UOG

1. Preoperative assessment and preparation for anaesthesia
Year III
Hailu Y.(Bsc, Msc)
A/Professor of anaesthesia

2. Session outline
 Preoperative assessment:
1. History taking
2. Physical examination
3. Surgical urgency
4. Investigations
 General preoperative measures
 Anaesthetic risk and consent

3. Preoperative assessment 1: History taking
 Learning objectives:
 By the end of this session you will be able to:
 Explain the importance of preoperative assessment
 Describe how to take a history for a preoperative assessment
 Explain how to plan perioperative care based on your findings
 Describe how to plan your preparation for anaesthesia

4. Introduction: what is POA?

5. Introduction
 What are the aims of POA?
 Reduce morbidity and mortality associated with surgery
 Assess pre-existing medical conditions
 Plan preoperative and postoperative management of these conditions

6. Introduction
What are the aims of POA?
 Prevent unnecessary cancellations
 Ensure the patient is fully prepared for surgery
 Reduce length of hospital stay
 Inform the patient of the proposed procedure and gain consent

7. Introduction
 Ideally, where should a patient be preassessed?
 Consider The four key questions
 What conditions can I treat prior to surgery that will reduce the overall risk to the patient?
 What conditions exist that increase the patient's risk and may alter my anaesthetic
management or the help I have available?
 How urgent is the surgery and therefore how much time is available to prepare the patient?
 What would be the consequences of delaying surgery?

8. Introduction
 Why is POA important?
1. Induction is Dangerous without correct preparation
2. Anaesthetic has profound effect on CVS and RS
3. Pre-existing medical conditions can have a dramatic influence
4. To enable you to adequately prepare for an anaesthetic type
5. To minimizes the risk to the patient
 Structured approach: Take a few moments to outline on a piece of paper a
plan for a preoperative assessment.

9. Preoperative assessment 1: History taking
 Structured Approach
 Key points
 VS
 Is resuscitation needed?
 Airway
 Do need help?

10. Preoperative assessment 1: History taking
 History of present compliant?
 Determine surgical urgency
 Influence anaesthetic technique
 Determine the acceptable starvation period
 Surgical condition which have systemic effect. E.g. bowl ca
How might bowel cancer effect the patient systemically?

11. Preoperative assessment 1: History taking

12. Preoperative assessment 1: History taking
 Medical History – CV disease
 For cardiovascular disease, ask:
 Exercise tolerance,
 Palpitations
 Collapse/syncope
 Ankle swelling
 History of MI/Hypertension/raised cholesterol/diabetes
 Known valvular or congenital heart disease

13. Preoperative assessment 1: History taking
 Medical History – RS disease
 For respiratory disease, ask:
 Exercise tolerance
 Cough/sputum/haemoptysis
 Smoking history
 Wheeze
 Exposure to industrial dusts
 Weight loss
 Night sweats
 Fever

14. Preoperative assessment 1: History taking
Medical history: exercise tolerance

15. Preoperative assessment 1: History taking
 Medical history: other conditions
 Malnourished
 Dehydration
 Elderly (>75 years)
 Diabetes mellitus
 Endocrine dysfunction
 Chronic renal failure
 Nephrotic syndrome
 Obstructive jaundice

16. Preoperative assessment 1: History taking
 Medical history: Anaesthetic history
 Note details of previous anaesthetics and any problems encountered
 Examine previous anaesthetic charts if available
 Note last exposure to halothane anaesthesia
 Medical history: family history
 Malignant hyperthermia
 Suxamethonium apnoea
 Porphyria
 Haemoglobinopathies

17. Preoperative assessment 1: History taking
 Medical history:
 Drug history
 Allergies and addiction
 Pregnancy
 Reflex

18. Preoperative assessment 1: History taking

19. Preparation
 What should you prepare prior to anaesthetising a patient for surgery?
1. Patients
2. Drugs and blood products
3. Equipment check
4. Communicate with ward
5. Communicate with theatre team

20. Preoperative assessment 2: physical examination
 Learning Objectives
 By the end of this session you will be able to:
 Recognize the importance of physical examination
 Recognize the importance of airway assessment
 Explain how to 'perform an airway assessment accurately in less than 1 minute'
 Explain what to do with your findings

21. Preoperative assessment 2: physical examination
 Look at your patient as a whole to decide how sick he/she
 Assess the degree of hydration
 Check peripheral perfusion (is he cold to touch?).
 Check for cyanosis (central and peripheral).
 Check for jaundice

22. Preoperative assessment 2: physical examination
 Cardiovascular System and respiratory Examination
Look
Listen(Auscultate)
Feel
 Look Other systems

23. Preoperative assessment 2: physical examination
 Airway assessment
 Airway assessment aims to predict:
Difficult mask ventilation (with or without adjuncts/aids)
Difficult placement of LMA Difficult intubation
Difficult surgical access to trachea (rarely required)

24. Preoperative assessment 2: physical examination
Poor management of the difficult airway can result in:
Dental trauma
Airway trauma
Pulmonary aspiration
Hypoxia
Death

25. Preoperative assessment 2: physical examination
 Airway assessment
 Successful intubation requires:
Good mouth opening
Extension of the upper cervical spine
The ability to move soft tissue within the mandible out of the way

26. Preoperative assessment 2: physical examination
 Quick airway assessment
Mallampati test(OPV)
Mouth opening(interinciser gab)
Jaw slide
Neck movement

27. Preoperative assessment 2: physical examination

28. Preoperative assessment 2: physical examination

29. Preoperative assessment 2: physical examination
mouth opening

30. Preoperative assessment 2: physical examination
neck movement

31. Preoperative assessment 2: physical examination
Jaw slide

32. Preoperative assessment 2: physical examination
Thyromental distance

33. Preoperative assessment 2: physical examination
Thyro-and sterno-mental distance

34. If you fail to prepare, prepare to fail...
 Which features are associated with difficult mask ventilation?
 Overweight/Pregnant
 Bearded or Burns/Trauma to face
 Edentulous (lack of teeth)
 Snoring/Obstructive Sleep Apnoea/space occupying lesion of oropharynx or
larynx
 Elderly

35. If you fail to prepare, prepare to fail...
 Which features are associated with difficult intubation?
 Protruding/awkward teeth
 Space occupying lesion of oropharynx and larynx
 Facial trauma or burns
 Obesity
 Previous tracheostomy/tracheal stenosis
 Pregnancy

36. Preoperative assessment 3: surgical urgency
 Why for anaesthetist?
 To communicate with surgeon
 To minimize the overall risk
 Aware the risks associated with the surgical urgency
 Risk – benefit analysis
 Consensus b/n the team and family

37. Preoperative assessment 3: surgical urgency
 In UK, There are four categories:
 Immediate life, limb or organ saving
 Urgent
 Expedited
 Elective

38. Preoperative assessment 3: surgical urgency
 Discussion
 Can you think of any non-obstetric surgical cases where:
 Immediate surgical intervention may be required?
 Urgent surgical intervention may be required?
 Expedited surgical intervention may be required?
 Elective surgical intervention may be required?

39. Preoperative assessment 3: surgical urgency
 Surgical grades Examples
 Grade 1 (minor)
 Excision skin lesion; drainage breast abscess
 Grade 2 (intermediate)
 Inguinal hernia; varicose vein(s); tonsillectomy; arthroscopy
 Grade 3 (major)
 Hysterectomy; TURP; lumbar discectomy; thyroidectomy
 Grade 4 (major+)
 Joint replacement; thoracic operations; colonic resection; radical neck dissection

40. Preoperative assessment 3: surgical urgency
 Urgency For obstetric patients:
 Category 1: DDI up to 30min
 Category 2: DDI up to 1 hours
 Category 3: DDI up to 24 hours
 Category 4: elective

41. The ASA (American Society of Anaesthesiologists)
classification of general preoperative health
 Extended version
ASA 1: Healthy patient.
ASA 2: Healthy patient with remarks.
ASA 3: Patient with moderate clinical illness.
ASA 4: Severely ill patient.
ASA 5: Patient with an immediately life-threatening condition.
 Add E for emergency

42. ASA
 Original version
 ASA I: A normal healthy patient
 ASA II: A patient with mild systemic disease
 ASA III: A patient with severe systemic disease
 ASA IV: A patient with severe systemic disease that is a constant threat to life
 ASA V: A moribund patient who is not expected to survive without the operation
 ASA VI: A declared brain-dead patient whose organs are being removed for donor
purposes

43. Preoperative Assessment 4: Investigations
 The decision to order tests will depend on:
 Age of the patient
 General health/co-morbidities of the patient
 Medications
 Presenting condition
 Urgency of surgery
 Nature of surgery planned
 Facilities available for testing
 Facilities available for treating

44. Age
 Healthy patients over 60 years old may need the following if major surgery is
planned:
 Electrocardiogram (ECG)
 Full blood count (FBC)
 Renal function tests (U&E)
 The type of surgery planned is a major determinant of preoperative investigations.

45. Full blood count (FBC)
 Full blood count (FBC)
 Measure when:
 The history or examination indicates anaemia
 The proposed operation is expected to cause substantial blood loss
 Measure in patients with:
 Jaundice
 Malignancy
 Infection
 HIV
 Significant blood loss
 Also measure in patients with cardiac/renal/respiratory disease.

46. Blood test(Group save and cross much)
 Group and save
 According to hospital guidelines for elective surgery
 Significant or continuing blood loss but patient not shocked
 Cross match
 When blood is required Immediately if blood loss >30% circulating blood volume (1.5 L in
adult)
 If blood loss >50% circulating blood volume (2.5 L in adult); use O negative blood until
crossmatched blood becomes available

47. Blood test(coagulation screen)
 Measure when the patient :
 Has hepatic disease
 Is on warfarin or anticoagulants
 Has eclampsia or pre-eclampsia (particularly if platelet count <100 or dropping acutely)
 History of inappropriate excessive bleeding
 If there is a family history of bleeding disorders
 Severe sepsis
 Major haemorrhage

48. Blood glucose
 Measure if the patient has:
Diabetes
Glycosuria
Steroid treatment
Altered conscious level

49. Chest Radiograph
 Chest X rays (CXR) are not routinely ordered
 Usually limited to patients listed for major surgery with
 Substantial cardiac or respiratory disease,
 Heavy smoking or exposure to TB
 They may be requested as part of the surgical work up of the patient.
 Acute respiratory symptoms:
 May require as part of their management
 These should be treated before elective surgery

50. Electrocardiogram
 Consider when patient scheduled for major surgery has:
 Cardiovascular risk factors or history of cardiovascular disease for example:
hypertension, smoking, high cholesterol, significant family history, and obesity
 Signs of heart failure
 You suspect an arrhythmia from clinical examination
 Atypical abdominal pain or cardiac sounding chest pain

51. Echocardiography
 Do not routinely offer resting echocardiography before surgery.
 Consider resting echocardiography if the patient has:
 a heart murmur and any cardiac symptom (including breathlessness, pre-
syncope, syncope or chest pain) or
 signs or symptoms of heart failure.
 Before ordering the resting echocardiogram, carry out a resting
electrocardiogram (ECG) and discuss the findings with surgeon

52. Pulmonary function test(Spirometry or PEFR)
 To assess the reversibility of obstructive airways diseases
 Useful to quantify severity of ventilatory dysfunction
 To differentiate restrictive from obstructive defects.
 May be indicated:
 Those with equivocal clinical and radiological findings or unclear diagnosis.
 Patients in whom functional ability cannot be assessed
 Part of the assessment of patients for lung parenchymal resection

53. Renal function test
 Measure:
 For all major surgery
 Measure in patients on:
 On diuretics or cardiovascular drugs
 Measure in patients with:
 Infection
 Diabetes
 Dehydration
 Hypertension
 Poor urine output

54. Liver function tests
 Measure in patients with:
 Cardiac/hepatic disease
 Biliary disease
 Infection
 Alcohol abuse
 Jaundice

55. Other tests
 Pregnancy tests
 Sickle cell tests
 Urine dipstick

56. NICE guideline
 Consider preoperative test by:
 Age
 Surgical grade
 ASA
 Co morbidity

57. NICE
 READING ASSIGNMENT

58. Preoperative Assessment 4: Investigations
 Scenario 1
 A 40-year-old woman requires evacuation of retained products of conception. She
is otherwise fit and well, estimated 150 mls blood loss, cardiovascularly stable.
 What preoperative tests does she require?
 Full Blood Count or WHO Hb colour scale if available

59. Preoperative Assessment 4: Investigations
 Scenario 2
 A 40-year-old woman requires evacuation of retained products of conception. She
is showing signs of shock by being clammy and having very low urine output
 What pre operative tests does she require?
 Full Blood Count or WHO Hb colour scale
 Group and Save, or
 Cross Match if suspicious of significant haemorrhage

60. Preoperative Assessment 4: Investigations
 Scenario 3
 A 26-year-old male presents for incision and drainage of an abscess.
 He is apyrexial, otherwise fit and healthy and not systemically unwell.
 What preoperative tests does he require?
 No tests are required

61. Preoperative Assessment 4: Investigations
 Scenario 4
 A 64-year-old male presents for an emergency laparotomy. He has a temperature
of 38°C and a two-week history of abdominal pain and vomiting with a productive
cough. His blood pressure is 100/60 heart rate 94 bpm.
 What preoperative tests would you consider?
 Full blood count - ?sepsis ?anaemia
 Urea and electrolytes – dehydration, renal dysfunction
 Liver function tests – if abnormal consider a coagulation profile and hepatitis screen
 Urine dipstick for glucose??
 Group and Save – discuss with surgeon likely blood loss
 ECG if available to ascertain preoperative cardiac status
 CXR if available to assist in diagnosis of pneumonia

62. Preoperative Assessment 4: Investigations
 Scenario 5
 A 45-year-old diabetic women presents for a below-knee amputation for chronic
osteomyelitis. She takes metformin and isosorbide mononitrate. She has a history
of angina.
 What preoperative tests would you consider?
 Full blood count - ?sepsis ?anaemia
 Urea and electrolytes – dehydration, renal dysfunction
 Blood glucose
 Group and Save – discuss with surgeon likely blood loss
 ECG if available to ascertain preoperative cardiac status

63. Consent and anaesthetic risks
 Consent is based on the ethical principle of respect for
persons
 Acknowledge the person’s autonomy
 Protect those with diminished autonomy

64. The importance of consent
 Ethical aspect
 Professional aspect
 Legal aspect
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65. 3 Components
 Information
 Specific items for disclosure
 Understanding
 Adapt the presentation to the subject’s needs
 Voluntary agreement
 No threat of harm (coercion) AND no improper reward (undue influence)
 Best interest??
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66. Informed consent
Protection from harm
 would protect patient from an “unwise choice”
Protection of autonomy
 allows “unwise choice”
 demands:
 full disclosure
 comprehension
 voluntary
 competence to consent
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67. Competence
In the context of this decision
 Standards of competence
 decision based on rational reasons
 decision leads to reasonable result
 capacity to make a decision
 Competence judgments are “value laden” / weighed down
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68. Comprehension of information
 Comprehension-understanding the meaning of the information
 Acceptance-believing that the information is true for them
 Appreciation-apply the information in a way that fosters understanding of how they will
feel
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69. Standards for provision of information
 Time
 Common components of anaesthetic technique
 Specific aspects related to procedure or condition
 Common/significant side-effects
 Serious side-effects
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70. Standards for provision of information
 Consent starts with early provision of written information
 Communication of risks is important
 The perception of risk is modified by a number of factors:
 Probability of occurrence
 Severity
 Vulnerability
 Controllability
 Certainty/uncertainty
 Familiarity
 Acceptability/dread
 Framing or presentation
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71. Voluntariness
 Disclosure of alternate choices
 Influential vs. controlling inducements (influenced by circumstances)
 coercion
 indoctrination
 manipulation
 seduction
 emotion-laden appeal
 rational persuasion
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72. 2 Situations
 Clinical practice
 for an immediate procedure
 Research
 For a complex protocol
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73. Content of consent
Statement that the activity is
research
New Findings to be provided
Purpose Consequences for withdrawal
Number of Subjects Reasons for involuntary termination
Study Procedures Compensation for injury
Duration Additional costs
Risks (including risks to fetus Confidentiality of records
Unforeseen risks Contact persons
Benefits Statement of Voluntary Participation
Alternatives
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74. Key points
 Advance decision
 Refusal of treatment
 Consent in an emergency
 Treatment without consent
 Restricted consent
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75. Assent
 Children <7: No Assent
 Children 7-12: Separate Assent Form
 Teens 13-17 and Incompetent Adults: Assent Section of Consent Form
 Documentation is vital during consent
 Providing new information
 Provision of new information in the anaesthetic room before induction is not acceptable
unless in exceptional circumstances.
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76. Anaesthetic risks
 Risk discussion during preoperative visit should be:
 Easy to understand
 Include all risks that a ‘reasonable patient’ considers significant.
 These can range from common but minor side effects to rare but serious
complications.
 Communication of risks is important. Use:
 Words and numbers
 Pictures and diagrams

77. Anaesthetic risks
1 in 10 1 in 100 1 in 1000 1 in 10 000 1 in 100 000
Very common Common Uncommon Rare Very rare
S. Family S. in a street S. in village S. in small town S. in large town

78. Anaesthetic risks
 The perception of risk is modified by a number of factors:
 Probability of occurrence—true incidence requires a large population sample
and may be susceptible to:
 Regional bias
 Exposure bias—catastrophic or dramatic over-publicity
 Compression/expansion bias
 Both patients’ and anaesthetists’ perceptions will contribute to the discussion of
risks.

79. Anaesthetic risks
 Severity—are perceived as higher overall risks than more common complications.
 Vulnerability—denial/optimism and a feeling of ‘immunity’ or ‘invincibility’ allow us
to ignore daily risks.
 Controllability—loss of conscious choice with a feeling of loss of control
increases vulnerability.
 Certainty/uncertainty
 Familiarity
 Acceptability/dread
 Framing or presentation

80. Anaesthetic risks

81. Anaesthetic risks

82. Anaesthetic risks

83. Anaesthetic risks

84. Anaesthetic risks

85. General preoperative measures
Fasting(NPO)
Venous thromboembolism prophylaxis

86. Fasting
 Why ?
 Gastric emptying
 Proportional to the volume of the stomach contents
 approximately 1-3 % enters the duodenum per minute
 Water and clear fluids have a t½ of 10–20 min; they are completely emptied from the
stomach within 2 h
 The emptying rate for carbohydrates is >proteins >fats
 MILK?

87. Risk factor for regurgitation
 Inadequate starvation period
 Decreased gastric motility:
 Pregnancy in labour
 Trauma
 Opioids
 Anxiety??
 Diabetes(metabolic illus)
 Decreased effectiveness of lower oesophageal sphincter:
 Gastro-oesophageal reflux
 Pregnancy
 Increased intra-abdominal pressure:
 Obesity
 Laparoscopic surgery
 Pregnancy
 Inadequate anaesthesia

88. Fasting guidelines

89. Fasting guideline
 Other information
 Clear fluids
 Light and solid meals
 Chewing gum
 Oral medication
 Postoperative resumption of oral intake

90. Fasting ---chemical control

91. Venous thromboembolism prophylaxis

92. Venous thromboembolism
 Precipitating perioperative factors:
 Hypercoagulability due to surgery, cancer, oestrogen therapy
 Stasis of blood in legs due to immobility
 Dehydration
 Poor cardiac output
 Obstructed venous return

93. Venous thromboembolism
 DVT symptoms
 Most patients are asymptomatic
 Calf swelling, pain and tenderness may indicate DVT in the leg
 Consequences of DVT:
 pulmonary infarction, inflammation and pleuritic chest pain
 Dyspnoea and haemoptysis
 Pulmonary hypertension
 Acute circulatory collapse
 Death

94. Risk Factors for Perioperative VTE
 Patient factors
 Age >60 years
 Previous DVT, PE, thrombophilia e.g. protein C, S deficiency, Factor V Leiden
 Pregnancy
 Puerperium
 Oestrogen therapy (HRT, oral contraceptive pill (OCP))
 Obesity (BMI >30 kg/m2)
 Immobility
 Continuous travel of >3 h approximately 4 weeks before/after surgery

95. Risk Factors for Perioperative VTE
 Associated diseases
 Active heart or respiratory failure
 Acute medical illness/infection
 Recent cerebrovascular event (CVE)/myocardial infarction (MI)
 Varicose veins with phlebitis
 Trauma (especially lower limb fractures or spinal injury)
 Haematological diseases, e.g. paraproteinaemia
 Nephrotic syndrome
 Inflammatory bowel disease (Crohn’s or UC)

96. Risk Factors for Perioperative VTE
 Operation factors
 Surgery lasting <30 min is considered minor (low risk)
 Surgery lasting >30 min is considered major (higher risk)
 Types of surgery considered high risk include major joint replacements, hip fracture
surgery and surgery to the abdomen and pelvis
 NB: Any patient confined to bed is at risk of VTE.

97. Methods of Perioperative Risk Reduction
 Inpatient surgical procedures:
 Assess individual patient risk factors for VTE.
 Stop taking the oral contraceptive pill (OCP) four weeks before elective surgery.
 Give written and verbal information on risk and prophylaxis
 Mechanical prophylaxis
 Pharmacological prophylaxis
 Other strategies