CRQ Paper 4 Flashcards
Question 1. Anita, a 30-year-old woman, collapses at work following the onset of a severe headache. On arrival at the Emergency Department, she is confused, and her Glasgow Coma Score is 14 (E4V4M6). A CTbrain scan is performed, which shows intraventricular blood. A diagnosis of subarachnoid haemorrhage is made. a) List the three most common causes of blood in the subarachnoid space. (3 marks)
• Rupture of berry aneurysm 1
**AVM rupture and traumatic subarachnoid account for 10% each, with
aneurysm rupture accounting for 80% of
subarachnoid haemorrhage.
• Rupture of arterio-venous
malformation (AVM)
• Traumatic subarachnoid
haemorrhage (SAH)
b) List four risk factors associated with the development of aneurysmal subarachnoid haemorrhage. (4 marks
• Genetic
• Associated conditions, e.g.
polycystic kidneys
• Smoking
• Cocaine use
• Amphetamine use
• Ehlers–Danlos type IV
Any 4 Familial risk is significant
if a first-degree relative
has SAH.
Complete the labels (i–vi) on the following figure. (3 marks)
i = Anterior cerebral artery
ii = Anterior communicating artery
iii = Middle cerebral artery
iv = Posterior cerebral artery
v = Basilar artery
vi = Posterior communicating artery
At which three arteries are berry aneurysms most likely to occur? (3 marks)
• Anterior communicating artery
• Middle cerebral artery
• Posterior communicating artery
** Berry aneurysms occur at
bifurcations of major
arteries.
State two early and two late neurological complications of subarachnoid haemorrhage. (4 marks)
Early: Any 2
• Re-bleeding Aneurysms are coiled or clipped within the first few days to prevent re-bleeding.
**The highest risk period is 7–10 days following bleed.
• Seizure
• Hydrocephalus
Late: Any 2
• Delayed cerebral ischaemia/
vasospasm
**Nimodipine is taken for 21 days to reduce risk.
• Cognitive impairment
• Neurocognitive symptoms such
as fatigue, mood disturbance
• Hypopituitarism
**Neuropsychiatric symptoms are common
following SAH.
Question 2. Steven is a 2-day-old boy who has presented to the Emergency Department following a sudden collapse. He was born by normal vaginal delivery at 37 weeks without complication. a) A common cause of sudden collapse in a neonate is congenital heart disease.
State two other common causes. (2 marks)
• Sepsis
• Hypoglycaemia
• Metabolic/endocrine disorder
• Trauma/non-accidental injury
Any 2 The differential diagnosis of
collapse in a neonate is
broad.
This is a critical time
for the circulation: ductus
rteriosus closure may
unmask congenital heart
disease
b) List four clinical signs that are supportive of a diagnosis of congenital heart disease. (4 marks
• Tachypnoea and sweating whilst
feeding
• Persistent tachycardia
• Hepatomegaly
• Oedema of face/forearm/back/
legs
• Radio-femoral delay
• Cyanosis, especially on crying
• Pathological murmur
**A history of feeding difficulty is common.
Breathing and feeding cannot happen
simultaneously, so cyanotic episodes are often
precipitated by feeding.
NB features of the history are not
clinical signs
Steven’s mother describes a history of irritability and cyanotic spells when feeding and crying. Following examination, you suspect a diagnosis of tetralogy of Fallot. c) List the tetrad of features seen in this condition. (4 marks)
• Right ventricular outflow tract obstruction/pulmonary valve stenosis
• Ventricular septal defect (VSD)
• Right ventricular hypertrophy
• Overriding aorta
d) List two conditions associated with tetralogy of Fallot. (2 marks)
• DiGeorge syndrome
• 22q11 chromosome deletion
syndrome
• Down’s syndrome
• Cleft lip/palate
• Hypospadias
e) Other than feeding, list two other precipitants of a cyanotic episode (tet spell). (2 marks)
• Tachycardia
• Hypotension
• Defaecation
• Crying
f) Describe the physiological changes in cardiac blood flow that arise during a t⁸et spell. (4 marks)
• Tet spell is usually precipitated by
an acute decrease in systemic
vascular resistance (SVR)
• Or an acute increase in
pulmonary vascular
resistance (PVR)
• → Increased right-to-left shunt
across VSD
• → Decreased PaO2/increased
PaCO2, decreased pH
• → Tachypnoea
• → Increased negative
intrathoracic pressure
• → Increased venous return
• → Increased right-to-left shunt
across VSD
• → Vicious cycle
g) List twoways of managing thesecyanotic episodes in the period leading up to corrective surgery. (2 marks
• Administer oxygen
**The objective is to increase SVR, correct hypoxia and correct acidaemia.
Oxygen administration decreases PVR.
• Console child in knee–chest
position
** This is the equivalent ofthe older TOF child’s
squatting – increasing SVR.
• Opioids/ketamine/midazolam
** Relieves stress and hypercapnoea, but may decrease SVR.
• Correct any underlying cause,
e.g. arrhythmia, hypothermia,
hypoglycaemia
Question 3. You are asked to review Sangeeta in the Emergency Department, a 19-year-old woman with a history of insulin-dependent diabetes. She was found collapsed at home and was previously seen 48 hours ago. Her capillary blood glucose is 21.4 mmol/L. a) In the space below, list the criteria (in mmol/L) required for a diagnosis of diabetic ketoacidosis (DKA). (3 marks)
• Blood glucose > 11 mmol/L
(accept > 13.9 mmol/L)
** As per the Joint British Societies Group.
• Ketonaemia > 3.0 mmol/L
** (The American Diabetes Association has slightly different guidance.)
• Bicarbonate < 15.0 mmol/L
(accept < 18.0 mmol/L)
** A pH < 7.30 can be used inplace of bicarbonate in the diagnostic criteria.
List the pathophysiological changes that occur as a consequence of insulin deficiency which explain the biochemical findings of hyperglycaemia, ketonaemia, acidosis and glycosuria. (4 marks
Hyperglycaemia:
• Lack of insulin-facilitated
glucose uptake to muscles
• Increase in antagonistic
hormones (glucagon, cortisol,
growth hormone)
• Enhanced hepatic
gluconeogenesis and glycogenolysis
Ketonaemia:
• Enhanced lipolysis increases free
fatty acids
• Fatty acids undergo β-oxidation
into ketoacids
Acidosis:
• Ketoacids dissociate, releasing
hydrogen ions
• High anion gap metabolic
acidosis
Glycosuria:
• Plasma glucose concentration
exceeds capacity of proximal
convoluted tubule to completely
reabsorb glucose from filtrate
The results of her arterial blood gas are as follows: pH 7.17
PCO2 4.0 kPa PO2 12.1 kPa HCO3‾ <5 mmol/L Base excess −19.2 mEq/L K+ 7.8 mmol/L 40 Na+ 129 mmol/L
c) Based on the arterial blood gas results above, what would be your immediate management? (1 mark)
• 10 mL of 10% calcium gluconate
• 10 mL of 10% calcium chloride
(accept 10–20 mL)
Immediate management
also includes 50 mL of 50%
dextrose together with 10
units of soluble insulin.
d) List the ECG changes that may be seen with hyperkalaemia. (5 marks)
• Peaked T waves
• Prolonged PR segment
• Loss of P-wave
• Prolonged QRS complex
• ST-segment elevation
• Ectopic beats and escape rhythm
• Widening of QRS complex
• Sine wave
• Ventricular fibrillation
• Asystole
• Axis deviation
• Bundle branch block
* A vast array of ECG changes may be seen in hyperkalaemia. They are
normally classified as mild
(5.5–6.5 mmol/L), moderate (6.5–7.5 mmol/L), and severe (>7.5 mmol/L),
although classifications
vary.
** Calcium reduces the
excitability of cardiomyocytes, reducing
the risk of fatal arrhythmias.
e) List four other serious complications of DKA. (4 marks)
• Hypokalaemia
• Hypoglycaemia
• Renal impairment
• Cerebral oedema
• Pulmonary oedema
• Death
** Insulin administration may
cause hypokalaemia and
hypoglycaemia. Fluid
administration has been
postulated to cause cerebral
and pulmonary oedema
f) List the three endogenous ketone bodies. (3 marks)
• 3-β-hydroxybutyrate
• Acetoacetate
• Acetone
** The predominant ketone in
the body is 3-β- hydroxybutyrate, which is
measured in point-of-care testing.
Question 4. Diego, a 3-week-old boy born uneventfully at term,is brought by his mother tothe Emergency Department with progressively worsening non-bilious vomiting, usually directly after a feed.
a) On assessment, Diego is severely dehydrated. List four clinical signs consistent with this class of dehydration. (4 marks)
• General condition: abnormally
sleepy/lethargic
• Anterior fontanelle: markedly
sunken/depressed
• Weak rapid pulse
• Rapid respiratory rate
• Urine output: <0.5 ml/kg/h
• Skin turgor: decreased with tenting
• Mucous membranes: very dry
• Eyes: markedly sunken
** Dehydration is classified in
the context of fluid loss as a
percentage of body weight.
Mild = 5%
Moderate = 10%
Severe = 15%
The classification can help
guide fluid resuscitation.
Avenous blood gas is taken, giving the following results:
pH 7.61
PCO2 7.2 kPa
PO2 11.0 kPa
Base excess +30.1 mmol/L
Na+ 136 mmol/L
K+ 3.0 mmol/L
Cl‾ 72 mmol/L
b) Interpret the venous blood gas. (1 mark)
Hypokalaemic, hypochloraemic
metabolic alkalosis
(NB must state all three components
for the mark)
1 Whilst PCO2 is raised,
which may represent partial
respiratory compensation,
conclusions cannot easily
be drawn due to this being a
venous rather than an
arterial blood sample.
Onthe basis of the history and blood gas, you suspect a diagnosis of pyloric stenosis. c) List four risk factors for developing pyloric stenosis. (4 marks)
• More common in boys
• Young maternal age
• Maternal family history
• Infants born in autumn and
spring
• Maternal smoking
• Postnatal erythromycin
• Association with bottle feeding
4:1 male:female ratio,
especially common in first-
born boys.
d) List two additional features of the clinical examination consistent with a diagnosis of pyloric stenosis. (2 marks)
• Visible peristalsis
** Crossing abdomen from left
to right.
• Olive-like 2–3 cm palpable mass
in right side of epigastrium
**This clinical sign is less
frequently found due to
earlier diagnosis using
ultrasound
) List two hormones secreted as a direct response to severe dehydration. (2 marks)
• Antidiuretic hormone (ADH)
** By the hypothalamus/posterior pituitary in response to increased
plasma osmolarity.
• Renin
** Secreted in response to decreased tubular filtrate flow rate or decreased
perfusion of the macula densa
Despite the raised plasma pH, Diego’s urine is found to be acidic. f) Which hormone is responsible for this paradox? (1 mark)
Aldosterone
** Acts at principle cells in the
DCT and collecting ducts to absorb water and Na+ in
exchange for K+ and H+. In severe dehydration, the
conservation of water takes precedence over
normalising plasma pH.
After 48 hours of intravenous rehydration, Diego’s venous gas has normalised. The surgeons would like to perform a pyloromyotomy. g) List six intra-operative and post-operative considerations specific to this age group and procedure. (6 marks)
• Risk of aspiration on induction, but rapid sequence induction/ cricoid pressure difficult in this age group
• Nasogastric or orogastric tube insertion and ‘four quadrant’ aspiration I.e. aspirating the tube with
the infant supine, left lateral decubitus, prone and
right lateral decubitus.
• Use a 3.5 mm cuffed or uncuffed endotracheal tube
• Temperature control: increase the theatre ambient temperature to 26°C, use radiant heaters/forced air warmers
• Analgesia provided using local anaesthetic techniques and paracetamol
• Maintain normoglycaemia in the perioperative period: use of glucose-containing maintenance fluid
• Apnoea monitoring in a high-dependency environment
Mandatory for infants < 44 weeks post-conceptual age, or for ex-premature infants < 60 weeks post post-conceptual age.
• Reduced IV paracetamol dose: 7.5 mg/kg every 6 hours for post-conceptual age 36–44 week
Question 5. Siobhan presents to the Emergency Department with a short history of painless vaginal bleeding. She is 38 weeks pregnant and is visiting family in England. She remembers being told about a low-lying placenta but has been unable to attend any follow-up antenatal clinics.
a) Describe the four grades of placenta praevia by their relationship to the internal cervical os. (4 marks)
Grade 1: does not abut the internal
cervical os/low-lying
* Placenta praevia has also
been classified as minor or
major.
Grade 2: reaches margin of internal
cervical os/marginal
** Only 10% of those with a low-lying placenta at the20-week scan will go on to
have placenta praevia.
Grade 3: partially covers internal os/partial
Grade 4: completely covers internal
cervical os/complete
b) Aside from a low-lying placenta, list five risk factors for placenta praevia. (5 marks)
• Previous placenta praevia
• Previous termination of
pregnancy
• Multiparity
• Advanced maternal age (>40
years)
• Smoking
• Deficient endometrium –
scarring, endometritis, manual
removal of placenta, curettage,
fibroid
• Assisted conception
• Previous caesarean section
** In women who have
previously had a caesarean
section, 50% of those with a
low-lying placenta at 20
weeks’ gestation will go on
to have placenta praevia.
Following ultrasonography, Siobhan is told that her placenta is anterior and in a position that rules out normal vaginal delivery. Her observations are normal and her symptoms have now subsided. A decision is made to perform a caesarean section.
c) How may your anaesthetic differforthis procedure when compared to that of a low-risk elective caesarean section? (7 marks)
• Senior input – consultant
anaesthetist
• Additional monitoring – arterial
line
• Additional large bore
intravenous access
• Regional anaesthesia (must
qualify association with reduced
blood loss)
** Women with a placental
edge < 2cm from the
internal os are likely to be
delivered by caesarean
section. If uncomplicated,
this is usually after 38
weeks’ gestation.
• Consider general anaesthesia, or
consent for rapid conversion
• Cell salvage
• Cross-match
• Rapid infusor
• Tranexamic acid
• Consent for blood transfusion
In women with a history of
caesarean section and an
anterior low-lying placenta,
the risk of placenta accreta
should be considered.
Abnormal placental adherence describes the degree to which there is an invasion of chorionic villi into the myometrium because of a defect in the decidua basalis. d) List the three forms of abnormal placental adherence (3 marks) in order of increasing incidence. (1 mark)
Least common: placenta percreta 1
Intermediate: placenta increta 1
Most common: placenta accreta 1
Correct order of increasing incidence 1
Question 6. Karen, a 65-year-old woman, is referred to pain clinic by her general practitioner. She has a 3-month history of pain on one side of her face in an area affected by a recent episode of shingles. a) Namethe virus that causes shingles. (1 mark)
Varicella zoster virus (VZV) (accept
human herpes virus type III)
1 Following a primary
infection with VZV
(chickenpox), the virus lies
dormant in spinal and
cranial nerve ganglia.
b) List the two most common sites for the shingles rash. (2 marks)
• Thoracic dermatome 1
• Ophthalmic division of
trigeminal nerve (ophthalmic
division must be specified)
c) List three comorbidities which put patients at greater risk of developing shingles.(3marks)
• Diseases affecting the immune
system, e.g. lymphoma, human
immunodeficiency virus (HIV)
Cell-mediated immunity
normally prevents
reactivation, but inhibition
of the immune system may
allow reactivation of VZV,
causing the characteristic
rash of shingles.
• Pharmacological
immunosuppression: e.g.
following organ transplant,
autoimmune disease
• Treatment of malignancy:
chemotherapy, radiotherapy
d) List four risk factors for the development of post-herpetic neuralgia (PHN). (4 marks)
• Age > 60 years
• Female
• More intense initial pain
• More severe rash
• Prodrome of dermatomal pain
before development of rash
• Fever (>38°C)
e) List six clinical features of PHN. (6 marks)
• Prodromal pain in a single
dermatome before onset of rash
Pain:
• Continuous or intermittent
• Throbbing or burning
• Allodynia – unable to wear
clothing over the involved region
Other neurological:
• Sensory loss
• Motor weakness
• Autonomic disturbance – abnormal skin temperature/
colour, abnormal sweating
Psychological symptoms:
• Isolation
• Depression/anxiety
• Chronic fatigue
• Sleep disturbance
Systemic symptoms:
• Weight loss
f) Regarding the pharmacological management, state a drug used to prevent PHN. (1 mark)
• VZV vaccine booster
• Antiviral drugs: acyclovir,
valaciclovir, famciclovir
Any 1 Antiviral drugs shorten the
period of viral replication,
and halve the incidence of
PHN at 6 months.
g) List three first-line treatment options following the onset of PHN. (3 marks)
• Simple analgesics: paracetamol ±
codeine
• Gabapentinoids: gabapentin,
pregabalin
• Tricyclic antidepressants
• Topical agents: lignocaine and
capsacin
• Weak opioids: tramadol
Question 7. Kevin, a 32-year-old man, is listed for excision of a parathyroid adenoma under general anaesthesia. The parathyroid adenoma was discovered following a series of investigations to identify the cause of Kevin’s hypercalcaemia.
a) List six clinical features of hypercalcaemia. (6 marks)
The classical description of ‘stones, bones, abdominal
groans and psychic moans’ is rarely seen, with the
majority of patients having few symptoms on diagnosis.
• Bone pain
• Muscle weakness, reduced reflexes
• Fatigue
Gastrointestinal:
• Constipation
• Anorexia
• Nausea and vomiting
Renal:
• Polyuria resulting in dehydration
• Renal stones
The mechanism of polyuria
is nephrogenic diabetes
insipidus secondary to
nephrocalcinosis.
Neuropsychiatric:
• Depression/anxiety
• Cognitive dysfunction:
confusion, psychosis
• Insomnia
Depression is common, up
to 40% of patients are
affected.
b) Where are the parathyroid glands normally located? (2 marks)
• Two pairs of parathyroid glands 1 There is considerable
variability in the number of
glands and their location.
The parathyroid glands may
even descend into the thorax
with the thymus.
• Embedded in the superior and
inferior poles of the thyroid gland
bilaterally
c) Whichinvestigation is used to locate the parathyroid adenoma pre-operatively? (1 mark)
Technetium-99 m-sestamibi
scintigraphy
d) List four physiological effects of excess secretion of parathyroid hormone (PTH). (4 marks)
Kidney:
• Increased Ca2+ resorption in the loop of Henle, distal convoluted tubule and collecting duct
• Increased phosphate (PO43–) excretion in the proximal convoluted tubule
• Increased production of 1,25-dihydroxycholecalciferol (vitamin D3)
PTH increases the activity of 1-α-hydroxylase enzyme, which converts 25-hydroxycholecalciferol to vitamin D3.
Bone:
• Increased bone resorption to
release Ca2+
• Inhibits osteoblast activity,
stimulates osteoclasts activity
Intestine:
• Ca2+ is reabsorbed indirectly
**The PTH-induced increase
in vitamin D is responsible
for this effect
The patient’s serum Ca2+ concentration on the day of surgery is 2.9 mmol/L. Your unit’s policy is that surgery should proceed if the serum Ca2+ is below 3.0 mmol/L. e) List two perioperative considerations in patients with moderate hypercalcaemia. (2 marks)
• Lower doses of anaesthetic
agents may be needed if
somnolent
• Hypercalcaemia may augment
neuromuscular blockade: reduce
doses of muscle relaxants and use
neuromuscular monitoring
The risk of intra-operative
cardiac arrhythmias is
much greater for patients
with Ca2+ > 3.0 mmol/L.
• Increased incidence of cardiac
arrhythmias
f) Following surgery, the patient becomes markedly hypocalcaemic. List four clinical features of acute hypocalcaemia. (4 marks)
• Peri-oral/digital parasthesias
• Positive Trousseau’s sign
** Trousseau’s sign is
inducing carpal spasm by
inflating a blood pressure
cuff.
• Positive Chvostek’s sign
** Chvostek’s sign is facial
spasm induced by tapping
the inferior zygoma.
• Carpopedal spasm
• Laryngospasm
• ECG changes: prolonged QT
interval and torsades de pointes
• Negative chronotropy/inotropy
Mnemonic for severe
hypocalcaemia: CATS go
numb = convulsions,
arrythmias, tetany,
laryngospasm, go numb =
paraesthesias.
Thepatient has a family history of hyperparathyroidism. Name an inherited endocrine condition which includes hyperparathyroidism. (1 mark)
g
• Multiple endocrine neoplasia
(MEN) type 1 and 2A
Any 1 The multiple endocrine
neoplasias are syndromes
characterised by tumours of
several endocrine glands.
** MEN 1 is characterised by
the ‘3Ps’ – pituitary, parathyroid and pancreatic
** MEN 2A by ‘2Ps and
1 M’: phaeochromocytoma, parathyroid, medullary thyroid.
• Familial isolated hyperparathyroidism
Question 8. You are asked to review Geraint, a 69-year-old man, in the Emergency Department. He has been vomiting violently throughout the night and has developed central chest pain. The general surgical registrar is concerned that he has Boerhaave syndrome (transmural oesophageal perforation). a) List four clinical signs specific to a diagnosis of oesophageal perforation. (4 marks)
• Chest/neck surgical emphysema
• Resonant percussion
** Due to pneumothorax.
• Dull percussion Due to atelectasis or
consolidation.
• Reduced air entry on auscultation
**Due to atelectasis or consolidation.
• Hamman crunch
**Cracking sound of pneumomediastinum on auscultation.
b) List four signs consistent with oesophageal perforation that may be seen on a CT scan. (4 marks
• Peri-oesophageal air
• Pneumomediastinum
• Pneumopericardium
• Cervical surgical emphysema
• Pneumothorax
• Pleural effusion (usually left
sided)
• Lung abscess
• Pneumoperitoneum
Any 4 Which tissues are
contaminated by air/gastric
contents depends on the
location of the oesophageal
perforation. Boerhaave
syndrome most commonly
affects the mid-thoracic
oesophagus, whilst trauma
secondary to
oesophagoscopy most
commonly results in
perforation at the
cricopharyngeus, and just
proximal to the lower
oesophageal sphincter.
A diagnosis of oesophageal perforation is made and an open oesophageal repair via a thoracotomy is planned. c) State two considerations that may affect your drug choices during induction of anaesthesia. (2 marks)
• Sepsis is likely with potential for haemodynamic instability –consider use of cardiostable induction agent, e.g. ketamine
• Rapid sequence induction is indicated, but suxamethonium Increases intragastic pressure – use rocuronium
The use of cricoid pressure (which may increase the risk of exacerbating mediastinal contamination through coughing/straining) must be balanced against the risk of soiling
lungs.
d) List the two options for airway management in this case. (2 marks
• Double-lumen endotracheal tube
(DLETT)
1 Left sided DLETT is usually
preferred, as right-sided
DLETT risks occlusion of
the right upper lobe
bronchus.
• Single lumen endotracheal tube
with bronchial blocker
1 An endotracheal tube of at
least 7.5 mm is required.
e) List two strategies that you would take to prevent lung injury during the case. (2 marks)
• Low tidal volume: 6–8 mL/kg
during two lung ventilation, 5–6
mL/kg whilst on one-lung
ventilation
Any 2
• Permissive hypercapnoea
• Avoid fluid overload Fluid guided by pulse
contour analysis cardiac
output monitor – clearly
this is not the time to use an
oesophageal Doppler!
The procedure is difficult, and intra-operatively, the patient spends 8 hours in the lateral position. f) List six complications of prolonged lateral positioning in this case. (6 marks)
• Displacement of double-lumen
endotracheal tube
** A fibre-optic scope should be immediately available, and the DLETT position checked following any patient repositioning.
• V̇ /Q̇ mismatch and shunt, leading
to hypoxaemia
• Radial nerve palsy in superior arm
**The radial nerve is
particularly at risk if the arm is abducted > 90°; an axillary roll is used to prevent mid-humeral radial nerve compression.
• Common perineal nerve palsy in
the inferior leg
** Due to compression between the fibular head and the operating table.
• Saphenous nerve palsy of
either leg
** A pillow is usually placed between the knees to prevent this complication.
• Brachial plexus injury
** The neck must be in a neutral position to prevent brachial plexus stretch.
• Ear injury
**Ensure that the ear has not folded during positioning.
• Optic neuropathy
** The lower globe is at risk from external compression from the pillow in the
lateral position.
• Pressure injury to bony
prominences, e.g. iliac cres
Question 9. Sarah, a 42-year-old woman, is listed for a laparoscopic cholecystectomy. Her body mass index (BMI) is calculated as 45 kg/m2. a) In which category of obesity would she be placed? (1 mark)
• Obesity class III
** According to the WHO
classification of obesity 2014. This BMI would
previously have been classified as morbidly obese.
At pre-operative assessment, the patient completes a STOP-BANG questionnaire which suggests she is at high risk of obstructive sleep apnoea (OSA). b) Other than obesity, list four risk factors for the development of OSA in all patient groups. (4 marks)
• Craniofacial abnormalities (such as Pierre–Robin and Down’s syndromes, acromegaly)
• Tonsillar and adenoidal hypertrophy = the major cause of OSA in children.
• Male gender
** Male gender: possibly as a result of a relatively
increased amount of fat deposition around the pharynx.
• Age 40–70 years
• Enlarged neck circumference >37 cm women,
>43 cm men.
• Neuromuscular disease
c) List three health conditions that may result as a consequence of OSA. (3 marks)
• Neuropsychiatric: depression, anxiety
**OSA patients experience many neuropsychiatric
symptoms such as daytime somnolence, impaired
concentration, irritability.
These are not considered ‘health conditions’.
• Endocrinological: diabetes mellitus, dyslipidaemia,
infertility, hypothyroidism
• Cardiovascular: hypertension, myocardial infarction, stroke, atrial fibrillation, pulmonary hypertension
d) List four options that you would recommend to this patient for the management of her OSA. (4 marks
• Weight loss
• Reduce/stop alcohol intake
• Smoking cessation
• Nasal continuous positive airway
pressure (nCPAP)
** Overnight nCPAP set at between +5 and +20 cmH2O
probably works by acting as a pneumatic splint to maintain upper airway patency. It has the effect of reducing daytime sleepiness, improving mood and cognitive function, and improving blood pressure control.
• Sleep modification (i.e. sleeping in lateral position or 30° head up instead of supine)
The patient is established on OSA treatment and presents for a laparoscopic cholecystectomy. e) List four physiological consequences of a raised intra-abdominal pressure as a result of pneumoperitoneum. (4 marks
• Increased systemic vascular
resistance this is thought to be due to
mechanical compression of the aorta, release of vasoactive substances –vasopressin, catecholamines, and activation of the renin-angiotensin-aldosterone
system.
• Decreased preload due to compression of the inferior vena cava
• Diaphragmatic splinting/reduced functional residual capacity
** Results in atelectasis and V̇ /Q̇ mismatch
• Raised intrathoracic pressure/reduced pulmonary compliance
• Decreased liver/renal/splanchnic arterial and venous blood flow
** Glomerular filtration rate
decreases by ~25%; gut mucosal blood flow decreases by ~40%.
• Decreased cerebral venous drainage, which leads to raised intracranial pressure
** This is of particular relevance for prolonged surgical procedures performed in a steep Trendelenburg position, which may result in cerebral oedema.
• Activation of the sympathetic nervous system ±
parasympathetic nervous system
f) List four complications of the surgical positioning used when performing a laparoscopic cholecystectomy in this patient. (4 marks
• Manual handling of the patient
** Greater number of members of staff required for lateral transfer, plus special equipment (e.g. hover
mattress).
• Width of operating table Side extensions are often
required for bariatric patients.
• Patient movement on operating table once positioned in reverse Trendelenburg, Bariatric patients are often
positioned prior to induction of anaesthesia in
a seated position with a support under bent knees to
limit movement.
• Reduced venous return in reverse Trendelenburg position
** In combination with pneumoperitoneum may
result in hypotension.
• Peripheral nerve injury
**This is a complication of surgical positioning in any
patient, but particularly in the left arm following left
lateral tilt.
Question 10. Matt, a 24-year-old man, is listed for a bimaxillary (combination of maxillary and mandibular) osteotomy.
a) List six perioperative airway concerns specific to bimaxillary osteotomy. (6 marks)
• Shared airway
• Nasal intubation required
**The mouth must be free to enable the occlusion of the teeth to be checked intra-operatively.
• Nasal intubation risks epistaxis
** Due to direct trauma to Kisselbach’s plexus of Little’s area.
• Intra-operative damage to nasal
endotracheal tube
** The site of surgery is inclose proximity to the nasal
tube.
• Bimaxillary surgery may be performed in patients with comorbidities associated with difficult laryngoscopy
E.g. previous cleft palate repair, obstructive sleep apnoea.
• Possibility of patient being woken with rigid inter-maxillary fixation (IMF) IMF is ‘wiring’ the teeth together – more commonly, elastic bands are applied after the patient has left PACU.
• Intra-operative throat pack commonly used
• Intra-operative head movement may result in extubation or endobronchial intubation
• Post-operative bleeding/haematoma
**Post-operative bleeding may rapidly result in airway
obstruction, particularly in patients with rigid IMF.
) On examination, you notice that Matt has obstructed nasal passages. List three alternative methods of airway management for this case. (3 marks
• Retromolar reinforced oral
endotracheal tube
**An oral flexible endotracheal tube is pushed behind the molar teeth, so that the teeth can still be occluded.
• Submental intubation
** The end of a conventional endotracheal tube (minus
its connector) is passed through the floor of the
mouth.
• Tracheostomy
c) List four techniques for minimising intra-operative blood loss during a bimaxillary osteotomy. (4 marks)
Position the patient head up
• Induced hypotension
• Surgical infiltration with adrenaline-containing local
anaesthetic
• Tranexamic acid
** The bony mid-face receives an extensive blood supply, and the posterior maxilla is close to the pterygoid venous plexus.
d) List three advantages for using total intravenous anaesthesia (propofol and remifentanil) for this case ( osteotomy). (3 marks
• Reduced incidence of post-operative nausea and vomiting (PONV)
**PONV is common in bimaxillary osteotomy
surgery, and may be dangerous if jaws are wired
post-operatively.
• Used to induce intra-operative hypotension, improving operative field
• Smooth extubation without coughing or straining
**Coughing and straining may promote bleeding
e) List four precautions that you would take to reduce the risk of a retained throat pack. (4 marks
• Label or mark the patient’s head
with an adherent sticker
• Label the endotracheal tube or
laryngeal mask airway
• Attach the pack to the artificial
airway
• Leave part of the pack protruding
• Include in the swab count
• Not using a throat pack
Any 4 Retained throat pack is a
‘never event’. The National
Patient Safety Agency
issued a Safer Practice
Notice with these
recommendations in 2009.
Question 11. Pete, a 22-year-old man with epilepsy and severe learning difficulties, is listed for a magnetic resonance (MR) scan of his brain under general anaesthesia.
a) Pete’s parents ask you to provide premedication to avoid unnecessary distress during IV cannulation. List four pharmacological options. (4 marks)
• Topical Eutectic Mixture of Local
**Anaesthetics (EMLA)/Ametop, If accepted by the patient!
• Midazolam Oral/buccal (10–20 mg) has
an unpleasant taste that can be masked with
squash/juice; intranasal (0.2 mg/kg) stings.
• Temazepam Dose 10–30 mg, tablets
may not be acceptable to the
patient.
• Ketamine Side effects: increased
salivation, dissociative state.
** Routes of
administration are oral
5–10 mg/kg, intranasal
3–5 mg/kg, intramuscular 4 mg/kg.
• Clonidine Oral dose 4 μg/kg
b) Outline the physical principles of magnetic resonance imaging. (4 marks)
• Hydrogen atoms are abundant within the body within water molecules
• Hydrogen atoms possess a property called ‘spin’
• When surrounded by a strong magnet, spin aligns with the magnetic field
• Spin can be turned out of alignment with the magnetic
field by applying pulses of electromagnetic radiation
• The energy emitted is detected by three receiving coils, and translated into a series of grey pixels on a screen
* The three coils are positioned to generate a
three-dimensional image.
c) TheMRscanner uses a superconducting magnet. What is superconductivity (2 marks), and how is it achieved (1 mark)?
Superconductivity:
• A phenomenon where electrical resistance in a coil of wire decreases to zero below a critical temperature
• Passing of an electric current through a coil of wire results in a strong magnetic field (electromagnet)
**A typical MR scanner uses a magnetic field strength of 1.5 Tesla.
Achieved by:
• Cooled to 4.2 K by surrounding the coils in liquid helium
* This is usually surrounded by a jacket of liquid
nitrogen, which has a boiling point of 77 K, to
keep the expensive liquid helium from boiling away.
The patient is sedated and the radiographers go through their safety checklist with his parents. d) List four implanted ferromagnetic objects that may cause harm to the patient if subjected to the strong static magnet. (4 marks)
• Cardiac pacemaker/loop recorder
• Aneurysm clip
• Cochlear implant
• Shrapnel/penetrating eye injury
involving metal
• Cardiac defibrillator
• Any type of nerve/neuro
stimulator
• Joint replacement
• Hydrocephalus shunt
The patient is now anaesthetised and ready to enter the MR scanning room. A laryngeal mask airway (LMA) was chosen for airway management. e) Which part of the LMA risks degradation of the MR image? (1 mark)
The pilot balloon
**The pilot balloon contains a ferromagnetic spring whichis normally secured by tape, away from the area to be
scanned.
f) Asidefromtheinteraction between ferromagnetic objects and the strong static magnetic f ield, list four additional classes of hazards specific to the MR environment. (4 marks)
• Time-varying magnetic gradient fields
** Small dynamic magnetic fields can induce a current sufficient to stimulate peripheral nerve and muscle cells, causing
discomfort.
• Acoustic noise
** Switching of gradient fields creates loud acoustic noise, above the safe level of
85 dB – patients and staff need ear protection.
• Radiofrequency heating
**Power dissipation within the patient, causing an increase in body
temperature. There is a risk
of severe, rapid burns from
any conductive material left
on the patient’s skin: ECG
leads, metal in clothing etc.
• Helium escape
** In the event of a spontaneous or emergency field shutdown (a ‘quench’),
the liquid helium (and nitrogen) expands to a gas and must be vented very
rapidly, with the potential for a hypoxic environment within the MRI scan room.
Question 12. You are asked to assess Ash, a 32-year-old man who has been admitted to the Emergency Department after being trapped in a house fire. He has burns across his chest, abdomen and left arm. His estimated weight is 100 kg. a) List five clinical features that would lead you to suspect a significant inhalational injury. (5 marks)
• Singed hairs of eyebrows/
eyelashes/nasal hair
• Swelling of the face, lips, tongue
or uvula
• Soot in nose/mouth/sputum
• Inspiratory stridor
• Change in voice/hoarseness
• Dyspnoea
• Coughing
• Wheezing
• Copious secretions
b) Whatare the distinguishing features of the following degrees of burn injury? (3 marks)
○ First-degree burn: red, painful, dry,
no blisters
** Only epidermis involved.
○ Second-degree burn: red, blistered,
painful, oedematous
** Epidermis and dermis involved.
○ Third-degree burn: white, painless,
no bleeding on pricking with a needle
○ Full thickness burn causing destruction of all skin layers plus underlying tissues.
c) The ED registrar states that the patient has burns covering an estimated 30% body surface area (BSA). How has she come to this conclusion? (2 marks)
• Wallace ‘Rule of nines’ (accept:
Lund-Browder chart)
• Chest/abdomen represents 18% BSA; one arm represents 9% BSA
*The adult head represents 9% BSA, whereas a child
has a proportionally bigger head (representing 18%
BSA) and smaller legs (representing 13.5% BSA
each)
The ED nurse asks you to prescribe fluid for the patient. It has now been 1 hour since the patient was burnt. d) What formula will you use to calculate this patient’s intravenous resuscitation fluid? (2 marks) What will you prescribe? (2 marks)
Parkland formula:
** The Parkland formula is the most widely used in the UK.
It does not incorporate maintenance fluid which
should be considered in addition to the resuscitation
fluid.
• Fluid requirement 4 mL × weight
kg × % burn
• Half of the fluid given within the first 8 hours, the other half over the next 16 hours.
Prescription:
4 mL × 100 kg × 30% = 12,000 mL
⇒ Prescription: 6000 mL Hartmann’s over 7 hours, then
6000 mL Hartmann’s over 16 hours
e) TheEDregistrar discusses the case with the regional burns centre. List three indications for transfer to a specialist burns centre. (3 marks)
• Age: < 5 years or > 60 years old
• Site of burn: hands, feet,bperineum, any flexure (e.g. neck, axilla), circumferential burn of limb, torso or neck.
• Inhalational injury
• Mechanism of burn: chemical, steam, ionising radiation
• > 10% BSA burn (adult) or > 5% BSA burn (child)
• Significant comorbidities
• Significant associated injuries, e.g. head injury, crush injur
Although the patient’s airway is currently patent, you remain concerned about an inhalational injury. You decide to intubate the patient prior to transfer to the regional burns centre. f) List three management considerations specific to inhalational burn injury. (3 marks)
• Rapid sequence induction
• Uncut endotracheal tube
• Tape the endotracheal tube in place rather than use a tie
• Minimum of size 8.0 mm endotracheal tube to facilitate bronchoscopy
• Insert a nasogastric tube at the same time
** If inhalational injury is suspected, early intubation
is crucial. The specialist burns centre will be happy
to receive an intubated patient who they can
extubate the following day if there are concerns about the airway.
** Suxamethonium is not contraindicated until 48
hours after the burn.
Ap
• Apnoea monitoring in a high-dependency environment
Mandatory for infants < 44
weeks post-conceptual age,
or for ex-premature infants
< 60 weeks post post-
conceptual age.
• Reduced IV paracetamol dose:
7.5 mg/kg every 6 hours for post-
conceptual age 36–44 week
e) List the three most common scoring systems in the United Kingdom for grading the severity of aneurysmal subarachnoid haemorrhage. (3 marks
Hunt andHess grading scale for subarachnoid haemorrhage (clinical)
WFNS=World Federation of Neurological Surgeons
•WFNS Gradingc Scale for Aneurysmal Subarachnoid Haemorrhage(clinical)
•Fisher grade (based on CT scan)
**There are many more scoring systems, but these three are byfar thecmost commonly used.
