Acute smoking increases ST depression in humans during general anesthesia

Area of Science:

• Cardiology
• Anesthesiology
• Cardiovascular Physiology

Background:

• Acute smoking is a potential risk factor for perioperative cardiac events.
• ST segment depression during general anesthesia can indicate myocardial ischemia.
• Patients undergoing noncardiac surgery often have undiagnosed ischemic heart disease.

Purpose of the Study:

• To investigate the association between acute smoking and ST segment depression during general anesthesia in patients without ischemic heart disease.
• To identify predictors of ST segment depression in this patient population.

Main Methods:

• Prospective study measuring expired carbon monoxide (CO) concentration and hemodynamic data during general anesthesia.
• Logistic regression analysis to determine predictors of ST segment depression (≥1 mm).
• Inclusion of patients undergoing noncardiac or nonperipheral vascular surgery without symptoms or evidence of ischemic heart disease.

Main Results:

• Expired CO concentration (indicator of recent smoking) and rate pressure product were significant predictors of ST segment depression.
• Increased expired CO concentration (OR 1.05 per ppm) and rate pressure product (OR 1.20 per 1000 increase) were associated with higher odds of ST depression.
• Approximately 25% of chronic smokers smoked on the morning of surgery despite pre-operative instructions.

Conclusions:

• Patients under 65 without ischemic heart disease symptoms who smoked shortly before surgery experienced more rate pressure product-related ST segment depression.
• Females were at greater risk of ST segment depression compared to males.
• Acute smoking is an independent risk factor for perioperative ST segment depression in specific patient groups.