Effect Of Bispectral Index Monitoring On Postoperative Delirium In Elderly Patients With Moderate Or Severe Hypertension Undergoing Total Knee Arthroplasty Surgery

Objective Hypertension is the most common cardiovascular disease in the elderly.The abnormal of blood pressure is closely related to cardiovascular and cerebrovascular mortality.In addition,long-term hypertension can lead to extensive cognitive impairment and reducing the quality of life in elderly patients.Moreover,elderly patients with hypertension due to the decline of physiological function,reduced of the cardiovascular adaptability,,reduced tolerance to the stress such as surgery,pain and anesthesia,elderly patients are prone to various anesthesia related complication.It is vital to strengthen the anesthesia management of elderly patients with hypertension and reduce the stress response in perioperative period.Bispectral（BIS）can reflect the depth of anesthesia objectively.And studies have pointed out that BIS monitoring can guide the use of anaesthetics and reduce the incidence of postoperative delirium（POD）.This experiment is intended for investigate the effect of BIS-guided intravenous anesthesia on POD in elderly patients with moderate or severe hypertension undergoing total knee arthroplasty surgery.Methods Eighty patients from the First Affiliated Hospital of Anhui Medical University with moderate or severe hypertension,aged 60-80 years old,ASAⅡorⅢ,NYHAⅠorⅡ,with preoperative mini-mental state examination（MMSE）score≥23scheduled for total knee arthroplasty surgery were enrolled in this study.The patients were randomly assigned to two groups with 40 patients per group:Experience anesthesia group（group E）and BIS monitoring group（group B）.The group B adjusted the depth of anesthesia according to intraoperative BIS value,and experience anesthesia group anesthesia was adjusted according to traditional clinical signs and hemodynamic parameters.The hemodynamic parameters was recorded before anesthesia induction（T₀）,3min after induction（T₁）,before use tourniquet（T₂）,30min after tourniquet use（T₃）,before tourniquet release（T₄）and after tourniquet release（T₅）.Observe the respiratory recovery time,eye opening time,extubation time,PACU residence time,the dosage of propofol,the dosage of vasoactive agent and the adverse reactions after extubation.POD was assessed within 3 days after operation using the confusion assessment method（CAM）.Results（1）The general condition（age,weight,sex）,ASA classification,NYHA cardiac function classification,preoperative mini-mental state examination score and hypertension classification were no statistics significance differences in the two group of patients.（2）Compared with group E,the dosage of propofol decreased significantly in group B （P<0.05）.There was no significant difference in the dosage of sufentanil,cis-atracurium,vasoactive drug,liquid,anesthetic time,operation time and tourniquet use time between the two groups（P>0.05）.（3）Comparison of intraoperative hemodynamic indexes between two groups:The systolic blood pressure（SBP）at the time of T₁,T₂ in group E were（112±9）（103±7） mmHg（1mmHg=0.133kPa）and those in group B were（119±11）（108±9） mmHg,respectively.The diastolic blood pressure（DBP）at the time of T₁ in group E were（66±7）mmHg and that in group B were（72±10）mmHg.Compared with group E,the SBP at the time of T₁,T₂ and DBP at the time of T₁ in group B were higher than those in group E（all P<0.05）.（4）Comparison of postoperative recovery between the two groups:the time of respiratory recovery,eye opening,extubation and PACU residence in group B were significantly shorter than those in group E（P<0.05）.There was no significantdifference between the two groups in the incidence of complications during anaesthesia resuscitation,including dysphoria,shivering,delayed recovery and Intraoperative awareness with recall（P>0.05）.（5）The incidence of delirium in the first day and overall incidence of postoperative delirium in group B were significantly lower than groupE（P<0.05）.Visual Analogue Score and incidence of nausea and vomiting three days after operation were no statistics significance differences in the two group of patients（P>0.05）.Conclusion 1.Total knee arthroplasty surgery in the elderly with moderate and severe hypertension,the use of bispectral index monitoring to guide the implementation of general anesthesia can reduce anesthetic dosage,significantly reduce postoperative extubation time and PACU residence time,then increase postoperative recovery quality in elderly.2.Bis monitoring reduces the incidence of POD,which is beneficial to the rapid recovery of elderly patients with hypertension after total knee arthroplasty.