Preoperative Assessment & Premedication Craigavon Area Hospital CT1 Education Series (Intro) Dr. Andrew Ferguson

Overview Setting the scene Preoperative testing Components of the preoperative visit History & Physical Examination [emphasis on Airway] Introduction to organ-specific issues Evaluating Cardiovascular Disease Evaluating Respiratory Disease Perioperative Medication Management Stopping patient medications….or not Premedication Fasting Dr. Andrew Ferguson

Setting the scene

Preoperative testing

Components of the preoperative visit

History & Physical Examination [emphasis on Airway]

Introduction to organ-specific issues

Evaluating Cardiovascular Disease

Evaluating Respiratory Disease

Perioperative Medication Management

Stopping patient medications….or not

Premedication

Fasting

Pre-op Assessment - AAGBI Guidance (2001) The anaesthetist is uniquely qualified to assess risk i s responsible for deciding fitness for anaesthesia must see all patients before operation The aim of assessment is to improve outcome Blanket pre-op investigations waste resources & time Dr. Andrew Ferguson

The anaesthetist

is uniquely qualified to assess risk

i s responsible for deciding fitness for anaesthesia

must see all patients before operation

The aim of assessment is to improve outcome

Blanket pre-op investigations waste resources & time

Goals of assessment Screen for and manage co-morbid disease To assess and minimise risks of anaesthesia To identify need for specialised techniques To identify need for advanced post-op care To educate about anaesthesia To obtain informed consent To avoid unnecessary delays/cancellations To motivate patients to improve pre-op Dr. Andrew Ferguson

Screen for and manage co-morbid disease

To assess and minimise risks of anaesthesia

To identify need for specialised techniques

To identify need for advanced post-op care

To educate about anaesthesia

To obtain informed consent

To avoid unnecessary delays/cancellations

To motivate patients to improve pre-op

Preoperative Assessment Systems Screening questionnaire (F2F, online, PC) Preoperative assessment clinic nurse led consultant supported coordinates availability of information coordinates preoperative investigations Preoperative visit Dr. Andrew Ferguson

Screening questionnaire (F2F, online, PC)

Preoperative assessment clinic

nurse led

consultant supported

coordinates availability of information

coordinates preoperative investigations

Preoperative visit

Pre-operative Testing Only when indicated from history/examination, or based on surgical plan ECG for example Abnormal in 62% of patients with known cardiac disease Abnormal in 44% of patients with strong IHD risk factors Abnormal in 7% of over-50s with no risk factors Abnormal in 3% of 50-70 year olds with no risk factors New Q waves or arrhythmias < 2% Limited use as predictor of outcome - may alter plan Dr. Andrew Ferguson

Only when indicated

from history/examination, or

based on surgical plan

ECG for example

Abnormal in 62% of patients with known cardiac disease

Abnormal in 44% of patients with strong IHD risk factors

Abnormal in 7% of over-50s with no risk factors

Abnormal in 3% of 50-70 year olds with no risk factors

New Q waves or arrhythmias < 2%

Limited use as predictor of outcome - may alter plan

NICE CG3 (2003) Dr. Andrew Ferguson

Dr. Andrew Ferguson

Dr. Andrew Ferguson

Dr. Andrew Ferguson

Dr. Andrew Ferguson

Dr. Andrew Ferguson

Dr. Andrew Ferguson

Pre-op Testing Schema Example Dr. Andrew Ferguson

ASA Minimum Pre-op Visit Components Medical, anaesthesia and medication history Appropriate physical examination Review of diagnostic data (ECG, labs, x-rays) Assignment of ASA physical status Formulation and discussion of anesthesia plan Dr. Andrew Ferguson

Medical, anaesthesia and medication history

Appropriate physical examination

Review of diagnostic data (ECG, labs, x-rays)

Assignment of ASA physical status

Formulation and discussion of anesthesia plan

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

History Medical problems (current & past) Previous anaesthesia & related problems Family anaesthesia history Allergies and drug intolerances Medications, alcohol & tobacco Review of systems (include snoring and fatigue) Exercise tolerance and physical activity level Dr. Andrew Ferguson

Medical problems (current & past)

Previous anaesthesia & related problems

Family anaesthesia history

Allergies and drug intolerances

Medications, alcohol & tobacco

Review of systems (include snoring and fatigue)

Exercise tolerance and physical activity level

Dr. Andrew Ferguson

Physical Examination Minimum requirements Airway Heart & lungs Vital signs including O 2 saturation Height & weight (BMI) Dr. Andrew Ferguson

Minimum requirements

Airway

Heart & lungs

Vital signs including O 2 saturation

Height & weight (BMI)

Airway Examination Teeth and bite Ability to protrude lower incisors beyond upper Mouth opening (inter-incisor distance) Mallampati score Facial hair Thyromental distance Length & thickness of neck Range of motion of head & neck Dr. Andrew Ferguson

Teeth and bite

Ability to protrude lower incisors beyond upper

Mouth opening (inter-incisor distance)

Mallampati score

Facial hair

Thyromental distance

Length & thickness of neck

Range of motion of head & neck

Mallampati & Samsoon Score Dr. Andrew Ferguson

Mallampati Class 1 !!!! Dr. Andrew Ferguson

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

Cormack & Lehane Score 1 2 3 4 Dr. Andrew Ferguson

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

Evaluating Cardiac Disease Ischaemic heart disease Heart failure Arrhythmia Abnormal ECG Undiagnosed murmur Pacemaker or IACD Dr. Andrew Ferguson

Ischaemic heart disease

Heart failure

Arrhythmia

Abnormal ECG

Undiagnosed murmur

Pacemaker or IACD

CVS evaluation for non-cardiac surgery Dr. Andrew Ferguson

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

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

Arrhythmias/ECG abnormalities Further work-up or therapy needed New onset AF Symptomatic bradycardia High-grade heart block (2 nd or 3 rd degree) Uncontrolled AF VT Prolonged QT New LBBB RBBB with right precordial ST elevation (Brugada) Dr. Andrew Ferguson

Further work-up or therapy needed

New onset AF

Symptomatic bradycardia

High-grade heart block (2 nd or 3 rd degree)

Uncontrolled AF

VT

Prolonged QT

New LBBB

RBBB with right precordial ST elevation (Brugada)

Pacemakers/IACD Determine type Determine features Pacemaker check/interrogation pre-op Disable rate-adaptive mechanisms Disable anti-tachyarrhythmia functions Magnet not recommended for modern devices Dr. Andrew Ferguson

Determine type

Determine features

Pacemaker check/interrogation pre-op

Disable rate-adaptive mechanisms

Disable anti-tachyarrhythmia functions

Magnet not recommended for modern devices

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

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%

Pulmonary Hypertension High risk ECG & echo Disease severity indicators SOB at rest Metabolic acidosis Hypoxaemia Right heart failure Syncope Dr. Andrew Ferguson

High risk

ECG & echo

Disease severity indicators

SOB at rest

Metabolic acidosis

Hypoxaemia

Right heart failure

Syncope

URTI & anaesthesia Mild symptoms - can usually proceed huge inconvenience to patient if cancelled Severe symptoms or underlying disease postpone Intermediate severity - ? ? risk of increased bronchial reactivity Dr. Andrew Ferguson

Mild symptoms - can usually proceed

huge inconvenience to patient if cancelled

Severe symptoms or underlying disease

postpone

Intermediate severity - ?

? risk of increased bronchial reactivity

Sleep-disordered Breathing 24% of middle aged men (< 15% diagnosed!) OSA - complete obstruction for 10s + OH (obstructive hypopnoea) > 4% drop in sats CVS disease common Berlin Questionnaire Snoring Daytime sleepiness Hypertension Obesity 2 or more = high risk for OSA Dr. Andrew Ferguson

24% of middle aged men (< 15% diagnosed!)

OSA - complete obstruction for 10s +

OH (obstructive hypopnoea) > 4% drop in sats

CVS disease common

Berlin Questionnaire

Snoring

Daytime sleepiness

Hypertension

Obesity

Periop Medication Management What to stop (suggestions! - discuss with cons) What to keep What else to give Dr. Andrew Ferguson

What to stop (suggestions! - discuss with cons)

What to keep

What else to give

Hold on day of surgery Diuretics unless thiazide for hypertension unless severe heart failure Insulin & OHA - see hospital diabetic protocol Vitamins & iron ACEI’s or ARB’s (individual choice) depends on procedure/risk of hypotension Hold sildenafil/tadalafil from night before Dr. Andrew Ferguson

Diuretics

unless thiazide for hypertension

unless severe heart failure

Insulin & OHA - see hospital diabetic protocol

Vitamins & iron

ACEI’s or ARB’s (individual choice)

depends on procedure/risk of hypotension

Hold sildenafil/tadalafil from night before

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

Premedication Alleviate anxiety/sedation/amnesia e.g. temazepam 10-20 mg, midazolam pre-induction Reduce risk of reflux e.g. ranitidine/lansoprazole/citrate/metoclopramide Manage pain e.g. paracetamol, gabapentin, topical LA Control perioperative risk e.g.  blockade,  -2 agonists Dry secretions e.g. glycopyrollate Decrease anaesthetic requirements e.g. clonidine Dr. Andrew Ferguson

Alleviate anxiety/sedation/amnesia

e.g. temazepam 10-20 mg, midazolam pre-induction

Reduce risk of reflux

e.g. ranitidine/lansoprazole/citrate/metoclopramide

Manage pain

e.g. paracetamol, gabapentin, topical LA

Control perioperative risk

e.g.  blockade,  -2 agonists

Dry secretions

e.g. glycopyrollate

Decrease anaesthetic requirements

e.g. clonidine

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