Effect of Anesthesia on Post-operative Delirium in Elderly Patients Undergoing Hip Fracture Surgery

Postoperative delirium (POD) is an acute confusional state associated with changes in consciousness, arousal level and cognitive status. Elderly patients with hip fractures have the high incidence of delirium. The high risk factor of delirium include: Age 65 years or older, cognitive impairment/dementia, current hip fracture, severe illness and so on. Many previous studies predict that the majority of general anesthetic and sedative agents can favour postoperative delirium. However, none of studies have investigated the effect of general anesthesia and the effect of regional anesthesia and general anesthesia on the postoperative delirium in elderly patients undergoing hip fracture surgery in China. This multicentre, prospective, randomized controlled clinical trial is designed to evaluate postoperative delirium after general anesthesia and regional anesthesia in elderly patients undergoing hip fracture surgery. Our research hypotheses are: (1) regional anesthesia may contribute to decrease the incidence of postoperative delirium. (2) Regional anesthesia may improve the outcome of elderly patient and reduce healthcare costs associated with postoperative delirium. (3) Postoperative delirium may result in poor long-term functional outcomes.

This trial has the following nine investigational centers: Department of Anesthesiology, The Second Affiliated Hospital \& Yuying Children hospital of Wenzhou Medical University, Wenzhou, China; Department of Anesthesiology, Tongji Hospital, Tongji Medical college, Huazhong University of Science \& Technology, Wuhan, China; Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China; Department of Anesthesiology, Southwest Hospital, Chongqing, China; Department of Anesthesiology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China; Department of Anesthesiology, Beijing Jishuitan Hospital, Beijing, China; Department of Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang, China; Department of Anesthesiology, The Second Hospital of Anhui Medical University, Anhui, China; The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China;

Eligible patients will be assigned into two study groups (group RA: regional anesthesia will be used, group GA: General anesthesia will be used) by centre-minimization randomization (web or telephone). There are 3 stratification factors: age (65-79,≥80), presence of delirium(yes, no), dementia(yes, no). There will be two teams of investigators involved in trial procedure and the patient's follow-up. Investigator A (experienced anesthetist), who are competent in caring for patients undergoing hip fracture surgery, will perform following works, which includes informed consent, randomization, anesthesia and recovery parameters. Investigator B will visit patient the day before surgery and 7days after surgery or until discharge to assess patient for presence, type and severity of delirium, collect other data during in hospital stay and follow up patients at 6 and 12 months. Investigator B will receive uniform training of using of CAM, Delirium Rating Scale-Revised-98 (DRS-R-98), MMSE and other test used in this trial) and will be not clear about protocol.

Within 24 h before surgery, cognitive function of each patient will be assessed with the MMSE, the presence of delirium will be diagnosed with the CAM, the type and severity of delirium will be assessed with DRS-R-98 and the pain will be assessed with a 100-mm visual analog scale (VAS). Routine monitoring (NBP, continuous ECG, and pulse oximetry) was initiated on all patients. Premedication for anesthesia will be avoided before surgery. Any medication impairing cognitive function will not be recommended, if administered, must be recorded it in detail.

Investigator A will allocated the patient into group GA or group RA according the centre-randomization with a unique registration number for each eligible patient. Treatment protocols for both groups will also stipulate no sedative be administrated during operation. Routine monitoring was initiated on all patients. Hypotension (Systolic Blood Pressure<90mmHg or drop of Mean Arterial Pressure>30%) should be treated with vasoactive agents or fluid boluses as deemed appropriate by anesthetists.

Postoperative analgesia will be administered according to the local procedures of each clinical trial site, aiming to maintain a VAS pain score ≤ 30 mm. Both groups will receive routine postoperative care on orthopedic ward.

All randomized patients will be followed up to 7 days after surgery (or discharge from the hospital). The 7 days follow-up includes: CAM, DRS-98-R (if applicable), VAS, Analgesic use (if applicable), Sedative use (if applicable), Post-operative morbidity and laboratory results (including serum hemoglobin, hematocrit, leucocytes, aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, serum creatinine and urea concentrations, serum sodium and potassium and serum glucose concentration). Concomitant medications, adverse events and serious adverse events are record in all study visits. Economic parameters include: time to be discharged from post operation, total cost in hospital and cost for anesthesia of patient. Investigator B will also assess patient with POD in clinic or at their residence at 6 and 12 months to assess for presence of delirium, its type and severity (CAM, DRS-98-R), cognitive function using MMSE, and quality of life using The MOS 36-item Short-Form Health Survey (SF-36) questionnaire.

The study will be monitored regularly by the clinical research associate (CRA) through visits or telephone. CRA will verify the consistency of the data recorded on the case report forms with the source documents and the management of therapeutic batches, the presence and completeness of the investigator file.