Preoperative Assessment (Intro)

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  • Dr. Andrew Ferguson
  • Preoperative Assessment (Intro)

    1. 1. Preoperative Assessment & Premedication Craigavon Area Hospital CT1 Education Series (Intro) Dr. Andrew Ferguson
    2. 2. Overview <ul><li>Setting the scene </li></ul><ul><li>Preoperative testing </li></ul><ul><li>Components of the preoperative visit </li></ul><ul><ul><li>History & Physical Examination [emphasis on Airway] </li></ul></ul><ul><li>Introduction to organ-specific issues </li></ul><ul><ul><li>Evaluating Cardiovascular Disease </li></ul></ul><ul><ul><li>Evaluating Respiratory Disease </li></ul></ul><ul><li>Perioperative Medication Management </li></ul><ul><ul><li>Stopping patient medications….or not </li></ul></ul><ul><ul><li>Premedication </li></ul></ul><ul><li>Fasting </li></ul>Dr. Andrew Ferguson
    3. 3. Pre-op Assessment - AAGBI Guidance (2001) <ul><li>The anaesthetist </li></ul><ul><ul><li>is uniquely qualified to assess risk </li></ul></ul><ul><ul><li>i s responsible for deciding fitness for anaesthesia </li></ul></ul><ul><ul><li>must see all patients before operation </li></ul></ul><ul><li>The aim of assessment is to improve outcome </li></ul><ul><li>Blanket pre-op investigations waste resources & time </li></ul>Dr. Andrew Ferguson
    4. 4. Goals of assessment <ul><li>Screen for and manage co-morbid disease </li></ul><ul><li>To assess and minimise risks of anaesthesia </li></ul><ul><li>To identify need for specialised techniques </li></ul><ul><li>To identify need for advanced post-op care </li></ul><ul><li>To educate about anaesthesia </li></ul><ul><li>To obtain informed consent </li></ul><ul><li>To avoid unnecessary delays/cancellations </li></ul><ul><li>To motivate patients to improve pre-op </li></ul>Dr. Andrew Ferguson
    5. 5. Preoperative Assessment Systems <ul><li>Screening questionnaire (F2F, online, PC) </li></ul><ul><li>Preoperative assessment clinic </li></ul><ul><ul><ul><li>nurse led </li></ul></ul></ul><ul><ul><ul><li>consultant supported </li></ul></ul></ul><ul><ul><ul><li>coordinates availability of information </li></ul></ul></ul><ul><ul><ul><li>coordinates preoperative investigations </li></ul></ul></ul><ul><li>Preoperative visit </li></ul>Dr. Andrew Ferguson
    6. 6. Pre-operative Testing <ul><li>Only when indicated </li></ul><ul><ul><li>from history/examination, or </li></ul></ul><ul><ul><li>based on surgical plan </li></ul></ul><ul><li>ECG for example </li></ul><ul><ul><ul><li>Abnormal in 62% of patients with known cardiac disease </li></ul></ul></ul><ul><ul><ul><li>Abnormal in 44% of patients with strong IHD risk factors </li></ul></ul></ul><ul><ul><ul><li>Abnormal in 7% of over-50s with no risk factors </li></ul></ul></ul><ul><ul><ul><li>Abnormal in 3% of 50-70 year olds with no risk factors </li></ul></ul></ul><ul><ul><ul><li>New Q waves or arrhythmias < 2% </li></ul></ul></ul><ul><ul><ul><li>Limited use as predictor of outcome - may alter plan </li></ul></ul></ul>Dr. Andrew Ferguson
    7. 7. NICE CG3 (2003) Dr. Andrew Ferguson
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    14. 14. Pre-op Testing Schema Example Dr. Andrew Ferguson
    15. 15. ASA Minimum Pre-op Visit Components <ul><li>Medical, anaesthesia and medication history </li></ul><ul><li>Appropriate physical examination </li></ul><ul><li>Review of diagnostic data (ECG, labs, x-rays) </li></ul><ul><li>Assignment of ASA physical status </li></ul><ul><li>Formulation and discussion of anesthesia plan </li></ul>Dr. Andrew Ferguson
    16. 16. The ASA Physical Status Classification Dr. Andrew Ferguson ASA 1 Normal healthy patient Mortality ASA 2 Mild systemic disease - no impact on daily life 0.1% ASA 3 Severe systemic disease - significant impact on daily life 0.2% ASA 4 Severe systemic disease that is a constant threat to life 1.8% ASA 5 Moribund, not expected to survive without the operation 7.8% ASA 6 Declared brain-dead patient - organ donor 9.4% E Emergency surgery
    17. 17. History <ul><li>Medical problems (current & past) </li></ul><ul><li>Previous anaesthesia & related problems </li></ul><ul><li>Family anaesthesia history </li></ul><ul><li>Allergies and drug intolerances </li></ul><ul><li>Medications, alcohol & tobacco </li></ul><ul><li>Review of systems (include snoring and fatigue) </li></ul><ul><li>Exercise tolerance and physical activity level </li></ul>Dr. Andrew Ferguson
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    19. 19. Physical Examination <ul><li>Minimum requirements </li></ul><ul><ul><li>Airway </li></ul></ul><ul><ul><li>Heart & lungs </li></ul></ul><ul><ul><li>Vital signs including O 2 saturation </li></ul></ul><ul><ul><li>Height & weight (BMI) </li></ul></ul>Dr. Andrew Ferguson
    20. 20. Airway Examination <ul><li>Teeth and bite </li></ul><ul><li>Ability to protrude lower incisors beyond upper </li></ul><ul><li>Mouth opening (inter-incisor distance) </li></ul><ul><li>Mallampati score </li></ul><ul><li>Facial hair </li></ul><ul><li>Thyromental distance </li></ul><ul><li>Length & thickness of neck </li></ul><ul><li>Range of motion of head & neck </li></ul>Dr. Andrew Ferguson
    21. 21. Mallampati & Samsoon Score Dr. Andrew Ferguson
    22. 22. Mallampati Class 1 !!!! Dr. Andrew Ferguson
    23. 23. Dr. Andrew Ferguson Independent Predictors of Difficult Mask Ventilation and Intubation Difficult Mask Ventilation P-value Beard 0.0001 History of snoring 0.001 BMI > 30 0.0001 Mallampati III or IV 0.001 Age > 50 0.01 Severely limited jaw protrusion 0.03 Difficult Mask Ventilation & Intubation Severely limited jaw protrusion 0.0001 Thick neck/mass 0.02 History of sleep apnoea 0.04 BMI > 30 0.05 History of snoring 0.05
    24. 24. Cormack & Lehane Score 1 2 3 4 Dr. Andrew Ferguson
    25. 25. Dr. Andrew Ferguson Physical Examination - Risk Factors for Difficult Intubation Risk Factor Detail Level of Risk Weight < 90 kg 0 90-110 kg 1 > 110 kg 2 Head & Neck Movement > 90 o 0 Approx 90 o 1 < 90 o 2 Jaw movement IG = Interincisor gap Slux = mandibular subluxation IG > 5 cm or Slux > 0 0 IG < 5 cm or Slux = 0 1 IG < 5 cm or Slux < 0 2 Receding Mandible Normal 0 Moderate 1 Severe 2 Protruding maxillary teeth Normal 0 Moderate 1 Severe 2
    26. 26. Evaluating Cardiac Disease <ul><li>Ischaemic heart disease </li></ul><ul><li>Heart failure </li></ul><ul><li>Arrhythmia </li></ul><ul><li>Abnormal ECG </li></ul><ul><li>Undiagnosed murmur </li></ul><ul><li>Pacemaker or IACD </li></ul>Dr. Andrew Ferguson
    27. 27. CVS evaluation for non-cardiac surgery Dr. Andrew Ferguson
    28. 28. NYHA Functional Class Dr. Andrew Ferguson Class I No limitation of physical activity; ordinary activity does not cause fatigue, palpitations or syncope Class II Slight limitation of physical activity; ordinary activity results in fatigue, palpitations or syncope Class III Marked limitation of physical activity; less than ordinary activity results in fatigue, palpitations or syncope; comfortable at rest Class IV Inability to do any physical activity without discomfort; symptoms at rest
    29. 29. Metabolic Equivalents (METs) 1 MET = 3.5 ml O 2 utilisation/kg/min Tolerance < 4 METs = higher risk Dr. Andrew Ferguson Activity METS min METS max Cycling 5 mph 2 3 Cycling 10 mph 5 6 Cycling 13 mph 8 9 Ballroom Dancing 4 5 Swimming 8 10 Tennis 4 9 Walking 1 mph 1 2 Walking 2 mph 2 3 Walking 3 mph 3 3.5 Walking 4 mph 5 6 Activity METS min METS max Bed making 2 6 Carrying heavy bags 5 7 Cleaning windows 3 4 Dressing 2 3 General housework 3 4 Grocery shopping 2 4 Painting/decorating 4 5 Sexual intercourse 3 5 Showering 3 4 Vacuuming 3 3.5 Walking up stairs 4 7
    30. 30. Arrhythmias/ECG abnormalities <ul><li>Further work-up or therapy needed </li></ul><ul><ul><li>New onset AF </li></ul></ul><ul><ul><li>Symptomatic bradycardia </li></ul></ul><ul><ul><li>High-grade heart block (2 nd or 3 rd degree) </li></ul></ul><ul><ul><li>Uncontrolled AF </li></ul></ul><ul><ul><li>VT </li></ul></ul><ul><ul><li>Prolonged QT </li></ul></ul><ul><ul><li>New LBBB </li></ul></ul><ul><ul><li>RBBB with right precordial ST elevation (Brugada) </li></ul></ul>Dr. Andrew Ferguson
    31. 31. Pacemakers/IACD <ul><li>Determine type </li></ul><ul><li>Determine features </li></ul><ul><li>Pacemaker check/interrogation pre-op </li></ul><ul><li>Disable rate-adaptive mechanisms </li></ul><ul><li>Disable anti-tachyarrhythmia functions </li></ul><ul><li>Magnet not recommended for modern devices </li></ul>Dr. Andrew Ferguson
    32. 32. Evaluating Respiratory Disease Dr. Andrew Ferguson Established Risk Factors for Pulmonary Complications Urea > 10.7 mmol/L (30 mg/dL) [OR 2.29] Partially or fully dependent [OR 1.92] Age > 70 [OR 1.91] COPD [OR 1.81] Neck, thoracic, upper abdominal, aortic or neurological surgery Prolonged procedures (> 2 hours) Emergency surgery [OR 3.12] Hypoalbuminaemia (< 30 g/L) [OR 2.53] Exercise tolerance < 1 flight of stairs / 100 yards BMI > 30
    33. 33. Dr. Andrew Ferguson VAMC Respiratory Failure Risk Index [Arozullah Ann Surg 2000;232:242-53] Preoperative Predictor Point Value Abdominal aortic aneurysm surgery 27 Thoracic surgery 21 Neurosurgery, upper abdominal, peripheral vascular surgery 14 Neck surgery 11 Emergency surgery 11 Albumin < 30 g/L 9 Urea > 10.7 mmol/L (30 mg/dL) 8 Partially or fully dependent status 7 COPD 6 Age > 70 6 Age 60-69 4 Class Point total N (%) Predicted PRF Actual PRF Phase 1 Actual PRF Phase 2 1 < 10 39,567 (48%) 0.5% 0.5% 0.5% 2 11-19 18,809 (23%) 2.2% 2.1% 1.8% 3 20-27 13,865 (17%) 5% 5.3% 4.2% 4 28-40 7,976 (10%) 11.6% 11.9% 10.1% 5 >40 1,502 (2%) 30.5% 30.9% 26.6%
    34. 34. Pulmonary Hypertension <ul><li>High risk </li></ul><ul><li>ECG & echo </li></ul><ul><li>Disease severity indicators </li></ul><ul><ul><ul><li>SOB at rest </li></ul></ul></ul><ul><ul><ul><li>Metabolic acidosis </li></ul></ul></ul><ul><ul><ul><li>Hypoxaemia </li></ul></ul></ul><ul><ul><ul><li>Right heart failure </li></ul></ul></ul><ul><ul><ul><li>Syncope </li></ul></ul></ul>Dr. Andrew Ferguson
    35. 35. URTI & anaesthesia <ul><li>Mild symptoms - can usually proceed </li></ul><ul><ul><li>huge inconvenience to patient if cancelled </li></ul></ul><ul><li>Severe symptoms or underlying disease </li></ul><ul><ul><li>postpone </li></ul></ul><ul><li>Intermediate severity - ? </li></ul><ul><li>? risk of increased bronchial reactivity </li></ul>Dr. Andrew Ferguson
    36. 36. Sleep-disordered Breathing <ul><li>24% of middle aged men (< 15% diagnosed!) </li></ul><ul><li>OSA - complete obstruction for 10s + </li></ul><ul><li>OH (obstructive hypopnoea) > 4% drop in sats </li></ul><ul><li>CVS disease common </li></ul><ul><li>Berlin Questionnaire </li></ul><ul><ul><ul><li>Snoring </li></ul></ul></ul><ul><ul><ul><li>Daytime sleepiness </li></ul></ul></ul><ul><ul><ul><li>Hypertension </li></ul></ul></ul><ul><ul><ul><li>Obesity </li></ul></ul></ul>2 or more = high risk for OSA Dr. Andrew Ferguson
    37. 37. Periop Medication Management <ul><li>What to stop (suggestions! - discuss with cons) </li></ul><ul><li>What to keep </li></ul><ul><li>What else to give </li></ul>Dr. Andrew Ferguson
    38. 38. Hold on day of surgery <ul><li>Diuretics </li></ul><ul><ul><ul><li>unless thiazide for hypertension </li></ul></ul></ul><ul><ul><ul><li>unless severe heart failure </li></ul></ul></ul><ul><li>Insulin & OHA - see hospital diabetic protocol </li></ul><ul><li>Vitamins & iron </li></ul><ul><li>ACEI’s or ARB’s (individual choice) </li></ul><ul><ul><ul><li>depends on procedure/risk of hypotension </li></ul></ul></ul><ul><li>Hold sildenafil/tadalafil from night before </li></ul>Dr. Andrew Ferguson
    39. 39. Dr. Andrew Ferguson Preop Medicines Management Stop 48 hours pre-op NSAIDs Stop 4 days pre-op Warfarin (convert to enoxaparin) Stop 7 days pre-op Clopidogrel Aspirin 75 mg usually continued (check with consultant) Herbal remedies HRT
    40. 40. Premedication <ul><li>Alleviate anxiety/sedation/amnesia </li></ul><ul><ul><ul><li>e.g. temazepam 10-20 mg, midazolam pre-induction </li></ul></ul></ul><ul><li>Reduce risk of reflux </li></ul><ul><ul><ul><li>e.g. ranitidine/lansoprazole/citrate/metoclopramide </li></ul></ul></ul><ul><li>Manage pain </li></ul><ul><ul><ul><li>e.g. paracetamol, gabapentin, topical LA </li></ul></ul></ul><ul><li>Control perioperative risk </li></ul><ul><ul><ul><li>e.g.  blockade,  -2 agonists </li></ul></ul></ul><ul><li>Dry secretions </li></ul><ul><ul><ul><li>e.g. glycopyrollate </li></ul></ul></ul><ul><li>Decrease anaesthetic requirements </li></ul><ul><ul><ul><li>e.g. clonidine </li></ul></ul></ul>Dr. Andrew Ferguson
    41. 41. Fasting Guidelines Dr. Andrew Ferguson Time before anaesthesia Food or fluid intake Up to 8 hours Unrestricted Up to 6 hours Light meal Up to 4 hours Breast milk Up to 2 hours Clear liquids only (no solids, no fat) 2 hours pre-anaesthesia Nothing permitted

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