Preoperative assessment

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 SurgeryLee et alCirculation 1999;100:1043-1049
Risk factorCriteriaHigh-risk surgeryAAA repair, thoracic, abdominal surgeryIHDMI, Q on ECG, angina, nitrates, EST+CCFHistory, examination, CXRCerebrovascular diseaseStroke, TIADiabetesInsulin treatmentRenal impairmentCreatinine >177 mol/LNumber of factors% populationMajor cardiac complications036%0.5%139%1%218%5%37%10%415%530%


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 airwaybe 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 SurgeonYour 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