Effects of Different Doses of Dexmedetomidine on Postoperative Cognitive Dysfunction in Elderly Hypertensive Patients

Effects of Different Doses of Dexmedetomidine on Postoperative Cognitive Dysfunction in Elderly Hypertensive Patients-A Single Center,Randomized, Double-blinded,Controlled Study

The purpose of this study is to identify the effects of different doses of dexmedetomidine on postoperative cognitive dysfunction in elderly hypertensive patients

Inclusion Criteria:

• Written informed consent
• Elective gastrointestinal surgery
• American Society of Anesthesiologists class II to III
• Aged between 65 and 80 years old
• Weight between 45 and 75 kilogram,Body Mass Index between 19 and 24 kg.m-2
• With primary hypertension reaching or more than 1 year
• Normal cognitive function,mini-mental state examination more than 27

Exclusion Criteria:

• Severe arrhythmia,atrioventricular block and secondary hypertension
• Liver and kidney dysfunction,pulmonary disease,endocrine disease
• Suspected or confirmed difficult airway
• Any disease or pathologic change will interfere study result
• Inability to exchange with serious visual and hearing impairment
• Long term use of sedative-hypnotic drugs and antidepressant drug
• Addicted to alcohol, tobacco or drug
• Neuromuscular disease
• Suspected of malignant hyperthermia
• Allergic to investigational products or with other contraindication
• Participated in other study within 30 days