CRQ Paper 8

Question 1

Question 1.
You are due to anaesthetise Brenda, a 15-year-old girl who is listed for a definitive correction of scoliosis.
a) Define scoliosis. (2 marks)

Answer 1

Lateral curvature and rotation

*Scoliosis is defined as the lateral curvature and rotation of the thoracolumbar vertebrae, leading to rib cage deformity

Question 2

Adolescent scoliosis is most commonly idiopathic.
b) List four other causes of scoliosis. (4 marks)

Answer 2

• Neuromuscular disorders: cerebral palsy, myopathies,poliomyelitis, syringomyelia,
• Friedrich’s ataxia
• Traumatic: fractures, radiation, surgery
• Syndromes: Marfan’s, rheumatoid, osteogenesis imperfecta, mucopolysaccharidoses, neurofibromatosis
• Malignancy
• Infection: tuberculosis, osteomyelitis
• Congenital: vertebral anomalies, rib anomalies, spinal dysraphism
**Depending on aetiology, further investigations may be required prior to surgery.
**Surgery is performed to prevent progression of the disease.

Question 3

c) The severity of Brenda’s scoliosis has previously been defined using radiological imaging.
What radiologically determined parameter is calculated to assess the severity of scoliosis, and at what value is surgical intervention indicated? (2 marks)

Answer 3

Cobb angle 40° (accept 40°–50°)

Cobb angle > 10° is abnormal.

Question 4

Your pre-operative assessment includes a comprehensive history, examination and airwayassessment. Brenda tells you she has struggled to keep up with her peers recently when playing sport at school.
d) List two investigations of the respiratory system and two cardiac investigations that areindicated prior to surgery. (4 marks))

Answer 4

Cobb angle > 65° will impede respiratory function. Cobb angle > 100°can lead to respiratory failure, pulmonary hypertension and right heart failure.
Respiratory:
• CXR
• Lung function tests
Cardiac:
• ECG
• Echocardiogram

Question 5

Brenda is worried about the risk of paralysis following the procedure. You explain that
spinal cord monitoring will be used intra-operatively to help prevent irreversible damage.
e) Describe the neurophysiological monitoring used and how it indicates potential spinal
cord injury. (4 marks

Answer 5

• Somatosensory evoked potentials (SSEPs) and motor
evoked potentials (MEPs)
• SSEPs stimulate peripheral nerve and detect response with
epidural/scalp electrode
• SSEPs evaluate the integrity of ascending sensory tracts
• MEPs stimulate motor cortex and detect response with epidural electrodes/compound
motor action potentials
(CMAPs)
• MEPs are designed to evaluate the integrity of descending motor tracts
• Nerve injury: indicated by decrease in amplitude/latency
of SSEPs or loss of CMAPs in MEPs

**An increase in SSEP latency of > 10% and decrease in amplitude of > 50% is considered significant.
MEPs: a transient loss of
CMAPs may not indicate
nerve injury, but complete loss of CMAPs should be taken seriously

Question 6

f) List four pharmacological agents that may interfere with spinal cord monitoring.
(4 marks)

Answer 6

• Propofol
• Volatile agents
• Nitrous oxide
• Muscle relaxants
**SSEPs are affected by propofol, volatile agents and nitrous oxide.
MEPs are affected by propofol, volatile agents, nitrous oxide and muscle relaxants. A decrease in blood pressure and temperature may also affect signals.

Question 7

Question 2.
Amare is a 69-year-old man listed for coronary artery bypass grafting. He has triple vessel
disease that is not amenable to stenting.
a) Complete the labels (i–vii) on the following figure. (7 marks)

Answer 7

i = aortic cross-clamp
ii = venous reservoir
iii = systemic blood pump
iv = vent pump (accept ‘vent’)
v = cardiotomy reservoir
vi = gas exchanger (accept
‘oxygenator’)
vii = cardioplegia solution (accept
‘cardioplegia’)

Question 8

b) What is the standard dose of heparin given before initiation of cardiopulmonary bypass, and what activated clotting time (ACT) value should be attained prior to commencement of cardiopulmonary bypass? (2 marks)

Answer 8

○ Heparin 300–400 IU/kg
○ ACT > 400,
**monitors the anticoagulant effect of unfractionated heparin.

Question 9

c) The surgeons are using cardioplegia for myocardial protection. State the mechanism by which the potassium-containing cardioplegia solution invokes diastolic arrest. (1 mark)

Answer 9

○ Potassium inactivates fast inward sodium channels, preventing the upstroke of the myocyte action potential
○ This renders the myocardium unexcitable and in diastolic arrest.
○ Cardioplegia can be administered by an anterograde approach (via the aortic root, provided aortic valve is competent), via a retrograde approach
(via the coronary sinus), or both. It is usually delivered intermittently (every 15–30 min).

Question 10

d) State three physiological advantages of blood cardioplegia over crystalloid cardioplegia.
(3 marks)

Answer 10

• Oxygen carrying capacity
• Hydrogen ion buffering
• Free-radical scavenging
• Improved microvascular flow
• Reduced myocardial oedema
• Delivery of other nutrients
**Glutamate and aspartate are sometimes added to cardioplegia to promote oxidative metabolism in energy-depleted hearts.

Question 11

e) Systemic hypothermia is a common feature of cardiopulmonary bypass. Give four physiological advantages and three physiological disadvantages of utilising systemic hypothermia during cardiopulmonary bypass. (7 marks)

Answer 11

Advantages:
• Reduced cerebral oxygen consumption/reduced cerebral ischaemia (accept ‘cerebral protection’)
**More challenging operations may require deep hypothermia (15°–22°C) to allow periods of low blood flow or deep hypothermic circulatory
• Increased blood viscosity (accept ‘increased embolic risk’)
• Increased infection risk
• Impaired wound healing
• Peripheral vasoconstriction
• Impairs liberation of O2 from haemoglobin
• Increased bleeding risk /impaired coagulation
• Hyperglycaemia
• Metabolic acidosis
• Cardiac arrhythmias
** At a biochemical level, changes in temperature alter reaction rates and
metabolic processes by a factor known as the Q10 effect, which defines the
amount of increase or decrease in these processes relative to a 10°C difference in temperature.

Question 12

e) Systemic hypothermia is a common feature of cardiopulmonary bypass. Give four physiological advantages and three physiological disadvantages of utilising systemic
hypothermia during cardiopulmonary bypass. (7 marks)

Answer 12

Advantages:
• Reduced cerebral oxygen consumption/reduced cerebral ischaemia (accept ‘cerebral protection’)
** More challenging operations may require deep hypothermia (15°–22°C) to allow periods of low blood flow or deep hypothermic circulatory
• Increased blood viscosity
(accept ‘increased embolic risk’)
• Increased infection risk
• Impaired wound healing
• Peripheral vasoconstriction
• Impairs liberation of O2 from haemoglobin
• Increased bleeding risk/impaired coagulation
• Hyperglycaemia
• Metabolic acidosis
• Cardiac arrhythmias
At a biochemical level, changes in temperature alter reaction rates and
metabolic processes by a factor known as the Q10 effect, which defines the
amount of increase or decrease in these processes relative to a 10°C difference in temperature.

Question 13

Question 3.
Justin, a 38-year-old man, is referred to the Intensive Care Unit with a possible diagnosis of Guillain–Barré syndrome (GBS).
a) What is GBS? (1 mark)

Answer 13

Acute demyelinating polyneuropathy
**It is an autoimmune phenomenon, usually following a gastrointestinal
or respiratory infection.
** This infection may be very minor.

Question 14

b) List five clinical features of GBS. (5 marks)

Answer 14

• Motor: progressive, usually ascending, motor weakness
• Reflexes: areflexia
• Cranial nerves: facial nerve palsy, bulbar weakness
• Eyes: ophthalmoplegia, ptosis, diplopia
• Sensory symptoms: pain, numbness, paraesthesia
• Respiratory: respiratory muscle weakness → respiratory failure
• Autonomic dysfunction: arrhythmias, labile blood pressure, urinary retention, paralytic ileus and hyperhidrosis
**Several clinical pictures of GBS are described, including
– Acute inflammatory demyelinating polyradiculopathy (most common)
– Acute motor axonal neuropathy
– Acute motor and sensory axonal neuropathy
– Miller Fisher syndrome (affects eyes but not always accompanied by limb
weakness)
○ Usually ascending sensory loss. ‘Glove and stocking’ distribution also seen.
○ GBS often has a variable presentation and should be suspected in any patient with unexplainable weakness or sensory deficit affecting the limbs.

Question 15

The neurologist reviews Justin and recommends immunoglobulin therapy.
c) List four side effects of immunoglobulin therapy. (4 marks)

Answer 15

• Nausea
• Fever
• Headache
• Transient rise in liver enzymes
• Encephalopathy
• Meningism
• Malaise
• Erythroderma
• Hypercoagulability
• Renal tubular necrosis
• Anaphylaxis
Any 4 Side effects (<5% of
patients) are usually mild.

Question 16

The neurologist reviews Justin and recommends immunoglobulin therapy.
c) List four side effects of immunoglobulin therapy. (4 marks)

Answer 16

• Nausea
• Fever
• Headache
• Transient rise in liver enzymes
• Encephalopathy
• Meningism
• Malaise
• Erythroderma
• Hypercoagulability
• Renal tubular necrosis
• Anaphylaxis
**Side effects (<5% of patients) are usually mild.

Question 17

d) What alternative treatment may be administered instead of immunoglobulin therapy?
(1 mark)

Answer 17

Plasmapheresis/plasma exchange
**Plasmapheresis reduces the duration of ventilator dependence and hospital stay, and leads to earlier mobilisation if commenced within 2 weeks of the onset of illness.

Question 18

e) List six parameters or clinical indicators used to aid decision-making with regard to intubation in patients with GBS. (6 marks)

Answer 18

• Vital capacity < 15–20 mL/kg
• Maximum inspiratory pressure < 30 cmH2O
• Maximum expiratory pressure < 40 cmH2O
• Bulbar involvement
• Respiratory failure on arterial blood gas (rising PaCO2)
• Significant autonomic instability
• Impairs cough and ability to protect the airway
**Deterioration in respiratory function may be rapid: patients should have vital capacity measured three times daily.

Question 19

f) List three clinical features of GBS associated with a poorer overall outcome. (3 marks)

Answer 19

• Campylobacter spp. infection
• Old age
• Need for ventilatory support
• Anti-GM1 antibody
• Neurone specific enolase
• S-100 proteins in the cerebrospinal fluid
• Absent or reduced compound muscle action potential
• Inexcitable nerves
• Upper limb paralysis

Question 20

Question 4.
You are called to the Emergency Department to assess Florence, a 2-year-old girl who presented with a 4-hour history of pyrexia and irritability. On examination, you notice a non-blanching rash. A presumptive diagnosis of meningococcal meningitis is made.
a) List four further clinical features of meningococcal meningitis. (4 marks)

Answer 20

• Headache
• Neck stiffness
• Nausea/vomiting
• Photophobia
• Drowsiness
• Coma
• Seizures

Question 21

b) What is the normal weight, heart rate, systolic blood pressure and capillary refill time for a child of this age? (4 marks)

Answer 21

○ Weight:
‘Old’ formula: (age+4) × 2 = 12 kg
‘New’ formula: (age×2) + 8 = 12 kg
○ Heart rate: 80–140 beats/min
○ Systolic blood pressure: 85–100 mmHg
○ Capillary refill < 2 seconds

Question 22

c) Outline the initial management of this patient.(4 marks) meningitis

Answer 22

• ABCDE assessment Any 4
• Early administration of broad-spectrum antibiotics, e.g. ceftriaxone
In the pre-hospital setting, intravenous or intramuscular benzylpenicillin is indicated.
• Oxygen
• Fluid resuscitation
• Dexamethasone
• Prepare for intubation

Question 23

d) Which investigations will guide the care of this child? (2 marks) For each investigation, state the results that you would expect in this case. (4 marks)

Answer 23

Investigation:
○ CT scan of brain
* CT imaging is carried out to exclude complications of bacterial meningitis that may make lumbar puncture risky, most commonly subdural collections in H. influenzae, meningitis, and obstructive hydrocephalus in M. tuberculosis meningitis.
Results:
• Most commonly normal appearance
• Subdural collection
• Obstructive hydrocephalus
• Leptomeningeal enhancement
• Evidence of raised intracranial pressure e.g. effacement of
ventricles
Investigation:
○ lumbar puncture
* In a child with neurological signs, lumbar puncture should only be performed after CT has excluded causes of raised intracranial pressure. Otherwise, lumbar puncture potentially risks precipitating cerebellar herniation.
Results:
• Cloudy and turbid cerebrospinal fluid
• Elevated opening pressure
• Raised white cell count
• Elevated protein
• Low glucose
• Culture: gram negative diplococci

Question 24

e) Other than Neisseria meningitidis, name two common bacteria causing meningitis in this age group. (2 marks)

Answer 24

• Haemophilus influenzae type B
• Streptococcus pneumoniae
• Group B Streptococcus
• Mycobacterium tuberculosis
**Asking about the child’s immunisation history is important.

Question 25

Question 5.
Megan, a 28-year-old primigravida, presents 2 days following an uneventful vaginal delivery. She is unwell with a temperature of 38.4°C and the obstetricians are concerned about puerperal sepsis.
a) List five risk factors for puerperal sepsis. (5 marks)

Answer 25

• Obesity
• Diabetes/impaired glucose tolerance
• Immunosuppression
• Anaemia
• History of pelvic infection
• Amniocentesis
• Cervical cerclage
• Prolonged rupture of membranes
• Group A streptococcal infection in family members
• Black or minority ethnic group A
The management of maternal sepsis comprises a bundle of measures:
• High-flow oxygen
• Blood cultures
• Broad-spectrum antibiotics
• Fluid resuscitation
• Serum lactate measurement
• Catheterisation

Question 26

b) List three reasons why regional anaesthesia is usually avoided in septic patients. (3 marks)

Answer 26

• Cardiovascular stability
**Septic, vasodilated patients may not tolerate a sympathetic block well.
• Infection risk
** Includes risk of epidural abscess and meningitis.
• Haematoma risk
** An associated coagulopathy will increase the risk of
haematoma formation.

Question 27

c) List five common causes of non-obstetric sepsis in parturients. (5 marks

Answer 27

• Urinary tract infection
• Mastitis
• Pneumonia
• Skin/soft tissue
• Gastroenteritis
• Pharyngitis
Causes of genital tract sepsis include:
• Chorioamnionitis
• Endometritis
• Septic abortion
• Wound infection
(vaginal tear,episiotomy, caesarean ÈQQ section)

Question 28

d) State the pathogen most commonly associated with maternal mortality. Name the two most common laboratory tests used in its identification. (3 marks

Answer 28

Pathogen:
○ Group A Streptococcus
Other major pathogens:
Laboratory tests: E. coli, influenza, S. aureus (methicillin-sensitive and resistant), S. pneumoniae, Clostridium septicum, Morganella morganii.
• Throat swab
• Blood cultures

Question 29

The Guideline for the Provision of Anaesthetic Services (GPAS) for an Obstetric Population (2018) describes standards of care for the acutely ill obstetric patient.
e) List four recommendations made regarding the care of the acutely ill obstetric patient. (4 marks)

Answer 29

• Early warning score system modified for obstetric use
• Access to critical care support
• Where possible, escalation should not lead to separation of mother and baby
• Named consultant anaesthetist and obstetrician responsible for
the woman’s care 24 hours per day
• Women requiring critical care in a non-obstetric facility should be reviewed daily by an obstetric team
• Midwives providing a level of care beyond their routine scope of practice should be appropriately trained
• NICE guidance on acute illness in adults should be implemented
** The GPAS guidelines are intended to define the standards for the provision of anaesthetic care in all UK consultant-led maternity
units. They discuss staffing, equipment and facilities, training and education and care for patients with special requirements. This includes care for the acutely ill obstetric patient as well as care for obese women and patients under the age of 18.

Question 30

Question 6.
Deepak is a 74-year-old man listed for a left total shoulder replacement. He has
a background of rheumatoid arthritis, and you have opted to supplement your general
anaesthetic with a brachial plexus block.
a) From which nerve roots does the brachial plexus arise? (1 mark)

Answer 30

C5, C6, C7, C8 and T1

Question 31

b) Complete the following table regarding approaches to the brachial plexus and the level
of the plexus at which the block is targeted. (6 marks)

Answer 31

Approach → level
○ The interscalene block is most commonly used for shoulder and upper arm surgery. It is the only
brachial plexus approach that reliably blocks the suprascapular nerve. It has limited use in lower arm
surgery due to the C8/T1 ulnar component often being missed.
• Interscalene → roots
• Supraclavicular → trunks
• Infraclavicular → cords
• Axillary → terminal branches

Question 32

c) You opt to perform an awake interscalene block under ultrasound guidance prior to
inducing anaesthesia. Please give four complicationsspecific to interscalene block. (4 marks

Answer 32

• Horner’s syndrome (accept
stellate ganglion block)
• Hoarseness (accept recurrent
laryngeal nerve block)
• Epidural/intrathecal spread of
anaesthesia/total spinal
anaesthesia
• Intervertebral artery injection/
seizures
• Direct spinal cord damage from
needle
Any 4 Phrenic nerve palsy occurs
in nearly 100% of
interscalene blocks, and
therefore has not been listed
here as a complication – it
is rather a well-recognised
side effect.

Question 33

d) What length of block needle should be used for an interscalene block? (1 mark)

Answer 33

50 mm needle 1
**A short needle helps improve safety of the block as the brachial plexus is very superficial when
performing an interscalene approach.

Question 34

e) Describe the anatomical location and vertebral level of the brachial plexus of relevance
to an ultrasound-guided interscalene block. (2 marks)

Answer 34

• The trunks of the brachial plexus
are located in the interscalene
groove (accept between anterior
and middle scalene muscles)
• The ultrasound probe is usually
placed at the level of C6 (accept
C5–C7)

Question 35

f) Aside from reducing the risk of complications (including intraneural or intravascular
injection), give three advantages of using an ultrasound-guided technique over an
anatomical approach. (3 marks)

Answer 35

• Accuracy of needle placement
• Visualisation of degree of local
anaesthetic spread
• Compensation for anatomical
variation/approach not landmark dependent
• Rapid block onset
• Reduced volume of local Anaesthesia required
• Reduced procedural pain/improved patient satisfaction
** There is level 1b evidence
available to demonstrate that ultrasound guidance improves both the quality and the speed of block onset.
Dynamic visualisation of the relevant anatomical structures and needle along with observation of local
anaesthetic spread in real time are arguably the biggest advantages of
ultrasound-guided regional
anaesthesia.

Question 36

g) Given his history of rheumatoid arthritis, state three reasons why performing an
interscalene block may be more difficult in Deepak’s case. (3 marks)

Answer 36

• Difficulty with patient positioning
• Variable anatomy
• Potential respiratory involvement may increase risk of respiratory embarrassment with phrenic nerve palsy
• May have existing peripheral neurological deficit
** Patients with rheumatoid arthritis merit special consideration as
atlantoaxial instability is found in ∼25% of sufferers.
Therefore, regional anaesthesia as the sole technique is always worth
considering to avoid laryngoscopy or other airway manoeuvres.

Question 37

Question 7.
Luis, a 25-year-old man, is brought into the Emergency Department after a high-speed road
traffic collision. He has significant facial bleeding.
a) List six signs of airway compromise in facial trauma. (6 marks)

Answer 37

• Brisk bleeding
• Dyspnoea
• Stridor
• Drooling
• Odynophagia/painful swallowing
• Tracheal deviation
• Trismus
• Subcutaneous emphysema of
neck and chest
• Voice changes
• Burns
**Early intubation may be required for issues related to the trauma, such as concurrent head injury and cervical spine injury

Question 38

b) The patient is bleeding profusely from his mid face. Describe the three characteristic patterns of mid face fractures (Le Fort fractures). (3 marks)

Answer 38

○ Le Fort I = maxilla fractured from rest of face
**The mobility of the mid face is much greater with Le Fort II and III fractures, and will often also involve mandibular fractures.
○ Le Fort II = maxilla and nasal complex fractured from rest of face
○ Le Fort III = whole mid face dissociates from the skull base and facial bones

Question 39

c) Give three methods to control the bleeding. (3 marks) maxillofascial #

Answer 39

• Anterior and posterior nasal packing/Epistat (stating nasal packing is not sufficient)
• Manual reduction of fractures
• Foley catheter balloon tamponade/Rapid Rhino®
• Interventional radiology embolisation of bleeding artery/external carotid artery
• External carotid artery ligation
** Profuse bleeding risks airway obstruction, especially in the supine
position. It is most commonly as a result of trauma to the facial or
maxillary arteries and usually responds to packing or balloon tamponade.

Question 40

The bleeding has stopped and no other injuries are identified. A CT scan demonstrates a Le
Fort III fracture pattern. The following day, Luis is listed for surgical stabilisation of his
facial fractures.
d) List two airway management options for the surgical correction of a Le Fort III fracture.
(2 marks)

Answer 40

• Nasal endotracheal tube
• Submental endotracheal tube
• Tracheostomy
**Oral endotracheal tubes cannot be used for Le Fort fractures, as dental
occlusion must be checked intra-operatively

Question 41

e) List six intra-operative anaesthetic considerations specific to this case. (6 marks) maxillofacial

Answer 41

Airway considerations:
• Throat pack required
• Surgical damage of endotracheal tube/cuff
**There is always a risk of surgical damage to a nasal endotracheal tube at the posterior nasal space.
• Surgical wiring of endotracheal tube to the maxilla
• Post-operative intermaxillary fixation (wiring or elastic bands) may be required
**The patient should always have wire cutters/scissor sat the bedside.
• Facial nerve monitoring may be required
**A single induction dose of muscle relaxant is acceptable.
• Shared airway/difficult intra-operative access to the airway/ increased risk of intra-operative circuit disconnection
○ Blood loss can be extensive:
• 2 × wide-bore IV access
• Group and save sample
Other:
• Reflex bradycardia when manipulating the mid face
• IV dexamethasone to reduce facial swelling
• Antibiotics indicated if wound is contaminated/exposed cartilage
**Significant oropharyngeal swelling mandates a critical care admission.

Question 42

Question 8.
Lynda, a 61-year-old woman, is listed for a total abdominal hysterectomy for uterine cancer.
She has a history of chronic liver disease secondary to alcoholism but has been abstinent from alcohol for over 6 years.
a) Apart from alcohol abuse, list four causes of chronic liver disease. (2 marks)

Answer 42

• Hepatitis B/C
• Cytomegalovirus/Epstein-Barr virus
• Drug induced, e.g. amiodarone, methotrexate
• Autoimmune hepatitis
• Primary biliary sclerosis
• Primary sclerosing cholangitis
• Non-alcoholic steatohepatitis
• Haemochromatosis
• α-1 antitrypsin deficiency
• Wilson’s disease
• Congestive cardiac failure

Question 43

b) Give two systemic effects of chronic liver disease on the body systems listed below. (8 marks)
Cardiovascular:
Respiratory:
Haematological:
Renal:

Answer 43

○ Cardiovascular:
• Hypotension/reduced systemic vascular resistance
• Increased cardiac output
• Adrenal insufficiency
• Masked coronary artery disease
• Cardiomyopathy
○ Respiratory:
• Pleural effusion
• Diaphragmatic splinting (must specify secondary to ascites)
• Porto-pulmonary hypertension
• Hepato-pulmonary syndrome
• Increased risk of acute respiratory distress syndrome
Haematological:
• Anaemia (gastrointestinal blood loss)
• Vitamin K dependent factor coagulopathy
• Thrombocytopenia/ hypersplenism
○ Renal:
• Pre-renal failure
• Hepato-renal syndrome
• Hyperaldosteronism
Other systemic effects
include:
• Vitamin B1 (thiamine) deficiency risks Wernicke’s encephalopathy
• Depletion of hepatic and muscle glycogen stores may result in hypoglycaemia
• Muscle wasting is common due to impaired protein synthesis and malnutrition.
**The development of hepatic encephalopathy in patients with chronic liver disease can be precipitated by infection, gastrointestinal
haemorrhage, electrolyte or acid–base disturbance,sedative drugs, hypoglycaemia, hypoxia, hypotension or excessive dietary intake of protein.
**Alternatively, it may be a sign of gradual progression of the liver
disease.

Question 44

c) For the common anaesthetic drugs listed below, please detail the specific pharmacoki-
netic reason for reducing the dose in a patient with chronic liver failure. (4 marks)
Thiopental:_____________________________________________________________
Rocuronium:___________________________________________________________
Morphine:_____________________________________________________________
Alfentanil:

Answer 44

○ Thiopental: reduced plasma protein binding increases available unbound drug
*The pharmacokinetics of suxamethonium may be affected by chronic liver disease. Duration of action is prolonged due to a reduced pseudocholinesterase concentration (rarelyclinically significant).
○ Rocuronium: prolonged elimination phase due to degree of hepato-biliary excretion
○ Morphine: risk of accumulation secondary to reduced metabolism/
reduced hepatic blood flow and reduced extraction ratio
Alfentanil: plasma protein binding reduced due to reduced α1-acid glycoprotein concentrations (accept reduced rate of elimination
due to increased volume ofdistribution)
**It is usually preferable to choose drugs whose metabolism is not dependent on hepatic function:
• Atracurium and cisatracurium are metabolised by plasma esterases and Hofmann elimination.
• Remifentanil is metabolised by tissue and plasma esterases
(which are preserved even in patients with severe liver disease).

Question 45

d) Give two options for Lynda’s post-operative analgesia (appropriate for this type of surgery). State a specific disadvantage for each given her past medical history. (4 marks) Laparotomy for cancer surgery

Answer 45

Option 1: fentanyl PCA
Disadvantage:
• Can accumulate in higher doses
• Constipation increases risk of ammonia accumulation and subsequent encephalopathy
option 2: regional anaesthesia (accept epidural, transverse abdominis plane block)
°Paracetamol is sometimes used with caution in this patient group, depending on the aetiology of liver disease.
°Non-steroidal anti-inflammatory medications are usually avoided due to the risks of gastrointestinal bleeding, platelet dysfunction and nephrotoxicity
Disadvantage:
• Potential for bleeding-related complications, e.g. haematoma

Question 46

e) What is the estimated perioperative mortality (%) for patients with chronic liver disease
in the following Child–Pugh classes? (2 marks)
Child–Pugh class A, B, C

Answer 46

○ Child–Pugh class A: 5%–10%
○ Child–Pugh class B carries a risk of 20%–30%.
○ Child–Pugh class C: >50% (accept 50%–60%)
**The Child–Pugh score is made up of five variables:
• Grade of encephalopathy
• Ascites
• Serum bilirubin
• Serum albumin
• Prothrombin time
*Each variable scores 1, 2 or3 depending on degree of severity.
Total score of 5–6 = Child–Pugh class A
Total score of 7–9 = Child–Pugh class B
Total score of >9 = Child–Pugh class C.

Question 47

Question 9.
You are reviewing Jen, an 82-year-old woman in pre-operative clinic who is listed for a total
knee replacement. She has a history of chronic obstructive pulmonary disease and atrial
fibrillation, for which she takes dabigatran.
a) State the mechanism of action for each of the following oral medications. (5 marks)
Warfarin:______________________________________________________________
Dabigatran:____________________________________________________________
Rivaroxaban:___________________________________________________________
Aspirin:_______________________________________________________________
Prasugrel

Answer 47

○ Warfarin: antagonises vitamin k epoxide reductase
○ Dabigatran: direct thrombin inhibitor
○ Rivaroxaban: direct factor Xa inhibitor
○ Aspirin: cyclo-oxygenase 1 inhibitor
○ Prasugrel: adenosine P2Y12 receptor antagonist (accept inhibition of ADP binding

Question 48

b) List four advantages and four disadvantages of direct oral anticoagulants (DOACs) when compared to warfarin. (8 marks)

Answer 48

Advantages:
• Rapid onset of activity
• Short half-lives
• Similar or improved efficacy
• Fewer drug interactions
• Fixed dosing guidelines
• No requirement for monitoring
Warfarin remains the most efficacious agent for anticoagulation of patients
with metallic heart valves.
Disadvantages:
• No antidote for most DOACs
• No widely available measure of activity
• Not licensed for management of anticoagulation for patients with metallic heart valves
• Drug interactions
• Less clinical experience than warfarin
• Renal impairment affects pharmacokinetics

Question 49

c) Your supervising consultant suggests utilising spinal anaesthesia for the case. For each
of the following oral medications, state the recommendations regarding cessation of the
drug or acceptable drug activity level. (5 marks)
Warfarin:______________________________________________________________
Dabigatran:____________________________________________________________
Rivaroxaban:___________________________________________________________
Aspirin:_______________________________________________________________
Prasugrel:

Answer 49

• Warfarin: INR ≤1.4
☆ These are the recommendations of the AAGBI, 2013.
• Dabigatran: 48–96 hours, depending on renal function
• Rivaroxaban: 48 hours
• Aspirin: no need to stop
• Prasugrel: 7 days

Question 50

Before the date of surgery, Jen has a fall down the stairs. She is unconscious, and a CT scan identifies an intracranial haemorrhage.
d) List two methods for rapidly correcting the effects of dabigatran. (2 marks)

Answer 50

• Idarucizumab is a specific monoclonal antibody against dabigatran
*Licensed by the National Institute for Health and Care Excellence in 2016.
• Dialysis
**Two-thirds of the drug is removed during a 2-hour dialysis session.
• Prothrombin complex concentrate (PCC)/fresh frozen
plasma (FFP)
**The dose of PCC/FFP required is uncertain.

Question 51

Question 10.
You review Stefan, a 64-year-old man, in the pre-operative anaesthetic clinic 1 month prior
to planned colorectal surgery. Stefan is a lifelong smoker – you advise him to stop smoking
and refer him to the smoking cessation service.
a) Give two reasons why smoking affects blood oxygen carriage. (2 marks)

Answer 51

• Carbon monoxide (CO) has a greater affinity for haemoglobin than O2 –
decreases oxygen carriage
☆ CO has 250 times more affinity for Hb than O2.
• CO shifts the oxyhaemoglobin dissociation curve to the left/reduces ability of haemoglobin (Hb) to release O2
CO also inhibits cytochrome oxidase, the enzyme needed for the synthesis of ATP in mitochondria.

Question 52

b) List five perioperative complications of smoking related to the respiratory system. (5 marks)

Answer 52

• Hypoxaemia
• Laryngospasm
• Bronchospasm
• Retained or thickened secretions
• Atelectasis
• Infection
Respiratory effects include decreased oxygen carriage, irritable airways, decreased ciliary function, decreased FEV1 and increased closing capacity.

Question 53

c) State four effects of nicotine on the cardiovascular system. (4 marks)

Answer 53

• Stimulates adrenaline release
• Activates sympathetic nervous
system
• Resets aortic and carotid bodies
• Increases myocardial
contractility
• Increases myocardial oxygen
demand
• Increases heart rate/blood
pressure
Any 4 The half-life of nicotine is
approximately 2 hours.
Abstinence from smoking
on the day of surgery will
reduce myocardial demand.

Question 54

d) List three potential adverse effects of smoking cessation prior to surgery. (3 marks)

Answer 54

• Anxiety
• Withdrawal or agitation
• Increased risk of post-operative
nausea and vomiting
• Airway reactivity
• Increased secretions
Any 3 Smoking cessation in
patients with asthma may
briefly worsen symptoms
and increase airway
reactivity.

Question 55

Question 11.
a) Define ultrasound. (1 mark) Outline the principles by which ultrasound generates an

Answer 55

Definition: sound waves of
frequency > 20 kHz
1 Audible limits of human
hearing are 20 Hz to
20 kHz.
Principles:
• Transducer contains material
with piezoelectric properties
• Piezoelectric material deforms
when an alternating electric
current is applied
• This results in sound wave
formation
• Sound waves are reflected back
at tissue interfaces
• Difference in tissue density at
interfaces will determine
degree of reflection
• Sounds reflected to the
transducer are amplified and
converted to an image
**There are many types of
ultrasound used:
• ‘A’ mode = amplitude
• ‘B’ mode = brightness
• ‘M’ mode = motion

Question 56

b) Explain how changing gain and frequency can alter the image produced. (2 marks)

Answer 56

• Gain: increasing the gain
amplifies the overall signal
1 The proportion of sound
waves beam reflected to the
transducer can be altered
through small changes to
the angle of the transducer.
‘Rocking’ the ultrasound
probe is used to improve the
image of structures: this is
known as anisotropy.

Question 57

c) List three forms of acoustic artefact, and for each, explain how it affects the image
produced. (6 marks)

Answer 57

• Acoustic enhancement → more
sound energy passes through
fluid filled structures,
enhancing the tissues behind
these structures
6 E.g. ultrasound of
gynaecological structures
behind an intentionally full
bladder.
• Acoustic shadowing → when
sound energy hits a highly
reflective structure, tissues
behind this structure appear
dark
• Reverberation → ultrasound
pulse becomes ‘caught’
between two parallel surfaces
and reverberates between them
causing a repetitive artefact on
the image
‘Comet tails’ on lung
ultrasound are an example
of reverberation. The loss of
comet tails is abnormal and
seen in pneumothorax.
• Refraction → as ultrasound
travels through different
mediums, a change in velocity
can alter its direction
One mark per artefact, and
1 mark for each correct
explanation

Question 58

Echocardiography can be used to determine cardiac output by measuring the stroke volume
and heart rate.
d) What two measurements are required to calculate stroke volume during echocardio-
graphy? (2 marks)

Answer 58

Left ventricular outflow tract
(LVOT) area
1 SV = LVOT area × VTI
Velocity time integral (VTI) 1 CO = SV × HR

Question 59

e) With the exception of echocardiography, list four uses of ultrasound in anaesthesia.
(4 marks)

Answer 59

• Venous/arterial cannulation
• Lung imaging: pneumothorax/
pleural effusions
• Locating neck vessels prior to
tracheostomy
• Regional anaesthesia
• Cardiac output monitoring
• Epidural space location
• Transcranial Doppler

Question 60

Question 12.
Bill, a 78-year-old man, has atrial fibrillation for which he takes warfarin. He is listed for
a cataract operation as a day case under regional block.
a) List three benefits of day surgery to the patient. (3 marks)

Answer 60

Reduced risk of nosocomial
infection
• Earlier return to normal
activity and mobilisation
• Reduced anxiety if overnight
stay avoided
• Reduction in venous
thromboembolic events
• Recovery at home
• Increased patient satisfaction
Any 3 The British Association
of Day Surgery publishes
targets for day and short-
stay surgery for more than
200 different procedures.

Question 61

b) List three benefits of day surgery to the hospital. (3 marks)

Answer 61

• Reduced waiting times
• Value for money and reduced
cost to hospital
• Best practice tariff
• Quicker turnover of patients
• Possible reduction of post-
operative complications
• Lower risk of cancellation
• Overnight beds spared for
major surgical cases
• More efficient theatre
utilisation

Question 62

c) List three social factors which must be in place for a patient to be suitable for a day-case
procedure. (3 marks)

Answer 62

• Patients must understand,
engage with and consent to the
surgical procedure
• There must be a responsible
person to escort the patient
home and remain with them for
24 hours
• Home circumstances suitable
for post-operative care
• Access to a telephone
• Geographical proximity to
hospital/transport time
< 1 hour
• Toilet facilities and central
heating required in some
geographical locations
Any 3 Some units employ carers to
stay with a post-operative
patient overnight if they live
alone, as this is more cost-
effective than an overnight
hospital stay.

Question 63

d) Bill’s latest INR is 3.0. How would you manage Bill’s perioperative anticoagulation?
(1 mark)

Answer 63

Continue warfarin at usual dose:
anticoagulation should not be
stopped
1 Anticoagulants and
antiplatelet agents should
be continued in the
perioperative period for
patients undergoing
cataract operations as day
patient surgery. Normal
therapeutic targets should
be maintained, as the risk of
bleeding is outweighed by
the increased risk of
significant thrombotic
events.

Question 64

You plan to perform a sub-Tenon’s block for this procedure.
e) Describe how you would perform a sub-Tenon’s block. You may assume you have
consented the patient, applied appropriate patient monitoring and have a trained
assistant. (6 marks)

Answer 64

• Stop before you block 1
• Apply topical anaesthesia to
the eye
Any 5 E.g. amethocaine 0.5%
or 1%.
• Aqueous sterilising solution E.g. povidone-iodine 5%
aqueous solution.
• Barraquer lid speculum
• Ask the patient to look ‘up and
out’ to expose the infranasal
quadrant
• Use non-toothed (Moorfields)
forceps to lift the conjunctiva
and Tenon’s fascia 5–10 mm
from the limbus
• Make a small cut with Westcott
scissors to expose the
underlying scleral layer
• Carefully make a passage with
Westcott scissors
• Attach a blunt ended sub-
Tenon’s cannula to a syringe
containing local anaesthetic
and advance this along the
passage following the contour
of the eyeball until the syringe
is vertical
• Aspirate then inject the local
anaesthetic
E.g. 3–5 mL of a 50:50
solution containing 2%
lignocaine and 0.5%
bupivacaine.

Question 65

f) List four specific complications of regional anaesthesia of the eye. (4 marks)

Answer 65

• Sub-conjunctival haemorrhage
• Pain
• Ecchymoses
• Retro-bulbar haemorrhage
• Globe injury
• Optic nerve atrophy
• Muscular palsy
• Brainstem anaesthesia
Any 4 Globe perforation, retro-
bulbar haemorrhage and
optic nerve damage all have
approximately 1%
incidence.

Answer 66

• Clearance of CO
• Improved ciliary function
• Nicotine levels return to normal
• Reduced myocardial oxygen
demand (accept reduction in
heart rate)
Any 3 Quitting 14 days prior to
surgery improves airway
reactivity and returns
sputum levels to normal.

Answer 67

• Polycythaemia
• Enhanced platelet function
• Increased fibrinogen
• Pre-existing vessel disease
Any 3 This risk is further
increased in women taking
the oral contraceptive pill.