Correlation Between Perioperative Parathyroid Functional Changes And Postoperative Cognitive Dysfunction In Patients With Cardiopulmonary Bypass

Objective:To study the changes of parathyroid hormone（PTH）during the perioperative period of heart valve replacement under cardiopulmonary bypass（CPB）supporting and analyze its correlation with postoperative cognitive dysfunction（POCD）.Method:1.This study is a prospective trial,focusing on patients undergoing heart valve replacement surgery under hypothermic cardiopulmonary bypass（group A）,and the control group is patients undergoing off-pump surgery（group B）.According to the inclusion and exclusion criteria,a total of 73 patients undergoing thoracic and cardiac surgery in Chengdu Second People’s Hospital from October 2020 to February 2022 were selected,including 43 patients in experimental group（group A）,and there were 30 cases in the control group（group B）.Patients with POCD in group A were identified as A1 and patients without POCD were identified as A2.2.（1）Neuropsychological tests were carried out one day before operation and 7 days after operation to compare the probability of POCD after operation between the two groups;（2）The arterial blood of the two groups was taken before the operation after anesthesia（T1）,half an hour after CPB（half an hour after the operation in the control group）（T2）,after rewarming to 33℃（one hours after the operation in the control group）（T3）,half an hour after stoppage of CPB（The control group was at the end of the procedure）（T4）and twenty-four hours after operation（T5）,The changes of perioperative PTH were compared and analyzed;（3）After anesthesia induction and intubation,patients in group A were punctured in the right internal jugular vein by reverse catheterization to ensure that the tip of the puncture catheter was located at the bulb of the right jugular vein,and the blood of the right internal jugular vein was collected in this way.Left radial artery puncture and catheterization was done to collect arterial blood samples.2ml blood samples were collected from the right internal jugular vein and left radial artery before anesthesia,half an hour after CPB,after rewarming to 33℃,half an hour after stoppage of CPB and 24 hours after operation.The levels of blood glucose and free calcium were measured,and the brain glucose uptake Glu（A-V）was calculated.（4）The age,sex,extracorporeal circulation time,aortic occlusion time and other general conditions of patients in the A and B groups were recorded.（5）Binary Logistic regression was used to analyze risk factors for postoperative cognitive dysfunction in group AResults:1.The baseline level of cognitive function in the two groups before operation was the same.After operation,18 cases（41.9%）in group A had POCD,which was significantly higher than that in group B（4 cases/13.3%）.2.There was no statistically significant difference in PTH levels between T1 and T5 time points in Group A（P>0.05）,and there were statistically significant differences between the remaining time points（P<0.05）.There was no significant change in PTH levels between time points in Group B（P>0.05）.In group A,PTH began to rise from T2（30min after the start of CPB）,rose to the highest level of PTH at T3（rewarming to 33°C）,followed by a continuous decrease in PTH to T5（24 hours postoperatively）to preoperative levels.At the time of T2,T3 and T4,the PTH level in group A was significantly higher than that in group B（P<0.01）.3.The difference in PTH levels between the time points of A1 group and A2 group was not statistically significant（P>0.05）between the time points of T1 and T5,and the difference between the remaining time points was statistically significant（P<0.05）.In patients in the A1 group,the PTH levels in T2,T3,and T4 was significantly higher than that in the A2 group（P<0.01）.4.In patients in the A1 group,Glu（a-v）decreased significantly at T2,to a minimum at T3,and then gradually increased to preoperative levels 24 hours postoperatively.In patients in group A2,there was no significant change in perioperative Glu（a-v）levels（P>0.05）.Compared with patients in A2 group A1,Glu（a-v）in group A1 was significantly lower than patients in T2,T3 and T4（P<0.05）.5.Free Ca²⁺levels in group A1 were minimized at T2 and then gradually increased to preoperative levels at T5.There was no significant difference in the free Ca²⁺levels in the A1 group and the A2 group at T1 and T5（P>0.05）,and the free Ca²⁺levels in the A1 group were significantly lower than those in the A2,T3 and T4 groups（P<0.01）..6.Comparing the CPB time and aortic blockade time in the A1 group and the A2 group,the CPB time and aortic blocking time in the A1 group were significantly longer（P<0.01）7.In group A,both aortic blockade time and CPB time were positively correlated with PTH levels at rewarming to 33℃（T3）（r=0.64,P<0.01;r=0.69,P<0.01）,free Ca²⁺of30min after CPB started（T2）were inversely correlated with PTH levels of T3（r=-0.43,P<0.01）,and PTH levels in T3 were negatively correlated with Glu（a-v）of T3（r=-0.94,P<0.01）.8.According to the determination of cognitive dysfunction in group A,POCD is the dependent variable y,and the factors which have statistically significant differences between two groups(PTH,Glu（a-v）,free Ca²⁺,aortic blockade time,CPB time)and y-line multivariate binary Logistic regression analysis,and the results show that PTH（T3）and Glu（a-v）（T4）are risk factors for POCD commencing（P<0.05）.Conclusion:1.There may be a correlation between PTH,Glu（a-v）and the concurrency of POCD.2.Patients with cardiac valve replacement surgery under extracorporeal circulation are prone to cognitive dysfunction in the early postoperative period,and the incidence rate is significantly higher than that of the non-CPB surgery group.