Effects Of Creatine Phosphate Sodium Preconditioning On The Short-term Cognitive Function In Patients Undergoing Off-pump Coronary Artery Bypass Grafting Surgery

ObjectiveTo investigate the effects of creatine phosphate sodium preconditioning onthe short-term cognitive function in patients undergoing off-pump coronary arterybypass grafting surgery.Methods Forty patients scheduled for OPCABG were divided randomly into Groupcreatine phosphate sodium (group L) and Group normal saline (group C) with20patients in each group. Morphine (10mg) and scopolamine (0.3mg) were injectedmuscularly30minutes before patients’ entry into the operation room. A large-bore veinwas accessed in the right arm. The left radial artery catheter was indwelled under localanesthesia. All patients were monitored with ECG, SPO2, MAP, CVP and BIS in theoperation room. Midazolam(0.1mg/kg), sufentanil(0.8μg/kg), etomidate(0.3mg/kg)and rocuronium(0.8mg/kg) were used through intravenous injection during anesthesiainduction. The patients in all groups were intubated by way of mechanical ventilationafter anesthesia induction. The ventilated parameters were adjusted to maintain PETCO2between35and45mmHg. Propofol (1.0~2.0μg/ml) and sufentanil(1.0μg·kg-1·h-1) wereinfused to maintain anesthesia complemented with the bolus injection ofsufentanil(0.5μg/kg) before skin incision and sternotomy. BIS was adjusted in40~60during the surgery. The muscle relaxation was maintained with intermittent injection ofpipecuronium(2mg). After anesthesia induction, the patients in group L were infusedcreatine phosphate sodium dissolved into100ml of normal saline on the basis of15mg/kg; the patients in group C were injected equal volume of normal saline. Theinjections of both groups should be completed within30minutes.Hemodynamic stability was maintained through intravenous infusion pump injectiondopamine (2~5μg·kg-1·min-1), nitroglycerin (0.1~0.5μg·kg-1·min-1) and norepinephrine(0.01~0.05μg·kg-1·min-1). The patients in all groups were transferred to ICU after operation. Samples of blood were collected from the radial artery at different timepoints: before the induction of anesthesia (T0), at the beginning of the surgery (T1),after aortic side-bite clamping (T2), after aortic side-bite unclamping (T3),before theend of the surgery (T4),24hours after the surgery (T5),48hours after the surgery(T6).Blood samples were obtained from T0to T4to measure the level of blood lactic acidand blood glucose. The variables of C-reactive protein (CRP), troponin T (cTnT) andN-terminal pro-brain natriuretic peptide (NT-pro BNP) were measured at the followingtime points: before the induction of anesthesia (T0), before the end of the surgery (T4),24hours after surgery (T5),48hours after the surgery(T6). The cognitive function wasassessed respectively1day before and7days after the operation using comprehensivecognitive function tests and the results were scored.Statistical analysis was performed by using SPSS12.0software package.P<0.05wascosidered statistically significant.The normal distribution data was described byMean±SD and skewed distribution data was described by M(P25,P75).Twoindependent samples t test was used for the between-group comparisons statisticalanalysis. The normal distribution and homogeneity variance data was analyzed bypaired-samples t test, otherwise using nonparametric test (Wilcoxon Signed RanksTest). The categorical statistics was analyzed by Fisher’s exact test.Results1The general information (age, height, weight, gender, education), preoperative leftventricular ejection fraction (EF) and heart function grading had no significantdifference between two groups (P>0.05).2There is no significance difference between the two groups concerning theperioperative data (the operation time, the aortic side-bite clamping time, the numberof coronary artery bypass grafting, the intraoperative transfusion amount, theintraoperative blood transfusion amount,extubation time, the duration of ICU stay andthe VAS score in48h)(P>0.05). 3There is no significant difference between the two groups concerning the use of drugdoses in the operation(P>0.05).4There is no significant difference between the two groups concerning hemodynamicchanges (P>0.05).5Compared to group C, the concentrations of blood lactic acid in group L were significantly lower at T2,T3and T4(0.93±0.02mmol/L vs.1.47±0.03mmol/L、0.98±0.09mmol/Lvs.1.48±0.08mmol/L、1.05±0.02mmol/L vs.1.48±0.05mmol/L,P<0.05).6Compared to group C, the concentrations of blood glucose in group L weresignificantly lower at T2,T3and T4(7.03±1.56mmol/L vs.8.00±1.80mmol/L、7.45±1.32mmol/L vs.8.39±1.77mmol/L、8.05±2.54mmol/L vs.9.17±2.30mmol/L，P<0.05).7The concentrations of CRP in two groups were progressively increased at T4.Compared to group C, the concentrations of CRP in group L were significantly lowerat T5and T6[56.53mg/L（50.24-112.32）vs.90.52mg/L（49.51-152.20）、125.30mg/L（90.25-155.20）vs.161.00mg/L（105.60-256.60），P<0.05].8The concentrations of cTnT in two groups were progressively increasedatT4.Compared to group C, the concentrations of cTnT in group L were significantly lowerat T5and T6[0.12ng/m（l0.10-0.52）vs.0.32ng/m（l0.11-0.85）、0.11ng/m（l0.09-0.32）vs.0.28ng/ml（0.09-0.65），P<0.05].9Compared to group C, the concentrations of NT-pro BNP in group L weresignificantly lower at T5[500pg/ml（350-985）vs.875pg/ml（586-1250），P<0.05].10The differences between preoperative and postoperative values were compared inthree aspects: the number sign test,the trail marking test and the accumulate test; group C had significantly worse results than group L(P <0.05，P<0.01).11The incidence of postoperative cognitive dysfunction (POCD) was25%in group Land60%in group C (P<0.05).Conclusion1Preconditioning with creatine phosphate sodium can decrease the incidence ofshort-term POCD in patients undergoing on-pump coronary artery bypass graftingsurgery.2Preconditioning with creatine phosphate sodium can protect myocardium againstinjury in patients undergoing on-pump coronary artery bypass grafting surgery.3Preconditioning with creatine phosphate sodium can protect myocardium againstinjury and decrease the incidence of short-term POCD in patients undergoing on-pumpcoronary artery bypass grafting surgery through inhibiting systemic inflammatoryresponse.