PREOPERATIVE ASSESSMENT

CONTENTS

1. Objectives

2. Preop assessment, where & when?

3. Recommended preoperative investigations

4. Fasting guidelines

5. Premedication

6. Medications

7. Summary

OBJECTIVES

1. Confirmation of pt identification, review of diagnosis & proposed procedure

2. Thorough history: - medical history e.g: IHD, HPT, DM - surgical related history - anaesthetic - drug

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

OBJECTIVES

PREVIOUS ANAESTHETIC HISTORY difficult airway PONV Malignant hyperthermia allergies difficult IV access awareness death following anaesthesia in the family

OBJECTIVES

DRUG HISTORY

- very useful, often forgotten Current medications Smoking/alcohol history History of allergy Medic alert bracelets Other drugs abuse

OBJECTIVES

3. Thorough Physical Examination: i) General examination:- General – mental status, body weight

- CVS – blood pressure, heart murmur

- RS - abnormal breathing sounds

- GI - abnormal masses, previous scar

OBJECTIVES

Musculoskeletal – kyphoscoliosis

Skin – local skin infection especially at thoracolumbar area

Neurological – peripheral neuropathy

OBJECTIVES

ii) Specific examination

- directed to the disease

e.g: cardiovascular disease

young HPT – look for sign for secondary

causes

OBJECTIVES

4. Optimization of patient’s medical condition for anaesthesia

-e.g: uncontrolled blood sugar/hypertension in diabetic patients

OBJECTIVES

5. Airway assesment

- certain features of concern

obesity

limited mouth opening

poor dentition

limited neck mobility

scars/ surgery/ anatomical abnormalities

neck mass

mallampati scoring

MALAMPATI SCORING

FEATURES OF DIFFICULT INTUBATION

OBJECTIVES

6. Classify physical status

ASA grading (American Society of Anesthesiologists)

Functional capacity

ASA GRADING

• Medical co-morbidity increases the risk associated with anaesthesia and surgery

• ASA grading is the most commonly used grading system

• ASA accurately predicts morbidity and mortality

ASA Grade  

Definition   Mortality (%)  

I Normal healthy individual   0.05

IIMild systemic disease that does not limit activity   0.4

IIISevere systemic disease that limits activity but is not incapacitating   4.5

IVIncapacitating systemic disease which is constantly life-threatening  

25

V Moribund, not expected to survive 24 hours with or without surgery  

50

Application of ASA Grading

Cardiovascular disease

ASA Grade 2 ASA Grade 3

Angina Occasional use of GTN. 

Regular use of GTN or unstable angina

HypertensionWell controlled on single agent

Poorly controlled.  Multiple drugs

Diabetes Well controlled.  No complications

Poorly controlled or complications

Respiratory disease

ASA Grade 2 ASA Grade 3

COPD Cough or wheeze.  Well controlled

Breathless on minimal exertion

Asthma Well controlled with inhalers

Poorly controlled  limiting lifestyle

• This is a measure of the metabolic demands of various daily activities on the heart

• For e.g: a patient who was breathless at rest, or after walking a short distance, would have a low functional capacity, which is a predictor of increased risk

Functional Capacity

• Poor functional capacity is associated with increased cardiac complications in noncardiac surgery.

• A patient's functional capacity can be expressed in metabolic equivalents (METs).

• One MET equals the oxygen consumption of a 70-kg, 40-year-old man in a resting state

Functional Capacity

Functional Status Assessment

Excellent (>7 METs)

Moderate (4 to 7 METs) Poor (<4 METs)

Squash Jogging (10-minute mile) Scrubbing floors Singles tennis

Cycling, Climbing a flight of stairs Golf (without cart)Walking 4 mph Yardwork (e.g., raking leaves, weeding, pushing a power mower)

Vacuuming Activities of daily living (e.g., eating, dressing, bathing) Walking 2 mph Writing

OBJECTIVES

7. Planning of anaesthetic technique, perioperative care & pain management

8. Clarification with surgeon if required

9. Obtain consent

- anaesthesia

- surgical

- blood transfusion

ANAESTHETIC DISCLOSURE AND CONSENT

- Planned anaesthetic procedure- Anaesthetic options if applicable - Possible risks & complications pertaining to

anaesthesia- Benefit vs risks of each technique- High risk consent with possible ICU admission

ANAESTHETIC CONSENT

- For underaged patient, obtain from parent/ guardian

- Discussion should be documented

OBJECTIVES

10. Establishment of rapport

- reduce anxiety & facilitate conduct of anaesthesia

11. Give instruction on medications, time of fasting

12. Prescription of premedicant drugs

PREOPERATIVE ASSESSMENTWhere & when ?

1. Elective surgery

- assessment done either in pre-anaesthetic clinic or ward

- advantages of early referral• Allows preoperative optimization• Reduces risk of unnecessary cancellation• Appropriate lab investigation can be done &

reviewed

2. Emergency surgery ill patient will be assessed in the ward

prior to surgery

May need ICU admission preoperatively for stabilization

RECOMMENDED PREOPERATIVE INVESTIGATIONS FBC- Age above 60- Clinical anaemia- Haematological disease- Renal disease- Chemotherapy- Procedures with blood loss > 15%

Renal profile- Age > 60- Renal ds- Liver ds- DM- Cardiovacular disease- Procedures with blood loss >15%

RECOMMENDED PREOPERATIVE INVESTIGATIONS ECG- Age > 50- Cardiovascular disease- DM- Renal disease

CXR- Age > 60- Signs of significant respiratory disease- Cardiovascular disease

RECOMMENDED PREOPERATIVE INVESTIGATIONS Coagulation profile- Haematological disease- Liver disease- Anticoagulations- Intrathoracic/ intracranial procedures

RBS- Age > 60- DM- Liver dysfunction

RECOMMENDED PREOPERATIVE INVESTIGATIONS Liver function test- Hepatobiliary disease- Alcohol abuse

RECOMMENDED PREOPERATIVE INVESTIGATIONS

OTHER SPECIFIC INVESTIGATIONS

1. ABG

2. Lung function test

3. Thyroid function test

FASTING GUIDELINES

ADULTS SOLID FOOD 6H

PAEDS CLEAR FLUID 2H

BREAST MILK 4H

FORMULA MILK/

SOLID 6H

PREMEDICATION

1. NO SEDATIVE PREMED

- ill, septic, elderly

- potential diff airway

- day care surgery

- most neurosurgical pts

- neonates & infants < 6 month

PREMEDICATION

2. ORAL BENZODIAZEPINE (e.g midaz)

- most elective pts

- night & before sending to OT

PREMEDICATION

3. PAED PTS- Omit premed in ill babies, neonates & infants

< 6 month esp prem babies- Syrup midazolam 0.2 mg/kg- EMLA cream

PREMEDICATION

4. OBSTETRIC PTS- Oral ranitidine 150mg ON & morning of op- 0.3M sodium citrate 30 ml- Iv metoclopramide 10 mg

5. PTS AT RISK OF ASPIRATION

Prophylaxis vs acid aspiration- H2 receptor antagonist e.g ranitidine- Proton-pump Inhibitor e.g omeprazole

PREMEDICATION

- Non particulate antacids e.g 0.3M sodium citrate

- Gastrokinetic agents e.g metoclopramide

MEDICATIONS

Take all usual medications- Antihypertensives- β blocker- Statins

Think about discontinuing/ replacing- Aspirin- Anticoagulants- Diabetic medications- MAOIs

SUMMARY

Preoperative assessment is very important History and physical examination are most

important assessor of disease and risk ASA and functional status are good predictors

of risk Lab tests are useful and ordered when

indicated