Transcript Pre-operative evaluation and preparation (prior to procedure under

Aishah
Awatif
Haziq
Introduction
Anaesthesia = absence of all sensation
 Analgesia = absence of pain
 General anaesthesia = a state where all
sensation is lost and the patient is
rendered unconscious by drugs.
 GA should be performed by qualified
anasthetists in a hospital setting with
access to appropriate medical support.
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Assessment of risk
Patient should be made as fit as
possible for the operation.
 The anticipated benefit should outweigh
the anesthetic and surgical risks
involved.
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Overall mortality rate ≈ 1 in 100 000
 Surgical mortality ≈ 1 in 1000
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Factors contribute to this mortality:
 Poor preoperative assessment
 Inadequate supervision and monitoring in
the intraoperative period
 Inadequate postoperative care
Aims of Pre-operative evaluation
and preparation
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To provide diagnostic & prognostic information.
To ensure the patient understands the nature,
aim, and expected outcome of surgery.
To relieve anxiety and pain.
Ensure that the right patient gets the right
surgery.
Get informed consent.
Assess/balance risks of anaesthesia ans
maximize fitness.
Check anaesthesia/analgesia type with
anesthesia.
Preoperative assessment
and premedication
History
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Past medical history:
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Asthma
Diabetes
Tuberculosis
Seizures
Chronic organ dysfunction
HIV infection
Drug allergy
DVT
Post-operative nausea and vomiting
Drug history
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Drug interactions
 Anticoagulant might be contraindicated to
spinal, epidural or other regional techniques
 Anticonvulsants might increase the
requirements for anasthetic agents,
enflurane should be avoided as it might
precipitate seizures
 Beta-blockers – negative ionotropic effect –
hypotension
 Corticosteroids – extra cover might be
needed
 Diuretics – might have hypokalaemia
 Insulin – careful monitoring of plasma
glucose
 Antibiotics: tetracycline and neomycin may ↑
neuromuscular blockade.
Social history
Ceasing smoking 12h before surgery
can improve the oxygen carrying
capacity of the blood.
 Excessive alcohol – hepatic and cardiac
damage
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Family history
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Hereditary traits:
 Haemophilia
 Porphyria
 Cholinesterase abnormalities – prolongation
of muscle relaxants such as suxamethonium
Physical examination
Assess cardiorespiratory system, exercise
tolerance, existing illness, drugs, and
allergies.
 Is the neck unstable (eg; arthritis
complicating intubation?)
 Assess past history of; MI, diabetes,
asthma, hypertension, rheumatic fever,
epilepsy, jaundice.
 Assess any specific risk, eg is the patient
pregnant? Is the neck/jaw immobile and
teeth stable (intubation risk)?
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Has there been previous anaesthesia?
 Were there any complications (eg
nausea, DVT)?
 Is DVT/PE prophylaxis needed?
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Per-op investigation of
elective patients
Indications of preoperative
investigations
 Full blood count
 anaemia
 females post menarche
 cardiopulmonary disease
 possible haematological pathology, e.g.
 haemoglobinopathies
 likelihood of significant intraoperative blood loss
 history of anticoagulants
 chronic diseases such as rheumatoid disease
 Clotting
screen
 liver disease
 anticoagulant drugs or a history of bleeding or
 bruising
 kidney disease
 major surgery
 Urea
and electrolyte concentrations
 major surgery >40 years
 kidney disease
 diabetes mellitis
 digoxin, diuretics, corticosteroids, lithium
 history of diarrhoea and vomiting
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Liver function tests: these will be carried out
when there
 is any suspicion of liver disease
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ECG
 >40 years asymptomatic male or >50 years
asymptomatic female
 history of myocardial infarction or other heart or
vascular disease
 <40 years with risk factors e.g. hyperlipidaemia,
diabetes mellitus, smoking, obesity, hypertension and
cardiac medication
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Chest radiography
 breathlessness on mild exertion
 suspected malignancy, tuberculosis or chest infection
 thoracic surgery
American Society of Anesthesiologists
(ASA) classification
Class I
Normally healthy
Class II
Mild systemic disease
Class III
Severe systemic disease that limits
activity but is not incapacitating
Class IV
Incapacitating systemic disease
which poses a constant threat to
life
Moribund: not expected to survive
24h even with operation
Class V
Pre-op therapy
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Pt with respiratory disease –
physiotherapy or bronchodilator therapy
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Infective endocarditis – prophylactic
antibiotic
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Hypertension – adjustment of drug
therapy to obtain optimal control
(diastolic pressure below 110 mmHg)
Postponement of surgery
Pt with acute upper resp tract infection
 Cardiac/endocrine diseases that are not
yet under optimal control
 Elective surgery should not be
undertaken unless:
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 Pt has fasted for 6h for solid food, Infant
formula or other milk
 4h for breast milk
 2h for clear non-particulate and noncarbonated fluids
Pre-medication
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benzodiazepines – anxiolysis, anterograde
amnesia
Anticholinergic drug – reduce excessive
secretions in the airway
Antiemetic
Antihistamine
Metoclopramide - enhance gastric
emptying
Sodium citrate, H2 blockers, proton pump
inhibitor – reduce gastric acidity
Preparation for anesthesia
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Fast patient.
 Nil by mouth ≥ 2h pre-op for clear fluid and ≥
6h for solids
Is there any bowel or skin preparation
needed, or prophylactic antibiotic?
 Start DVT prophylaxis as indicated, eg:
graduated compression stockings +
heparin 5000U sc 2h pre-op, then every
8-12h sc for 7d or until ambulant.
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Write up the pre-meds; book any pre-,
intra-, or post-operative x-rays or frozen
sections. Book post-op physiotherapy.
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If needed, catheterize and insert Ryle’s
tube before induction. These can reduce
organ bulk, making it easier to operate
in the abdomen.