Pre-operative assessment

Table of Contents

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

Examination

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

Investigations

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 ‘NG45 Routine preoperative tests for elective surgery’ 2016

Preparation

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.

Medications

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

Medication	Time to stop pre-operatively	Details
Warfarin	5 days	Therapeutic-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 anticoagulants	24 hours for minor surgery; 48 hours for major surgery
Therapeutic-dose LMWH	24 hours
Unfractionated heparin infusion	4 hours	Restart post-operatively
Aspirin/clopidogrel/dipyridamole/ P2Y₁₂-receptor inhibitors	7 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
Insulin	Avoid morning dose	Prescribe 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 hypoglycaemics	Avoid on day of operation	Prescribe 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 inhibitors	Avoid on day of operation
Long-term corticosteroids	Change to equivalent dose hydrocortisone	Liaise with anaesthetist
COCP	4 weeks	Restart 2 weeks after

Forms

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

Fasting and admission

Fasting guidelines
- ‘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