The pre-anaesthetic visit: history, examination and tests

What it is

The pre-anaesthetic visit is the consultation, days or weeks before an elective operation (or minutes before an emergency), in which the anaesthesia team gathers what it needs to plan a safe anaesthetic. The history covers previous anaesthetics and their problems, family reactions to anaesthesia (which can point to malignant hyperthermia or a slow breakdown of certain muscle relaxants), heart and lung disease, functional capacity, snoring and sleep apnoea, diabetes, kidney and liver disease, bleeding tendency, reflux, pregnancy, smoking and alcohol, every medicine and supplement, allergies and loose or capped teeth. The examination concentrates on the airway, heart, lungs, blood pressure, weight, the veins for access and the back if a spinal or epidural is planned. Tests are chosen for the patient and the operation, not ordered as a routine battery: a healthy person having a low-risk procedure often needs none. The visit ends with an ASA class, a risk estimate, an optimisation plan (anaemia, blood pressure, glucose, smoking), instructions on fasting and medicines, an anaesthetic plan and the patient's informed consent.

What to assess

• Anaesthetic history: previous anaesthetics, difficult intubation, nausea and vomiting, awareness, delayed waking, family reactions.
• Systems: heart (angina, breathlessness, syncope, murmurs), lungs (asthma, COPD, recent infection), sleep apnoea, kidney, liver, endocrine.
• Medicines and allergies: anticoagulants, antiplatelets, antidiabetics, antihypertensives, steroids, herbal products; true allergy versus intolerance.
• Examination: airway, heart and lung sounds, blood pressure, weight and BMI, venous access, spine for neuraxial blocks.
• Targeted tests: haemoglobin, kidney function, glucose, coagulation, ECG, pregnancy test and others only when the history, examination or surgery call for them.
• Outcome of the visit: ASA class, risk estimate, optimisation plan, fasting and medicine instructions, anaesthetic plan and consent.

How it is done (and why)

1. Confirm the operation, its urgency and expected blood loss — the surgical risk sets how deep the work-up must go.
2. Take the anaesthetic and family history — earlier problems and inherited reactions are the strongest predictors of the next one.
3. Review each system and ask about functional capacity — exercise tolerance estimates cardiopulmonary reserve better than most tests.
4. List every medicine, supplement and allergy — some must continue, some stop, and a true allergy changes drug choices.
5. Examine the airway, heart, lungs, veins and back — findings here change the technique and the equipment that must be ready.
6. Order only tests that could change management — routine batteries cause delays and false positives without benefit.
7. Assign an ASA class and estimate risk — this guides monitoring, postoperative care level and the conversation with the patient.
8. Optimise what can be optimised and decide if surgery should wait — elective surgery can be delayed; risks from untreated disease cannot.
9. Explain fasting, medicines and the plan, then obtain consent — clear instructions prevent cancellations and aspiration.

Findings that change the plan

• Unstable angina, decompensated heart failure, a significant arrhythmia or severe valve disease: delay elective surgery and refer.
• A family history of death or high fever under anaesthesia: plan a trigger-free anaesthetic and seek specialist advice.
• Predicted difficult airway: plan the technique, equipment and senior help in advance.
• Uncontrolled diabetes, severe hypertension or significant anaemia: consider postponing elective surgery to correct them.
• Possible pregnancy in a woman of reproductive age: clarify before anaesthesia, as it changes drug choices and timing.

Next step

• Document the ASA class, airway findings, risk estimate and plan so that the anaesthetist on the day can act on them.
• Discuss with a senior anaesthetist any patient who is ASA III or above, has a predicted difficult airway or a personal or family anaesthetic reaction.
• Refer to the relevant specialist when a condition needs optimising before elective surgery, and agree the new date.
• Give written instructions on fasting, which medicines to take or stop and when to arrive.
• Plan the postoperative care level (day case, ward, high dependency or intensive care) before the day of surgery.

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Elsewhere in DurgiPedia

• Preoperative care: assessment, teaching, fasting, skin preparation and the checklist
• The clinical history: its parts and their order
• Past medical, surgical, family and social history
• Informed consent: elements and how to obtain it

Connections

← All of anaesthesia

Educational content; it does not replace supervised training, your institution's protocols or the anaesthetist's or intensivist's decision. It contains no doses and no ventilator or infusion settings.

Sources: American Society of Anesthesiologists Physical Status Classification System (StatPearls (NCBI Bookshelf), 2025); Perioperative Cardiac Management (StatPearls (NCBI Bookshelf), 2023).

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