Objective To explore the influencing factors of postoperative delirium in elderly patients in ICU with lung cancer.

Methods The incidence of postoperative delirium was investigated in the elderly patients with lung cancer who were admitted to the Intensive Care Department of Shanghai Chest Hospital from September 2019 to May 2020. The incidence of postoperative delirium was observed by using the ICU patient fuzzy Consciousness assessment (CAM-ICU) scale. The Chinese version of the Richards-Campbell sleep questionaire (RCSQ) scale was used to observe the sleep quality of patients after surgery. Mini-mental state examination (MMSE) scale was used to observe the preoperative cognitive status of patients. The influencing factors of postoperative delirium in elderly patients with lung cancer in ICU were determined by univariate and logistic regression analysis.

Results A total of 208 patients were included in this study, of which 32 developed delirium (15.38%) and 176 did not (84.62%). Twenty-two variables were included, including 11 preoperative variables and 11 postoperative variables, among which hypoxia (≤60 mmHg), history of coronary heart disease, and history of sedation were risk factors for delirium in ICU elderly patients after lung cancer surgery. Meanwhile, logistic regression analysis showed that patients who scored more than 20 points in the Chinese version of the RCSQ had significantly lower risk of delirium than those who scored less than 20 points. Patients whose preoperative MMSE score was higher than 27 had significantly lower risk of delirium than patients whose score was lower than 27 (P < 0.05).

Conclusions Hypoxia, history of coronary heart disease, history of sedative drug use, preoperative cognitive impairment and postoperative sleep disorder are all factors affecting postoperative delirium in elderly patients with lung cancer in ICU. For elderly patients with lung cancer, effective identification of high-risk factors and early intervention can be carried out to reduce the incidence of clinical delirium and improve the clinical outcome of patients.