2.1. Study design and patients

The retrospective study of patients with PD undergoing elective subthalamic nucleus-DBS (STN-DBS) surgery between January 2021 and January 2023 was conducted at the Department of Anesthesiology of Changhai Hospital. The ethics committee of our hospital approved this study (CHEC2020-151). The present study was published in clinicaltrials.gov ({"type":"clinical-trial","attrs":{"text":"NCT05833308","term_id":"NCT05833308"}}NCT05833308). The requirement for informed consent was exempted by the ethics committee due to the retrospective nature of the study.

Patients scheduled to undergo the first DBS operation under total intravenous anesthesia were included in this retrospective study. Patients aged 55 years or older, having an American Society of Anesthesiologists (ASA) physical status I-III, and with unilateral STN-DBS surgery were included. Exclusion criteria included preoperative delirium, psychiatric symptoms, missing preoperative laboratory parameters on fibrinogen or albumin, persistent infectious diseases, coagulopathy, and autoimmune illness or malignancies.