PRE-OPERATIVE ASSESSMENT
LEARNING OBJECTIVES
- To recognise the key elements in a pre-operative assessment
- To assess the effects of a patient’s co-morbid disease on having a general anaesthetic
- To identify patients that require pre-operative optimisation and to determine principles of optimisation
- To describe the principles of management of medications in the pre-operative period
- To explain existing fasting protocol and to recognise the principles and implications of fasting in the peri-operative period
- To perform a basic pre-anaesthetic assessment
Three Simple Questions
- Do they WANT the operation?
- Do they NEED the operation?
- Are they fit for surgery?
Assessment Content:
- Confirm the patient’s identity, and consider ‘capacity’
- Check the procedure the patient is booked for
- Take a history of the current problem (presenting complaint)
- Take a past medical and surgical history
- Ask about functional status / exercise capacity
- Ask about previous personal or family problems with general anaesthesia
- Ask about any allergies, particularly to medications
- Note current medications including dose and frequency
- Ask for smoking and alcohol intake
- Ask about gastro-oesophageal reflux disease
- Proceed with systems review (concentrating on cardiovascular and respiratory systems)
- Note baseline observations, including BMI
Risk Assessment:
The American Society of Anaesthesiologists (ASA) physical status classification system is a way of grading a patient’s fitness to undergo a general anaesthetic.
- ASA 1: A normal healthy patient
- ASA 2: A patient with mild systemic disease
- ASA 3: A patient with a severe systemic disease that is not life-threatening
- ASA 4: A patient with a severe systemic disease that is a constant threat to life
- ASA 5: A moribund patient who is not expected to survive without the operation
- ASA 6: A brain-dead patient whose organs are being removed with the intention of transplanting them into another patient
- The addition of “E” denotes an emergency surgery
- For examples, see https://www.asahq.org/standards-and-guidelines/asa-physical-status-classification-system
Assessment of the Airway
Cervical spine mobility: ask patient to extend and flex their neck. Ask if there is any pain on movement and does this pain limit movement (imaging is of limited benefit in most cases).
Dentition: ask about loose teeth, caps/crowns, dentures and look in the mouth for yourself as part of the Mallampati.
Mallampati: sit in front of the patient, at the same shoulder height. Ask the patient to open their mouth as wide as they can and stick their tongue out. They should not make any noice (including “ah”).
Investigations
Blood tests: most patients will need baseline blood tests
ECG: anyone over 60 years of age or a patient with known cardiac history, risk factors for cardiovascular disease, or is undergoing vascular surgery.
Further tests: if you think a patient needs further investigation….they probably do! If you are unsure, ask a member of your team or an anaesthetist. If you request an investigation, find out the result.
Side Effects and Complications of Anaesthesia
Patients should be warned about the risk of surgery and this includes the specific risks of the anaesthetic. There are also risks associated with specific anaesthetic procedures such as regional anaesthesia.
Mild/Frequent:
- Nausea/Vomiting
- Sore throat
- Shivering
- Dental damage
- Corneal abrasion
- Confusion
Severe/Rare:
- Nerve damage
- Allergy/Adverse drug reaction/Anaphylaxis
- Myocardial infarction
- Cerebrovascular accident
- Awareness
- Death
At the end of this webpage is a PDF of a summary of the key elements to a pre-operative assessment.
MEDICATIONS IN THE PRE-OPERATIVE PERIOD
Oral hypoglycaemics:
Insulin:
Antiplatelets: A discussion should be had with the surgeons as well as the specialist managing the antiplatelets (e.g. cardiologist or neurologist). A decision needs to be made based on the risk of bleeding versus the risk of a cardiovascular/cerebrovascular event.
If the antiplatelet needs to be stopped, below is a suggested timing of stopping the agent prior to surgery:
Warfarin: A discussion should be had with the surgeons as well as the specialist managing the warfarin (e.g. cardiologist, haematologist). A decision needs to be made based on the risk of bleeding versus the risk of a thromboembolic event.
If it needs to be stopped, a further decision needs to be made as to whether the patient requires bridging therapy with heparin OR clexane, based on the risk of thromboembolism.
DOACs: A discussion should be had with the surgeons as well as the specialist managing the DOAC (e.g. cardiologist, haematologist). A decision needs to be made based on the risk of bleeding versus the risk of a thromboembolic event.
If it needs to be stopped, the guidelines are outlined below. Bridging therapy is not generally required.
Beta blockers: Continue in patients who are usually on beta blockers.
ACEI/ARBS: Consider withholding on the day of surgery (less hypotension) but also reasonable to continue on day of surgery.
Statins: Continue in patients who are usually on statins.
Analgesia: Continue. It is important to ensure that a patient’s usual analgesia is continued and that pain is managed appropriately in the peri-operative period.
Steroids:
FASTING
In general, patients can have solids up to 6 hours before surgery, and clear fluids 2 hours before surgery. This is mainly to reduce the risk of peri-operative regurgitation which may result in aspiration.
It is important not to withhold certain medications (see above), just because a patient is nil by mouth/fasting for surgery. Continuing medications (e.g. analgesia, beta blockers, statins) with sips of water is perfectly reasonable in the fasting period.
Guidelines on peri-operative management of steroids
Click to access guidelines-for-perioperative-steroids-v1.pdf
Anaesthesia for Medical Students 