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October 14, 2006
9:00 AM - 11:00 AM
Room Hall E, Area B
Perioperative Circadian Rhythm and Neuropsychological Status in CABG Patients
Yiqing Yin, M.D., Assistant Professor, Ailun Luo, Professor, Xiangyang Guo, M.D., Professor, Yuguang Huang, Professor, Hongzhi Ren, Professor.
Anesthesia Department, China-Japan Friendship Hospital, Beijing, China
Background The incidence of neuropsychologic deficits after cardiac surgery is very high. It remains unclear whether neuroendocrine variations have any relation with neuropsychologic status in these patients. Melatonin and cortisol, both secreted in circadian manner, were studied in patients undergoing coronary artery bypass grafting surgery (CABG).

Methods Forty male patients scheduled CABG under hypothermic cardiopulmonary bypass (CPB) (n=20) or off-pump coronary artery bypass grafting (OPCAB) (n=20) were enrolled in this study. Blood samples were taken at specific time-points intraoperatively and every 3 hours within the first postoperative 24 hours to determine plasma concentrations of melatonin and cortisol. A neuropsychologic tests battery, including depression and anxiety, was administered preoperative and 7 to 10 days after surgery.

Results Postoperatively, patients in the CPB group had poorer performances on the Digit Span subtest of the WAIS-R and the Stroop colour word interference test, while patients in the off-pump group had poorer performances on MMSE and the Stroop colour word interference test. The patients in the CPB group displayed a significantly higher deficit on the Digit Span subtest of the WAIS-R and the Stroop colour word interference test. Patients showed more depressed 7 to 10 days postoperatively than preoperative and recovered 3 months after surgery. Depression and anxiety correlated with some items of cognitive dysfunctions. During postoperative 24h, two patients in CPB group and six patients in OPCAB group regained circadian rhythm of melatonin. As for cortisol the figure was three in CPB group and seven in OPCAB group respectively. Parameters of melatonin circadian rhythm in CPB group and those of cortisol secretion rhythm in both groups correlated with depression and some neuropsychologic tests.

Conclusions The incidence of neuropsychological deficits was higher in CABG patients under CPB than those without CPB, status of mood may contribute to the perioperative cognitive dysfunctions. The disordered circadian rhythm of melatonin and cortisol in patients undergoing CABG surgery may correlate directly or indirectly through mood with neuropsychological deficits.[table1][table2]

Anesthesiology 2006; 105: A57
The serum melatonin concentration (ng/ml) during surgery in CPB and OPCAB groups (x¯ ±s)
T1:before induction;T2: 10 min after intubation;T3:10 min after heparinization;T4: 30 min after CPB;T5:before neutralization of heparin;T6: at the end of the surgery. *P<0.05 vs T1;'P<0.05;"P<0.01 CPB vs OPCAB
The serum cortisol concentration during surgery in CPB and OPCAB groups (nmol/L)(¯x±s)
GroupCortisol (nmol/L)
T1: before the induction of anesthesia; T2:10 min after the induction of anesthesia; T3:10 min after heparinization; T4:30 min after commencement of CPB; T5:before reversal of heparin with protamine; T6:at the end of surgery. ♣P<0.05,♣♣:P<0.01, vs T1;†P<0.05, CPB vs OPCAB