Manual of Anaesthesia Arun Kumar Paul
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Preanaesthetic EvaluationCHAPTER 1

 
OBJECTIVES
  1. History and physical examination of the patient
  2. To review medical records including past anaesthetic records
  3. To get laboratory studies
  4. To determine physical status and anticipate difficulties
  5. For planning of anaesthesia management
  6. To ensure obtaining consent
  7. To develop anaesthetist-patient rapport
  8. To make advanced preparation relating facilities, equipment and expertise, to enhance patient safety and minimise the chance of errors.
 
HISTORY
  1. Patient's medications: Aspirin, insulin, antihypertensives, MAO inhibitors, lithium, anticoagulants, etc.
  2. Any allergy
  3. Past hospitalisation, any anaesthesia/operation
  4. Family history
  5. Any addiction: Smoking, alcohol, drugs
  6. Any associated illness: Metabolic, endocrinal, renal, hepatic, cardiac, pulmonary disease, sexually transmitted disease, hepatitis, HIV
  7. Menstrual history in case of females.
 
ASSOCIATED ILLNESS NEEDING FURTHER INVESTIGATIONS
  1. Central nervous system: Cerebrovascular insufficiency, convulsion.
  2. Cardiovascular system: Chest pain, myocardial infarction, hypertension, rheumatic fever, palpitations, dysrhythmias.
  3. Respiratory system: Dyspnoea, cough, bronchospasm, pneumonia, smoking, upper respiratory infection.
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  4. Liver: Alcoholism, hepatitis, jaundice
  5. Kidney: Polyuria, pyuria
  6. Endocrine system: Diabetes mellitus, adrenal dysfunction, thyroid dysfunction.
  7. Miscellaneous: Allergy, bleeding tendency, myalgia, arthritis, osteoporosis, strabismus, etc.
 
COMMON MEDICATIONS AND ANAESTHETIC IMPLICATIONS
  1. Aspirin: Bleeding tendency, platelet dysfunction
  2. Alcohol abuse: Resistance to anaesthetic drugs
  3. Antibiotics: Potentiation of muscle relaxants
  4. Antihypertensives: Impaired sympathetic nervous system activity, hypertensive crisis
  5. Beta blockers: Bradycardia, bronchospasm
  6. Benzodiazepines: Potentiation of muscle relaxants, resistance to anaesthetic drugs
  7. Calcium channel blockers: Interaction with muscle relaxants, hypotension
  8. MAO inhibitors: Increased response to sympathomimetic drugs
  9. Lithium: Potentiation of muscle relaxants, impaired thyroid function
  10. Digitalis: Dysrhythmias
  11. Diuretics: Hypotension, hypovolaemia, hypokalaemia
  12. Anticoagulant therapy: Excessive bleeding.
 
PHYSICAL EXAMINATION
  1. Vital signs: Pulse, respiration, blood pressure, body temperature
  2. General: Weight, weakness
  3. Airway examination:
    Cervical spine: head mobility, Mobility of temporomandibular joint, Teeth : Central incisor prominency, Artificial teeth, if any, loose teeth, Attempt of visualise uvula, any lesion in mouth, hyromental distance (Normal more than 6.5 cm)
    Nose and throat: Sore throat, sinusitis, epistaxis, deviated nasal septum, dysphagia, sunken cheeks, patency of nares opening of mouth. Appearance of neck (long or short).
  4. Respiratory: Breathing rate and pattern, any moist sound, wheezing, cough, sputum, emphysema, pneumonia, tuberculosis, bronchitis.
  5. Cardiac: Heart rate, rhythm, murmur, blood pressure, pulse, peripheral oedema, dyspnoea, orthopnoea, veins, heart failure.
  6. Central nervous system: Level of consciousness, numbness, paralysis, skeletal muscle dysfunction, convulsion.
  7. Gastrointestinal system: Nausea/vomiting, constipation, diarrhoea, jaundice, hepatitis.
  8. Haematologic: Bruising, anaemia, bleeding.
  9. Endocrine system: Diabetes, thyroid dysfunction.
  10. Urinary system: Nocturia, dysuria, haematuria, incontinence.
  11. Prosthesis, if any: Eye glasses, contact lens, hearing aid, ornaments, ring
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  12. Miscellaneous: Examination of eye; examination of ear, extremities: Claudication, thrombophlebitis, arthritis; skin examination: rashes, wounds, infection; psychiatric problems, anxiety.
    • Breath holding test: It is the time to hold his breath after full inspiration. Normal more than 25 seconds. Less than 15 seconds indicates severely diminished cardiorespiratory reserve.
    • Match test: Patient is asked to blow off the lighted match stick with his open mouth at a distance 15 cm. Failure indicates low maximum breathing capacity.
 
PREOPERATIVE DIAGNOSTIC INVESTIGATIONS
  1. Blood examination
    TC, DC, haemoglobin, haematocrit
  2. Blood biochemistry
    Glucose, urea, nitrogen, creatinine, electrolytes, liver enzymes
  3. Urine analysis
  4. Coagulation studies
    Prothrombin time, platelet count, partial thromboplastin time
  5. Chest X-ray
  6. Electrocardiogram
  7. Pulmonary function tests
    FEV1, vital capacity, peak expiratory flow rate
    Arterial blood gas study, pH
    [Normal Values :
    Vital capacity 5 lits.
    FEV1 4 lits.
    PEFR 600 lits/min.
    PaO2 75 to 100 mm Hg.
    PaCO2 36 to 46 mm Hg. ]
 
ASA PHYSICAL STATUS INDEX
Grade 1: Normal healthy patient
Grade 2: Patient with mild/moderate systemic disease
Grade 3: Patient with severe systemic disease that causes functional limitation
Grade 4: Patient with incapacitating systemic disease that causes a constant threat to life
Grade 5: Moribund patient not expected to survive 24 hours without operation
Emergency Operation E: Any patient in whom emergency operation is required. Here the suffix E is added.
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FACTORS FOR SELECTION OF ANAESTHETIC TECHNIQUE
  1. Safety of the patient
  2. Coexisting systemic disorders
  3. Site of operation
  4. Elective or emergency procedure
  5. Age of the patient
  6. Preference of the patient, if any
  7. Ability of the anaesthetist concerned
  8. Convenience of the surgeon.
 
PREANAESTHETIC ROUTINE PREPARATION
  1. Psychological support, reassurance
  2. No food/drink for at least 6 hours before anaesthesia
  3. Urinary bladder should be emptied before taken to OT
  4. False teeth, artificial limbs, artificial eyes, contact lenses, shoes, ornaments, etc. should be taken off
  5. No tight clothing, no lipstick, no nail vernish
  6. Adequate oral hygiene
  7. Identification label should be checked
  8. Consent for anaesthesia/surgery is mandatory
  9. Resuscitative drugs, fluids, etc.
  10. Night sedation
  11. Preanaesthetic medication. It should be given in adequate dose and at proper time.
  • No routine preparation is needed in extreme emergencies:
    1. Rupture of major vessels
    2. Severe obstetric emergencies: ectopic rupture
    3. Acute upper airway obstruction
    4. Surgery on patients trapped and immobile.
 
COMMON CAUSES OF POSTPONEMENT OF OPERATION
  1. Acute respiratory infection
  2. Coexisting systemic illness not under optimal control
  3. Lack of adequate resuscitation
  4. Full stomach
  5. Nonavailability of written consent
  6. Failure to obstain recent investigation reports.
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ROUTINE REQUIREMENT BEFORE INDUCTION OF ANAESTHESIA
  1. Anaesthesia machine
    • Anaesthesia breathing system
    • Gas cylinders
    • Soda lime
    • Vaporisers
    • Mechanical ventilator
    • Suction apparatus
    • Monitoring equipment.
  2. Drugs
    • Local anaesthetic drugs iv inducing agents
    • Muscle relaxants
    • Opioids and opioid antagonist
    • Benzodiazepines and its antagonist
    • Anticholinergic drugs
    • Vasopressor drugs
    • Bronchodilators
    • Catecholamines.
  3. Miscellaneous
    • Infusion set, fluids
    • Suction catheter, oral/nasal airway
    • Laryngoscope, endotracheal tubes
    • Nasogastric tube, Magill forceps.
  4. Blood should be crossmatched and available in time.