Effects of ultrasound-guided high ankle block combined with general anesthesia on postoperative cognitive function in fragile elderly patients based on the analysis of scale and EEG monitor

IntroductionUltrasound-guided high ankle block can provide prolonged analgesia for foot and ankle surgeries while preserving ankle motor function. Given that fragile elderly patients are prone to cognitive impairment after general anesthesia, this study intends to implement high ankle block for fragile elderly patients undergoing foot and ankle fracture surgery, and use intraoperative electroencephalogram (EEG) analysis combined with postoperative scales to investigate its effect on patients postoperative cognitive function. Methods and analysisThis randomized controlled trial will be conducted in Xuzhou Central Hospital. A total of 126 elderly patients scheduled to undergo unilateral ankle fracture (uni/bi-/triple ankle) incision and reduction internal fixation (ORIF) surgery will be randomly assigned to either the HAB group or the GB group in a 1:1 ratio. Patients will receive ultrasound-guided high ankle block and general anesthesia (HAB group) or general anesthesia alone (GB group). Multimodal analgesia will include intraoperative flurbiprofen ester and postoperative patients will be given appropriate medications according to the postoperative pain management "three-step ladder". The primary outcome indicator was the incidence of dNCR at 7th day postoperation. The secondary outcome indicators were the incidence of dNCR at 1st and 30th days postoperation; alpha relative power, alpha power, and burst inhibition ratio in each brain region at 30 min after induction of anesthesia; MoCA scores, patient stress response indexes: ACTH, NE, Ang-II, {beta}-EP, Glu, and Cor levels; patients VAS pain scores; patients satisfaction scores; first time getting out of bed postoperatively; and time of discharge from the hospital. Safety outcomes were dizziness, headache, vomiting, urinary retention, bradycardia, tachycardia, hypotension, and hypertension. Ethics and disseminationEthics approval was obtained from the Ethics Committee of the Xuzhou Central Hospital. All patients will provide written informed consent. The results of this study will be published in a peer-reviewed journal. Trial registration numberChinese Clinical Trial Registry (ChiCTR2400050927)