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Pre-op Assessment for Elective Surgery

Objectives

• Identifying latent pathology requiring treatment
• Optimizing pre-existing medical conditions
• Ensuring appropriate preoperative investigations are arranged
• Promoting lifestyle modifications, including smoking cessation, weight loss, alcohol reduction
• Streamlining day-of-surgery admission
• Reducing day-of-surgery cancellations
• Highlighting high-risk or challenging patients to the appropriate anaesthetic team
• Discussion of anaesthetic techniques prior to admission

History and Examination

• Aim of identifying medical co-morbidities and the functional effect of the conditions.
• Previous anaesthetic history should be taken and ideally previous anaesthetic records should be examined to identify any problems related to anaesthesia or airway management.
• A family history of any significant problems with anaesthesia should be sought, including malignant hyperthermia and suxamethonium apnoea.
• Risk factors for gastro-oesophageal reflux should be identified; these include hiatus hernia, a history of reflux, and medical conditions which may delay gastric emptying.
• Appropriate plans for airway management can then be formulated and antacid prophylaxis prescribed.
• A review of all regular medications should be undertaken and the patient should be instructed as to which drugs to continue or withhold in the peri-operative period.
• A general physical examination should reveal any abnormalities such as obesity, scoliosis, and flexor contractions which may have implications for positioning while under anaesthesia.
• A cardiovascular and respiratory examination should be performed to confirm the presence of cardiac murmurs, dysrhythmias, and lung pathologies.

Airway Assessment

Predictors of Difficulty with BMV Include

• Obesity (neck circumference >60 cm)
• Beard
• Edentulous
• Snoring
• Anatomical facial abnormality

Predictors of Difficult Laryngoscopy Include

• Inter-incisor gap
  • Mouth opening is vital for most airway interventions.
  • The ability to open less than 3 cm is regarded as a sign of potential difficulty.
• Mallampati Scoring System
  • This assesses the view of the oropharynx.
  • Sit in front of the patient and ask them to open their mouth maximally and protrude their tongue whilst observing the view.
  • Class 3 and 4 can be associated with difficult laryngoscopy.

Mallampati Scoring System

Class	Structures Visible
1	Faucial pillars, soft palate, and uvula
2	Uvula tip masked by base of tongue
3	Visualization of base of uvula only
4	Soft palate not visible

• Thyromental distance
  • This is the distance from the upper border of the thyroid cartilage to the tip of the jaw and is measured with the head extended.
  • A distance of less than 6.5 cm can be associated with a difficult view at laryngoscopy.
  • Traditionally measured with finger breadths, with a distance of less than three finger widths being associated with a poor view at laryngoscopy.
  • Recommended to be measured accurately with a ruler to avoid subjective results.
• Jaw protrusion
  • Assesses temporomandibular joint movement.
  • Patients can be asked to protrude their lower jaw or to ‘bite your upper lip’.
  • Inability to protrude the lower jaw can be associated with a poor view at laryngoscopy.
• Neck movement
  • Examines the patient’s ability to achieve the optimal position for airway management, both for intubation and mask ventilation.
  • The ‘sniffing position’ is achieved by cervical flexion and atlanto-axial extension.
  • With the neck fully flexed, the patient should be able to lift their head more than 15 degrees, demonstrating normal occipito-axial movement.
• Dentition
  • Presence of any loose teeth, prominent teeth including single maxillary incisors, dentures, and any loose dental work.

Scoring Systems

Wilson’s Score

• A scoring system assessing multiple components of airway assessment:
  • Obesity
  • Restricted head and neck movements
  • Restricted mandibular movements
  • Receding mandible
  • Prominent upper incisors
• Risk factors are assigned a score of 0, 1, or 2, with a score greater than 2 predicting more than 75% of difficult intubations.
• Scoring systems have an increased positive predictive value compared with single tests but have a high incidence of false-positives.

Medical Co-morbidities

Hypertension

• Increased risk of an exaggerated fall in systolic blood pressure on induction of anaesthesia (especially in uncontrolled hypertension) and an exaggerated sympathetic response to stresses such as laryngoscopy and pain.
  • Can potentially precipitate myocardial ischaemia and cerebrovascular accidents.
• Review for end-organ damage and control.
• Review ECG.
• Treatment of hypertension returns vascular reactivity towards normal levels, improving cardiovascular stability in the peri-operative period. Patients with severe hypertension (diastolic BP >110 mmHg) require control prior to elective surgery.

Coronary Artery Disease (CAD)

• Well-controlled, stable angina need not delay elective surgery.
• Unstable angina, which occurs at rest, or angina increasing in frequency or severity, may require further investigation and cardiologist review to optimize medical treatment.

Myocardial Infarction

• Patients who have had a recent myocardial infarction need a thorough discussion of the risks of surgery with both the anaesthetic and surgical teams.
• Recommendations suggest waiting more than 60 days before undergoing elective surgery following a medically managed myocardial infarction, with risks decreasing over time.

Percutaneous Coronary Intervention

• Elective non-cardiac surgery should be:
  • Delayed 14 days after balloon angioplasty.
  • Delayed 30 days after bare metal stent (BMS) insertion.
  • Optimally delayed 1 year after drug-eluting stent (DES) insertion.
• Elective non-cardiac surgery should not be performed in patients where dual antiplatelet therapy will need to be discontinued perioperatively within 30 days of BMS implantation or 12 months after DES insertion due to increased risk of in-stent thrombosis.

Valvular Heart Disease

• Valvular heart lesions significantly increase cardiac risk.
• Patients with suspected moderate or severe valvular stenosis or regurgitation should have a preoperative echocardiogram if there hasn’t been one in the past year or if there has been a significant change in clinical status or physical examination since the previous echocardiogram.

Implantable Cardiac Devices

• Cardiac pacemakers are used in the presence of an abnormal cardiac conduction system.
• Devices are categorized by a code (chambers paced, chambers sensed, response to sensing, rate modulation, multisite pacing).
  • O = none, A = atrium, V = ventricle, D = dual, I = inhibited, R = rate modulation.
• Devices are checked annually, and results should be reviewed, focusing on percentage paced and underlying rhythm.
• Increasing use of left ventricular assist devices and implantable cardioverter defibrillators (ICDs) for end-stage heart failure and ventricular arrhythmias.
• ICDs need to be deactivated for surgery; liaison with cardiology should begin early in the pre-assessment process.

Stroke

• Patients with cerebrovascular disease are at risk of further events peri-operatively and may be intolerant of swings in blood pressure.
• Detailed account of pre-existing neurological impairment should be noted.
• Little evidence available to guide decisions regarding optimal timing of elective surgery following a stroke. Risks are most elevated in the first three months but remain elevated beyond this period. A balance of risks should be considered.

COPD

• Severity of airflow limitation classified by FEV1 % predicted:
  • Mild: >80%
  • Moderate: 50-79%
  • Severe: 30-49%
  • Very severe: <30%
• Increasing severity is associated with higher risk of postoperative respiratory complications.
• Full history is essential, focusing on functional status (e.g., “how many stairs can you climb before stopping to catch your breath?”).
• Details on the frequency and timing of exacerbations, steroid use, hospital admissions, and previous ventilation needs.
• Consider presence of pulmonary hypertension in long-standing COPD patients.
• Smoking increases the risk of postoperative complications; cessation advice should be given early, with maximum benefit seen if stopped at least 8 weeks before surgery.

Pre-op Wheeze Management

• Active treatment with bronchodilators.
• Consider presence of respiratory tract infection (RTI).
• Duration of treatment is unclear.
• Decision made in context with patient’s severity and urgency of operation.
• Use of perioperative steroids is also unclear.

Respiratory Tract Infection

• Patients with symptoms and signs of lower respiratory tract infection on the day of surgery should be treated and postponed until symptom-free.
• Viral upper respiratory tract infection can cause bronchial reactivity persisting for 3-4 weeks. Unless urgent, such patients should be postponed for 4 weeks to minimize postoperative respiratory infection risk.

Diabetes

• Diabetic patients are at higher risk of medical and surgical adverse events, including cardiac and septic complications.
• Assess diabetic control through sugar levels and HbA1c.
  • If HbA1c >69 mmol/mol (8.5%) or patients have hypoglycaemic unawareness, consider referral to diabetic services.
• Consider underlying complications such as renal impairment and latent cardiac disease.
• Strategy for perioperative diabetic control should be established at the pre-assessment clinic (PAC) appointment.
  • Diabetic patients should ideally be first on the surgery list and promptly return to normal oral intake and usual diabetic regimen.

Obesity

• Obesity, a significant public health issue, is of particular relevance to anaesthetic practice due to associated co-morbidities:
  • Diabetes, CAD, gastro-oesophageal reflux, difficult airway, sleep apnoea, challenges with regional anaesthesia.
• The Society for Obesity and Bariatric Anaesthesia (SOBA) provides guidelines for the bariatric patient (BMI >35 kg/m2) including preoperative evaluation and recommendations for preoperative continuous positive airway pressure.

Anaemia

• Anaemia limits tissue oxygenation and is poorly tolerated in patients with CAD or ventricular failure.
• Anaemia is a strong predictor of adverse surgical outcomes. If identified at the PAC, categorize iron deficiency anaemia, anaemia of chronic disease, or primary haematological cause.
  • Unexpected iron deficiency should be investigated to exclude malignancy.
  • Decision on surgery based on priority and anaemia severity.
  • Commence iron replacement therapy in parallel with investigations.

Frailty

• Increasingly common with an ageing population.
• No standard method to measure frailty, various research tools available.
  • Factors include low muscle mass and cognitive decline.
  • Recent weight loss or nutritional concerns should generate a dietetic service referral.
• Preoperative exercise and strengthening evidence is limited.
• Issues of capacity and consent should be explored before admission.

Rheumatoid Arthritis

• Multisystem inflammatory disorder with many anaesthetic implications.
• Significant cervical spine or temporomandibular joint involvement may require awake intubation technique.
• Severe disease may include pericardial effusions, pulmonary fibrosis, and renal impairment.
• Often associated with anaemia of chronic disease and non-steroidal anti-inflammatory drug use.
• Medication protocols should be in place in consultation with the rheumatology service.
• Skin fragility and chronic pain management should be considered, and medications should ideally be continued perioperatively.

Functional Assessment

American Society of Anaesthesiologists (ASA) Physical Status Classification

• The American Society of Anaesthesiologists (ASA) scoring system was devised in 1963 for the standardized reporting of preoperative functional status.
• This consists of five categories, with a sixth added later
• The ASA classification is widely used, although should not be used as a risk stratification tool.
• The ASA grade is often criticized for a high rate of inter-observer variability and uses no information regarding the proposed surgical intervention.
• A suffix ‘E’ is used for emergency surgery.

Grade	Definition
I	A normal, healthy patient
II	Mild systemic disease
III	Severe systemic disease
IV	Severe systemic disease that is a constant threat to life
V	A moribund patient who is not expected to survive without the operation
VI	A declared brain-dead patient whose organs are being removed for donor purposes

Detailed Examples by ASA Classification

ASA PS Classification	Definition	Adult Examples	Pediatric Examples	Obstetric Examples
ASA I	A normal healthy patient	Healthy, non-smoking, no or minimal alcohol use	Healthy (no acute or chronic disease), normal BMI	Normal pregnancy
ASA II	A patient with mild systemic disease	Mild diseases without substantive functional limitations. Current smoker, social alcohol drinker, pregnancy, obesity (≤30 BMI<40), well-controlled DM/HTN, mild lung disease	Asymptomatic congenital cardiac disease, well controlled dysrhythmias, asthma without exacerbation, well controlled epilepsy, non-insulin dependent diabetes mellitus, abnormal BMI percentile for age, mild/moderate OSA, oncologic state in remission, autism with mild limitations	Normal pregnancy, well controlled gestational HTN, controlled preeclampsia without severe features, diet-controlled gestational DM
ASA III	A patient with severe systemic disease	Substantive functional limitations; One or more moderate to severe diseases. Poorly controlled DM or HTN, COPD, morbid obesity (BMI ≥40), active hepatitis, alcohol dependence or abuse, implanted pacemaker, moderate reduction of ejection fraction, ESRD undergoing regularly scheduled dialysis, history (>3 months) of MI, CVA, TIA, or CAD/stents	Uncorrected stable congenital cardiac abnormality, asthma with exacerbation, poorly controlled epilepsy, insulin dependent diabetes mellitus, morbid obesity, malnutrition, severe OSA, oncologic state, renal failure, muscular dystrophy, cystic fibrosis, history of organ transplantation, brain/spinal cord malformation, symptomatic hydrocephalus, premature infant PCA <60 weeks, autism with severe limitations, metabolic disease, difficult airway, long term parenteral nutrition. Full term infants <6 weeks of age	Preeclampsia with severe features, gestational DM with complications or high insulin requirements, a thrombophilic disease requiring anticoagulation
ASA IV	A patient with severe systemic disease that is a constant threat to life	Recent (<3 months) MI, CVA, TIA or CAD/stents, ongoing cardiac ischemia or severe valve dysfunction, severe reduction of ejection fraction, shock, sepsis, DIC, ARD or ESRD not undergoing regularly scheduled dialysis	Symptomatic congenital cardiac abnormality, congestive heart failure, active sequelae of prematurity, acute hypoxic-ischemic encephalopathy, shock, sepsis, disseminated intravascular coagulation, automatic implantable cardioverter-defibrillator, ventilator dependence, endocrinopathy, severe trauma, severe respiratory distress, advanced oncologic state	Preeclampsia with severe features complicated by HELLP or other adverse event, peripartum cardiomyopathy with EF <40%, uncorrected/decompensated heart disease, acquired or congenital
ASA V	A moribund patient who is not expected to survive without the operation	Ruptured abdominal/thoracic aneurysm, massive trauma, intracranial bleed with mass effect, ischemic bowel in the face of significant cardiac pathology or multiple organ/system dysfunction	Massive trauma, intracranial hemorrhage with mass effect, patient requiring ECMO, respiratory failure or arrest, malignant hypertension, decompensated congestive heart failure, hepatic encephalopathy, ischemic bowel or multiple organ/system dysfunction	Uterine rupture
ASA VI	A declared brain-dead patient whose organs are being removed for donor purposes	–	–	–

Problems with ASA

• Subjective
• Lots of user variability (especially in specific patient groups – obstetrics and paediatrics)
• Incomplete assessment of the patients status can be combined with other scores to generate prediction of patient outcome (e.g. NSQIP)
• No assessment of functional capacity.
• In trauma patients there is no indication of their current state, other than the designation “E”. Which could reflect an stable pt with an open fracture or a patient who is periarrest.

Metabolic Equivalents (METs)

• Functional status can be used as a predictor of perioperative events.
• Metabolic equivalents allow estimation of an individual’s functional capacity.
• One metabolic equivalent is the resting oxygen consumption of a 40-year-old 70-kg man (3.5 ml kg/min).
• Simplified MET score systems using routine activities are available and should be used in preoperative assessment
• In general, perioperative cardiac risks are increased in patients with a MET lower than 4.
• It must be remembered that this score is subjective and patients may overestimate or underestimate their exercise tolerance.

Simplified MET Score System (each Number Refers to 1 MET)

1. Walking around at home
2. Eating/Dressing
3. 200 yards on flat ground
4. 1 flight of stairs
5. 1 flight of stairs
6. Brisk walking
7. 2 flights of stairs
8. Jogging
9. Jogging (continued)
10. Brisk swimming

Risk Assessment

Surgery Grade

Grade	Example
Grade 1 (minor)	Excision of skin lesion, drainage of breast abscess
Grade 2 (intermediate)	Knee arthroscopy, primary inguinal hernia repair, excision varicose veins
Grade 3 (major)	Total abdominal hysterectomy, endoscopic resection of prostate, lumbar discectomy, thyroidectomy
Grade 4 (major complex)	Thoracic surgery, colonic resection, radical neck dissection, elective abdominal aortic aneurysm repair

Cardiovascular Risk

1. Revised Cardiac Risk Index (RCRI)

• Predicts risk of perioperative cardiac complications (MI, CHF, arrhythmias, death).
• Components (each scores 1 point):
  • High-risk surgery (intraperitoneal, intrathoracic, vascular)
  • History of ischemic heart disease
  • History of congestive heart failure
  • History of cerebrovascular disease (stroke/TIA)
  • Diabetes mellitus (requiring insulin)
  • Preoperative creatinine >177 µmol/L (2 mg/dL)
• Interpretation:
  • 0 points: low risk (0.4%)
  • 1 point: 0.9%
  • 2 points: 6.6%
  • ≥3 points: 11%

Bleeding Risk

1. HAS-BLED Score (for Bleeding risk on anticoagulants)

• Components:
  • Hypertension (uncontrolled)
  • Abnormal renal/liver function (1 point each)
  • Stroke history
  • Bleeding predisposition/history
  • Labile INR
  • Elderly (>65)
  • Drugs (NSAIDs, antiplatelets) or alcohol excess
• Interpretation: ≥3 indicates high bleeding risk.

Risk of Thrombosis

1. Caprini Score (VTE Risk Assessment)

• Stratifies venous thromboembolism risk perioperatively.

• Components include patient age, history of DVT/PE, malignancy, immobility, obesity, hormonal therapy, surgery type.

• Interpretation:

  • 0-1: Low risk
  • 2: Moderate risk
  • 3-4: High risk
  • ≥5: Highest risk (extended thromboprophylaxis indicated

Airway Difficulty Prediction

1. Mallampati Classification

• Predicts difficult laryngoscopy/intubation.
• Class I-IV based on visibility of structures (uvula, soft palate, tonsillar pillars).

2. Thyromental Distance (TMD)

• <6cm: predicts difficult intubation.

3. Upper Lip Bite Test (ULBT)

• Predicts difficult airway based on mandibular protrusion.

4. LEMON Assessment (emergency airway)

• Look externally, Evaluate 3-3-2 rule, Mallampati, Obstruction, Neck mobility.

Postoperative Nausea and Vomiting (PONV)

1. Apfel Score

• Components:

  • Female gender
  • Non-smoker
  • History of PONV/motion sickness
  • Opioid administration

• Interpretation:

  • 0: 10% risk
  • 1: 20% risk
  • 2: 40% risk
  • 3: 60% risk
  • 4: 80% risk

2. POVOC Score (Pediatric patients)

• For pediatric PONV prediction.

Post-Discharge Nausea and Vomiting (PDNV)

1. PDNV Risk Score

• Components:

  • Female gender
  • Age <50 years
  • History of PONV
  • Use of opioids post-discharg
  • Nausea in PACU

• Interpretation:

  • Score ≥3 indicates high risk for PDNV.

Delirium and Cognitive Dysfunction

1. Confusion Assessment Method (CAM)

• Identifies delirium perioperatively.
• Acute onset, inattention, disorganized thinking, altered level of consciousness.

2. Mini-Mental State Examination (MMSE)

• Cognitive function screening (not delirium specific).

3. Frailty Scores

• Clinical Frailty Scale (CFS)
• Edmonton Frail Scale

Pulmonary Risk

1. ARISCAT Score

• Predicts postoperative pulmonary complications.
• Components include age, preoperative SpO₂, respiratory infection, anemia, surgical incision type, duration.

2. STOP-BANG (OSA risk)

• Identifies obstructive sleep apnea (OSA) risk.
• Snoring, Tiredness, Observed apnea, Pressure (HTN), BMI, Age, Neck circumference, Gender (male).

General Surgical Risk and Mortality

1. ASA Physical Status Classification

• General patient health assessment predicting perioperative risk.
• I–VI (Healthy → Brain-dead).

2. POSSUM and P-POSSUM Scores

• Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity.
• Predict morbidity and mortality based on patient and surgical factors.

Renal Risk

1. Mehran Score (Contrast-Induced Nephropathy Risk)

• Predicts acute kidney injury risk post contrast exposure.

Hepatic Risk

1. Child-Pugh Score

• Cirrhosis severity: predicts surgical risk in liver disease patients.

2. MELD Score

• Liver disease severity, predicts perioperative mortality.

Neurological Risk (Stroke)

1. CHA₂DS₂-VASc (Atrial Fibrillation Stroke Risk)

• Guides anticoagulation decisions:
• Components: CHF, HTN, Age ≥75, Diabetes, Stroke/TIA history, Vascular disease, Age 65-74, Sex (female).

Infection Risk

1. NNIS Risk Index

• Predicts surgical site infection (SSI) risk.

Transfusion Risk

1. Maximum Surgical Blood Order Schedule (MSBOS)

• Predicts blood transfusion requirements based on surgical procedure

2. ABC (Assessment of Blood Consumption) Score

• Predicts massive transfusion needs in trauma.

Critical Care Mortality and Severity Scores

1. APACHE II

• Acute Physiology and Chronic Health Evaluation: ICU mortality prediction.

2. SOFA Score

• Sequential Organ Failure Assessment: predicts ICU morbidity and mortality

3. qSOFA

• Quick bedside SOFA for early identification of sepsis.

Pain Assessment

• Numerical Rating Scale (NRS)
• Visual Analog Scale (Was)
• Behavioral Pain Scale (BPS) (for sedated patients)

Summary of the Most Frequently Used Scores

Category	Key Scores
Cardiac	RCRI, NSQIP
Bleeding	HAS-BLED, CRUSADE
Thrombosis	Caprini, PADUA
Airway	Mallampati, TMD
Nausea/Vomiting	Apfel, PDNV
Cognitive	CAM, MMSE
Pulmonary	ARISCAT, STOP-BANG
General Surgical Risk	ASA, POSSUM
Renal/Hepatic	Mehran, Child-Pugh, MELD
Neurological	CHA₂DS₂-VASc
Infection	NNIS
Transfusion	MSBOS, ABC
Critical Care	APACHE II, SOFA

Pre-operative Testing

Electrocardiogram (ECG)

• Indicated for patients with a history of cardiovascular disease such as CAD, arrhythmia, peripheral arterial disease, cerebrovascular disease, or structural heart disease.
• Consider in asymptomatic patients with no history of CAD if undergoing intermediate or high-risk surgery.
• Not required in patients with no history of CAD undergoing low-risk surgery.

Echocardiogram

• To assess left ventricular (LV) function if patients are known to have LV dysfunction and no echocardiogram has been performed within a year.
• For patients with known heart failure with increasing dyspnoea or a change in their clinical status.
• Reasonable to perform preoperative evaluation of LV function in patients with dyspnoea of unknown cause.
• For patients with clinically suspected moderate or greater degrees of valvular stenosis or regurgitation if there has been no echocardiogram within 1 year or a significant change in clinical status or physical examination since their last echocardiogram.

Exercise Tolerance Test

• Consider in patients with increased risk and unknown functional capacity if it will change management.
• Consider in patients with increased risk and poor/unknown functional capacity along with cardiac imaging to assess for myocardial ischaemia.
• Not indicated for patients with increased risk if they have moderate to excellent functional capacity (>4-10 METs).

Cardiopulmonary Exercise Testing (CPET)

• CPET offers a global assessment of a patient’s cardiorespiratory response to exercise.
• Provides information regarding oxygen consumption at the onset of anaerobic metabolism (AT, anaerobic threshold), aiding risk stratification and management strategy planning.
• CPET is not widely available and there is uncertainty regarding the optimal CPET-derived variables and thresholds to use.
• Consider CPET in patients for high-risk procedures where functional capacity is unknown.

Disease-Specific Approach to Preoperative Special Investigations

Patient Criteria	Investigations
Active, no documented medical illness, no medications	Finger prick Hb only
Hypertension	Formal Hb, Creatinine, ECG and Na/K if using digoxin, diuretics, ACEIs or ARBs.
Diabetes	Formal Hb, Finger prick glucose in all, HBA1C, Creatinine, Na/K if using digoxin, diuretics, ACEIs or ARBs
Ischemic Heart Disease	Formal Hb, Creatinine, ECG and Na/K if using digoxin, diuretics, ACEIs or ARBs.
Heart Failure	Formal Hb, Creatinine, ECG and Na/K if using digoxin, diuretics, ACEIs or ARBs. Decision to perform an echo (formal or screening) should be decided on a case by case basis.
Respiratory Disease: Well controlled, compliant, asymptomatic	Nil
Respiratory Disease: Poorly controlled/uncharacterized dyspnea or exercise intolerance that is unexplainable, Symptomatic COPD or asthma, Admission for respiratory aetiology or oral steroid use in last year	Lung function tests

ASA Category Approach to Preoperative Special Investigations

Test	ASA 1	ASA 2	ASA 3 or 4	Any Level of Surgery Risk	Time
Finger prick Hb	Not routinely	Routinely	Routinely	CAD, liver disease, anemia	All patients
Formal Hb	Not routinely	Routinely	Routinely	CAD, liver disease, anemia	3 months unless recent bleeding documented
Glucose – finger prick	Not routinely	All diabetics	All diabetics	–	–
Glucose formal	Not routinely	All diabetics	All diabetics	–	If not done within 3 months
HBA1C	Not routinely	All diabetics	All diabetics	–	6 months
Creatinine	Not routinely	Not routinely	Routinely	Patients aged more than 45 or 18-44 years with known cardiovascular risk factors (CAD, Diabetes, Hypertension, CVD), History of renal impairment	6 months earlier if on dialysis or previously documented Cr >177 or GFR <30ml/kg/min
Urea	Not routinely	Not routinely	Routinely	–	6 months
Na/K	Not routinely	Routinely	Routinely	Patient is taking digoxin, diuretics, ACEIs or ARBs, History of CKD, CCF	6 months otherwise earlier if change in clinical symptoms
Thyroid function TSH/T4	Not routinely	Not routinely	Routinely	Patient on thyroid medication, Screening for hypothyroidism in elderly if clinically indicated	6 months
INR/PTT	Not routinely	Routinely	Routinely	All patients on warfarin, Chronic liver disease, hemophilia, inherited platelet disorder	No time frame
ECG	Not routinely	Routinely	Routinely	Patients with known coronary heart disease, significant arrhythmia, peripheral arterial disease, cerebrovascular disease, other significant structural heart disease, Hypertension	Within 12 months unless onset of new symptoms
CXR	Not routinely	Not routinely	Routinely	Patients with uncharacterized dyspnea or exercise intolerance that is unexplainable, Symptomatic COPD or asthma, Admission for respiratory aetiology or oral steroid use in last year	Within 12 months
Pulmonary function test	Not routinely	Not routinely	Routinely	–	Within 12 months
FATE Echo	Not routinely	Not routinely	Not routinely	Consider in the following cases: VHD, Unknown dyspnoea, Worsening symptoms of cardiac failure, “Decompensation”, Documented pulmonary hypertension	Within 12 months
Formal Echo	Not routinely	Not routinely	Not routinely	Decision to perform an echo (formal or screening) should be decided on a case by case basis	Within 12 months
Pacemaker assessment	Not routinely	Not routinely	Not routinely	All pacemakers	Within 12 months
Pregnancy test	Females of child-bearing age	–	–	–	–

Links

• Premedication
• Paediatric pre op assessment
• Exercise testing and optimization
• Thoracic pre-op assessment
• Airway anatomy and assessment
• Hypertension
• Cardiac for non-cardiac surgery

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Past Exam Questions

ASA Risk Scoring System

a) List shortcomings of the ASA Risk Scoring System. (8)

b) Provide 2 suggestions to improve its reliability in predicting patient outcomes. (2)

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References:

1. Gray, C. and Baruah-Young, J. (2015). Preoperative assessment in patients presenting for elective surgery. Anaesthesia &Amp; Intensive Care Medicine, 16(9), 425-430. https://doi.org/10.1016/j.mpaic.2015.06.014
2. Pre-Operative Investigations for Elective Surgery GSH SOP. 2019
3. Fitz-Henry, J. (2011). The asa classification and peri-operative risk. The Annals of the Royal College of Surgeons of England, 93(3), 185-187. https://doi.org/10.1308/rcsann.2011.93.3.185a

Summaries:
Video from GasNovice.com

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© 2025 Francois Uys. All Rights Reserved.

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