Pre-Anaesthetic Assessment

Preoperative assessment can be divided into:

This section covers identification of medical issues that influence anaesthetic technique and outcome. Management of identified issues is covered under Perioperative Management, and assessment of the paediatric patient is covered under Paediatric Anaesthetic Assessment.

History
Examination

History

This assessment template uses the mnemonic IIF AMPLE. Fasting status is in there twice, to ensure it’s not forgotten.

Identification of the patient
Indication for surgery
Fasting status
Allergies
- Including issues with previous anaesthetic
- Family history of anaesthetic issues
  - MH
  - Atypical cholinesterase
  - Other reactions
Medications
Perioperative management of medication is covered here. In particular, evaluate:
- Respiratory drugs
- Cardiac drugs
- Opioid/analgesic use and tolerance
- Antiplatelet and anticoagulant use
- Drugs with many side-effects or interactions
- Alcohol use
- Drug use
Past Medical History
- Previous surgeries
- Previous anaesthetics
  - Previous airway management difficulty
  - PONV
- Respiratory disease
  - Asthma
    ↑ risk of bronchospasm from intubation & desflurane
    - Consider cancellation or delaying elective procedures in poorly controlled asthma
  - Smoking
    Impaired mucous secretion & clearance, ↓ small airway calibre, altered immune response.
  - COAD
    ↑ risk of atelectasis, bronchospasm, pneumonia, mechanical ventilation, respiratory failure.
  - Recent URTI
  - OSA
    Screening should be performed with the STOP-BANG questionaire.
- Cardiac disease
  - CAD
    CCS Angina class.
  - MI
    Recommend postponing elective operations 4-6/52 following an MI - ↑ risk of reinfarction/death (periop MI mortality is 20-50%).
    - <3/12: 37% chance reinfarction
    - 3-6/12: 15% chance reinfarction
    - Over 6/12: Constant 5% risk
    - If surgery cannot be avoided, post-op ICU monitoring ↓ risk to 6%, 2%, 1% respectively
  - CHF
    NYHA class.
  - Valvular disease
  - Arrhythmias
  - PVD
  - Exercise tolerance
- Neurological disease
  - Seizures
  - CVA
  - Raised ICP
  - Spinal disease
  - Neuromuscular disease
- MSK
  - Obesity
    Obesity is associated ↑ rates of multiple complications. Perioperative evaluation should include:
    - Screening for OSA
    - HbA1c and Hb
    - Potential for difficult intubation
  - Arthropathies
  - Cervical spine disease
    Abscess, trauma, tumours, scleroderma, obesity fixation.
- Endocrine disease
  - Diabetes
    - Check and test HbA1c in known diabetics with planned major orthopaedic or vascular surgery
    - Evaluate for complications:
      - CVS
      - Renal
      - Neuropathy
  - Thyroid
  - Adrenal
- Renal
  - Insufficiency
    Perioperative AKI is more likely with:
    - Age
    - Emergency surgery
    - Obesity
    - Smoking
    - ETOH abuse
    - DM
    - HTN
    - Anaemia
    - Elevated Urea/Creatinine ratios
  - Dialysis
- GIT
  - GORD
  - Hepatic disease
- Haematological diseases
  - Objection to blood products
  - History of bleeding problems
    Asking patients about their risk of bleeding is a sensitive tool to identify patients with impaired haemostasis or platelet function.
  - Anaemia
  - Coaguolpathy
  - Dyscrasias
- Pregnancy
  - Issues with this pregnancy
  - Issues with previous pregnancies
  - Problems with prior epidurals
Last eaten
Events
Of the last 24 hours and concurrent illnesses.

Examination

Examination follows an ABCDE approach:

Airway assessment:
- Previous grade of intubation
- Ability to assume sniffing position/cervical spine stiffness
- Mallampati: 1: Full visibility of tonsils, uvula and soft palate 2: Visibility of hard and soft palate, upper portion of tonsils and uvula 3: Soft and hard palate and base of uvula visible 4: Only hard palate visible
- Thyromental distance
  Distance of lower mandible in the midline from the mentum to the thyroid notch.
  - < 6cm is associated with difficult intubation
- Mouth opening
  - < 2 finger breadths is associated with difficult intubation
- Tongue size
- Dentition
Breathing assessment
CVS asssessment
Neuro assessment
Extremity assessment
- Cannula sites
- Bony landmarks and anatomy for regional techniques
Fluid state
- Filling state
- Nutritional state

Checklist

An alternative pre-anaesthetic/peri-operative checklist is also described using the mnemonic A₂B₂C₂D₂E₂F₂G₂:

Affirmative history
- Surgical condition
- Past illnesses and treatment
Airway
- Perform a detailed airway exam
Blood loss
- Current Hb
- Blood loss estimation
- Blood availability
Breathing
- Respiratory examination
Clinical exam
- Cardiac examination
- Exertional tolerance
Co-morbidities
Particualarly DM, HTN, asthma, epilepsy.
Drugs
Current medications and anaesthesia plan.
Details
Of previous anaesthetics and surgeries.
Evaluate investigations
Other relevant investigations.
End point to take up the case for surgery
Conduct operation if further postponement will not be beneficial.
Fluid status
Fasting status
Give physical status
Get consent

References

Hemanth Kumar VR, Saraogi A, Parthasarathy S, Ravishankar M. A useful mnemonic for pre-anesthetic assessment. Journal of Anaesthesiology, Clinical Pharmacology. 2013;29(4):560-561. doi:10.4103/0970-9185.119127.
De Hert, S., Staender, S., Fritsch, G., Hinkelbein, J., Afshari, A., Bettelli, G., … Wappler, F. (2018). Pre-operative evaluation of adults undergoing elective noncardiac surgery: Updated guideline from the European Society of Anaesthesiology. European Journal of Anaesthesiology (Vol. 35).