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Pre-operative assessment

Summarise core details

  • Patient details
  • Operation (and anaesthesia if required)
  • Background

NB: look through past notes/documents to confirm details.

Current health

  • Recent/current illnesses (within 2 weeks)
  • Full systems review
  • Baseline exercise tolerance (what makes them stop: SOB/chest pain/claudication)
  • Symptoms of sleep apnoea (paroxysmal nocturnal dyspnoea, excessive sleepiness, morning headaches)
  • Smoking/alcohol use

Medical and drug history

  • Medical conditions: ask specifically about hypertension, diabetes (should be put first on list), asthma/COPD, cardiovascular disease, liver disease. Determine if conditions are adequately controlled.
  • Drug history (including allergies!)

Anaesthetic history

  • Previous anaesthetics and reactions
  • Family anaesthetic history


Anaesthetic assessment

  • Neck movement limitation/jaw opening limitation/dentures
  • Airway assessment: use Mallampati classification and note BMI

    • See all soft palate and uvula
    • See half of uvula
    • See a small gap at end of soft palate
    • Can only see hard palate

  • Back examination (if having spinal/epidural): look for skeletal malformations

Multi-system examination

  • General: GCS, limb movements
  • Hands: cyanosis, warm peripheries, cap refill, peripheral pulses
  • Neck: JVP, carotid bruits
  • Chest: heaves/thrills, chest expansion, percussion resonance, lung and heart sounds
  • Abdomen: tenderness, masses/organomegaly, bowel sounds
  • Calves: swelling/tenderness, oedema


Tests that may be required for patients having surgery include:

  • Blood tests: FBC, U&Es, LFTs, clotting, group and save
  • ECG
  • Other tests may be considered in advance
    • Pregnancy test (if chance of pregnancy)
    • Echocardiogram (if murmur/heart failure/cardiac symptoms)
    • Spirometry (if significant lung disease)
    • Pacemaker check(if have pacemaker)
    • TFTs (if on known thyroid disease)

Reference: NICE β€˜NG45 Routine preoperative tests for elective surgery’ 2016


Correct investigation abnormalities

For an immediate pre-operative assessment (day prior to the operation)

  • Correct INR if abnormal (>1.4)

    • Aggressive correction (if on warfarin for AF): 5-10mg IV vitamin K, then repeat INR in 6 hours – if still high, discuss with haematology regarding giving prothrombin complex concentrate pre-operatively
    • Cautious correction (if on warfarin for artificial heart valve/recent PE): discuss with senior and haematology – will usually require reversal of warfarin and cover with unfractionated heparin infusion, which will be stopped 4 hours pre-operatively and restarted after
    • If INR raised due to liver disease: 10mg IV vitamin K, then repeat INR in 6 hours – if still high, discuss with haematology who may advise FFP/cryoprecipitate

  • Blood transfusion if Hb <9g/dL, or <10g/dL if elderly/cardiovascular/respiratory disease
  • Consider platelet concentrate transfusion if platelets <50×109/L (discuss with haematology if cause unclear)
  • Correct electrolyte abnormalities


Note, if there are significant abnormalities, bloods must be repeated again pre-operatively (e.g. at 6am) to show they have been corrected.

For an early pre-operative assessment (>1 week pre-operatively)

  • INR may be corrected by stopping warfarin as below
  • Anaemia should be investigated and the cause treated – e.g. with iron tablets/infusion for iron-deficiency anaemia

If there are any concerns, contact the consultant or an anaesthetist.


  • IV fluids: only prescribe fluids overnight (when NBM) if instructed by consultant, or if patient needs variable rate insulin infusion, or is dehydrated
  • New medications
    • Operation preparation: give drugs required for specific operation (specified in pre-operative checklist), e.g. bowel prep for colorectal
    • VTE prophylaxis: prophylactic LMWH should usually be given the night before the operation, but omit any doses when the operation is due to start in <12 hours
    • Antiemetics and analgesia: as required
  • Regular medicines
    • Vital drugs should usually be taken on the day of the operation: cardiovascular medications (excluding antihypertensives), antipsychotics, Parkinson’s medications, inhalers, glaucoma medications, immunosuppressants, thyroid medications, drugs of dependence (e.g. benzodiazepine)
    • Most other drugs should not be taken on the day of the operation (restarted the day after)
    • Some medications must be stopped/changed pre-operatively:

Medications that should be stopped/changed pre-operatively

MedicationTime to stop pre-operativelyDetails
Warfarin5 daysTherapeutic-dose LMWH can be prescribed in the interim in most cases; patients with high risk indication (e.g. mechanical heart valve) may need to be admitted for unfractionated heparin infusion
Direct oral anticoagulants24 hours for minor surgery; 48 hours for major surgery 
Therapeutic-dose LMWH24 hours 
Unfractionated heparin infusion4 hoursRestart post-operatively
Aspirin/clopidogrel/dipyridamole/ P2Y12-receptor inhibitors7 days ideally (but risk/benefit decision)If patient has a cardiac stent or other high risk indication, liaise with cardiology and surgeon to make decision regarding stopping
InsulinAvoid morning dosePrescribe variable rate insulin infusion with surgical fluid [5% dex/0.45% NaCl/0.15% KCl @ 80ml/h] from midnight the night before (unless minor surgery)
Oral hypoglycaemicsAvoid on day of operationPrescribe variable rate insulin infusion as above if blood glucose not well controlled. Also avoid metformin for two days after (due to risk of lactic acidosis). 
Diuretics/ACE inhibitorsAvoid on day of operation 
Long-term corticosteroidsChange to equivalent dose hydrocortisoneLiaise with anaesthetist
COCP4 weeksRestart 2 weeks after


  • VTE prophylaxis Proforma 
  • Consent form (complete this only if you have sufficient knowledge, if not call registrar/consultant)

Fasting and admission

  • Fasting guidelines
    • β€˜2-6 rule’ = NBM for 2 hours pre-operatively; clear fluids only for 6 hours pre-operatively
    • If you are unsure of the operation time, prepare the patient for 8am (e.g. say clear fluids only from 2am, NBM from 6am).
  • Pre-operative patients only generally need admission the night before if they are diabetic (and therefore require a variable rate insulin infusion from midnight); or if they need specific medications which must be given overnight; or if INR/Hb/platelets need correction

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