Pre-operative assessment

1. Pre-operative assessment

2. 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

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

4. 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

6. Derivation and Prospective Validation of a Simple Index for Prediction of Cardiac Risk of Major Noncardiac SurgeryLee et alCirculation 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%

7. Risk and ASA classification

8. 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.

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

10. 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

11. 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

12. 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?

13. 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)

14. 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 METsParticipate in strenuous sports like swimming, singles tennis, football, basketball, or skiing?

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

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

18. Mallampati scoring system

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

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

21. “The more tests, the better”

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

30. 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

31. 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?

33. 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?

34. 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?

35. 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?

36. Questions