Postoperative delirium is one of the common complications in the older aldults after surgery, which can lead to longer hospita stay，memory loss and reduced quality of life. There is currently no specific treatment. Therefore, it is important to prevent the occurrence of postoperative delirium. This study investigated the effect of intranasal insulin administration on the prevention of postoperative delirium and compared different doses of insulin to find a safe and acceptable method for preventing delirium.

Hip fractures are a common trauma in older adults and occur mainly in older people with osteoporosis. Surgery is the preferred choice for the vast majority of patients with severe pain and limited mobility in older aldults with hip fractures, resulting in higher mortality and disability rates with conservative treatment. But postoperative delirium becomes a challenge. At present, the treatment of delirium includes pharmacological and non-pharmacological methods, but the effect is limited, and now the focus is on preventing delirium, so this study investigated the effect of intranasal insulin administration on the prevention of postoperative delirium.

Inclusion Criteria:

Patients with hip fracture scheduled for unilateral hip arthroplasty or intramedullary nailing under subarachnoid block.

Both genders. Age ≥65 years old. Body mass index (BMI) ≤24kg/m2. American Society of Anesthesiologists (ASA) grade I-III.

Exclusion Criteria:

Contraindications to nasal administration (nasal defects or lesions). History of insulin allergy. Inability to communicate preoperatively (coma, severe visual or hearing impairment).

History of severe heart,Liver and kidney disease. History of psychiatric disorders. Preoperative delirium. Multiple traumas or fractures. Contraindications to subarachnoid block.