CRQ Paper 10

Question 1

Question 1.
Eliza, an 8-year-old girl, is unwell and is brought into the Emergency Department (ED) by
a paramedic crew. On arrival at the ED, she has a tonic-clonic seizure.
a) List four causes of seizures in this age group. (4 marks)

Answer 1

a • Epilepsy: either known history
or first fit
• Metabolic: hypoglycaemia, hyponatraemia (maximum 1
mark for metabolic causes)
• Intracranial pathology:
haemorrhage, tumour,
infection (meningitis,
encephalitis, HIV) (maximum 2
marks for intracranial causes)
• Poisoning
Any 4 Two seizures are required
before epilepsy can be
diagnosed.
Not acceptable: febrile convulsion
(typically age 6 months to 5 years)

Question 2

b) List three seizure types other than tonic-clonic. (3 marks)

Answer 2

• Focal seizure (also known as
partial seizure)
• Absence seizure (also known as
petit mal)
• Atonic seizure (also known as
drop attack)
• Clonic seizure
• Tonic seizure
• Myoclonic seizure
Any 3 The patient may retain
awareness (simple partial
seizure) or lose awareness
(complex partial seizure).

Question 3

c) Outline your initial patient management. (3 marks) seizure

Answer 3

• ABC assessment
• Confirm clinically that this is a seizure
• Apply oxygen
• Establish IV access
• Blood glucose
• Venous blood gas for Na+

Question 4

d) State your pharmacological management (with per kilogram doses) of this situation according to the following time frames. (6 marks) child with seizures
At 5 min:
1. ___________________________________________________________________
or 2.__________________________________________________________________
At 15 min:
______________________________________________________________________
At 25 min:
1. ___________________________________________________________________
or 2.__________________________________________________________________
At 45 min:

Answer 4

5 min: Must have drug and per kg
• Midazolam 0.5 mg/kg buccal 1 dose to gain each mark.
• Lorazepam 0.1 mg/kg IV 1
15 min:
Lorazepam 0.1 mg/kg IV 1
25 min:
• Phenytoin 20 mg/kg IV
infusion over 20 min

• Phenobarbital 20 mg/kg IV
over 5 min
45 min:
Thiopentone 4 mg/kg IV (accept
3–6 mg/kg)

Question 5

e) Which endotracheal tube (ETT) size would you use for this child? (1 mark)

Answer 5

• 6.0 mm uncuffed ETT
• 5.5 mm cuffed ETT
* Formula is (age/4)+4 for uncuffed ETTs, with 0.5 mm subtracted for cuffed ETTs.

Question 6

Eliza is now successfully intubated, and you need to transfer her for a CT scan. Three full
oxygen cylinders of different sizes are available.
f) What is the volume of oxygen stored within each? (3 marks)
Size CD _______________________________________________________________
Size E _________________________________________________________________
Size F _

Answer 6

Size CD = 460 L (accept 400–600 L)
Size E = 680 L (accept 600–800 L)
Size F = 1360 L (accept
1200–1500 L)

Question 7

Question 2.
Bob is a 79-year-old man with known coronary artery disease. The surgical team would like
to perform off-pump coronary artery bypass grafting.
a) List four features of a patient’s past medical history that might make an off-pump procedure preferable. (4 marks)

Answer 7

• Aortic disease precluding bypass
• Renal disease
• Ventricular dysfunction
• Diabetes
• Advanced age
• Chronic lung disease
• Previous cerebrovascular accident (CVA)
In off-pump procedures:
• aortic cannulation is not required, which reduces the risk of aortic
dissection or embolisation.
• an aortic cross-clamp is not required, which reduces the risk of
plaque embolism and subsequent CVA.
Patients who are at higher risk of complications from conventional
cardiopulmonary bypass may benefit from off-pump surgery.

Question 8

b) What is the target activated clotting time (ACT) for off-pump coronary artery bypass
graft surgery? (1 mark)

Answer 8

250–300 s
*A typical dose of heparin to achieve this degree of anticoagulation is 1–2 mg/kg
(100–200 U/kg).

Question 9

c) In order to work on the posterior and lateral surfaces of the heart, it must be lifted
vertically out of the pericardial sac. Give two physiological reasons why this may cause haemodynamic compromise. (2 marks)

Answer 9

• Need upward blood flow into
vertically positioned ventricle
* A greater filling pressure is required to maintain ventricular filling.
• Vertical position distorts mitral
and tricuspid annuli
* Distortion of annuli can result in significant valvular regurgitation.

Question 10

d) A decrease in mean arterial blood pressure is common during off-pump coronary artery bypass. List three intra-operative strategies used to restore blood pressure to normal limits. (3 marks)

Answer 10

• Trendelenburg position
• Fluid administration
• Commencement of noradrenaline
• Atrial pacing to a rate of 60 beats/min
*Target mean arterial pressure should be
> 70 mmHg.

Question 11

Tachycardia is deleterious during off-pump bypass surgery owing to the consequent
increase in myocardial oxygen demand; esmolol or verapamil is often used to decrease
myocardial oxygen demand.
e) Complete the following table regarding these two drugs. (6 marks)

Answer 11

e Esmolol:
• Receptor activity: β1-adrenoreceptor antagonist
• Metabolism: red cell esterases
• Affected phase: phase 4
* Esmolol is highly cardio-selective, has rapid onsetand offset and has a
metabolism independent of liver or renal function. The gradient of phase 4 of the
pacemaker potential is reduced, thus decreasing heart rate.
Verapamil:
• Receptor activity: competitive calcium channel blocker
• Metabolism: hepatic metabolism
• Affected phase: phase 0
* Verapamil is a specific antagonist of the L-type Ca2+ channel, with a particular
affinity for those at the SA and AV nodes.

Question 12

f) State four reasons why off-pump coronary bypass surgery is considered more ‘cost-
effective’ than cardiopulmonary bypass. (4 marks)

Answer 12

• Requires fewer staff (no perfusionist)
• Reduced transfusion costs
• Reduced length of stay
• Reduced number of ventilated days
• Reduced equipment requirements (no bypass circuit)

Question 13

Question 3.
You are asked to review Johnny, a 56-year-old man, on the respiratory ward. He
presented to hospital 2 days ago with acute severe pneumonia. An arterial blood gas
reveals type 1 respiratory failure, and you believe he has acute respiratory distress
syndrome (ARDS).
a) List four components of the Berlin definition of ARDS. (4 marks)

Answer 13

• Timing: within 1 week of the start of symptoms
• Chest imaging: bilateral opacities
• Not explained entirely by fluid overload
• PaO2/FiO2 ratio < 39.9 (accept a ratio < 300 when using mmHg) (minimum PEEP of 5 cmH2O)
* Causes of ARDS may be classified as follows:
• Direct causes:
pneumonia, aspiration, lung contusion, fat embolism, drowning, inhalational injury, reperfusion injury.
• Indirect causes: sepsis, multiple trauma, massive transfusion, pancreatitis, cardiopulmonary bypass.

Question 14

b) List four ventilatory strategies used to prevent further lung injury whilst maintaining oxygenation. (4 marks)

Answer 14

• Ventilation using 6–8 mL/kg tidal volume
• Permissive hypercapnia
• High positive end-expiratory pressure (PEEP)
• Plateau pressure < 30 cmH2O
• Recruitment manoeuvres
• Avoid hyperoxia
* A pH > 7.20 is commonly accepted; the actual PaCO2 is of lesser importance.

Question 15

Despite optimal management, Johnny’s oxygenation continues to decline, and a decision is
made to reposition him into the prone position.
c) List three effects of the prone position on the respiratory system that aid oxygenation.
(3 marks)

Answer 15

• Improved V̇ /Q̇ ratio
• Increase in functional residual capacity
• Recruitment of atelectatic lung
* Displacement of the heart which compresses surrounding lung tissue
also helps improve V̇ /Q̇ matching.

Question 16

Two days later, Johnny is discussed at the multi-disciplinary meeting, and it is suggested
that he be considered for extracorporeal membrane oxygenation (ECMO). You are asked to
calculate his Murray score.
d) List the four components used to calculate the Murray score. (4 marks)

Answer 16

• PaO2/FiO2 on 100% O2
• PEEP (cmH2O)
• Compliance (mL/cmH2O)
• Chest X-ray quadrants infiltrated
*Each component scored from 0 to 4.
A Murray score ≥ 3 represents severe
respiratory failure appropriate for referral for extracorporeal membrane oxygenation (ECMO).

Question 17

e) List four contraindications to ECMO. (4 marks)

Answer 17

• High peak inspiratory pressures > 30 cmH2O for more than 7 days
• High FiO2 ventilation (>0.8) for more than 7 days
• Intracranial bleed
• Any other contraindication to heparinisation
* To be eligible, patients must have a reversible cause of respiratory failure and
should not have a life-limiting comorbidity aside from the acute disease process.

Question 18

f) What type of ECMO circuit is most commonly used to facilitate gas exchange when
cardiac function is preserved? (1 mark)

Answer 18

Veno-venous circuit

Question 19

Question 4.
Olivia is a 3-year-old girl weighing 15 kg who is listed for elective day-case strabismus
surgery. She has no other past medical history of note, takes no regular medication and has
no drug allergies.
a) Name two syndromes associated with strabismus. (2 marks)

Answer 19

• Down’s syndrome
• Edward’s syndrome
• Cri du chat
• Goldenhar
• Treacher–Collins
• Smith–Lemli–Opitz
• Crouzon
• Apert
• Pfeiffer

Question 20

On clinical examination, you hear a cardiac murmur. List three clinical features of an
innocent murmur. (3 marks)

Answer 20

• Soft
• Early systolic
• Varies with position
• No abnormal signs/symptoms (e.g. failure to thrive, syncope, cyanosis)
* A murmur should be investigated prior to surgery in the following situations:
• <1 year old
• Pathological murmurs
(all diastolic, pansystolic, late systolic, loud or
continuous murmurs)
• Any abnormal symptoms or signs
• Abnormal ECG or chest

Question 21

c) You plan to administer the following pre- and intra-operative medication. Complete the
table. (5 marks)

Answer 21

• Paracetamol: 15 mg/kg (accept 20 mg/kg)
• Ibuprofen: 5 mg/kg
• Glycopyrrolate: 4–8 μg/kg
• Ondansetron: 0.1–0.15 mg/kg
• Dexamethasone: 0.15 mg/kg
* Strabismus surgery can cause severe pain. A
common analgesic regimen is topical local anaesthetic, opioid analgesia, e.g. fentanyl, paracetamol and ibuprofen; multimodal analgesia should be continued into the post-operative period. The use of opioids increases the risk of
post-operative nausea and vomiting (PONV), and
antiemetics are essential.

Question 22

d) During her strabismus surgery, Olivia suddenly becomes bradycardic. Name the reflex
causing this bradycardia, and state the specific afferent and efferent nerves involved.
(3 marks)

Answer 22

Reflex: oculocardiac
○ The relay for the oculocardiac reflex is via
the sensory nucleus in the fourth ventricle.
°Afferent: ophthalmic division (V1) of trigeminal nerve
° Efferent: vagus nerve
* Children with a positive oculocardiac reflex are more likely to develop PONV than those with no measurable reflex. It has been postulated that preventing the oculocardiac reflex may reduce the incidence of PONV.

Question 23

Olivia has met the criteria for day-case surgery. List four patient-related factors and three
social factors that would exclude a paediatric patient from day-case surgery. (7 marks)

Answer 23

○ Patient-related factors:
• Term baby < 1 month in age
• Preterm or ex-preterm baby < 60 weeks post-conception age
• Poorly controlled systemic disease
• Inborn errors of metabolism (including diabetes mellitus)
• Complex cardiac disease or cardiac disease requiring investigation
• Sickle cell disease (not trait)
• Active infection (especially of respiratory tract)
* Anaesthetic/operative factors that preclude
paediatric day-case surgery include:
• Inexperienced surgeon or anaesthetist
• Prolonged procedure
• Opening of a body cavity
• High risk of perioperative haemorrhage/fluid loss
• Post-operative pain unlikely to be relieved by
oral analgesics
Social factors:
• Parent unable to care for the child at home post-operatively
• Poor housing conditions
• No telephone
• Excessive journey time from home to the hospital (>1 hour)
• Inadequate post-operative transport arrangement
• Difficult airway (including obstructive sleep apnoea)
• Malignant hyperpyrexia susceptibility
• Sibling of a victim of sudden infant death
syndrome

Question 24

Question 5.
Hazra is a 34-year-old primigravida who is 38 weeks pregnant. She presents to the maternity
unit with a 1-week history of increasing shortness of breath, ankle swelling and fatigue.
a) Which three criteria must be met to make a diagnosis of peripartum cardiomyopathy
(PPCM)? (3 marks)

Answer 24

• Development of heart failure within the last month of pregnancy or up to 5 months following delivery
○ PPCM closely resembles dilated cardiomyopathy.
• Absence of another identifiable cause of heart failure
• Left ventricular systolic dysfunction on
echocardiogram/ejection fraction < 45%

Question 25

List three changes you may see on an ECG in a normal pregnancy. (3 marks)

Answer 25

• Left axis deviation • T-wave inversion (lateral leads/III) • Presence of Q waves (III/aVF) • Atrial/ventricular ectopics • Sinus tachycardia * The heart is physiologically dilated and displaced in both cephalad and lateral directions. Increasing circulating vasopressors and diaphragmatic changes may play a role.

Question 26

Hazra undergoes a caesarean section under combined spinal–epidural anaesthesia. d) List five principles of intra-operative management in this case. (5 marks)

Answer 26

• Invasive arterial monitoring • Maintain preload/left lateral tilt to avoid aortocaval compression • Avoid tachycardia • Avoid increases in afterload • Maintain sinus rhythm • Maintain contractility • Avoid hypotension/carefully titrated spinal block • Avoid fluid overload/cautious intravenous infusion/ furosemide on delivery *Vaginal delivery is favoured with low dose epidural analgesia. Effective analgesia will help prevent tachycardia. Assisted second stage can reduce cardiovascular instability.

Question 27

e) For each of the following uterotonics, state two deleterious effects that may occur in patients with PPCM. (4 marks) Oxytocin: 1. ___________________________________________________________________ 2. ___________________________________________________________________ Ergometrine:

Answer 27

Oxytocin: • Decrease in systemic vascular resistance/compensatory tachycardia • Coronary vasoconstriction * Oxytocin must be slowly titrated. Ergometrine: • Coronary vasoconstriction • Pulmonary vasoconstriction • Systemic vasoconstriction *Ergometrine should be avoided in patients with PPCM.

Question 28

Question 6. Ada, a 62-year-old woman, is listed for excision of a large ovarian mass through a lower- midline laparotomy. She has a history of chronic back pain, and her regular medication includes pregabalin 150 mg bd and modified-release oxycodone 40 mg bd. She has recently had a spinal cord stimulator (SCS) inserted. a) List two indications for SCS insertion. (2 marks)

Answer 28

• Failed back surgery syndrome • Complex regional pain syndrome • Neuropathic pain secondary to peripheral nerve damage • Ischaemic pain associated with peripheral vascular disease These are the four indications recommended by the National Institute for Health and Care Excellence (Technology appraisal guidance TA159). Not acceptable: chronic back pain

Question 29

b) List two contraindications to spinal cord stimulator insertion. (2 marks)

Answer 29

• Psychological unsuitability: personality disorder, significant depression/anxiety • Uncontrolled bleeding/anticoagulation • Systemic or severe sepsis • Implanted cardiac devices: demand pacemaker or defibrillator • Immunosuppression

Question 30

c) What are the two component parts of a spinal cord stimulator? (2 marks)

Answer 30

• Stimulator leads: 4w–8 electrodes, either paddles (surgically placed) or catheters (percutaneously placed) • Pulse generator: external (for spinal cord stimulator trial) or implanted * The pulse generator is usually implanted subcutaneously in the anterior abdominal wall, lateral chest wall, gluteal or infraclavicular areas.

Question 31

d) State two perioperative implications of the spinal cord stimulator. (2 marks)

Answer 31

• Avoid unipolar diathermy if possible • If not possible, place neutral plate so that SCS components are outside the electrical field of diathermy • Risk of damaging/causing infection of leads with neuraxial blockade • Care with patient positioning/padding of SCS pulse generator * There is no need to give patients antibiotic prophylaxis specifically due to the presence of an SCS.

Question 32

e) List four methods that utilise local anaesthesia which may be used to manage this patient’s post-operative pain. (4 marks)

Answer 32

• Rectus sheath block/catheters • Bilateral transverse abdominis plane block/catheters • Wound catheters • Surgical infiltration of the wound • Lignocaine infusion Any 4 Lignocaine infusions are increasingly commonly used for intra-operative analgesia. An ongoing lignocaine infusion mandates a bed in a higher care area. Not acceptable: neuraxial techniques, due to presence of SCS

Question 33

The surgery was complicated by bowel injury, and a primary anastomosis was performed. Despite administering intra-operative paracetamol and parecoxib and using a regional anaesthetic technique, Ada has severe pain in the post-anaesthesia care unit. f) List, with doses, three non-opioid analgesics which could be used in this case. (3 marks)

Answer 33

• Clonidine 1 μg/kg intravenous • Ketamine 0.2–0.75 mg/kg intravenous • Lignocaine 1.5 mg/kg intravenous

Question 34

g) Ada is expected to be nil by mouth for the next 2 days. List three early symptoms or signs of opioid withdrawal. (3 marks)

Answer 34

• Agitation/restlessness • Anxiety • Muscle aches • Insomnia • Rhinorrhoea/tears • Sweating • Yawning • Tachycardia/tachypnoea Any 3 Symptoms such as goose bumps, dilated pupils and abdominal cramps are later symptoms.

Question 35

What are the ratios of conversion from oral oxycodone into oral morphine and oral morphine into intravenous morphine? (2 marks)

Answer 35

• Oral oxycodone:oral morphine ratio is 1: 2 • Oral morphine:intravenous morphine ratio is 3:1 **The different opioid equivalence of oral and intravenous morphine is due to first-pass

Question 36

Question 7. Derrick, a 68-year-old man, is listed for a laparoscopic anterior resection for a recently diagnosed bowel cancer. He has a past medical history of hypertension. a) List two cytokines thought to initiate the surgical stress response. (2 marks)

Answer 36

• Interleukin 1 (IL-1) • Interleukin 6 (IL-6) • Tumour necrosis factor alpha (TNF-α) ** Cytokines contribute to the haematological consequences of the surgical stress response, including • hypercoagulability • fibrinolysis.

Question 37

b) For each of the following hormones, state two phphysiological effects of their release related to the surgical stress response. (4 marks) Cortisol: Growth hormone:

Answer 37

Cortisol: • Increased protein breakdown • Promotes gluconeogenesis • Increased lipolysis • Peripheral insulin resistance/hyperglycaemia • Anti-inflammatory activity/ immunomodulatory effect Growth hormone: • Increased protein synthesis • Reduced proteolysis • Promotes lipolysis • Anti-insulin effect • Glycogenolysis **Other hormones implicated in the surgical stress response include the following: • Antidiuretic hormone (increased secretion) • Insulin (reduced secretion) • Adrenocorticotrophic hormone (increased secretion) • β-endorphin (increased secretion) • Prolactin (increased secretion). The other major contributor in the surgical stress response is the activation of the sympathetic nervous system.

Question 38

A pre-operative full blood count has revealed a microcytic anaemia with a haemoglobin of107 g/L. Derrick’s surgery is listed for 6 weeks’ time. c) What are the two treatment options? Give one advantage and one disadvantage for eachoption. (6 marks)

Answer 38

Option 1: Oral iron therapy Advantages: • Ease of administration • Low cost Disadvantages: • Poor tolerance/gastrointestinal side effects • Poor bioavailability • Limited time for effect Option 2: Intravenous iron therapy Advantages: • More effective rise in haemoglobin • Adequate time frame for effect Disadvantages: • Requires hospital admission • Risk of anaphylaxis Anaemia may be corrected by allogenic transfusion, but it is now established that transfusion itself is associated with increased perioperative morbidity and mortality. Treatment of pre-operative anaemia should be directed at correcting the underlying cause. Correcting anaemia before surgery reduces perioperative transfusion rates, post-operative infective and ischaemic complications and length of hospital stay. It also conserves blood stocks and is associated with cost savings.

Question 39

Derrick is admitted on the day of surgery as per the enhanced recovery pathway. Once he is anaesthetised, you insert an oesophageal Doppler probe. d) How would you use this cardiac output monitor for goal-directed fluid therapy? (3 marks)

Answer 39

• Administration of a 250 mL crystalloid fluid bolus 1 • Observation of changes in stroke volume over subsequent 10 min 1 • An increase in stroke volume of < 10% means a further bolus of IV fluid is not indicated. An increase in stroke volume of > 10% means a further fluid bolus should be administered

Question 40

e) Aside from goal-directed fluid therapy, state two further elements of your intra- operative care for Derrick in the context of an enhanced recovery pathway. (2 marks)

Answer 40

• Use of short-acting anaesthetic agents *There is little evidence to favour one anaesthetic technique over another, but the general principles of enhanced recovery support the use of agents that have minimal post-operative hang-over and effects on gastrointestinal motility. • Multi-modal analgesia/avoidance of long-acting opioids • Temperature homeostasis • Risk stratification/prophylaxis against post-operative nausea and vomiting •Total intravenous anaesthesia can be used and may play an increasing role in cancer surgery in the future. • Consideration of regional anaesthesia *Neuraxial blockade offers advantages over other regional techniques, such as • reduction in the duration of ileus, • reduced blood loss, • reduction in post-operative pulmonary complications, including pulmonary embolism • modification of the stress response. However, potential disadvantages include • complications associated with their insertion • reduced mobilisation • excessive fluid administration to combat hypotension.

Question 41

f) State three features of post-operative care for a patient, such as Derrick, on an enhanced recovery pathway. (3 marks)

Answer 41

• Multi-modal analgesia/ avoidance of excessive intravenous opiates • Early discontinuation of intravenous fluids/early enteral intake • Early removal of drains/ catheters Another vital part of enhanced recovery is audit to review compliance with the pathway. • Early mobilisation • Multi-disciplinary approach to post-operative care • Telephone follow-up on discharge

Question 42

Question 8. John is a 31-year-old cyclist who has suffered major injuries following a road traffic collision. On arrival at the Emergency Department, he is noted to be tachycardic and hypotensive with a tense abdomen. A trauma CT reveals a ruptured spleen and multiple liver lacerations. He is listed for an emergency laparotomy, and you have activated the major haemorrhage protocol. a) Give a definition for ‘major haemorrhage’ and a definition for ‘massive transfusion’. (2 marks)

Answer 42

Major haemorrhage • Loss of total blood volume within 24 hours • Loss of 50% blood volume in < 3 hours • Bleeding in excess of 150 mL/min • Bleeding leading to a systolic blood pressure of < 90 mmHg and pulse of > 110 beats/min ○ There is no one accepted definition for either major haemorrhage or massive transfusion. Massive transfusion • Transfusion of ≥10 red blood cell (RBC) units within 24 hours • Transfusion of >4 RBC units within 1 hour, with anticipation of continued need for blood product support • Replacement of > 50% of the total blood volume by blood products within 3 hours

Question 43

b) List the three components of the lethal triad of trauma (3 marks), and for each component, give one deleterious consequence specific to the coagulation process. (3 marks)

Answer 43

○ Component: metabolic acidosis Consequence: • pH affects activity of factors V, VIIa and X • Acidosis inhibits thrombin ○ Component: hypothermia Consequence: • Decreases platelet activation • Increases platelet sequestration in liver and spleen • Reduces functions of factors XI and XII • Inhibits fibrinolysis ○ Component: acute coagulopathy Consequence: • Systemic anticoagulation • Consumption of coagulation factors • Hyperfibrinolysis ° Early trauma-induced coagulopathy (ETIC) is associated with systemic anticoagulation and hyperfibrinolysis. ° Tissue injury from trauma releases local and systemic tissue factor which activates coagulation pathways. • The initiation results in massive consumptive coagulopathy leading to a consumptive disseminated intravascular coagulation-like syndrome, most commonly seen in patients with severe head injury or extensive muscle damage.

Question 44

Intra-operatively, John continues to bleed, and you administer blood products. c) For each listed blood product, state the target value which would indicate adequate transfusion. (4 marks) Packed red blood cells: Cryoprecipitate: Platelets:

Answer 44

• RBCs: haemoglobin >80 g/L (accept 70–90 g/L) • Fresh frozen plasma: international normalised ratio (INR) < 1.5/prothrombin time < 15 s. • Cryoprecipitate: fibrinogen > 1.5 g/L Fibrinogen target is > 2 g/L in obstetric haemorrhage • Platelets: platelet count > 75 ×

Question 45

d) Using the sub-headings provided, list the complications of massive transfusion. (6 marks) Transfusion reactions: Metabolic complications:

Answer 45

Transfusion reactions: • Allergic reaction (accept urticaria anaphylaxis) • Haemolytic transfusion reaction • Febrile non-haemolytic transfusion reaction Other complications include the following: • Infection • Transfusion-associated circulatory overload (TACO) (infants and patients with pre-existing cardiac disease are at increased risk) • Air embolism: rare and potentially fatal complication of rapid infusor use. Immunological reactions: • Transfusion-related acute lung injury (TRALI) • Transfusion-related immunomodulation (TRIM) • Transfusion-associated graft vs host disease (Ta-GVHD) • Post-transfusion purpura (PTP) Metabolic complications: • Hypocalcaemia * Hypocalcaemia due to citrate overload. • Hypomagnesaemia • Hyperkalaemia * Hyperkalaemia is due to haemolysis of RBCs duringnstorage, irradiation or both. • HypokalaemiaHypokalaemia may occur because of K+ re-entry into transfused RBCs • Metabolic alkalosis *Metabolic alkalosis may occur because of citrate overload. • Metabolic acidosis * Metabolic acidosis occurs because of hypoperfusion, liver dysfunction and citrate overload. • Hypothermia * Hypothermia occurs through conduction: infusion of cold blood products. A blood warmer should always be used.

Question 46

What effect does tranexamic acid have on the coagulation cascade, and what dose would you use in an adult major trauma patient? (2 marks) Effect Dose:

Answer 46

Pharmacodynamic effect: Competitive inhibitor of conversion of plasminogen to active plasmin Dose: • 1 g intravenous bolus, followed by infusion of a further 1 g over 8 hours

Question 47

Question 9. You attend the departmental morbidity and mortality meeting where recent critical incidents are reviewed. Two corneal abrasions are reported, and preventative steps are discussed. a) List three causes of corneal abrasion under general anaesthesia (3 marks) and three physical measures you can take to help prevent corneal abrasions from occurring. (3 marks) Causes of corneal abrasion:

Answer 47

○ Causes of corneal abrasion: • Direct trauma • Exposure keratopathy • Chemical injury Physical prevention measures: • Taping of the eyelid • Instillation of ointment • Bio-occlusive dressings • Use of non-toxic antiseptic ○ Clinical features of corneal abrasions are pain, gritty sensation, redness, tearing and photophobia. ○ The diagnosis may be confirmed with fluorescein staining and slit lamp examination. ○ Treatment includes lubricants and topical antibiotics. Occasionally patching of the eye or bandage lens is required.

Question 48

Liz discussed a case of common peroneal nerve palsy after prolonged surgery in the lithotomy position which had led to legal action. b) List three clinical features of common peroneal nerve palsy. (3 marks)

Answer 48

Weakness of dorsi flexion • Foot drop • Weakness of eversion • Weakness of extensor hallucis longus • Paraesthesia over the dorsal aspect of the foot/lower lateral part of the leg Common peroneal nerve palsy is classically described following surgery in the lithotomy position and is due to pressure on the common peroneal nerve as it passes in close proximity to the head of the fibula.

Question 49

Aside from common peroneal nerve injury, list the two most common nerve injuries associated with general anaesthesia. (2 marks)

Answer 49

• Ulnar nerve injury 1 • Brachial plexus injury

Question 50

Jim presented a new guideline for the management of accidental dental trauma. The pathway starts with the pre-operative identification of patients at high risk of dental injury. d) List four steps that you can take to mitigate the risk of dental injury in a patient with poor dentition planned to undergo lower limb surgery. (4 marks)

Answer 50

• Pre-operative dental review • Use laryngeal mask airway (LMA) over an endotracheal tube • Use regional anaesthesia/neuraxial blockade • Blind nasal intubation • Bite block • Deep extubation • Senior operator If a tooth is avulsed, relocate it as soon as possible and apply pressure or a splint. Apologise and explain to patient, offer analgesia and refer to a dentist.

Question 51

The meeting ends with an audit presentation by a junior trainee on the incidence of post-operative sore throat. e) List five factors that increase the risk of a post-operative sore throat. (5 marks)

Answer 51

• Larger diameter endotracheal tubes • Poor endotracheal insertion technique (accept trauma)/ difficult intubation • High endotracheal cuff pressures • Duration of anaesthesia • Use of nasogastric tubes • Use of non-humidified breathing systems

Question 52

Question 10. Gwendoline is an 87-year-old woman who has been admitted with a fractured neck of femur following a fall at home. She has a background history of hypertension and atrial fibrillation, for which she takes warfarin. a) According to AAGBI guidelines, within what time period should surgery for hip fracture be performed? (1 mark

Answer 52

Less than 36–48 hours * Surgery should be performed within 48 hours of hospital admission after hip fracture. ○ A target of 36 hours was introduced in England and Wales in April 2010.

Question 53

b) List four pre-operative investigations that are indicated based on the clinical history provided above. (4 marks)

Answer 53

• Full blood count • Urea and electrolytes • Coagulation screen/international normalised ratio (INR) • Group and save/hold • Electrocardiogram (ECG) ** A coagulation screen is only required where clinically indicated (e.g. patient taking oral anticoagulants). Chest X-ray is only indicated in specific circumstances, e.g. newly diagnosed cardiac failure or suspected pneumonia.

Question 54

On further examination, you notice that Gwendoline has an ejection systolic murmur. She is not known to have valvular heart disease. c) Give two findings from Gwendoline’s history and clinical examination that would indicate the need for echocardiography prior to anaesthesia. (2 marks)

Answer 54

• Breathless at rest/on minimal exertion • A history of angina on exertion • Unexplained syncope • A slow rising pulse • Absent second heart sound * Echocardiography is also indicated if there is evidence of left ventricular hypertrophy on ECG without a history of hypertension.

Question 55

d) State three acceptable reasons for delaying surgery for acute hip fracture patients. (3 marks)

Answer 55

• Haemoglobin concentration < 80 g/L • Plasma sodium < 120 mmol/L or > 150 mmol/L • Plasma potassium < 2.8 mmol/L or > 6.0 mmol/L • Uncontrolled diabetes • Uncontrolled or acute onset left ventricular failure • Chest infection with sepsis • Reversible coagulopathy • Correctable cardiac arrhythmia with a ventricular rate > 120 beats/min The AAGBI gives the following as unacceptable reasons to delay surgery: • Lack of facilities or theatre space • Awaiting echocardiography • Unavailable surgical expertise • Minor electrolyte abnormalities

Question 56

Due to her ejection systolic murmur, you opt to perform the procedure under general anaesthesia. e) Aside from AAGBI standard monitoring and the use of an arterial line, state two other monitoring devices you would consider utilising intra-operatively; give a reason for each. (4 marks) Monitoring device 1:_____________________________________________________ Clinical reason:_________________________________________________________ Monitoring device 2:_____________________________________________________ Clinical reason:__

Answer 56

• Device: cardiac output monitor (accept oesophageal Doppler, LiDCO, etc.) • Reason: to provide goal-directed fluid therapy/improve haemodynamic performance • Device: depth of anaesthesia monitor (accept bispectral index, E-entropy, etc.) • Reason: avoid potential cardiovascular depression from excessive anaesthesia • Device: central venous pressure monitoring • Reason: guide intra-operative fluid therapy (do not accept for drug delivery) • Device: cerebral oxygen saturation monitoring • Reason: reduce post-operative cognitive dysfunction through early recognition and management of reduced intra-operative cerebral oxygen saturations

Question 57

Gwendoline’s international normalised ratio is 1.4. You opt to perform a psoas compart- ment block to supplement her analgesia. f) Give three potential complications specific to this peripheral nerve block. (3 marks)

Answer 57

f • Damage to abdominal viscera • Retroperitoneal haematoma • Psoas abscess • Epidural spread • Intrathecal injection Any 3 Unlike a psoas compartment block, a femoral nerve⁄fascia iliaca block does not reliably block the obturator nerve. However, a femoral nerve/ fascia iliaca block is more amenable to ultrasound- guided placement and still significantly reduces post- operative analgesic requirements

Question 58

How long after her surgery would you re-instigate Gwendoline’s warfarin therapy? (1 mark

Answer 58

6–24 hours 1 Some centres re-instigate warfarin therapy on the day of surgery.

Question 59

If Gwendoline had been a candidate for spinal anaesthesia, what two modifications could you have made to your technique to reduce the risk of intra-operative hypotension? (2 marks)

Answer 59

• Utilising a lower dose of intrathecal bupivacaine • Using intrathecal fentanyl to facilitate a reduced dose of intrathecal bupivacaine • Using hyperbaric bupivacaine with the patient positioned laterally (fractured hip lowermost)

Question 60

Question 11. a) Describe the molecular structure of adult haemoglobin (Hb). (3 marks)

Answer 60

a • Four polypeptide chains/two alpha and two beta chains • Four haem moieties/porphyrin rings with iron atoms • Iron in ferrous state • Chains bound together by hydrogen bonds Any 3 In adults 95% of haemoglobin (Hb) exists in the form of HbA1 containing two alpha and two beta chains. Foetal Hb consists of two alpha a

Question 61

b) Describe how oxygen (O2) binds to Hb (2 marks). Explain the term ‘cooperative binding’. (1 mark)

Answer 61

• Four polypeptide chains/two alpha and two beta chains • Four haem moieties/porphyrin rings with iron atoms • Iron in ferrous state • Chains bound together by hydrogen bonds In adults 95% of haemoglobin (Hb) exists in the form of HbA1 containing two alpha and two beta chains. Foetal Hb consists of two alpha and two gamma chains.

Question 62

List four factors that enhance the binding of O2 to adult Hb. (4 marks)

Answer 62

Oxygen (O2) binding: • O2 forms a reversible bond to ferrous iron in Hb • There are four O2 binding sites/four O2 molecules bind • Each ferrous iron binds a molecule of O2/each Hb molecule binds four O2 molecules ** Cooperative binding is explained by allosteric modulation: when O2 binds to Hb, the two beta chains move closer together and the haem moieties adopt a ‘relaxed’ state which has an increased affinity for O2. ** When O2 dissociates from Hb the ‘taut’ state is favoured, reducing Hb’s affinity for O2. ○ Cooperative binding: ° Binding of an O2 molecule to Hb increases Hb’s affinity for O2, facilitating the uptake of additional O2 molecules

Question 63

Hypoxia can be defined as a deficiency in O2 supply or the inability to utilise O2. d) Define the four classes of hypoxia. (4 marks)

Answer 63

• Hypoxaemic hypoxia: due to reduced PaO2 1 Hypoxaemic hypoxia has a number of causes, e.g. • inadvertent low inspired O2 • hypoventilation • V̇ /Q̇ mismatch • diffusion impairment. • Anaemic hypoxia: PaO2 is normal, but oxygen carrying capacity is reduced 1 Anaemic hypoxia may be due to anaemia or carbon monoxide poisoning. • Stagnant hypoxia: normal arterial oxygen content, circulatory failure leading to inadequate oxygen delivery 1 Stagnant hypoxia may be seen in cardiogenic shock. • Histotoxic/cytotoxic hypoxia: normal arterial oxygen content and delivery to tissues, but an inability of tissues to utilise O2 at a cellular level 1 Cyanide inhibits cytochrome c oxidase in the mitochondrial electron transport chain, resulting in histotoxic hypoxia.

Question 64

e) List the three forms in which carbon dioxide is transported in the blood. (3 marks)

Answer 64

• Dissolved 1 CO2 diffuses into red blood cell, combines with water to form carbonic acid (catalysed by carbonic anhydrase) which dissociates to form bicarbonate. Bicarbonate diffuses out of red blood cells and is carried in the plasma.

Question 65

f) Name the enzyme that is essential in facilitating the transport of carbon dioxide. (1 mark)

Answer 65

Carbonic anhydrase

Question 66

g) What is the Haldane effect? (1 mark) What is its relevance in the transport of carbon dioxide? (1 mark) Haldane effect:__________________________________________________________ Relevance

Answer 66

○ Haldane effect: The double Haldane effect describes how maternal uptake of CO2 increases whilst foetal CO2 affinity decreases, enhancing the transfer of CO2 from foetal to maternal circulations. ○ Increased ability of deoxygenated haemoglobin to carry carbon dioxide Relevance: • In the tissues, increases affinity for carbon dioxide • In the lungs, decreased affinity facilitates removal of carbon dioxide

Question 67

Question 12. Gillian is a 54-year-old woman listed for vocal cord polypectomy. The surgeons have informed you that the procedure will involve the use of LASER. a) What does the acronym LASER stand for? (1 mark)

Answer 67

○ Light Amplification by Stimulated Emission of Radiation • Albert Einstein published the theoretical basis for laser in 1917, but it was only in 1960 that the first functioning laser was constructed.

Question 68

b) State the three characteristic features of laser light. (3 marks)

Answer 68

Monochromatic ° Monochromatic: consisting of a single wavelength or colour. Coherent ° Coherent: photons are in phase. Collimated ° Collimated: photons are almost in parallel (aligned), with little divergence from the point of origin

Question 69

c) Provide definitions for the following terms implicated in the production of laser light. (3 marks) Spontaneous emission:___________________________________________________ Stimulated emission:_____________________________________________________ Population inversion

Answer 69

○ Spontaneous emission = photon is released from an electron that has spontaneously returned to ground state from a higher energy state ○ Stimulated emission = a photon collides with an electron in a higher energy orbit, causing a photon to be released as the electron decays back to ground state ** Stimulated emission is provoked in a lasing medium through the use of reflective mirrors which reflect photons back into the lasing medium, encouraging further collision. The photons are released in phase and in the same direction as the stimulating photon. ○ Population inversion: where more electrons exist in higher excited states than in lower unexcited states * Population inversion is achieved by continuous input from the energy pump (continuous wave laser) or by intermittent pumping (pulsed wave laser).

Question 70

d) Complete the following table regarding common medical lasers and their applications in clinical practice. (3 marks)

Answer 70

i) Carbon dioxide (CO2) ○ A CO2 laser utilises a photo-thermal effect, rapidly heating tissues. Depending on the exposure time, tissue vapourisation (ablation), coagulation or both may occur. ii) Accept lithotripsy, endoscopic sinus surgery or tissue ablation ○ Holmium:YAG laser utilises a photo-mechanical effect. It causes an extremely intense but brief pulse of laser. This results in explosive expansion of the tissue or water within the renal calculi, causing photoacoustic disruption. iii) Accept: excimer or argon fluoride ○ These lasers break down covalent bonds in protein molecules (photodissociation), resulting in non-thermal ablation.

Question 71

e) List two safety features of a laser-resistant endotracheal tube. (2 marks)

Answer 71

• Saline filled cuff • Methylene blue/dye-filled cuff • Twin distal cuffs • PVC tube wrapped with self-adhesive, non-reflective metal tape ** Cuffs of endotracheal tubes are vulnerable to rupture by laser beams. If a cuff inflated with air is ruptured, it allows a massive leak of anaesthetic gases and provides a richer environment for ignition.

Question 72

f) List three precautions which are taken to protect theatre staff from injury when using laser light. (3 marks)

Answer 72

• Protective goggles (glasses/spectacles not acceptable, as they do not give reliable peripheral visual field protection) ** The protective eyewear must correspond to the wavelength of laser light being used. • Divergent laser beam ** To reduce the risk of focussed laser light striking the retina. • Matt-black surgical instruments • Appropriately trained designated laser safety officer ** To minimise reflection from the main laser beam. • ‘Laser in use’ signage/locked theatre doors/theatre windows covered **To prevent accidental injury to passers-by • Non-water based fire extinguisher available

Question 73

g) Despite safety precautions, an airway fire occurs. Give five specific management steps that you would immediately take. (5 marks)

Answer 73

• Declare incident/call for help • Discontinue use of laser • Stop ventilation/discontinue oxygen source • Remove the burnt endotracheal tube • Douse the operative site with water • Reinstate ventilation with bag–mask ventilation or re-intubation using room air • Perform bronchoscopy to determine degree of thermal injury **Further (non-immediate) management may include: • Tracheostomy • Steroid therapy to treat inflammation • Antibiotic therapy • Transfer to critical care for ventilatory support if concerned about upper airway swelling or lung injury.

Question 74

Risk factors for

Answer 74

• Hypertensive disorders • Maternal age > 30 years • Multiparity • Multiple pregnancy • Obesity • Cocaine use • Afro-Caribbean descent

Question 75

factors that shift the adult oxyhaemoglobin dissociation curve to the left.

Answer 75

• Increased pH/alkalosis • Reduced PaCO2 • Reduced 2,3- diphosphoglycerate • Reduced temperature • Carboxyhaemoglobin • Methaemoglobinaemia Any 4 This question is looking for factors that shift the adult oxyhaemoglobin dissociation curve to the left. Not acceptable: foetal Hb, as the question asks specifically about adult Hb