative congnitive function in patients underging valve replacement operation under CPB by measuring several serum indicators. To Choose suitable anesthetic dosage for heart surgery anesthesia,so that reduce the incidence of postoperative cognitive impairment and provide clinical basis for heart surgery anesthesia medicine.Methods After consenting by the hospital ethics committee,180 low risk patients undergoing elective surgery under general anesthesia were included in this study from January,2014 to November, 2014. They were randomly divided into three groups according to the concentration of prorofol: Propofol TCI 1.5μg·ml-1(P1)、Propofol TCI 2.0μg·ml-1(P2)、Propofol TCI 2.5μg·ml-1(P3).Each group of 60 cases of patients accepted more than secondary education. After entering the operating room, monitor patients with ECG, noninvasive blood pressure, pulse oxygen saturation, brain local temperature and the spectrum index(BIS).Giving patients oxygen using simple oxygen mask. Giving sufentanil 0.05μg·kg-1, and then conducting the left the radial artery puncture and internal jugular vein puncture under local anesthesia. Anesthesia induction with sufentanil 0.5μg·kg-1 and rocuronium 0.6 mg· kg-1, Propofol were target controlled infusion according to the propofol concentration, TCI 1.5μg· ml-1(P1)、Propofol TCI 2.0μg·ml-1(P2)、Propofol TCI 2.5μg·ml-1(P3). Maintain anesthesia with propofol and remifentanil TCI. intraoperative rocuronium was administrated to maintain muscle relaxant. The level of plasma cortisol were measured before and after surgery. The level of IL-6,IL-10,TNF-ɑ and S100, NSE, MBP, Glu, Gly, Asp, glucose were measured before operation. MMSE and HAD test scale was to evaluate the cognitive function 1 day before operation,3 days, 1 week and 3 months. The changes in cardiovascular response and BIS were recorded. Analysis of the influence of different concentration of propofol on the serum index, evaluate the correlation between each index and POCD, so as to determine ideal dose of propofol for the cardiac surgery.Results 1. Cytokine levels(TNF-ɑ, IL- 6, IL- 10) after surgery were significantly higher than the levels before surgery(p < 0.05). The increasing concentration of cytokines in P1 and P3 group is more obvious than that in the P2 group(p < 0.05). 2. Postoperative serum indices(S100β, NSE and MBP) were significantly increased than that before anesthesia(p < 0.05). The increasing concentration of serum indices in P1 and P3 group is more obvious than that in the P2 group(p < 0.05). 3. The changes of cortisol concentration during operation period in P2 and P3 were very small. The cortisol concentration in P1 was elevated after operation significantly(p < 0.05). But 4 hours after operation, the cortisol concentration in P1 and P3 were significantly higher than the P2(p < 0.05). 4. Cerebral oxygen uptake rate had no changes during the CPB( p > 0.05). Cerebral sugar intake rate increased significantly in the patients of POCD, p < 0.05. While the glu(a-v)roup brain did not increase, in the patients of none POCD(p> 0.05). 5. The concentration of brain amino acid(Glu, Asp, Gly) were increased after operation in three groups(p < 0.05). The concentration of amino acids achieved peak concentration 24 h after surgery and reduced gradually. The increasing concentration of Glu, Asp, Gly in P1 and P3 group were more obvious than that in the P2 group(p < 0.05). 6. The incidence of POCD in group P1 and P3 were significantly higher than those in group P2, 3, 7 and 30 days after operation,( p < 0.05). While 90 days later, the incidence of POCD in three groups had no differences,(p > 0.05). 7. With the increase of concentration of propofol, the ICU stay time, wake time and auxiliary ventilation time will be extended accordingly,(p < 0.05). While the in-hospital time in P1 and P3 group were significantly longer than that in P2 group(p < 0.05).Conclusions 1.Levels of cytokines(TNF-ɑ, IL- 6, IL- 10), neural index(S100β, NSE and MBP), brain amino acid(Glu, Asp, Gly), concentration of cortisol and brain sugar taken rate had some certain relativity with the incidence of POCD. 2. With the increase of concentration of propofol, anesthesia depth deepening, the incidence of early cognitive dysfunction in patients get lower, but the ICU stay time, awake time and auxiliary ventilation time will be extended accordingly. But when the concentration of propofol rise further, and the depth of anesthesia intensify further, the incidence of POCD did not decline.In this study, 2.0μg· ml-1 can serve as a suitable target concentration when the propofol TCI.