Understanding the risks of anaesthesia

Anaesthesia is generally very safe, but risk is never zero. The single most important driver of risk is the patient’s underlying health (e.g., ASA Physical Status, frailty, heart/lung disease), followed by the procedure (minor day-case vs major emergency surgery), and the type of anaesthesia (general, regional, neuraxial, sedation).

Risk is individualized: patient + procedure + context
Most perioperative deaths are due to disease/surgery, not the anaesthetic itself
Serious anaesthesia-attributable mortality in high‑income settings is very low
If you want a procedure-specific risk estimate, the best validated public tool is the ACS NSQIP Surgical Risk Calculator.

Start here: ASA class and why health status matters most

What ASA I–VI means, what it does and does not predict, and how emergency surgery changes risk.

Go to ASA & risk stratification

General vs regional vs local vs sedation

Benefits, trade-offs, and when a “lighter” technique is safer—or not.

Go to types of anaesthesia

Airway emergencies and aspiration

Difficult airway concepts (CICO, eFONA), fasting, and newer issues like GLP‑1 agonists.

Go to airway & aspiration

Cardiac, blood pressure, DVT/PE

Why hypotension matters, arrhythmias, myocardial ischemia, and clot prevention.

Go to cardio & thromboembolism

Awareness and depth monitoring (e.g., BIS)

How common awareness is, who is at higher risk, and what monitoring can and can’t do.

Go to awareness & monitoring

Environmental footprint of anaesthetic choices

Why desflurane and nitrous oxide are climate-intensive, and practical alternatives.

Go to environmental impact

What you can do before anaesthesia