Academic motivation and burnout among Chinese doctoral students: the mediating role of academic resilience and the moderating role of perceived stress.

Hip fracture has become a major global public health concern with a high incidence in the elderly population, which is closely associated with age-related osteoporosis, reduced muscle mass, and impaired balance ability. Approximately 1.6 million hip fractures occur worldwide each year, with more than 30% of these cases in China. In 2019, the age-standardized incidence rate of hip fractures in China was 117.8 per 100,000 population. Driven by the accelerating aging of the population, the incidence of hip fracture in the Asia-Pacific region is projected to surge fourfold by 2050. Clinically, geriatric hip fracture is even dubbed the “last fracture of life” due to its high short-term mortality rate and significant risk of disability. More than half of the survivors fail to regain their pre-fracture mobility and independent living ability, imposing a heavy burden on patients’ families and the healthcare system. For the vast majority of patients, surgical intervention is the first-line and most effective treatment for restoring hip joint function, relieving pain, and reducing bed rest-related complications such as deep vein thrombosis and pulmonary infection. In this process, the selection of anesthetic method plays a crucial and irreplaceable role in ensuring perioperative safety, promoting postoperative recovery, and improving long-term functional prognosis in these patients. The physiological challenges posed by high‑altitude environments may further complicate perioperative management in geriatric hip fracture patients. Chronic exposure to hypobaric hypoxia triggers a series of adaptive changes, including increased pulmonary vascular resistance, polycythaemia, and reduced cardiopulmonary reserve. While these adaptive mechanisms are beneficial under steady‑state conditions, they may increase patients’ vulnerability to intraoperative hypoxaemia, hypotension, and cerebral hypoperfusion—all of which are recognised risk factors for postoperative cognitive impairment and delirium. Moreover, chronic hypoxia has been shown to exacerbate neuroinflammation and oxidative stress, key pathways implicated in the pathogenesis of postoperative cognitive dysfunction (POCD). Despite these concerns, few prospective studies have specifically examined the comparative effects of general and spinal anaesthesia on cognition and functional recovery in this unique population. Therefore, it is important to determine whether the choice of anaesthetic technique influences short‑term outcomes in elderly patients adapted to chronic hypoxia. At present, GA and SA are the two most commonly used anesthetic methods for geriatric hip fracture surgery, yet their effects on postoperative cognitive function and ADL in geriatric remain a highly controversial topic in academic circles. The differences in the potential mechanisms by which these two anesthetic methods affect neurological function have also become a key focus of academic research. GA exerts a global inhibitory effect on the central nervous system (CNS) via intravenous and inhaled anesthetics, which may interfere with synaptic plasticity, neuroinflammatory responses, and cerebral blood perfusion, thereby increasing the risk of POCD. In contrast, SA achieves regional nerve block with low doses of local anesthetics, avoiding the direct inhibitory effect of general anesthetics on the CNS. It can also reduce the release of pro-inflammatory cytokines by inhibiting the stress response, which is theoretically more conducive to cognitive function protection. Some clinical studies have shown that regional anesthetics such as SA can reduce the incidence of POCD and POD in elderly surgical patients and accelerate the recovery of physical function. However, other research analyses have indicated no significant differences in the incidence of POCD and POD between patients receiving the two anesthetic methods within weeks after hip fracture surgery, and pointed out that anesthetic method is not a risk factor for cognitive impairment. Although anesthetic drugs act on multiple targets in the CNS, there is currently insufficient clinical evidence to confirm that the anesthetic method itself directly causes persistent cognitive impairment.