Here is the design of a clinical trial:

Official Title: Comparison of Combined Lumbar and Sacral Plexus Block With Sedation Versus General Endotracheal Anesthesia on Postoperative Outcomes in Elderly Patients Undergoing Hip Fracture Surgery(CLSB-HIPELD): Rationale and Design of a Prospective, Multicenter, Randomized Controlled Trial

Included conditions:
- Anesthesia Morbidity
- Anesthesia; Adverse Effect

Study Armgroups:
- {'label': 'GA group', 'type': 'EXPERIMENTAL', 'description': 'general anesthesia(GA) group:\n\n1. Open peripheral vein fluid infusion, radial arterial cannulation under local lidocaine anesthesia and arterial blood pressure monitoring\n2. Propofol (1.5-3mg/kg), cis-atracurium(0.1-0.15mg/kg) and sulfentanyl(0.2-0.6μg/kg) anesthesia-induced intubation, mechanical ventilation to maintain normal PETCO2\n3. Use sevoflurane, propofol and sulfentanyl to maintain anesthesia, and add cis-atracurium as needed\n4. Transfer to ICU after surgery', 'interventionNames': ['Procedure: anesthesia']}
- {'label': 'CLSB group', 'type': 'EXPERIMENTAL', 'description': 'combined lumbar plexus and sacral plexus block(CLSB) group:\n\n1. Open peripheral vein fluid infusion\n2. In lateral position (affected side upward), ultrasound-guided lumbar plexus block (0.375% ropivacaine, Lumbar 2-3 or/and 3-4vertebral space level, 25ml), then sacral plexus block (0.375% ropivacaine, 20ml)\n3. Radial arterial cannulation under local lidocaine anesthesia and arterial blood pressure monitoring, and blockade effectiveness was evaluated 30min after nerve block\n4. After reaching satisfactory blockade, target-controlled infusion of propofol was used to maintain Ramsay sedation score between 5-6 points, monitoring PETCO2 through nasopharyngeal airway, maintain autonomous respiration, and add small-dose fentanyl (10-20μg/time) as needed\n5. Transfer to ICU after surgery', 'interventionNames': ['Procedure: anesthesia']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'anesthesia', 'description': 'in this study, we plan to make a prospective, multicenter, randomized controlled clinical trial to compare the effects of general anesthesia with endotracheal intubation and ultrasound-guided combined lumbar plexus and sacral plexus block with sedative anesthesia on the prognosis of elderly patients with hip fracture to clarify the clinical value of combined lumbar plexus and sacral plexus block with sedative anesthesia in elderly patients with hip fracture.', 'armGroupLabels': ['CLSB group', 'GA group']}

Primary Outcomes:
- {'measure': 'mortality', 'description': 'Telephone follow-up will be performed to confirm whether the patient survival or not after surgery.', 'timeFrame': 'month 1'}
- {'measure': 'mortality', 'description': 'Telephone follow-up will be performed to confirm whether the patient survival or not after surgery.', 'timeFrame': 'months 3'}
- {'measure': 'mortality', 'description': 'Telephone follow-up will be performed to confirm whether the patient survival or not after surgery.', 'timeFrame': 'month 6'}
- {'measure': 'mortality', 'description': 'Telephone follow-up will be performed to confirm whether the patient survival or not after surgery.', 'timeFrame': 'month 12'}

Please estimate the sample size based on the assumption: 
Significance level is 0.05 (one-sided), power is 0.80, and an additional 20% is added to account for possible loss to follow-up.
Power and sample size calculation
        We estimate the sample size using the formula by Schoenfeld under the assumption of the validity of the proportional-hazards regression model.23 24 We take significance level 0.05 (one-sided) and power 0.80. Patients will be randomly assigned to one of the two anaesthesia groups in five different clinical centres. A retrospective study included patients over 65 years old showed that the 1-year mortality was 41.7% for GA group and 28.3% for combined peripheral nerve block group.14 In this study, only patients with age 75 years or older will be included, so we expect the actual mortality of the GA group will be higher than that in the previous study. Therefore, we assume the mortality to be 55% for GA group and 46.75% for CLSB group (15% relative reduction compared with GA group). Then the sample size needed for this study is 868 (with 434 in each of the two groups). When the mortality of the GA group is only 45%, the above calculated sample size can still detect a 20% improvement in the CLSB group with the power of at least 0.80. In consideration of the possible lost to follow-up, we add an additional 20% to the above calculated sample size. So, the total number of patients needed for this study is 1086.