El-Boghdadly - 2

Question 1

1. 5 days ago a 25-year-old woman suffered a traumatic brain injury. Despite a normal CT, she demonstrated bilateral motor posturing.

She therefore had an intracranial pressure (ICP) bolt inserted shortly after admission in order to
monitor her ICP. You begin your morning review by analysing her ICP waveform.
Which of the following would concern you most acutely?

A Lundberg A waves
B A flat trace
C A baseline value of 20mmHg
D Lundberg B waves
E The most prominent upstroke being the P2 (tidal) wave

Answer 1

D

1. A Lundberg A waves

An intracranial pressure (ICP) bolt is a solid, intra-parenchymal catheter containing either a fibreoptic sensor or a micro strain gauge in its tip. It can be inserted under local anaesthetic and extends up to 20 mm intracranially, thereby allowing the
transduction of intracranial pressure in that region of brain tissue.

The value is usually displayed as a number but can also be translated into a graphical display of the waveform.

The ICP waveform is a reflection of the intracranial arterial pulsation and subsequently has recognisable characteristics (Figure 2.1).

Lundberg A waves: Large plateau waves persisting for 5–10 minutes. These are always pathological and warn of impending herniation

• Lundberg B waves: Fluctuations in ICP that occur with a frequency of 0.5–2 waves per minute. They are thought to be associated with ICP instability and/ or vasospasm due to their correlation with increased flow velocity results from middle cerebral artery transcranial doppler studies

• Lundberg C waves:
Fluctuations in ICP at a frequency of 4–8 waves per minute.
These are considered normal in some patients and thought to correspond to the respiratory and cardiac cycles (Figure 2.3)

The advantages of an ICP bolt include ease of insertion, that does not require
transfer to the operating theatre, and output that is neither altered by patient
position nor susceptible to damping. The disadvantages are that it only reflects
regional pressure changes and once inserted, cannot be recalibrated. Therefore if the
bolt has been in-situ for several days, a degree of drift must be taken into account
and subsequently they often need replacing if required for longer than 5 days.
The most acutely worrying characteristic in the above scenario would be the
presence of Lundberg A waves. Lundberg B waves would be a matter for concern
but not as pressing. A baseline value of 20 mmHg may represent the true ICP
value but at 5 days could also incorporate an element of drift in calibration. When
interpreting a flat trace the possibility of displacement or kinking of the transducer
must be considered in the first instance.

Question 2

2. You are called to the emergency department to assist with a 20-year-old man who presented following a grand-mal seizure.
   He has begun fitting again and his conscious level has remained below baseline for 30 minutes. He has a history of
   epilepsy and has not been taking his usual medication since his prescription ran out 1 week ago.

He is otherwise well.
Which of the following is the most appropriate immediate action?

A Intubate the patient to protect his airway and optimise ventilation
B Check his blood glucose and treat any hypoglycaemia with intravenous dextrose
C Take blood for full blood count, electrolytes, urea, creatinine, liver function
tests and anti-epileptic medication levels
D Administer his anti-epileptic medication intravenously
E Apply pulse oximetry, blood pressure and ECG monitoring

Answer 2

A

Seizure activity that persists without return of conscious level to baseline for 30 minutes is defined as status epilepticus and is a medical emergency. Status can occur with any classification of seizure but the generalised form is that which is most commonly observed. Rapid assessment and swift management is required to minimise the complications of unremitting neuronal discharge.

If status persists, compensation in blood flow to meet increased metabolic demand begins to fail, leading to insufficient cerebral perfusion. Cerebral tissue damage follows. Cardiac arrhythmias, pulmonary hypertension, pulmonary oedema, global metabolic
disturbances and rhabdomyolysis may also ensue.

All of the options should be performed as soon as possible, and ideally in parallel.

National Institute for Health and Care Excellence (NICE) UK guidelines specify that airway securement should be implemented immediately but in order to perform this
safely, it is mandatory to have standard monitoring in situ.

Question 3

3. You are asked to pre-assess a 68-year-old man for elective open umbilical hernia repair. He suffers from exertional angina (three flights of stairs) and had coronary angiography 6 months ago, which showed right coronary and circumflex artery
   disease. He had a myocardial infarction 2 years ago. His symptoms have been stable over the past year and he is currently taking bisoprolol 2.5mg once a day (o.d.), aspirin 75mg o.d. and ramipril 2.5mg o.d. His creatinine is 120μmol/L. He is
   not diabetic and has not had a stroke. He is independent and performs all his own housework.

Which of the following is the most appropriate next step in this patient’s management?

A Schedule the patient for surgery. Cease the ramipril 24hours preoperatively. Continue the aspirin
B Schedule the patient for surgery. Cease the bisoprolol 2days preoperatively.
C Obtain non-invasive stress testing
D Refer for repeat coronary angiogram
E Refer for coronary artery bypass surgery

Answer 3

A

3. A Schedule the patient for surgery. Cease the ramipril
   24 hours preoperatively. Continue the aspirin

The European Society of Cardiology (ESC) has produced guidelines and a step-wise pathway for the assessment of cardiac patients for non-cardiac surgery.

The patient presented has stable coronary artery disease and scores 2 (for previous myocardial infarction and proposed intraperitoneal surgery) on the revised cardiac risk index
(also known as the Lee Index).

This gives an approximate risk of cardiac death or
non-fatal myocardial infarction of 2.4% (95% CI 1.3–3.5%). The factors included on this risk index include:

• History of ischaemic heart disease
• History of congestive heart failure
• History of cerebrovascular disease
• History of diabetes requiring preoperative insulin use
• Chronic kidney disease (serum creatinine > 170 μmol/L)
• Undergoing major surgery (suprainguinal vascular, intraperitoneal or intrathoracic)

The ESC guidelines for non-invasive testing (stress echo, exercise testing) use a slightly amended version of the above risk scale (with prior myocardial infarction being assigned a separate point) and recommend that patients with three or more
of the clinical factors listed below are referred for further assessment of myocardial perfusion and function preoperatively.

• Angina
• Prior myocardial infarction
• Heart failure
Stroke/transient ischaemic attack
• Renal dysfunction with serum creatinine > 170 μmol/L
• Diabetes requiring insulin therapy

In patients with extensive stress-induced ischaemia, referral for coronary revascularisation may be indicated.

The method of achieving this will depend on the
potential benefit of the procedure
(percutaneous coronary intervention vs coronary
artery bypass grafting) against the risk of the procedure.

Pre-operative diagnostic angiography is indicated in those patients with:
• Acute ST elevation myocardial infarction (STEMI)
• Non-STEMI (NSTEMI) and unstable angina
• Angina not controlled with medical therapy
It may also be considered in stable patients undergoing high-risk surgery. Referral for any procedure must take into account the risk to the patient as well as the
potential benefit. In this situation, the patient is relatively low-risk and has had a reasonably recent angiogram; it is therefore unlikely that a repeat angiography justifies the risk.

In patients already established on beta-blockers, these should be continued throughout the perioperative period. Although a topic of some debate, usual practice is to omit ACE-inhibitors 24 hours before surgery due to an increased risk of
intraoperative hypotension. Aspirin should be continued unless there are concerns regarding haemostasis during surgery

(certain neurosurgical procedures, for example).

The use of biomarkers including Brain Natriuretic Peptide (BNP) is under evaluation and may be of some use in the risk stratification of cardiac patients.

Question 4

4. A healthy 30-year-old man due for an appendicectomy is undergoing a rapid sequence induction. After full pre-oxygenation and administration of thiopentone
   and suxamethonium, three attempts at intubation have failed with an unexpected grade III Cormack & Lehane laryngoscopy view. His oxygen saturations are 92%
   and full cricoid pressure is being applied.
   What action is most appropriate in this situation?
   A Reattempt intubation using a different laryngoscope
   B Reattempt intubation whilst reducing the cricoid pressure
   C Attempt insertion of a supraglottic airway device
   D Postpone surgery and awaken the patient
   C Attempt cannula cricothyroidotomy

Answer 4

C

4. D Postpone surgery and awaken the patient
   The management of an unanticipated difficult intubation during a rapid sequence induction can often be a challenging experience for the anaesthetist and clear guidelines by the Difficult Airway Society have been developed to help keep patients safe should this occur. During routine inductions, four initial intubation
   attempts are allowed, however this is reduced to three in the rapid sequence scenario. Patients receiving a rapid sequence induction have an increased risk of regurgitation so their risk of aspirating during repeated attempts at tracheal
   intubation is higher. Furthermore, the short half-life of suxamethonium will also increase the risk of laryngospasm and difficult laryngoscopy should repeated
   intubation attempts be made when neuromuscular function is recovering.

The safest action in the above scenario is to postpone surgery and awaken the patient.

The first attempt at laryngoscopy should always be performed with the patient in the optimum intubating position after full pre-oxygenation. If intubation is unsuccessful, then reducing the cricoid pressure, using introducers or an alternative
laryngoscope can all improve the success rate. However these changes need to be
performed within the allocated initial three attempts.

The use of laryngeal mask airways do have a role during rapid sequence inductions, but should only be used after a failed initial intubation plan and failed face mask oxygenation whilst waiting for the patient to awaken. Failure of oxygenation is defined as oxygen saturations of < 90% whilst receiving 100% oxygen.
.
Only in a ‘cannot intubate and cannot ventilate’ scenario with increasing hypoxemia should a cannula or surgical cricothyroidotomy be performed (Figure 2.4).

Question 5

5. An 80-year-old woman, admitted with pneumonia 14days ago, suffers an episode of large haematemesis requiring endoscopic investigation. You anaesthetise her and secure her airway uneventfully with a size 7.5 endotracheal tube
   (ETT) secured at 24 cm to the teeth. Oxygen saturations are 99% (Fio2 0.4). The
   gastroenterologist then extends her head. At this point she becomes progressively
   hypoxic and chest wall movement becomes limited to the right side.
   What is the most likely reason for her desaturation?
   A Aspiration of gastric contents
   B Bronchospasm
   C Sputum plugging of a bronchus
   D Pneumothorax
   E Endobronchial intubation

Answer 5

E

5. E Endobronchial intubation
   When intubating a patient it is imperative that tube position is assessed clinically. It is important to bear in mind that change in patient position for a procedure may cause the endotracheal tube (ETT) to migrate. This lady’s ETT is originally placed at a
   depth most likely to be too great for a female patient. Extending her head probably resulted in confirming endobronchial intubation.

Aspiration of gastric contents would most likely result in right-sided decompensation or, in this scenario, be evident from viewing the oral cavity. She may have plugged off her left bronchus, although her saturations are surprisingly
robust for a patient with the amount of sputum that would be present for such an event. Bronchospasm and pneumothorax may occur independently or as a consequence of endobronchial intubation.

Question 6

6. A 56-year-old man is taken to the intensive care unit following a laparotomy a week ago for bowel obstruction. He is hypertensive, has a body mass index (BMI)
   of 42, and has had an ileus for the last 7days. His abdomen is tender and tensely distended. There are no signs of sepsis, but he has worsening renal function and a poor urine output, despite a very positive fluid balance.

He had become increasingly breathless with type II respiratory failure, and after a failed trial of non-invasive ventilation, is now mechanically ventilated. His ventilator pressures are worsening and his base excess and lactate are increasing.
Which of the following is the most correct regarding this patient?

A A measurement of intra-abdominal pressure is most safely performed with an intraperitoneal catheter and pressure transducer
B An intravesical measurement is performed at the end of inspiration
C Abdominal compartment syndrome may provoke a cardiac arrest at laparotomy
D An abdominal pressure of 24mmHg can be considered normal
E The only effective treatment is re-laparotomy leaving the abdomen open with a Bogota bag

Answer 6

C

6 C Abdominal compartment syndrome may provoke a
cardiac arrest at laparotomy

The management of abdominal hypertension and compartment syndrome can be imagined in a similar way to elevated intracranial pressure. Thus the initial management relies on the maintenance of abdominal perfusion pressure (APP),
which is mean arterial pressure (MAP) minus intra-abdominal pressure (IAP).

Maintenance of an APP > 60 mmHg has been shown to improve outcome in a condition with an untreated mortality otherwise approaching 100%.

Definitions and measurement
Normal IAP is in the region of 5–7 mmHg in the critical care setting, and this is increased by presence of intra-abdominal fluid or collections, upright position, and mechanical ventilation. Intra-abdominal hypertension is diagnosed with a pressure
persisting above 12 mmHg, and this is termed compartment syndrome when the pressure is consistently above 20 mmHg with new organ failure.

Measurement can be direct, using an intraperitoneal needle or catheter and
transducer system, or indirect via intra-vesical, intra-gastric, intrauterine or rectal
routes. The commonest route is the bladder, which can make use of a normal Foley catheter and gives usable results with lower risk than direct methods.

The process involves connecting a transducer to a three-way tap, which measures the pressure of 25 mL of sterile saline instilled into an empty bladder, after the catheter is clamped.
Readings should be taken at end-expiration and one minute following instillation of the saline to allow for bladder relaxation. The patient should have a relaxed abdominal wall, and not be coughing straining.

Systemic pathological effects
Elevated intra-abdominal pressure has wide-ranging systemic effects; high abdominal pressure produces collapsing of the vasculature. On the venous side, this gives rise to reductions in venous return and reduced stroke volume. Arteriolar compression gives an increased systemic vascular resistance (SVR) and afterload.

The combined effects are those of reduced cardiac output that can rapidly spiral to produce gut ischaemia.

Respiratory features are those of respiratory failure due to atelectasis, collapse and shunt. There is a reduction in chest wall compliance and diaphragmatic excursion. In ventilated patients the increased pressures required to maintain oxygenation and
ventilation can compromise cardiac output further.

Renal function is impaired as a combined result of reduced cardiac output and a reduction in filtration gradient (FG). The filtration gradient is the pressure difference across the glomerulus, and is therefore the difference between the perfusion pressure and the pressure in the proximal tubule.

Raised IAP compresses the collapsible renal outflow tracts and collecting systems, such that tubular pressure
rises, thereby lowering FG.

Thus a high IAP both reduces the APP and raises the
tubular pressure all of which reduce the FG required to drive filtration.

High IAPs also increase intracranial pressure (ICP). This occurs by a combination of high intrathoracic pressure and reduced venous return, and ventilatory difficulties and the consequences for arterial carbon dioxide tension. The combination of
pre-existing intracranial hypertension and abdominal compartment syndrome is particularly dangerous and may mandate surgical abdominal decompression to
lower ICP.

Management
Non-surgical management is directed toward the joint aims of lowering intraabdominal pressure and maintaining APP with careful fluid resuscitation to normovolaemia followed by vasopressor support if required.

Over enthusiastic fluid therapy may contribute to gut oedema and further compromise tissue perfusion.

Pressure in the abdomen may be lowered by reducing the volumes of the contents, with nasogastric tubes, endoscopic evacuation or invasive drainage of gas or fluid.

In addition, in the ventilated patient consideration can be given to optimal sedation and muscle relaxation to reduce straining and asynchrony.

Surgical management involves laparotomy and decompression.

The abdomen is then left open and covered with a temporary closure of a Bogota bag or vacuum dressing. It remains important to measure abdominal pressure even after
decompression, as 25% of patients with a Bogota bag go on to develop secondary hypertension. Serious caution should be exercised at laparotomy for raised IAP as profound haemodynamic instability may ensue as a consequence of abdominal reperfusion alongside a sudden fall in SVR. This can be massive and of sufficient magnitude to bring about cardiac arrest.

As described above, indirect methods of measurement reduce the risks of complications associated with needle or catheter techniques. Measurement takes place at the end of expiration. A pressure of 24 mmHg is more than double the cut-off for hypertension, and within the range of compartment syndrome, if
sustained. Management strategies are discussed above, with non-surgical options also available. Laparotomy is indeed a risk factor for cardiac arrest given the massive physiological changes that occur in this situation.

Question 7

7. A 60-year-old man awaiting surgical resection for his tracheal carcinoma presents to the emergency department with worsening dyspnoea. As part of his pulmonary
   function tests, a bedside flow-volume loop (spirogram) is ordered. What will be the most likely appearance of his flow-volume loop?
   A Flattening of the inspiratory limb only
   B Flattening of the expiratory limb only
   C Flattening of both the inspiratory and expiratory limbs
   D Saw-tooth pattern in both the inspiratory and expiratory limbs
   E Normal appearance of both inspiratory and expiratory limbs

Answer 7

C

7. C Flattening of both the inspiratory and expiratory limbs

A flow-volume loop is a plot of flow rate (y-axis) against lung volume (x-axis) during maximal forced inspiration and expiration.

The contour of this loop can aid in localising upper airway obstructions and assessing their functional impact.

Upper airway obstructions are classified as either intrathoracic or extrathoracic depending on whether they are present within or outside the thoracic inlet respectively. In addition, they are also described as either variable or fixed depending on whether the airway lesion calibre changes during the respiratory cycle.

For variable extrathoracic obstructions (such as vocal cord paralysis), the flow volume loop classically displays a flattened inspiratory and normal expiratory limb.

This is because during inspiration, the transmural pressure is negative as a result of a subatmospheric intraluminal pressure and an atmospheric extraluminal pressure.

Consequently, the extrathoracic portion of the upper airway will have a tendency to collapse during inspiration resulting in reduced airflow in the presence of an obstructing lesion.

During expiration, the intraluminal pressure surpasses the
pressure surrounding the airway thus reducing the obstruction.

Flow volume loops in the presence of variable intrathoracic obstructions (such as bronchogenic cysts) classically display a flattened expiratory and normal inspiratory limb.

Flow limitation is encountered during expiration because at this phase of the respiratory cycle, the pleural pressures exceed the airway pressures exacerbating the obstruction. During inspiration, the pleural pressures are negative relative to the
intrathoracic airways thereby creating no restriction to airflow.

Fixed upper airway obstructions are characterised by a constant degree of airflow limitation during the whole respiratory cycle as they limit the influence of transmural pressures on airway diameter. They can be extrathoracic (large goitres) or
intrathoracic (large tracheal tumours) and their flow loops display flattening of both the inspiratory and expiratory limbs. The above case is an example of a fixed airway obstruction.

A saw-tooth pattern describes small oscillations which can be observed throughout the inspiratory and expiratory limbs of the flow volume loops as a consequence of either equipment artifact, neuromuscular disease or pedunculated tumours (Figure 2.5).

Question 8

8. A 32-year-old woman was recently diagnosed with brainstem death following a subarachnoid haemorrhage. She was initially hypertensive, then developed polyuria and gradually became hypotensive. The patient has received 30mL/kg of
   crystalloid boluses. What is the next pharmacological intervention needed to restore the patient’s
   blood pressure?
   A Dopamine
   B Adrenaline
   C Vasopressin
   D Noradrenaline
   E Further bolus of colloid

Answer 8

C

8. C Vasopressin
   Brainstem herniation causes relative hypotension and bradycardia after an initial period of hypertension due to catecholamine release. This is due to loss of autonomic
   control of vasomotor tone and loss of vagal tone. Treating episodes of hypotension with adrenergic vasoactive drugs exacerbates end-organ ischaemia and they are
   contraindicated in a potential organ donor.

Vasopressin is the agent of choice to treat hypotension and maintain vascular tone following brainstem herniation as it
improves organ perfusion and corrects the polyuric component of diabetes insipidus caused by hypothalamic ischaemia.

Fluid boluses are useful to maintain euvolaemia,
but over filling patients also risks detrimental outcomes to organs.

Question 9

9. You have been asked to see a 32-year-old patient in recovery following a retrograde intramedullary femoral nailing. He works as a builder and fell from a ladder sustaining bilateral femoral fractures. The plan is to fix the other leg in the next few
   days. He is desaturating to 88% on oxygen via facemask and is confused, and one of the recovery staff has also noticed a petechial rash on the patient’s neck. In diagnosis and treatment of the likely condition, which of the following tests is
   most important?

A Arterial blood gas analysis
B Bronchoscopic alveolar lavage (BAL) for macrophages
C Trial of methylprednisolone for 48hours
D A CT of the chest
E Urine microscopy for lipid droplets

Answer 9

A

9. A An arterial blood gas analysis

Fat embolism indicates the presence of fat within the pulmonary or peripheral circulation, often without symptoms.

Fat embolism syndrome is the clinical
consequences of fat embolism occurring in some patients and has a quoted mortality of between 5–15%. The commonest implicated fractures are the closed fractures of the long bones and pelvis. The greater the number of fractures, the
higher the incidence. A third of patients with bilateral femoral fractures go on to develop the syndrome.

Presentation and diagnosis
The syndrome most often presents at 1–3 days. There are a variety of sets of published diagnostic criteria, but all have in common either an arterial blood gas (ABG) or clinical features of profound type I respiratory failure.

Clinically, the two other major tenets are neurological dysfunction, most commonly acute confusion, and the classical petechial rash. The rash may be a late sign and only present in 60% of cases.

Blood indices most often reflect a marked anaemia with thrombocytopenia. Other features such as fat in sputum, urine and alveolar macrophages may support the
diagnosis, but equally do not correlate well with the severity of the syndrome.

Pathophysiology
Two main theories exist. In the mechanical theory, physical disruption forces adipose marrow into the venous system and bones with high marrow content are indeed most associated with the syndrome.
However, studies have directly demonstrated embolic load in patients during orthopaedic surgery who have not progressed to
develop the clinical syndrome.

The mechanical theory also does not explain why,
despite the fact that embolism is greatest around the time of injury, occurrence of the syndrome peaks at 24–72 hours.

The biochemical theory ascribes toxicity to the hydrolytic degradation of neutral marrow fat to free fatty acids.

These free acids are shown to be able to induce acute
lung injury in animal models. C-reactive protein may also have a role in abnormal lipid metabolism in these patients.

Treatment
The treatment is essentially supportive with good oxygenation and ventilation in an intensive care environment if indicated.

Correction of blood indices may be needed.
Prevention is with operative fixation after early immobilisation, and some operative techniques exist to reduce intraosseous pressure during drilling or reaming to reduce the embolic load.

Some advocate steroid prophylaxis with methylprednisolone for those patients at highest risk, with some evidence to support this. There is no evidence to support the use of steroids as a treatment however. Aspirin may speed recovery of platelets and
possibly lung injury.

In this question, the stem highlights the diagnosis of fat embolism syndrome, which most candidates are likely to discern.

The real question relates to the most helpful test,
in both diagnosis and treatment, which requires a more extensive understanding of the disease. Special investigations which have been used to assist in the diagnosis do
include bronchoscopic alveolar lavage (BAL) for lipid-laden macrophages, and urine microscopy for lipid, but may not add much over clinical examination particularly given that the patient presents with the tell-tale petechial rash. CT and CXR findings
may be variable, and unlike in prevention, there is no beneficial role for steroids in treatment.

The ABG will, however both assist in diagnosis (Pao2 is in all diagnostic criteria) and help the clinician decide on level of respiratory support required

Question 10

10. A 50-year old woman for elective hand surgery is to have an ultrasound guided axillary brachial plexus block.
    Which of the following would be the most appropriate ultrasound probe to use?
    A Curved array probe
    B Linear array probe
    C Low frequency (2–5 MHz) probe
    D Phased array probe
    E Hockey stick footprint probe

Answer 10

B

10. B Linear array probe

The use of ultrasound is well established in regional anesthesia and pain medicine.

Ultrasound guided nerve blocks offer potential benefits over landmark technique including reduced complications and increased success rates.

The diagnostic ultrasound in current medical practice is usually in the range of 1–20 megahertz (mHz).

The ultrasound probe contains a large number of transducers in the form of piezoelectric crystals.
The piezoelectric transducer converts an electrical charge into
an ultrasound wave. The produced ultrasound wave then propagates into the tissues and is either scattered or reflected back onto the probe.

The reflected wave the piezoelectric crystal again, creating an electrical signal that can be processed and interpreted by the ultrasound machine to produce an image.

The probe transducers are activated in turn so that the probe is always discharging or receiving signals when operating.

Ultrasound probes may have different shapes:

1. Linear array probes:
   High frequency (6–13 MHz) probes where the piezoelectric crystals are arranged in a line along the surface.
   They provide the best axial resolution,
   however the higher the frequency the more attenuation
   therefore these probes have poor penetration.
   A rectangular ultrasound image is produced and they
   are best used for performing superficial blocks like interscalene, supraclavicular and axillary blocks.
2. Curved array probes: Low frequency (2–5 MHz) probes where the crystals are arranged along a curved surface. They provide lower resolution images when
   compared with linear probes. However, they have better penetration and allow visualisation of deeper structures. Curved array probes are best used for performing deep blocks such as sciatic nerve and infraclavicular brachial plexus blocks. These
   probes produce wide sector-shaped images with a curved upper and lower edge.
3. Phased array probes: Piezoelectric crystals are fired in phases to produce a sector-shaped image on the monitor with an expanding field of view. These probes are
   mainly used for echocardiography.
4. Hockey stick footprint probes:
   Also called J-shaped probes. These are a type of
   linear array transducer that are small in size and therefore ideally used in areas where space is limited or in paediatric patients.

As mentioned, higher frequency linear probes are better for more superficial blocks and lower frequency curved probes are better for deeper blocks. Thus in this clinical scenario,
the most appropriate ultrasound transducer is the linear high frequency probe.

Question 11

11. A 38-year-old man has sustained a stab wound in the left flank following an altercation. In the emergency department he is awake and has saturations of 99% on room air, a respiratory rate of 25 breaths per minute, a heart rate of 110 beats
    per minute and a blood pressure of 85/40mmHg. Initial resuscitation has started with intravenous access and blood samples taken.
    Any other injuries have been excluded apart from a dry puncture wound to the left flank associated with mild abdominal tenderness and no peritonism.
    What is the next step in the ongoing resuscitation of this patient?
    A A fluid bolus of 10ml/kg of colloid
    B A fluid bolus of 10ml/kg of crystalloid
    C No fluid bolus
    D Insert an arterial line
    E Admit the patient to the emergency department observation ward

Answer 11

D

11. C No fluid bolus

This patient has sustained a penetrating abdominal trauma and displays signs of at least class 2 haemorrhagic shock according to ATLS guidelines (see Table 2.3).

Initial fluid resuscitation uses the principle of permissive hypotension with the emphasis on early surgery in order to stop the bleeding.

The debate regarding choice of fluids rages on, but the definitive management of these patients is crucial. It is therefore
currently accepted that the optimal intervention is to refrain from fluid boluses as long as the patient is conscious and thus perfusing his vital organs.

Insertion of an arterial line is not part of the initial resuscitation, but may be required once operative management is to be undertaken.
Conservative treatment and observation might
be appropriate in certain abdominal injuries, but in a haemodynamically unstable patient early surgery is indicated

Question 12

12. A 55-year-old woman with a 1-month history of headaches presents with a severe headache followed by a collapse. In the emergency department of a large teaching hospital her Glasgow coma scale (GCS) was 3 and she was intubated
    and ventilated appropriately. A CT scan demonstrated a large subarachnoid haemorrhage (SAH) with blood in the intraventricular system and dilated lateral ventricles. A CT angiogram demonstrated a large posterior communicating artery
    aneurysm. Her pupillary response to light is sluggish.

The most beneficial intervention in this patient would be:

A Immediate transfer to neurosurgical theatre for an extraventricular drain (EVD)
B Immediate transfer to neurosurgical theatre for insertion of an intracranial bolt monitor
C Immediate transfer to the intensive care unit for medical stabilisation before embolisation of the aneurysm
D Administration of hypertonic saline and mannitol
E Administration of intravenous phenytoin

Answer 12

A

12. A Immediate transfer to neurosurgical theatre for an
    extra-ventricular drain (EVD)

The normal intracranial pressure (ICP) in the horizontal position is 7–10 mmHg and the normal waveform mirrors the arterial trace but consists of three peaks (P1-3), which reflect cardiac contraction, brain compliance (the pressure wave reflected
from the rigid skull) and aortic valve closure respectively (Figure 2.6).

An ICP > 15 mmHg is considered pathological, and in head injured patients, levels > 20 mmHg are usually treated. The Brain Trauma Foundation publishes
clinical guidelines regarding ICP monitoring and actively managing intracranial
hypertension is associated with improved survival.

This patient should initially be managed with an ABC approach, controlling the airway, ventilating appropriately to maintain Pao2> 10 kPa and PaCO2 at around 4.5 kPa while maintaining mean arterial blood pressure to optimise cerebral perfusion pressure (CPP).

Other key interventions include ensuring cerebral venous
drainage (by avoiding internal jugular vein central lines, endotracheal tube ties and
maintaining a 30° head-up position), ensure normoglycaemia, normothermia and avoiding seizure activity.

The important information given to you in the vignette is that she presented to a teaching hospital (which you may assume has neurosurgical services). Therefore
it suggests that the first 3 options may be most appropriate. The others may be important if you are awaiting transfer to a neurosurgical centre. In this case a large
subarachnoid haemorrhage (SAH) with dilated ventricles and sluggish pupillary
response to light is suggestive of obstructive hydrocephalus.

Thus the intracranial pressure may be assumed to be high and will only increase without intervention.

As you are assuming there is a neurosurgical service in the teaching hospital, your answer will recommend involving the neurosurgeon as soon as possible. Intracranial
monitoring will allow you to titrate the therapies to a measured end-point, which
reduces mortality. The options are:

• Extra-ventricular drain (EVD):
this is the gold standard, which involves a drain placed directly into the lateral ventricles via the frontal lobe and is therefore
the most invasive. It allows monitoring of the ICP and waveform morphology, therapeutic draining of CSF to reduce the ICP and administration of intra-thecal drugs if required. The complications include bleeding into the frontal lobe and
infection (rate 1–5%). Blockage may occur necessitating a revision.

• Intra-parenchymal monitors are almost as accurate with lower complication rates.
However no therapeutic interventions can be performed with it.

The sub-dural bolt is least invasive, has the least complications but is also the least accurate and is used for monitoring only, not therapeutic intervention.

Hyper-osmotic treatments are most useful for management of space-occupying mass lesions including an intra cranial blood clot. It may also be used as a rescue measure in this scenario to buy time if there is clinical evidence of impending
cerebral herniation.
Phenytoin is usually administered after the second witnessed
seizure.
Nimodipine should be given as early as possible via a nasogastric tube to
prevent vasospasm.

Therefore the most important intervention is inserting a device for monitoring and intervention, which allows you to optimise the medical management appropriately
.
Management of the aneurysm is undertaken once the ICP has been controlled and the aneurysm is secured, forced hypertensive treatment can begin to prevent cerebral infarction related to vasospasm. The other measures may be used to buy
time prior to an EVD insertion if it is not immediately available.

Question 13

13. A 52-year-old man is admitted to the emergency department one hour ago with
    worsening shortness of breath, fevers and productive sputum. His observations
    include a temperature of 38°C, Spo2 95% on high-flow oxygen, blood pressure
    88/49 mmHg, heart rate 126 beats per minute and respiratory rate 28 breaths per
    minute. His arterial blood gas is below (Table 2.1):

Blood cultures have been taken and a dose of co-amoxiclav and clarithromycin has
been administered.
The most appropriate next step would be:
A Intubation and ventilation
B Central venous access and noradrenaline
C Central venous access and measurement of Scv–o2
D Non-invasive ventilation
E 30 mL/kg crystalloid bolus

Answer 13

E

13. E 30 mL/kg crystalloid bolus

Sepsis is the commonest reason for a patient to be admitted to a critical care unit and therefore the 2012 Surviving Sepsis Guidelines is essential revision.

The bundle of care now mandates:
To be completed within 3 hours

1. Measure lactate level
2. Obtain blood cultures prior to administration of antibiotics
3. Administer broad-spectrum antibiotics
4. Administer 30 mL/kg crystalloid for hypotension or lactate ≥4 mmol/L

To be completed within 6 hours
5. Apply vasopressors
(for hypotension that does not respond to initial fluid
resuscitation) to maintain a mean arterial pressure (MAP) ≥ 65 mmHg

6. In the event of persistent arterial hypotension
   despite volume resuscitation
   (septic shock) or initial lactate ≥ 4 mmol/L (36 mg/dL):
   • Measure central venous pressure (CVP)
   • Measure central venous oxygen saturation (Scv–o2)
7. Re-measure lactate if initial lactate was elevated

This patient has recently been admitted to the emergency department with severe sepsis probably secondary to pneumonia, though the current history is inadequate
to exclude other causes. He has had antibiotics within one hour following blood cultures.

This is optimal care as for each hour delay in antibiotic administration there is a 7.6% increase in mortality from sepsis.

This patient has distributive shock based on cardiovascular parameters and a raised lactate, therefore immediate fluid resuscitation should be commenced as per the Surviving Sepsis Guidelines above. 30 mL/kg should be given in the next two hours. If hypotension persists despite this fluid resuscitation, then noradrenaline should be considered titrated to Scv – o2, MAP and CVP. The lactate level should be re-evaluated.

Question 14

14. An 18-year-old woman presents to the intensive care unit with diabetic ketoacidosis (DKA) for which she has had multiple admissions in the past. On
    examination her heart rate is 110 beats per minute and her blood pressure is
    100/60 mmHg. Her Glasgow coma scale (GCS) is 14 (E3, V5, M6). Her laboratory
    glucose was 39 mmol/L and the arterial blood gas demonstrated the following
    (Table 2.2):

Current treatment is an insulin infusion of 5 units/hour and 500 mL of intravenous Hartmann’s solution being administered over 4 hours.

How would you alter her treatment on admission to the ICU?
A Reduce the rate of insulin when her blood sugar drops below 30 mmol/L
B Increase the insulin infusion by 1 unit/hr if the bicarbonate concentration
remains 3 mmol/L after 1 hour
C Change the intravenous fluid from Hartmann’s solution to 0.9% sodium
chloride and add potassium 20 mmol to be given over 4 hours
D Give a fluid bolus of 500 mL of crystalloid to assess cardiovascular and
metabolic response
E Start an infusion of bicarbonate 1.26% 100 mL/hour to correct the acidosis
until the blood ketone level reduces as a result of insulin therapy

Answer 14

E

14. B Increase the insulin infusion by 1 unit/hour if the
    bicarbonate concentration remains 3 mmol/L after 1 hour

Diabetic ketoacidosis (DKA) is an endocrine emergency that presents in diabetic patients who do not produce endogenous insulin. Relative or absolute lack of insulin (endogenous or exogenous) results in a triad of hyperglycaemia, a ketotic state and acidaemia.

Eleven percent of Type 1 diabetics presented with DKA in 2004–2009.

Mortality is still 2%, most commonly attributable to cerebral oedema.

Glucose forces renal diuresis and results in profound hypovolaemia.

The patient presents with a metabolic acidosis (often partially compensated by a monumental minute ventilation) with a large anion gap due to unmeasured blood ketones.

Blood ketones can now be measured at the bedside and indicate severity of disease and response to treatment. The patient is often potassium-deplete which may not
be immediately obvious from initial lab results as a high level of acidosis causes intracellular potassium ions to migrate into the plasma.

As acidosis resolves and potassium once again returns to the intracellular space, the plasma potassium concentration decreases rapidly.

Management of DKA in critical care areas focuses on the following issues:

• Fluid management including resuscitation and replacement of ongoing losses

• Blood glucose control and providing glucose once the blood glucose drops below 15 mmol/L

• Acidosis and electrolyte management (in particular potassium maintained between 4 and 5 mmol/L)

• Insulin administration and titration

• Septic screening and appropriate antibiotics

• Thromboprophylaxis

• Monitoring for complications including cerebral oedema, sepsis, hypokalaemia, ischaemic cardiac events, acute kidney injury (AKI) and acute respiratory distress syndrome

• Management of psycho-social issues

• Involving of specialist teams for ongoing management

The management of DKA has undergone a recent change in 2011 and guidelines have been published by Diabetes UK. The sliding scale is no longer incorporated and titrating insulin to biochemical markers is the primary objective.

To summarise some of the new recommendations:

A ‘fixed rate’ infusion of 0.1 units/kg insulin should be administered. The rate is no longer adjusted solely according to blood sugar levels, but to blood ketone levels or
bicarbonate levels.

Aims of treatment are:
• A reduction of 0.5 mmol/L/hour blood ketone concentration
• An increase of 3 mmol/L/hour of venous bicarbonate concentration
• A reduction of 3 mmol/L/hour of blood glucose concentration

If this is being met then the current insulin infusion is to be unaltered regardless of current blood glucose levels. If treatment goals are not being met the infusion should be increased by 1 unit/hour.

1. DKA protocol should be terminated once pH> 7.3, venous plasma bicarbonate above 18 mmol/L and blood ketones < 0.3 mmol/L
2. If the patient is on long-acting insulin this should be continued simultaneously.

In the above clinical scenario, answer B is the most appropriate option that follows the suggested guidelines. The other options are also viable, but:

• Option A is following the ‘old’ sliding scale regime, which is used on ICUs for diabetics and non-diabetics alike (the difference between these groups should be distinguished as the pathology and resulting disease is very different);

• Option C may be performed if you wanted to add potassium but that may not be needed yet;

• Option D is possible but the patient is not hypotensive and lactate is not significantly raised;

• Option E may be indicated in shock unresponsive to inotropes or if the metabolic acidosis is in part caused by AKI, however administrating intravenous bicarbonate masks one of the biological markers of treatment responsiveness.

It is important to be aware of new guidelines and understand the difference between managing DKA (providing insulin and glucose to reduce ketosis) and maintaining normoglyaemia in unwell-adults due to a hormonal stress response.

Question 15

15. A 76-year-old patient is admitted to the postoperative care unit (POCU) following a prolonged and difficult laparotomy for ischaemic bowel. She underwent an
    extended right hemicolectomy, associated bowel oedema was noted. Her intraabdominal
    pressure (IAP) is monitored due to her risk of abdominal compartment
    syndrome (ACS).
    Which of the following would define abdominal compartment syndrome in this
    patient:
    A IAP > 12 mmHg with new organ dysfunction
    B IAP > 16 mmHg with new organ dysfunction
    C IAP > 20 mmHg with new organ dysfunction
    D IAP > 25 mmHg with new organ dysfunction
    E IAP > 30 mmHg with new organ dysfunction

Answer 15

C

15. C IAP > 20 mmHg with new organ dysfunction
    This elderly patient is at high risk of developing intra-abdominal complications following a complex laparotomy. Monitoring her intra-abdominal pressure (IAP) provides additional information to her clinical status. IAP can be measured using direct or indirect methods. A direct method would be to

leave a catheter or needle within the abdomen at the end of the laparotomy.
Indirect methods are the commonest measurement technique in the UK.

This involves the intravesical method via a bladder catheter; working on the principle that intravesical pressure is a surrogate for intra-abdominal pressure.

One technique involves introducing sterile saline into the bladder and clamping the catheter distally. A wide bore needle or cannula is introduced into the bladder catheter via the culture port and connected to a pressure transduction system. The system
is zeroed at the level of the symphysis pubis. In order to provide an accurate
measurement, the reading should be taken in the supine patient at the end of expiration. The measurement should be repeated four hourly.

Normal IAP is 5–7 mmHg. The World Society of the Abdominal Compartment
Syndrome (WSACS) classifies intra-abdominal hypertension as a sustained IAP
> 12 mmHg. Abdominal compartment syndrome is a sustained IAP > 20 mmHg with
new organ dysfunction, hence making option C correct.

Risk factors can be subdivided into:
• Intraluminal such as gastroparesis, ileus or pseudo-obstruction
• Extraluminal such as ascites or pelvic tumours
• Decreased abdominal wall compliance such as abdominal surgery with fascial closure, obesity, abdominal burns or trauma
• Capillary leak or excessive fluid resuscitation such as pancreatitis, sepsis or massive transfusion

This patient is at high risk due to the risk of ileus, risk of capillary leak from a systemic inflammatory response syndrome and reduced abdominal wall compliance following a laparotomy.

The principle of management is to optimise abdominal perfusion pressure. The strategies used broadly fall into medical and surgical categories.

Medical management involves:
• IAP monitoring if risk factors are present
• Draining abdominal fluid collections such as ascites or abscesses
• Reducing intraluminal contents; nasogastric and rectal decompression and the
cautious use of prokinetics
• Improving abdominal wall compliance such as sedation and analgesia with
possible neuromuscular blockade and removal of constrictive dressings or
escharotomy
• Maintain oxygen delivery with the use of fluid challenges and cardiovascular
support. Excessive fluid administration should be avoided and diuretics may have
a role
The main surgical option is decompression via a laparostomy with delayed closure.
Close liaison with the surgical team is mandated in the management of high-risk
patients, such as this case, and thresholds ascertained which alert the teams to
consider a surgical option.

Question 16

16. A 24-year-old asthmatic presents to the emergency department with wheeze, shortness of breath and a peak flow which is 20% of his usual. He has had two courses of steroids in the past year and has been hospitalised twice for acute
    asthma. The medical team has asked you to review him as they are worried he is tiring and not responding to initial treatment.

Which feature is most likely to suggest that this is the case?
A pH of 7.32
B Oxygen saturations of 88% on air
C Unable to complete sentences with single breath
D Responding to voice on the AVPU score
E No improvement despite optimum therapy including a salbutamol infusion

Answer 16

E

16. D Responding to voice on the AVPU score
    Asthma is characterised by reversible airways obstruction due to bronchial smooth muscle contraction, airway inflammation and increased airway secretion production.

Chronic management focuses on a step-wise approach to therapy escalation aiming for minimal requirement for rescue therapy.

Around 1400 people a year still die from
asthma despite improvements in chronic management

The definition of the severity of an acute attack can be summarised below (Table 2.4):

The first decision as the anesthetist or intensivist is which category your patient falls into as this dictates immediate management. The time delay from decision-to intubate
to actually intubating with all the drugs, equipment and help you need may
be significant and thus it is best to prepare early.
The next decision is whether the patient is on optimum therapy, which for lifethreatening
asthma should be:

• Oxygen-driven salbutamol nebulisers 5 mg continuously (allocate someone to monitor and change over the nebuliser when finished). Its worth noting however
if there is little respiratory effort the inhaled drug will just move in and out of conducting airways and not reach the desired site of action

• Magnesium 2 g intravenous infusion over 20 minutes

• Steroid therapy: either oral prednisolone 40 mg or hydrocortisone 200 mg intravenous

• Intravenous fluids as the patient may become profoundly dehydrated with a sustained high respiratory rate being treated with non-humidified oxygen therapy

• Salbutamol infusion 5–20 μg/min titrated to effect

• Aminophylline 5 mg/kg loading dose over 20 minutes (if not on oral theophylline) followed by 0.5 mg/kg/min

• Adrenaline infusion is an option but the patient is more likely to require an anaesthetic before this stage is reached

In the case above the most concerning feature is the drowsiness. Patients with
asthma have a high adrenergic response (otherwise known as fear) and should
be alert. You are not told what treatment the patient is on already. A pH of 7.32 is
worrying if it is a respiratory acidosis but both dehydration and salbutamol therapy
can cause metabolic acidosis, which if being appropriately compensated for, is less
worrying. Similarly this patient should be on oxygen as part of their treatment and

their oxygen saturations should be judged when receiving appropriate therapy. It
is helpful to quantify the ability to speak with the number of words used: obviously
unable to utter one word is more worrying than reciting the daily adventures of
one’s cat and pausing for breath. Response to treatment is important and if no
improvement is being made, a decision to ‘electively’ intubate may be made.
It is therefore crucial to look at the complete clinical picture and use good judgment
in the management of acute asthma. Alteration in consciousness is an ominous sign
and should be treated very seriously.

Question 17

17. A 37-year-old woman with a past history of asthma is 38/40 pregnant and undergoing a category 2 Caesarean section for pre-eclampsia. The baby and placenta have been delivered, 5 IU of syntocinon has been given and a syntocinon infusion commenced.

The estimated blood loss so far is 800 ml and the obstetric
registrar informs you “the uterus is still floppy”.

Which of the following is the best drug to use next?

A 5 IU syntocinon intravenously
B 5/500 syntometrine intravenously
C 250 μg carboprost intramuscularly
D 1 mg misoprostol rectally
E Atosiban 6.75 mg intravenously

Answer 17

C

17. A 5 IU Syntocinon IV

This woman is on her way to a post partum haemorrhage (PPH), which is the loss of
500 ml blood after vaginal delivery or 1000 mL after Caesarean section. She requires urgent control of the bleeding. In this case the cause is an atonic uterus, hence uterotonics are needed.

1. A further dose of syntocinon is the ideal choice in this situation. It is a synthetic oxytocin analogue that acts on oxytocin receptors in the uterus to increase uterine contractions.
   Its side effects include hypotension, fluid retention and tachycardia.

For these reasons it should be given slowly, and some advocate diluting prior to administration, especially in pre-eclamptic patients.

2. Ergometrine is an ergot alkaloid that acts on serotonergic receptors in the uterus.
3. Syntometrine contains 5IU of syntocinon and 500 μg of ergometrine. Although the syntocinon would help in this situation, this lady is pre-eclamptic and there is a risk the ergometrine could exacerbate hypertension. Other side effects of ergometrine
   include, nausea and vomiting.
4. Carboprost is a prostaglandin F2α analogue and also stimulates uterine contractions.

Side effects include hypotension, diarrhoea, nausea and bronchospasm; hence, it is avoided in asthmatic patients.

4. Misoprostol is a prostaglandin E1 analogue that is usually given rectally. Although it can also be given orally and by direct myometrial injection, the rectal route has fewer side effects. In this case, the operation is still ongoing and rectal misoprostol,
   even if given intraoperatively, will take a while to work. It can be used at the end of the procedure. Its side effects include nausea, vomiting, diarrhoea and pyrexia.
5. Atosiban is a tocolytic drug that antagonises oxytocin at its uterine receptors. It is used in preterm labour and has no application in this situation.

Question 18

18. A 6-year-old, 24 kg boy is seen in the emergency department having fallen on his right arm.

An X-ray confirmed a closed displaced fracture of the right distal radius.

There is no neurovascular compromise to the right hand. He was given 2.4 mg of oral morphine for pain. The surgeon wants to perform an urgent manipulation under anaesthesia with percutaneous wiring. The boy last ate 9 hours ago and the
fall occurred 7 hours ago. The immediate anaesthetic management should be:

A Proceed immediately with surgery with routine induction of general anaesthesia
B Proceed immediately with surgery under general anaesthesia following a rapid
sequence induction and intubation
C Delay general anaesthesia and surgery by a further 4 hours, and then perform a
rapid sequence induction and intubation
D Delay general anaesthesia and surgery by further 12 hours, and then proceed
as an elective case
E Proceed with surgery under an axillary brachial plexus block

Answer 18

B

18. B Proceed immediately with surgery under general
    anaesthesia following a rapid sequence induction and
    intubation The gastric volume in an injured patient is related to the interval between the last meal and the time of injury. Thus, this injured child should be considered as
    a patient with a full stomach. In addition, opioids further decrease gastric transit.

A routine induction of general anaesthesia is not appropriate in a child with a full stomach. There is insufficient evidence to conclude that prolonging fasting time pre-procedure decreases the incidence of adverse outcomes, therefore there is little
benefit in delaying surgery.

Performing an axillary block is a reasonable option, but
would not be feasible in a 6-year old child without sedation or general anaesthesia.

Thus immediate surgery under general anaesthesia is the most appropriate anaesthetic management in this clinical scenario.

Question 19

19. A 9-year-old 30 kg girl has woken up in the anaesthetic recovery area after an emergency open appendicectomy. She is in distress and complaining of pain over the surgical site.

Intraoperatively she was given 50 μg of fentanyl, 450 mg of
paracetamol, and 15 mg of ketorolac all intravenously. A right-sided transverse abdominal plane block was performed using 20 mL of 0.25% bupivacaine.

Her most recent set of clinical observations are:
• Heart rate 128 beats per minute
• Respiratory rate 22 breaths per minute
• Blood pressure 122/82 mmHg
• Spo2 99% on air

The most appropriate management is:
A Midazolam 20 μg/kg intravenous bolus to treat emergence delirium
B Propofol 0.5 mg/kg intravenous bolus to treat emergence delirium
C Fluid bolus of 20 ml/kg 0.9% NaCl to treat hypovolaemia
D Morphine 50 μg/kg intravenous bolus for analgesia
E Morphine 20 μg/kg/hour intravenous infusion for analgesia

Answer 19

D

19. D Morphine 50 μg/kg intravenous bolus for analgesia

Postoperative pain and emergence delirium (ED) present similarly and may overlap.

ED is more likely to occur in children between 2 and 5 years of age, patients undergoing painful procedures under volatile anaesthetics and after a rapid emergence.

Co-induction with fentanyl or midazolam reduces the risk of ED.
Midazolam and propofol can be used to treat ED.

Pain as a cause of this patient’s distress should be considered first and most likely, particularly since the patient’s main complain was pain.

The patient’s tachycardia and hypertension are consistent with pain, not hypovalaemia.

Starting a morphine infusion without a loading dose would take several hours for plasma levels to reach a therapeutic concentration. Therefore, a morphine intravenous bolus is the most appropriate management in this case, and may be repeated and titrated to effect.

Question 20

20. A 6-month-old 7 kg boy is scheduled for an elective orchidopexy for undescended testis. He was intubated successfully following an uneventful intravenous
    induction. A caudal block was performed with 7 ml of bupivacaine 0.25%. The ECG showed occasional ventricular premature beats immediately after the caudal
    block was performed. Shortly after that, the ECG showed a regular broad complex tachycardia at 160 beats per minute. You notice the end tidal CO2 trace becomes
    flat despite good bilateral chest movement. There are no palpable pulses.
    Your immediate first action is:

A Announce cardiac arrest, call for help, and start chest compressions
B Give 1.5 mL/kg of 20% lipid emulsion as an intravenous bolus over 1 minute,
followed by an infusion of 15 mL/kg/hour
C Request for the cardiac defibrillator and deliver a DC shock of 4 J/kg
D Request the local anaesthetic toxicity box
E Give 0.1 mL/kg of 1:10,000 epinephrine intravenously

Answer 20

A

20. A Announce cardiac arrest, call for help, and start chest
    compressions

This is a pulseless ventricular tachycardia (VT) cardiac arrest. The immediate first action should be to call for help and start chest compressions.

As per paediatric life support guidelines, pulseless VT is a shockable rhythm, and 4 J/kg of DC shock should be delivered as soon as the cardiac defibrillator is available and set up, and
epinephrine given as soon as available.

The most likely cause of the cardiac arrest in
this patient is local anaesthetic toxicity.

The young infant is at increased risk of amide local anaesthetic toxicity. The usual early warning signs and symptoms are not exhibited, and the first sign of toxicity may be a grand mal convulsion, apnoea or arrhythmia. Raised cerebral blood flow will increase delivery of local anaesthetic to the brain. The blood–brain barrier is not well developed in the neonate while decreased plasma protein binding and reduced
hepatic clearance result in increased free drug availability.

Treatment of local anaesthetic toxicity should include cessation of drug administration, measures to ensure a clear airway, artificial ventilation with oxygen 100%, external cardiac massage if necessary, and administration of 20% lipid emulsion (Intralipid). Intralipid is an emulsion in water of soybean oil, predominantly
neutral triglycerides, made isotonic with glycerin. In blood, these fat droplets form a lipid compartment, separate from the plasma aqueous phase, into which a lipophilic
substance such as bupivacaine might dissolve.

Question 21

21. A 6-year-old girl is admitted with acute appendicitis. After uncomplicated surgery she is noted to be in discomfort and crying.

In the assessment this child’s pain, which of the following is most correct:

A The FLACC scale is for 1 month and above
B Self-reporting is reliable over the age of 10
C The visual analogue scale (VAS) can be used in patients aged 12 years and above
D Physiological measures such as heart rate can be used alone
E The Wong-Baker FACES pain scale consist of 5 hand drawn faces

Answer 21

E

21. C The visual analogue scale (VAS) can be used in patients
    aged 12 years and above

There are a number of pain assessment systems that can be applied to paediatric patients.

The FLACC (Face, Legs, Arms, Cry, Consolability) scale is for children aged 1 year and above but it can be occasionally be used from 2 months (Table 2.5).

Each of the five criteria can have a score between 0 and 2, with a maximum score of 10. A score of 0 represents no pain.

Self-reporting is suitable for over 5 years of age but this is not always exact and some authors recommend 7 as the starting point. It is the most accurate assessment when correctly used.

The visual analogue scale (VAS) can be use in patients aged 8 years and above but it is recommended for patients over 12 years of age as it is more reliable

Although physiological markers have been used in some pain scales its use is always in the context of other signs, thus isolated physiological markers are inaccurate and
not recommended for use for pain assessment.

The Wong-Baker FACES pain rating scale is comprises 6 hand drawn faces ranging from a happy face (0) to a crying face (10) that represent pain intensity.
A change of one face at a time is considered clinically significant.

Question 22

22. A 45 kg, 83-year-old woman with dementia and chronic kidney disease is admitted with a right fractured neck of femur following a fall. She is in severe pain, is confused and agitated. She has been given regular paracetamol, and is booked for
    a dynamic hip screw.

Which of the following is the best method to provide her with adequate analgesia intra- and postoperatively?
A Fascia liaca block
B Femoral nerve block
C Spinal anaesthesia
D Codeine phosphate
E Intravenous morphine

Answer 22

A

22. A Fascia Iliaca block

Hip fractures are extremely painful. Typically, pain may be constant, or only on moving the joint, and this can limit the care that these patients receive on the ward, such as restricting nursing care, or transferring from trolley to bed. In the
postoperative period, persistent pain may delay mobility and recovery, leading to a prolonged hospital stay, and increased risk of complications.

Analgesia should be administered as soon as possible after the patient presents to hospital, and initially this may be with a dose of opioid. However, use of opioids and non-steroidal anti-inflammatory drugs (NSAIDs) should be minimised where
possible in this cohort of patients.

Opioids increase the risk of postoperative confusion, and many patients who present with femoral neck fractures have
comorbidities including renal impairment. This can lead to opioid accumulation and toxicity. NSAIDs increase the risk of further renal impairment.

Regular paracetamol is safe and very effective when used in combination with other analgesics. The addition to regional anaesthesia has been demonstrated to reduce
opioid requirements.

Increasingly, simple nerve blocks can be administered in the
emergency department by trained staff, and this can improve the entire patient experience, with less pain on transferring and moving, and reduced requirement for sedative analgesia.

Adequate blockade of the femoral nerve, obturator nerve, and the lateral cutaneous nerve of the thigh would be sufficient for preoperative, intraoperative as well as
postoperative analgesia.

A fascia iliaca block can achieve this. In this scenario, the patient is known to have chronic kidney disease (CKD), dementia
and is confused. This should defer your choice away from NSAIDs and opioids.

The choice between the blocks should lead you to choose the fascia iliac block. A femoral nerve block would not anaesthetise the lateral cutaneous nerve of the thigh, which supplies sensation to the incision site. Additionally, a spinal anaesthetic has not been shown to provide longer lasting analgesia than a peripheral nerve block.

Many would therefore advocate performing a spinal anaesthetic for intraoperative management, as well as a fascia iliaca block for postoperative analgesia.

Question 23

23. A 61-year-old woman presents with worsening left sided chest pain over the last 3 months.

She describes an intense burning sensation over the T5 distribution, which began after an episode of shingles 4 months ago. The pain gets worse through the day, and especially during the night when it disturbs her sleep.

It may be triggered by cold wind blowing over the painful part, or her clothes rubbing against it. She has been taking co-codamol with only modest effect.

Which of the following is the most appropriate next step in her management?
A Lignocaine patch
B Oral morphine sulphate
C Topical capsaicin
D Gabapentin
E Thoracic sympathectomy

Answer 23

D

23. D Gabapentin

‘Shingles’, also known as herpes zoster, is caused by reactivation of the varicella zoster virus (VZV), a virus in the same family as the herpes simplex virus Alphaherpesvirinae). Herpes zoster and herpes simplex are, however, independent
diseases. After causing its primary infection (chickenpox) the VZV lies dormant in a sensory ganglion, until it is given such conditions when it can re-emerge. The clinical manifestation of this re-emergence is called shingles. The most common
cause is immunosuppression, which may be due to malignancy, acquired syndromes including HIV, or immunosuppressive medication such as steroids.

On reactivation, VZV causes pain and a characteristic rash, limited to the dermatomal distribution of the dorsal root ganglion in which it lies. In this scenario the dorsal
root ganglion affected is T5. Some patients may describe a painful prodrome, followed by development of skin lesions. The associated pain can be intense, severe
and neuropathic in character.

Classically described as throbbing or burning, it is worse as the day progresses and maximal at night. Associated sleep disturbances are common, and it may subsequently lead to depression, fatigue and concentration difficulties.

The commonest site of pain is in the thoracic dermatomes, but it
may also affect the ophthalmic division of the trigeminal nerve, making it a key differential diagnosis for trigeminal neuralgia.

In the majority of patients, pain is acute, lasting less than 30 days, or subacute, lasting less than 120 days. In some patients, however, it lasts more than 3 months after skin lesions have healed, and this is described as post-herpetic neuralgia
(PHN).

PHN may last several years and can be severe and debilitating. Risk factors include increasing age, female gender, presence of a prodrome, more severe pain in the acute phase, and a more intense rash, as well as psychosocial factors such as higher
anxiety levels.

Management of PHN can be challenging.
Patients should be well educated about their condition, and given appropriate support and counselling.

Psychological therapies such as cognitive behavioural therapy may be of benefit.

In terms of pharmacological management, recommended first line agents include gabapentinoids (gabapentin, pregabalin) or tricyclic antidepressants (amitriptyline, nortriptyline).

Lignocaine patches have been used and are recommended but robust evidence for their benefit is lacking.
Opioids help reduce severity of the pain but long-term use is associated with several unwanted effects, and topical capsaicin has been used successfully for PHN, but may be painful to apply.

In this scenario, each of the options is possible, but the first line agent, and hence the most appropriate next step, would be gabapentin. Subsequently, other options
can be explored, depending on the patient’s response

Question 24

24. A 45-year-old man has undergone multiple spinal surgeries in the past and has been on 80 mg daily of slow release morphine for the past year.

He is asking for an increase in his medication.

Which of the following most appropriately describes this patient’s opioid therapy?

A There is no upper limit on the efficacy of opioids
B Respiratory depression is a significant risk at this dose
C Hyperalgesia may develop with increasing dosage
D Constipation is usually resolved after 1 year
E Levels of serum adrenocorticotrophic hormone (ACTH) may be increased

Answer 24

C

24. C Hyperalgesia may develop with increasing dosage
    Opioid-induced hyperalgesia occurs when pain is uncontrolled despite increasing use of long-term opioids.

The use of opioids has commonly been described without a ceiling in cancer pain and palliative care, but in this clinical picture is inappropriate. The use of opioids in non-cancer pain is becoming recognised as ineffective and potentially harmful due
to its suppression of the immune and hormonal systems.

Opioids can act directly on the hypothalamo-pituitary axis to reduce gonadotrophin releasing hormone (GnRH),
luteinizing hormone (LH) as well as gonadal testosterone.

Opioids also reduce adrenocorticotrophic hormone (ACTH) and cortisol with long-term use.

Respiratory depression is not observed at stable doses of opioids administered long term.

The constipating effects of opioids are long-term and do not resolve unless the opioids are withdrawn

Question 25

25. A 31-year-old woman with a history of acute intermittent porphyria presents with severe abdominal pain.

She is tachycardic, hypertensive and vomiting. A diagnosis
of small bowel obstruction is made and she is to go to theatre for a laparotomy.
Which of the following is the best option for her postoperative analgesia?

A Epidural with levobupivacaine and fentanyl
B Titrated intravenous ketamine
C Intravenous morphine
D Oxycodone
E Wound infiltration of 0.25% levobupivacaine

Answer 25

A

25. C Intravenous morphine

The expression ‘porphyria’ encompasses a collection of inherited disorders of haem synthesis. Haem is a key constituent of haemoglobin and an example of a naturally
occurring porphyrin. Its synthetic pathway consists of a series of enzyme-dependent steps. Genetic mutation causing a deficit of a particular enzyme in this pathway results in accumulation of the intermediate substrates that rely on it for their
metabolism.

The primary step in the haem synthetic pathway is the combination of glycine and succinyl CoA to form the compound 5-aminolevulinic acid (5-ALA) by the action of ALA synthase. Deficiency of any enzyme downstream from this step will cause the accumulation of 5-ALA. In all acute porphyrias, 5-ALA levels are elevated.

Whether this itself is the cause of the clinical manifestations of acute porphyria is unclear.

In any form of acute porphyria, an acute neurovisceral crisis may be triggered by
anything that increases the demand for haem, including infection, dehydration, starvation and drugs.

The key presenting features are abdominal pain, neurological
symptoms and tachycardia. As these are rather non-specific presentations, diagnosis is often made late. In this scenario, it is not a surgical condition causing the patient’s
pain, but this may additionally trigger a porphyric crisis
A number of drugs used in common anaesthetic practice may be unsafe for use
in patients with porphyria. The majority are, in fact, safe, and the Table 2.6 below
summarises drugs that are either known to be dangerous or those which are yet
unclassified for use in porphyric patients.

Morphine is a safe, effective, titratable drug that can be used in porphyria, and would be the drug of choice here. The patient is tachycardic with small bowel obstruction, and likely to be hypovolaemic. This would preclude the use of an
epidural. Levobupivacaine has indeterminate safety profile so should be avoided and relying on local infiltration of the surgical wound would not provide lasting analgesia.

Oxydone and ketamine are unsafe.

Question 26

26. A 32-year-old man is undergoing emergency surgery under general anaesthesia for a penetrating eye injury. During the procedure, the surgeon palpates the globe and tells you that the intraocular pressure (IOP) is too high.
    Which of the following measures is least likely to reduce the IOP?
    A Adequate muscle relaxation
    B Trendelenburg positioning
    C Increasing minute ventilation
    D Intravenous acetazolamide
    E Intravenous mannitol bolus

Answer 26

B

26. B Trendelenburg positioning
    During surgery for penetrating eye injury, control of intraocular pressure (IOP) is important to prevent expulsion of the contents of the orbit. Episcleral venous pressure, which is influenced by central venous pressure (CVP), is the most important
    factor determining IOP acutely; hence measures to prevent venous congestion must be employed. Such measures include taping, not tying, the endotracheal tube, keeping the head in the neutral position, reverse Trendelenburg positioning and
    avoiding coughing by ensuring adequate muscle relaxation.

Hypercarbia can lead to an increase in IOP; hence increasing the minute ventilation will reduce CO2 and help to reduce IOP.

Both acetazolamide and mannitol can be used to reduce IOP in the acute setting.

Acetazolamide is a carbonic anhydrase inhibitor that reduces the production of aqueous humour, while mannitol dehydrates the eye by its action as an osmotic diuretic. Both have systemic effects that must be taken into account when administered, such as electrolyte disturbance and dehydration.

Trendelenburg positioning is the correct answer, as the head down position will reduce venous drainage from the orbit and cause an increase in CVP and therefore the IOP

Question 27

27. A 71-year-old man is undergoing a bilateral ilio-femoral bypass graft with the aid of a cell salvage device.

The surgeons have completed the right ilio-femoral bypass
and are preparing to begin operating on the left side when you notice that the blood returned to the patient from the cell salvage device is 1,900 mL.

After sending a clotting sample to the lab, what is the most appropriate next step in the management of this patient’s blood loss?

A Await the lab results and treat the coagulation accordingly
B Request cryoprecipitate and platelets from the blood bank
C Administer a 1 g bolus of tranexamic acid intravenously
D Use hypotensive anaesthesia to decrease further blood loss
E Check the patients activated clotting time (ACT)

Answer 27

C

27. B Request cryoprecipitate and platelets from the blood
    bank

Cell salvage is the process of utilising a patients own blood retrieved from the surgical field to produce autologously transfused blood by filtering and washing it.

Cell salvage therefore returns red cells and reduces the requirement for allogenic transfusions, with the following indications:

• Expected blood loss of > 20% blood volume or > 1 litre

• Operations with an expected blood transfusion requirement

• Pro-haemorrhagic states

• Preoperative anaemia

• Rare blood groups

• Patients with rare blood antibodies

• Patient refusal for allogenic blood transfusion
___________________________________________________

As cell salvage only returns red blood cells,
other blood products such as plasma,
inflammatory mediators and,
importantly platelets and clotting factors,
are therefore discarded.

Patients receiving more than 2 litres of autologous red cells are at a significant risk of developing coagulopathy.

In this clinical scenario, the patient is likely to require coagulopathic support, due to anticipated further bleeding, in the form of platelets and cryoprecipitate.

Tranexamic acid is useful in reducing on-going bleeding as an antifibrinolytic, but it will not prevent the massive blood loss coagulopathy expected.

Hypotensive anaesthesia is not a recommended anaesthetic technique in vascular surgery and carries a significant hazard of complications in high-risk patients undergoing
vascular intervention.

Point of care measurement of activated clotting time (ACT)
guides intraoperative heparin therapy, but will not assist in the treatment of massive haemorrhage coagulopathy.

Finally, waiting for laboratory blood results will merely
delay the required intervention of administering clotting products in a timely manner.

Thus, requesting clotting products is the most appropriate step at this point as it prepares the anaesthetist for the ensuing coagulopathy.

Question 28

28. A 67-year-old man is admitted to the emergency department with a sudden onset of severe chest pain and breathlessness.

His ECG shows ST elevation in the following leads: I, aVL and V2–V6.
Which of the following is the most likely affected blood vessel?
A Left anterior descending artery
B Right coronary artery
C Left circumflex artery
D Left coronary artery
E Posterior descending artery

Answer 28

A

28. D Left coronary artery

Sudden occlusion of major coronary arteries is the most common cause of myocardial infarction (MI).

The area of myocardial ischaemia depends on the
coronary circulation.

Early recognition of acute coronary obstruction and quick
reperfusion is essential for good outcome after MI.

A good anatomical knowledge is essential for successful MI management (Figure 2.7).

The blood to the heart is mainly supplied by two main coronary arteries (CAs),
the right coronary artery (RCA) and the left coronary artery (LCA).

The RCA arises form the right anterior aortic sinus.

It mainly supplies blood to the right side of the heart.

However, the RCA also gives twigs to the right atrium and left
ventricle (LV).

The RCA travels along the right atrioventricular (AV) groove on its way to the crux of the heart. It gives off the right marginal artery, which descends along the acute margin of the heart and gives off branches to both sides of right ventricle.

The RCA continues on the diaphragmatic surface of the heart along the posterior longitudinal sulcus to continue to the apex of the heart as the posterior descending artery (PDA).

The PDA supplies the inferior and the posterior walls of the left ventricle (LV), the ventricular septum and part of the papillary muscles.

The LCA arises from the left anterior aortic sinus. It supplies blood to the left side of the heart and it is larger than RCA.

It usually runs for 1–25 mm as the left main coronary artery before bifurcating into left anterior descending artery (LAD)
and left circumflex artery (LCX).

The LAD runs in the interventricular groove along the anterior surface of the heart.
It gives off diagonal branches (supply the anterolateral surface) and septal branches (supply the interventricular septum) on its way toward the apex of the heart.

The LCX primarily supplies the lateral wall of the heart. It runs along the left atrioventricular groove, reaching as far as the posterior longitudinal sulcus.

It gives 1 to 3 marginal branches,
which supply the lateral free wall of the LV.

The coronary artery dominance is determined by the artery that gives the posterior descending artery.

In most of patient (85%), the RCA gives off the PDA and the
coronary circulation can be identified as right-dominant. In a left-dominant circulation, the PDA is given off by the LCX (15% of cases).

A 12-lead electrocardiogram (ECG) looks at the heart from different angles.

The changes seen in the ECG leads adjacent to the ischaemic area usually reflect the areas of the coronary arteries occluded (Table 2.7).

In this clinical scenario, the patient has acute occlusion of the left coronary artery (anterolateral V2-V6, I and aVL). This lesion results in rapid deterioration of the patient condition because it usually leads to entire LV infarction. These patients have
a poor prognosis if not treated immediately.

Area infarcted Leads adjacent Artery involved

Septal V1–V2 LAD

Anterior V2, V3 and V4 LAD

Anteroseptal V1–V4 LAD

Lateral I, aVL and V5–V6 LCX

Anterolateral V2–V6, I and aVL LCA (LAD + LCX)

Inferior II, III and aVF RCA

Posterior Reciprocal changes V1–V3 RCA

Question 29

29. A 7-year-old boy presents following a head injury by falling from a height of 3 metres. On assessing his neurological status he opens his eyes to a painful
    stimulus, cries to pain and withdraws from a painful stimulus.
    Which score on the paediatric Glasgow coma scale best represents the findings?
    A Eyes 2 Verbal 3 Motor 4
    B Eyes 1 Verbal 2 Motor 4
    C Eyes 2 Verbal 2 Motor 3
    D Eyes 3 Verbal 3 Motor 4
    E Eyes 2 Verbal 4 Motor 4

Answer 29

A

29. A Eyes 2 Verbal 3 Motor 4

In order to assess the conscious levels of infants and children a modified Glasgow coma scale (GCS) has been devised. The eye opening response is graded similarly to the standard GCS. The modifications are for the motor and verbal response.

Eye opening response
4- Spontaneous
3- Verbal
2- Pain
1- None

Verbal response
5- Age appropriate
4- Irritable and cries
3- Cries to pain
2- Moans to pain
1- None

Motor response
6- Spontaneous movement
5- Withdraws to touch
4- Withdraws to pain
3- Abnormal flexion

Using this scoring system, this patient scores: eyes 2; verbal 3; motor 4 giving a paediatric GCS of 9/15.

The current guidelines recommend that a CT scan is indicated if GCS < 12 and intracranial pressure monitoring is required if GCS is between 3-8, both of which
would be necessary in this case.

Question 30

30. You are called to urgently assess a 54-year-old man in outpatient clinic who has acutely deteriorated following administration of oral antibiotics. On assessment
    his heart rate is 145 beats per minute, blood pressure is 74/36 mmHg and saturations are 93% on 6 L/minute of oxygen via Hudson mask. He is wheezy and
    has a generalised rash all over his body.
    Which of the following would be the most appropriate pharmacological intervention for the patient?

A intravenous adrenaline 3 mg bolus
B intravenous adrenaline 0.5 mL of 1:1000
C intramuscular adrenaline 1 mL of 1:1000
D intramuscular adrenaline 0.5 mL of 1:1000
E intramuscular adrenaline 0.5 mL of 1:10000

Answer 30

D

30. D intramuscular adrenaline 0.5 mL of 1:1000

This scenario most likely represents an anaphylactic reaction to the intravenous cefuroxime administered to the patient.

Adrenaline (epinephrine) is the most appropriate drug for management of anaphylaxis.

The α-adrenoceptor agonistic effect reverses peripheral vasodilatation and oedema, whereas the β-adrenoceptor
agonistic effect increases cardiac output, dilates bronchial airways and attenuates the IgE-mediated reaction by acting on β-adrenoceptors on mast cells.

The intramuscular route is most appropriate for adrenaline as:

• ECG monitoring is not immediately available (patient being on a ward)

• There is a greater margin of safety required in a suspected case of anaphylaxis

Repeated intramuscular dose can be administered according to patient response,
with an initial dose of 0.5 mL of 1:1000 (500 mcg) adrenaline.

The intravenous route is recommended in certain specific conditions:

• The administrator has vast experience of using this route for adrenaline administration excluding cardiac arrest scenarios

• The patient is under full monitoring (ECG, BP, pulse oximetry)

• There is no doubt regarding the diagnosis