PAC (Pre-Anaesthetic Check-Up): Full Form, Tests Done and Fasting Rules Before Surgery

PAC stands for pre-anaesthetic check-up (also called pre-anaesthesia evaluation). It is a medical assessment by an anaesthetist before any surgery or procedure that needs anaesthesia. The anaesthetist reviews your medical history, examines you, looks at blood tests, ECG and other reports, grades your risk, plans the type of anaesthesia and tells you how to prepare, including when to stop eating and which medicines to continue.

The goal is to make surgery safer and avoid last-minute cancellations. This guide explains what happens at a PAC, which tests are commonly done and why, how doctors grade risk, the fasting and medicine rules, and how to prepare so your surgery goes ahead smoothly.

What a PAC covers

1. Your history

The anaesthetist will ask about:

• Current and past illnesses: diabetes, high blood pressure, heart disease, asthma or COPD, thyroid disease, kidney or liver disease, epilepsy, stroke
• Previous surgeries and any problems with anaesthesia, for you or family members (for example, unusual reactions)
• Medicines, including herbal and over-the-counter products, blood thinners and diabetes medicines
• Allergies to drugs, latex, foods
• Smoking, alcohol and substance use
• Loose, broken or capped teeth, dentures, and neck or jaw problems
• Snoring, breathing pauses during sleep (sleep apnoea)
• Ability to climb stairs or walk without becoming breathless or having chest pain
• Pregnancy possibility, for women
• Last meal and drink

2. Examination

• Height, weight, BMI, blood pressure, pulse, temperature and oxygen level
• Heart and lungs
• Mouth opening, teeth and neck movement, to predict how easy it will be to place a breathing tube (airway assessment)
• Spine, if spinal or epidural anaesthesia is planned
• Veins for IV access

3. Review of tests

Described below.

4. Risk grading and plan

The anaesthetist assigns an ASA grade, chooses between general, spinal, regional or local anaesthesia (with or without sedation), and explains the risks and the plan after surgery, including pain control.

5. Consent and instructions

You will be told how long to fast, which medicines to take or skip on the day, and what to expect. You sign consent for anaesthesia.

Tests commonly done before surgery

The tests ordered depend on your age, health and the type of surgery. A young, healthy person having minor surgery may need very few. Here is a typical list and why each is done.

| Test | Why it is done | |---|---| | Complete blood count (haemoglobin, WBC, platelets) | Detects anaemia, infection and low platelets that could cause bleeding | | Blood sugar (and HbA1c in diabetics) | Poor control raises risks of infection and poor healing | | Kidney function (urea, creatinine, electrolytes) | Affects drug choice and fluid management | | Liver function tests | When liver disease, jaundice or heavy alcohol use is suspected | | Coagulation tests (PT/INR, aPTT) | If you take blood thinners, have liver disease, a bleeding tendency or the surgery carries high bleeding risk | | Blood group and cross-match | When blood loss is expected | | ECG | For people with heart disease risk factors, age above about 40 to 50, or major surgery | | Chest X-ray | For lung or heart disease, smokers, older patients, or chest or major surgery | | Urine routine | Screens for infection, sugar, protein | | Viral markers (HIV, HBsAg, HCV) | Safety of staff and patients; many hospitals require them | | Echocardiography | For known or suspected heart disease, murmurs, breathlessness or before high-risk surgery | | Thyroid function | When thyroid disease is suspected | | Pulmonary function test | For significant lung disease before major surgery | | Pregnancy test | For women of reproductive age, when relevant | | Sleep apnoea screening | If snoring, daytime sleepiness and high BMI suggest it |

More tests, such as stress test, carotid ultrasound, cardiology consultation or coronary angiography, are done only for specific high-risk situations.

There is no single required set. Over-testing without need can lead to extra anxiety and delay, and under-testing may miss problems. The anaesthetist and surgeon decide together.

ASA physical status grading

The American Society of Anesthesiologists (ASA) classification summarises your health before surgery. It does not directly predict outcomes but helps communicate risk.

| ASA class | Description | Example | |---|---|---| | I | Healthy person | Non-smoker, no illnesses | | II | Mild systemic disease without limitation | Well-controlled diabetes or hypertension, smoker, obesity, pregnancy | | III | Severe systemic disease with limitation | Poorly controlled diabetes, COPD, stable heart disease, kidney disease | | IV | Severe disease that is a constant threat to life | Recent heart attack, unstable angina, severe valve disease | | V | Moribund, not expected to survive without the operation | Ruptured aneurysm | | VI | Brain-dead organ donor | |

An "E" is added for emergency surgery. ASA I or II patients generally have lower anaesthetic risk than III and above, but most people with ASA III have surgery safely after optimisation.

Fasting before surgery

Fasting empties the stomach, lowering the risk of stomach contents entering the lungs during anaesthesia (aspiration). Commonly followed guidelines for healthy adults (from anaesthesiology societies) are:

| What | Minimum fasting time | |---|---| | Clear liquids (water, clear juice without pulp, black tea or coffee without milk) | 2 hours | | Breast milk (infants) | 4 hours | | Infant formula, non-human milk | 6 hours | | Light meal (toast, tea with milk) | 6 hours | | Fried, fatty food or meat | 8 hours |

Your hospital may give a slightly different instruction (for example, "nothing by mouth after midnight") for convenience, especially for morning surgeries. Follow the instructions you are given. Fasting too long is uncomfortable and can cause dehydration, low blood sugar and headaches. Ask whether you may sip clear fluids up to two hours before, and tell the team if you've eaten or drunk anything by mistake, since surgery may need to be delayed. Chewing gum, paan and tobacco count as intake.

Diabetics and children need special instructions, and surgery is best scheduled early in the day.

Medicines: what to continue and what to stop

Never stop or start medicines on your own. The anaesthetist or surgeon will advise. General patterns:

| Medicine | Usual advice | |---|---| | Blood pressure tablets (such as beta-blockers, amlodipine) | Usually continue, including on the morning of surgery with a sip of water | | ACE inhibitors and ARBs | Sometimes held on the morning of surgery; follow instructions | | Diuretics | Often skipped on the morning of surgery | | Diabetes tablets | Metformin is often held on the day of surgery; SGLT2 inhibitors are stopped for a few days before (risk of ketoacidosis); others as advised | | Insulin | Dose is adjusted; follow instructions | | Blood thinners (warfarin, apixaban, rivaroxaban, clopidogrel, aspirin) | Management depends on why you take them. Do not stop on your own, especially after stents; the team will give a plan | | Asthma and COPD inhalers | Continue, and bring them | | Thyroid medicines | Continue | | Anti-epileptics | Continue | | Antidepressants and psychiatric medicines | Usually continue | | Herbal supplements, fish oil, vitamin E, ginkgo, garlic and ginseng | Often stopped a week or two before, because some affect bleeding | | Steroids | Continue; you may need extra cover on the day |

Bring all medicines, or a list, to the PAC.

How to prepare for surgery

• Stop smoking as early as possible. Even a few weeks before surgery reduces chest and wound complications; longer is better.
• Avoid alcohol in the days before.
• Control chronic conditions. Get blood sugar and blood pressure in order.
• Treat infections. A cold, cough, urinary infection or tooth infection may need treatment, and surgery may be postponed.
• Get anaemia treated.
• Practise deep breathing and walking, which speeds recovery and lowers lung complications.
• Tell the team about loose teeth, dentures and piercings.
• Remove nail polish, jewellery and contact lenses on the day.
• Arrange a responsible adult to accompany you home after day surgery.
• Ask questions. Know what type of anaesthesia you will have and how pain will be managed.

On the day of surgery

• Arrive on time with documents and test reports.
• Wear loose clothes and leave valuables at home.
• Take only the medicines you were told to take, with a sip of water.
• Tell the team about any new illness, fever, cough or change since the PAC.
• Women should inform staff of any chance of pregnancy or if their period has started.

Why surgery sometimes gets postponed after the PAC

• Uncontrolled blood pressure or blood sugar
• A fresh chest infection
• Not following fasting instructions
• Missing or abnormal reports that need review
• Recent heart attack, unstable heart condition
• Unreported blood thinner use
• Pregnancy detected
• Severe anaemia or low platelets

A short delay to put things right is much safer than rushing.

Frequently asked questions

What is the full form of PAC?

Pre-anaesthetic check-up.

Is PAC compulsory before surgery?

Yes, for any surgery under anaesthesia. It is a standard safety step.

What tests are done in PAC?

Commonly a blood count, sugar, kidney tests, ECG and chest X-ray, plus others depending on your health, age and the type of surgery.

How long before surgery should PAC be done?

Usually within days to a few weeks before surgery, depending on hospital policy and your health. It is repeated if your condition changes.

How long should I fast before surgery?

Typically 6 to 8 hours for solid food and 2 hours for clear fluids, but follow your hospital's instructions.

Can I take my regular medicines on the morning of surgery?

Many, such as blood pressure and thyroid tablets, are continued. Others, such as diabetes tablets and blood thinners, need specific instructions. Ask at the PAC.

Does a high ASA grade mean I can't have surgery?

No. It means closer planning. Many people with ASA III have surgery safely.

When to see a doctor

See the anaesthetist or your surgeon if, after the PAC, you develop fever, cough, chest pain, breathlessness, a new rash or any change in health, or if you are unsure about fasting or medicines. Do not stop blood thinners on your own.

Care at Prakash Hospital Noida

Whether you live in Sector 18, Sector 62, Greater Noida West, or anywhere nearby, Prakash Hospital Noida is a trusted name for surgery and anaesthesia care in Noida. Our anaesthesia team reviews your health carefully before surgery and gives clear instructions so that your procedure is as safe and comfortable as possible.

To book a consultation, call the number.

Sources: American Society of Anesthesiologists practice guidelines for preoperative fasting and ASA Physical Status Classification System. Hospital protocols vary; follow your team's instructions.

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