The World Health Organization (WHO) identifies malnutrition as a significant public health threat. It is a common issue among cancer patients due to various factors. Specific nutrient deficiencies can lead to severe cognitive problems. This study aims to evaluate the impact of preoperative nutritional status on the frequency of postoperative delirium. Additionally, we will compare different parameters that can be used to diagnose preoperative malnutrition.

We included a total of 120 patients aged over 18 years, classified as ASA I-IV, who were undergoing major abdominal surgery for gynecological or gastrointestinal tumors and were expected to remain in the postoperative care unit for more than 24 hours. The patients' preoperative scores, albumin levels, prealbumin levels, and other relevant data were recorded. In the first 24 hours post-surgery, delirium was assessed using the Ramsay Sedation Scale and the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU).

Inclusion Criteria:

• ASA I-IV
• Over 18 years of age
• Undergoing major abdominal surgery for gynecological and GIS tumor
• Expected to stay in postoperative care unit for more than 24 hours

Exclusion Criteria:

• Under age 18.
• Patients scheduled for emergency surgery, pregnancy, who want to withdraw from postoperative work.
• Patients with dementia, Alzheimer, psychiatric illness, illiterate people.
• Patients with speech, vision and hearing problems.
• Patients with a history of alcoholism.
• Patients who need postoperative mechanical ventilation support (patients who develop heart or respiratory failure due to COPD, heart failure, pulmonary embolism and similar reasons)

Patients undergoing major abdominal surgery, have gynecological and GIS tumor, expected to stay in postoperative care unit for more than 24 hours.