Effect of isoflurane preconditioning on brain injury in patients undergoing cardiac valve replacement under cardiopulmonary bypass / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of isoflurane preconditioning on brain injury in pa?tients undergoing cardiac valve replacement with cardiopulmonary bypass(CPB). Methods Forty patients of both sexes, aged 35-55 yr, with body mass index of 18-25 kg∕m2, of American Society of Anesthesiol?ogists physical statusⅡorⅢ(New York Heart Association classⅡorⅢ), scheduled for elective cardiac valve replacement with CPB, were divided into 2 groups(n=20 each)using a random number tablecontrol group(group C)and isoflurane preconditioning group(group P). After induction of anesthesia, 1.5% isoflurane was inhaled for 30 min followed by 15?min washout, and the end?tidal isoflurane concen?tration was less than 0.1% at the end of washout in group P. Immediately after internal jugular vein punc?ture(T1), immediately before beginning of CPB(T2), at 30 min after beginning of CPB(T3), imme?diately after the end of CPB(T4)and at 6 h and 1 day after the end of CPB(T5,6), blood samples were collected for determination of serum S100β protein concentrations(by enzyme?linked immunosorbent assay) and the concentration of glutamic acid in serum(by ion exchange chromatography). Mini?Mental State Exam?ination scores were recorded at 1 day before operation and 7 days after operation, and the occurrence of post?operative cognitive dysfunction was recorded. Results The serum concentrations of S100β protein and glu?tamic acid in the two groups are significantly higher at T3?5than at T1(P<0.05). Compared with group C, the concentration of S100β protein in serum was significantly decreased at T3?5, and serum glutamic acid con?centration was decreased at T4,5in group P(P<0.05). No postoperative cognitive dysfunction was found in the two groups. Conclusion Isoflurane preconditioning can reduce brain injury in patients undergoing cardi?ac valve replacement under CPB, and the mechanism may be related to inhibiting glutamic acid release.