Describe Preoperative Assessment & Preparation in detail.

The Concept

Preoperative assessment is the systematic evaluation and optimisation of a patient before surgery, with the aim of minimising the risk of the operation and anaesthetic. It brings together assessing the patient's fitness, identifying and improving any medical conditions, stratifying risk, obtaining informed consent, and preparing the patient physically for theatre. A good preoperative work-up prevents avoidable complications and cancellations.

Aims

The aims are to assess fitness for surgery and anaesthesia, identify and optimise comorbidities, stratify operative risk, obtain informed consent, and plan the perioperative care (fasting, prophylaxis, anaesthetic technique).

History & Examination

The assessment covers comorbidities (cardiac, respiratory, diabetes, renal, hepatic disease), current medications (especially anticoagulants, antiplatelets and steroids), allergies, previous anaesthetic and surgical history, functional capacity (exercise tolerance), and smoking and alcohol use, together with an airway assessment for anaesthesia.

Risk Assessment & Investigations

Risk is stratified using the ASA physical status classification, functional capacity and cardiac risk indices. Investigations are chosen according to the patient and the surgery, and may include full blood count, urea and electrolytes, blood glucose/HbA1c, coagulation, group-and-save or crossmatch, an ECG, and a chest X-ray, with further tests (liver/thyroid function, echocardiography, pulmonary function) as indicated.

Optimisation & Medication Management

Modifiable factors are optimised before surgery: good glycaemic control in diabetes, correction of anaemia, optimisation of cardiac and respiratory disease, and smoking cessation. Medications need careful management — anticoagulants and antiplatelets may need to be stopped or bridged, long-term steroids need perioperative stress dosing, the combined pill/HRT raises VTE risk, and drugs such as metformin need a plan for the day of surgery.

Preparation for Theatre

Final preparation includes fasting (typically nil-by-mouth for 6 hours for food and 2 hours for clear fluids), informed consent, VTE prophylaxis, antibiotic prophylaxis where indicated, correct site marking, and completion of the WHO Surgical Safety Checklist (and bowel preparation for certain operations).

Managing the Anticoagulated Patient

A frequently-examined practical area is the perioperative management of anticoagulants and antiplatelets, which balances bleeding risk against thrombotic risk. Warfarin is usually stopped several days before surgery (and the patient 'bridged' with LMWH if the thrombotic risk is high, e.g. A metal heart valve); DOACs are stopped a defined number of days before according to renal function; and decisions about aspirin/clopidogrel depend on why they are being taken (e.g. Recent coronary stents are high-risk). Getting this balance right avoids both catastrophic bleeding and dangerous thrombosis.

The Diabetic Patient & Steroid Cover

Two specific groups need particular planning. Diabetic patients are ideally placed first on the list, with a clear plan for their medication on the day (often omitting/adjusting oral agents and insulin, sometimes using a variable-rate insulin infusion) and close glucose monitoring, since both hyper- and hypoglycaemia are harmful. Patients on long-term steroids may have a suppressed adrenal axis and need perioperative 'steroid cover' (stress-dose steroids) to prevent an Addisonian crisis under the stress of surgery. Anticipating these needs is a key part of optimisation.

A Note on Consent & the WHO Checklist

Two safety pillars complete preparation. Informed consent is a process, not just a signature: the patient must understand the nature of the operation, its benefits, material risks, and the alternatives (including doing nothing), and consent voluntarily with capacity. Immediately before surgery, the WHO Surgical Safety Checklist is performed at three points — 'sign in' (before anaesthesia), 'time out' (before incision) and 'sign out' (before leaving theatre) — confirming patient identity, site, procedure, allergies, equipment and counts. Together these have been shown to reduce errors and improve surgical safety.

A Note on Functional Capacity & Cardiac Risk

A practical measure used throughout preoperative assessment is functional capacity, often expressed in metabolic equivalents (METs): a patient who can climb two flights of stairs or walk up a hill (roughly ≥4 METs) without symptoms generally has adequate cardiorespiratory reserve for major surgery, whereas poor exercise tolerance flags higher risk and may prompt further cardiac assessment (ECG, echocardiography, or specialist referral). Combined with the ASA class and any cardiac risk index, this simple question about exercise tolerance is one of the most informative parts of the whole assessment.

• Fasting: 6 hours for food/solids, 2 hours for clear fluids.
• Risk stratification with the ASA classification; investigations tailored to patient + surgery.
• Manage anticoagulants (stop/bridge), steroids (stress dose), diabetes; give VTE + antibiotic prophylaxis; WHO Surgical Safety Checklist.

Optimisation before surgery reduces complications more than any intraoperative step.

• Preoperative assessment = evaluate fitness, optimise comorbidities, stratify risk, obtain consent, prepare for theatre.
• Assess comorbidities, medications (anticoagulants, steroids), allergies, previous anaesthesia, functional capacity, airway.
• Investigations tailored to patient/surgery: FBC, U&E, glucose/HbA1c, coagulation, group-and-save, ECG, CXR as indicated; risk by ASA class.
• Optimise: glycaemic control, anaemia, cardiorespiratory disease, stop smoking; manage anticoagulants/steroids/OCP/metformin.
• Fasting (6 h food/2 h clear fluids), consent, VTE + antibiotic prophylaxis, site marking, WHO Surgical Safety Checklist.