Anaesthesiology - Pre-operative assessment Flashcards

1
Q

Define checklist for pre-operative assessment clinic (PAC) (Day 0 - Day of surgery)

A

Aim of pre-op assessment
* Formulate anaesthetic plan + analgesic regimen
* Optimize patient condition
* Determine fitness for surgery
* Decide post-op placement
* Plan fasting, premedication
* Establish rapport

Consist of:
* Taking a history (past and present) from patient, relatives, care-provider
* Physical examination
* Order/review appropriate investigation
* Explain anaesthetic plan
* Obtain consent with explanation of risks

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2
Q

List basic physical exams for pre-operative assessment

A

Airway assessment (including oro-facial exam)

Full respiratory exam

Full circulatory and cardiac exam

Sites of vascular access

Other system exams if chronic disease

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3
Q

Define CVS history relevant to pre-operative assessment

A

Primary disease and end organ involvement, enquire specifically about symptoms of:
* Ischemic heart disease, frequency + severity + predictability of angina
* Heart failure-increased risk of peri-op cardiac morbidity + mortality
* HT-treatment and control
* Valvular heart disease - AS in elderly, congenital heart disease into adulthood
* Conduction defects, arrhythmias
* PVD, previous DVT, PE
* PCI/pacemaker/anticoagulants

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4
Q

Define CVS risk factors associated with poor surgery outcome

A

Previous history of MI: further infarction, peri-op risks decreases as time elapsed since original event

Uncomplicated MI with normal exercise tolerance: elective surgery may need to be delayed by 6-8weeks

Complicated MI, infarction, residual angina, arrhythmias: need cardiac assessment before exam

Hypertention:
* Moderate SBP 160-179 mmhg, DBP 100-109 mmHg: consider review of treatment. If unchanged requires close monitoring to avoid swings during surgery and anaesthesia
* Severe SBP > 180 mmHg, DBP > 109 mmHg: postpone elective surgery until lower than 180/110 because risk of myocardial ischemia, arrhythmias + Intracranial haemorrhage

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5
Q

Define respiratory diseases relevant to pre-operative assessment

A

Asthma, COPD, infection, restrictive lung disease: increase risk of peri-operative chest infection

Acute URTI: anaesthesia and
surgery may be postponed unless it is a life threatening condition

Smoking: higher risk of post-op. respiratory crises

OSA: increase risk of respiratory depression

Assess exercise tolerance: Prediction of post-op morbidity and mortality
- Subjective measurement: e.g. Can you run for a bus? Can you do housework?
- Objective measurement: metabolic equivalents of
activity (MET); New York Heart Association (NYHA) classification of cardiac function of specific activity scale

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6
Q

Outline Metabolic Equivalent of Activity (MET)

A
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7
Q

Outline the New York Heart Association (NYHA) classification of cardiac function of specific activity scale

A
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8
Q

List chronic diseases associated with adverse outcome in surgery (excluding cardiovascular and respiratory diseases)

A
  • Indigestion, GERD: increase risk of regurgitation and aspiration pneumonia)
  • Rheumatoid arthritis: difficult to position deformed joints, C-spine subluxation affects airway, chronic anemia, S/E from drugs
  • DM: IHD, renal dysfunction, neuropathies, infection, orthostatic hypotension
  • Neuromuscular diseases: chest infection, poor bulbar function cause aspiration
  • Chronic renal failure: anemia, electrolyte abnormality, altered drug excretion
  • Hepatic diseases: coagulopathy, opioid metabolism
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9
Q

Relevant anesthetic history in pre-operative assessment

Relevant family history

A

Prior problem with anaes:
- Nausea and vomiting, awareness, jaundice, delayed recovery,
prolonged hypotension
- History of difficult intubation
- History of delayed recovery
- Difficult IV access, bleeding
- Potential anaes. access problems e.g. cardiac/pulmonary/spine

Family history:
- MH, Psuedocholinesterase deficiency, previous ICU admission

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10
Q

Relevant drug and allergy history in pre-operative assessment

A

Smoking: decreases ciliary function
 Stopping 8 weeks improve airway
 Stopping 2 weeks decreased airway irritability
 Stopping 2 days decreases CO level

Alcohol
 Enzyme induction-drug tolerance
 Post-op alcohol withdrawal syndrome

Drug abuse
 Difficult IV
 HBV, Hep B, Hep C carrier
 Drug withdrawal syndrome post-op (cocaine)

Pregnancy
 X Ray in first trimester
 First trimester-greater chance of abortion (though risk of spontaneous abortion is high, elective suxamethonium use during second trimester)
 increased risk of regurgitation and aspirations due to increased intra-abdominal pressure and delayed gastric emptying

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11
Q

Define the American Society of Anaesthesiologist
Classification for surgical outcome

A

Correlates well with outcome
1. A normal healthy patient
2. A patient with mild systemic disease
3. A patient with severe systemic disease
4. A patient with severe systemic disease that is a constant threat to life
5. A moribund patient who is not expected to survive without the
operation

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12
Q

Outline the anesthetic pre-operative management plan

A
  • Fasting: reduce gastric content and risk of aspiration
     Clear fluids 2hrs
     Breast milk 4hrs
     Light meal 6hrs
  • Define type of anaesthetic and consent
  • Any consultation + extra investigations of medical diseases
  • Adjust ongoing medications
  • Premedication
  • Post-operative placement deoending on:
     premorbid status
     nature and length of operation
     intraop and postop events
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13
Q

Plans to reduce regurgitation/ aspiration

A

 assert fasting time

 non diabetic patient: drinking fluids with carbohydrate and protein up to 2hrs before GA induction suffer less pre-op nausea and dehydration

 Rapid sequence intubation for emergency/ high-risk patients

 prophylaxis -chemical control of gastric volume and acidity for pt. with frequent GERD symptoms:
a. antacids-neutralize acidity
b. H2 blockers/PPI - decreases stoma acidity
c. metoclopramide-seldom used for gastric motility
d. NG tube suction

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14
Q

List pre-medications given during pre-operative preparation

A
  • Pain relief: IV Midazolam, Fentanyl/ ketamine; Acetaminophen, Gabapentine for post-op pain
  • Sedation, anxiolysis: Oral/ IV Midazolam, Nasal Dexmetomidine
  • DVT prophylaxis
  • Regurgitation and aspiration prophylaxis: Antacids, H2 blockers, PPI, Metoclopromide, Anti-emetics
  • Drug and pre-existing disease – DM, HT, herbal medicine, psychiatric drugs, drug abuse, anti-coagulants
  • Airway maniputation: Glycopyrolate (inhibit salivary gland and respiratory secretions)
  • Pacemaker programming
  • EMLA cream for paeds
  • Second trimester pregnancy: Sodium citrate+H2 blockers
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15
Q

Aims of pre-operative assessment

A
  1. Reduce hospital stay, bed occupancy, economic and psychological impact
  2. Identify patient’s at low risk of complications during anaesthesia and surgery - ASA 1, 2 patients, uncomplicated surgery - as day surgeries
  3. Identify medical problems and improve management/ investigations
  4. Reduce cancellation of intended surgery after admission due to fitness/ medical problems
  5. Obtain consetn

Time between surgery and PAC should not exceed 3 months (4 - 6weeks optimal)

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16
Q

List common, uncommon and rare risks of anesthesia

A

Common:
 bruising and attempts at IV access
 sore throat
 headache
 dizziness
 PONV
 itching(opioids)
 retention of urine

Uncommon:
 dental damage
 chest infection
 muscle pain (positioning, Suxamethonium rarely used except in emergency)
 an existing condition worsened-myocardial infarct, heart failure
 awareness during GA

Rare:
 allergy to anaesthetic drugs
 eye injury-particularly if prone
 nerve damage (tourniquet, surgery, positioning, regional)
 hypoxic brain damage
 death (most commonly Myocardial Infarction)

17
Q

Pre-requisites of valid consent

A

Any breach of a patient’s personal integrity including examination, invasive investigation, giving
an anaesthetic needs consent.

All people aged 16 or over are presumed by law to have capacity to consent unless there is
evidence to the contrary

5 pre-requisites
 understand what and why it is being proposed
 understand the benefits, risks and any alternatives
 understand the consequences of not receiving what is being proposed
 retain the information long enough to arrive at a decision
 be able to communicate their decision

18
Q

Conditions that require consent review

A
  • Reaffirmed if > 3 months since informed consent
  • Mental disorder/impairment (require
    psychology consultation)
  • Temporary incapacity from drug/alcohol intoxication, severe pain, shock
  • Minor, dementia, coma require 2 MO consent
  • Valid advanced refusal - Johovah witness

In these cases, consent can be given by:
* Welfare attorney, court appointed deputy, guardian