Bladder tumor is one of the most widespread tumors in the world, with increasing prevalence at the global level. One of the procedures in patients with bladder tumors is transurethral resection of the bladder (TURM) most often performed endoscopically under general anesthesia. This patient population has certain characteristics in common. One of them is exposure to common risk factors for the formation of bladder tumors, such as aniline dyes and solvents. These substances are associated with the onset of neurodegeneration and oxidative stress. Smoking is another factor that affects the formation of bladder tumor. A significant part of patients with bladder tumor are an elderly population, which is repeatedly exposed to surgical procedures, with numerous comorbidities, with a high risk of postoperative complications and the development of perioperative cognitive deficits, which can further complicate the postoperative course and further treatment. In the group of patients with a bladder tumor who will undergo TURM, no evaluation of risk factors related to perioperative cognitive deficit was performed, nor was there an examination of the perioperative cognitive deficit itself. In them, the identification of factors for postoperative cognitive disorder is essential. The concept of clinical frailty is becoming more important and relevant when providing healthcare services to patients. The use of the clinical frailty scale as a tool in clinical practice provides information on the adequate direction of care for patients. Decrease in muscle strength can lead to limitations in the functioning of a certain individuals. In recent years muscle strength has come to be a very important component of health, regardless of a person's age and clinical condition.The hand grip test is a test used to measure the maximum isometric strength of the hand and forearm muscles. The MMSE test and MoCA are the most frequently used methods in the detection of cognitive impairment in clinical and research fields. In addition to laboratory indicators of organic function, circulating indicators of neuroinflammation, like S100B and neuron-specific enolase, will be correlated with the patient's cognitive status.So far, no research has been conducted on the dynamics of indicators of organic function, circulating indicators of neuroinflammation, perioperative cognitive changes and clinical fraility in patients undergoing bladder tumor operation.