Effect Of Active Warming On Postoperative Cognitive Function In Elderly Patients Undergoing Total Hip Arthroplasty

Objective This study compared the changes in body temperature,postoperative cognitive function and IL-6,S100βand BDNF concentrations in peripheral blood during total hip arthroplasty in patients with conventional and active warming group to investigate the effect of active warming on the body temperature protection and postoperative cognitive function in elderly patients.Methods A total of 80 elderly patients（aged 65-85 years,ASA gradesⅠtoⅢ）undergoing total hip arthroplasty under combined spinal and epidural anesthesia were randomized with a digital table method and were divided into 2 groups（each group has 40people,n=40）:conventional group（group A）and active warming group（group B）.After entering the room,patients in group A were subjected to cotton blankets and sterile single-coverage passive insulation according to conventional methods.The patients in group B used the thermal blanket and heater to perform active pre-incubation for more than 20 minutes after entering the operating room.The infusion fluid and the rinsing fluid were heated during the operation,and all active thermal insulation measures were continued until the end of the operation.Heart rate,blood pressure,blood oxygen saturation and tympanic membrane temperature were recorded at the time of patient entry（T₁）,before anesthesia（T₂）,15minutes after anesthesia（T₃）,30 minutes after anesthesia（T₄）,1 hour after anesthesia（T₅）,and at the end of surgery（T₆）.The resting pain was assessed by VAS score at 6 h（H₁）,12 h（H₂）,24 h（H₃）and 72 h（H₄）after operation.Observe and record the occurrence of postoperative shiver in patients.The patient’s cognitive function status was assessed by MMSE and Mo CA scores on the day before surgery（D₀）,seven days after surgery（D₇）,and thirty days after surgery(D₃₀).Peripheral venous blood was collected from patients before the surgery（D₀）and at the end of surgery（T₆）and seven days after surgery（D₇）to detect serum IL-6,S100βprotein and BDNF.Results（1）There were no significant differences in the general condition,intraoperative hemodynamics,and postoperative resting pain between the two groups（P>0.05）.（2）Compared with T₁,the body temperature of group A was significantly decreased at T_2⁶（P<0.05）,while the body temperature of group B was only decreased at T₃and T₄（P<0.05）.（3）The incidence of hypothermia in group A was 82.5%,the incidence of hypothermia in group B was 0.The incidence of hypothermia in group A was significantly higher than that in group B（P<0.05）.The incidence of shivering in group A was 32.5%.The incidence of shivering in group B was 0.The incidence of shivering in group A was significantly higher than that in group B（P<0.05）.（4）Compared with D₀,the MMSE and Mo CA scores of group A were significantly decreased（P<0.05）;the difference of group B was not statistically significant（P>0.05）.There was no difference in the incidence of postoperative cognitive dysfunction between the two groups at D₇ and D₃₀（P>0.05）.（5）Compared with D₀,serum IL-6 and S100βlevels were increased in both groups at T₆and D₇（P<0.05）,and serum BDNF levels were decreased in group A at T₆（P<0.05）.Compared with group A,serum IL-6 and S100βlevels in group B decreased at T₆ and D₇（P<0.05）,and there was no significant difference in serum BDNF levels between the two groups（P>0.05）.Conclusion Active warming can effectively reduce the incidence of intraoperative hypothermia and postoperative shivering in elderly patients undergoing total hip arthroplasty,and improve early postoperative cognitive function,which may be related to maintaining normal body temperature can reduce the inflammatory response.However,there was no significant effect on the incidence of postoperative cognitive dysfunction after seven days and thirty days after surgery.