Pre-operative
assessment

Goals of preoperative assessment
• History and physical examination to
determine relevant tests and consultations
• Guided by patient choice and medical risk
factors choose a plan of care
• Informed consent
• Educate patient about anaesthesia, pain
management and perioperative care
• Reduce patient care costs

What is the risk of proceeding versus the
benefit to the patient?
Can we modify these risks before surgery?
Questions

Mortality related to anaesthesia
• Approx 1:26,000 anaesthetics
• One third of deaths are preventable
• Causes in order of frequency
– inadequate patient preparation
– inadequate postoperative management
– wrong choice of anaesthetic technique
– inadequate crisis management

Derivation and Prospective Validation of a Simple Index for Prediction of
Cardiac Risk of Major Noncardiac Surgery
Lee et al
Circulation 1999;100:1043-1049
Risk factor Criteria
High-risk surgery AAA repair, thoracic, abdominal surgery
IHD MI, Q on ECG, angina, nitrates, EST+
CCF History, examination, CXR
Cerebrovascular disease Stroke, TIA
Diabetes Insulin treatment
Renal impairment Creatinine >177 mol/L
Number of factors % population Major cardiac complications
0 36% 0.5%
1 39% 1%
2 18% 5%
3 7% 10%
4 15%
5 30%

Risk and ASA classification

Coronary Heart Disease
Class I: Ordinary physical activity does not cause angina. Angina
occurs on strenuous exercise only.
Class II: Slight limitation of ordinary activity. Angina occurs on
walking or climbing stairs rapidly, walking uphill, walking or
stair climbing after meals, or in cold, or in wind, or under
emotional stress, or only during the first few hours after
wakening. Angina occurs on walking more than 150 yards on the
level and climbing more than one flight of ordinary stairs at a
normal pace and in normal conditions.
Class III: Marked limitation of ordinary activity. Angina occurs
on walking 75–150 yards on the level or climbing one flight of
stairs in normal conditions and at normal pace.
Class IV: Angina on slight exertion; possible at rest.

History and
physical are the
most important
assessors of disease
and risk

Presenting complaint
Why does the patient need an operation now?
• Is it acute/chronic illness?
• Presenting symptoms?
e.g. anaemia, cachexia, pain, seizures etc
• What are the pathophysiological consequences?
e.g. thyroid mass
– Local - stridor, SVC obstruction
– Systemic - hypo/hyperthyroidism

Associated medical conditions
Given the presenting problems are there any other
conditions I am worried the patient could have?
• Bowel ca. - liver mets with abnormal LFTs,
abnormal coagulation, impaired drug metabolism
• Peripheral vascular disease - IHD, carotid disease,
HT, renal disease, COAD

Other medical conditions
Any other problems that may affect
perioperative morbidity and mortality?
• cardiac disease
• respiratory disease
• arthritis
• endocrine disease - diabetes, obesity etc
What is the patients functional capacity?

Functional capacity
• 1 MET Can you dress yourself?
• 4 MET Can you climb a flight of stairs?
• 10 MET Can you participate in strenuous
activities (swimming,
tennis,football)

Functional Capacity
All patients for major surgery should have METs > 4
Duke Activity Index
1 MET Can you take care of yourself? 4 METs Climb a flight of stairs or walk up a hill?
Eat, dress, or use the toilet? Walk on level ground at 4 mph or 6.4 km/h?
Walk indoors around the house? Run a short distance?
Walk a block or two on level ground
at 2 to 3 mph or 3.2 to 4.8 km per h? Do heavy work around the house like scrubbing
floors or lifting or moving heavy furniture?
Do light work around the house like
4 METs dusting or washing dishes? Participate in moderate recreational activities
like golf, bowling, dancing, doubles tennis, or
throwing a baseball or football?
>10 METs Participate in strenuous sports like swimming,
singles tennis, football, basketball, or skiing?

Anaesthetic history/assessment
• Family history
• Previous anaesthetics
– PONV
– allergy
– malignant hyperpyrexia
– difficult airway
– difficult IV access

Airway assessment
Best done by an anaesthetist
Certain features of concern
– small mouth
– poor dentition
– limited neck mobility
– scars/surgery/anatomical abnormalities
– obesity

Mallampati scoring system

Why would this man’s airway
be difficult to manage?

Drug history
Very useful, often forgotten
• Current medications
• ALLERGY
• Medic alert bracelets
• Smoking/alcohol history
• Other drugs of abuse!

“The more tests, the better”

Perioperative medications
• Take all usual medications
– Antihypertensives
– Beta blockers
– Statins
• Think about discontinuing/replacing
– Aspirin
– Anticoagulants
– Diabetic medications
– MAOIs

Summary
• History and physical most important assessors
of disease and risk
• ASA and functional status good predictors of
risk
• Lab tests have some usefulness
– add little in low risk patients
– may add false + ves
– add expense

Case example
You are an orthopaedic House Surgeon
Your Registrar tells you
“ There is a fractured femur in ED, get it ready
for theatre.”
What are you going to do?

Case example
A 49 yr old Samoan woman presents for
elective hemicolectomy. She has a 10 yr
history of NIDDM . She takes glipizide
and metformin
What are you going to do?

Case example
An 81 yr old man presents for elective
TURP. He has atrial fibrillation, has had
previous TIAs and is on warfarin.
What are you going to do?

Case example
A 76 year old man with PVD presents for
femoro-popliteal bypass surgery. He has
an ejection systolic murmur on
auscultation.
What are you going to do?

Questions