The Impact of Smoking on the Prognosis of Elderly Surgical Patients

After obtaining approval from the ethics committee, patients are recruited, informed of the trial process and potential risks, and their informed consent is obtained and signed. According to the WHO definition, patients are classified into smokers (defined as those who smoke more than one cigarette per day continuously or cumulatively for six months; more than four times a week but averaging less than one cigarette per day) and non-smokers (never smoked). Fecal and blood samples are collected from both groups of patients preoperatively, and perioperative data is gathered. Postoperatively, an uninformed observer assesses the patients for delirium and recovery quality.

Inclusion criteria

• Age >60 years;
• American Society of Anesthesiologists (ASA) preoperative anesthesia classification ASA Grades I and II;
• Undergoing elective surgery;
• Patients and their families are able to understand and complete various scoring scales and voluntarily sign informed consent.

Exclusion criteria

• Mini-Mental State Examination (MMSE) score <23;
• Preoperative biochemical tests indicate renal dysfunction or active liver disease;
• History of definite neurological or psychiatric disorders or history of taking corresponding medications before surgery;
• History of alcohol abuse or drug dependency;
• Taking antidepressant medications;
• American Society of Anesthesiologists (ASA) preoperative anesthesia classification > Grade II.