8. Regional / Trauma

Question 1

Q1 — Nerve block for shoulder surgery
a) List the specific nerves that need to be blocked to achieve
effective analgesia for shoulder surgery.

Answer 1

The shoulder area is supplied by both the cervical and brachial plexus as
follows:
Cervical plexus:
● Transverse cervical nerve.
● Supraclavicular nerve.

Brachial plexus:
● Upper lateral cutaneous branch of the axillary nerve.
● Medial cutaneous nerve of the arm.
● Intercostobrachial nerve.
● Suprascapular nerve.

Question 2

b) Name any six possible complications of an interscalene block.

Answer 2

● Subarachnoid/epidural injection.

● Stellate ganglion block.

● Pneumothorax.

● Phrenic nerve palsy — ipsilateral hemidiaphragmatic paralysis.

● Horner’s syndrome.

● Local anaesthetic toxicity.

● Accidental intravenous injection.

Question 3

c) What positioning is needed for shoulder surgery?

Answer 3

The deck chair (modified sitting position) is most commonly used for
shoulder surgeries.

Question 4

d) List any three complications of positioning for shoulder surgery.

Answer 4

● Hypotension due to venous pooling in the extremities.

● Intraoperative cerebral ischaemia.

● Activation of the Bezold-Jarisch reflex leading to profound
bradycardia, hypotension and even cardiac arrest.

● Neurological injuries.

Question 5

e) What postoperative advice would you give to a patient who has
received an interscalene block

Answer 5

1 After an interscalene block, your arm may remain weak for up to 24
hours.

2 ● As the numbness wears off, it is normal to feel pins and needles in the
hand.

3 ● Take regular analgesics postoperatively to avoid sudden intense pain
once the block wears off.

4 ● Protect and support your arm, preferably in a sling.

5 ● Avoid handling machinery, driving, and contact with very hot or cold
objects.

6 ● If the numbness lasts for more than 24 hours or you get breathless,
ring the hospital number provided

Question 6

Q2 — Regional block in hip fractures
An 80-year-old woman is admitted to hospital having sustained a proximal
femoral (neck of femur) fracture in a fall.
a) How would you optimise this patient’s pain preoperatively?
.

Answer 6

● Assessment of pain by recording pain scores should be done on
admission to the accident and emergency department, after 30
minutes and then regularly after starting regular analgesia.

● Immobilisation of the injured leg.

● Simple analgesia with paracetamol (avoid NSAIDs).

● Multimodal analgesia with sparing use of opioids.

● Regional nerve blocks.

Question 7

b) What is the nerve supply of the skin overlying the hip joint?

Answer 7

● Cluneal nerves — superior, medial and inferior.

● Anterior cutaneous branch of the femoral nerve.

● Cutaneous branch of the obturator nerve.

● Lateral cutaneous nerve of the thigh.

● Lateral cutaneous branch of the iliohypogastric nerve.

Question 8

c) What regional nerve blocks can be used to provide
preoperative analgesia?

Answer 8

● Femoral nerve block.
● Fascia iliaca block.
● Lateral cutaneous nerve of the thigh block.
● Psoas block.

Question 9

d) What nerves are blocked by the fascia iliaca block?

Answer 9

● Lateral femoral cutaneous nerve.
● Femoral nerve.
● Obturator nerve.

Question 10

e) List the scoring systems that can be used to predict 30-day
mortality in this patient.

Answer 10

● Nottingham Hip Fracture Score.

● Estimation of Physiological Ability and Surgical Stress (E-PASS).

● O-POSSUM
(Physiological and Operative Severity Score for the
enUmeration of Mortality and morbidity modified for orthopaedic
usage).

Question 11

f) List the AAGBI recommendations regarding unacceptable
reasons for delaying surgery

Answer 11

● Lack of facilities or operating theatre space.
● Awaiting echocardiography.
● Unavailable surgical expertise.
● Minor electrolyte abnormalities.

Question 12

Key Points

Answer 12

1 Hip fracture is a major and increasing concern for public health.

2 Timely hip fracture repair surgery is associated with lower morbidity and mortality.

3 There is little evidence to suggest that general or regional anaesthesia is superior; the conduct of each should account for a patient’s physiological limitations.

4 A quarter of patients with hip fracture experience postoperative delirium.

4 Hypotension is associated with an increased risk of mortality; in many cases, it can be avoided by minimising the doses of anaesthetic agents.

Question 13

Intro

comorb

30 day mortality changes

BPT in ireland

Answer 13

Disorders of cognition are common in patients with hip fracture, with 30% having severe cognitive impairment before surgery.

Although hip fracture remains the commonest cause of death after an accidental injury,

30 day mortality increased from 2007 to 18
Increased attention paid to processes and outcomes; the introduction of clinical guidelines; and, in England and Ireland, the introduction of Best Practice Tariffs (BPTs) for hip fracture care

1 Admission to an acute orthopaedic ward (or operating theatre) within 4 h of presentation

Surgery within 48 h of admission and within normal working hours

Does not develop a new Grade 2 or higher pressure ulcer during admission

Reviewed by a geriatrician at any point during admission

Bone health assessment

Specialist falls assessment

Varying focus of evidence / guidelines
More recent guidelines by the Association of Anaesthetists and Fragility Fracture Network

Question 14

POCD / delirium

Answer 14

specifies postoperative screening for delirium using the 4AT

delirium and long-term complications, such as loss of function, cognitive impairment and increasing dependency, have profoundly negative impacts on patients’ lives

Question 15

Evidence-based anaesthesia for hip fracture repairp

Spinal GA

Answer 15

that there is no convincing evidence that either regional or GA is superior.

Cochrane review concluded that the only benefit to regional anaesthesia
is a lower rate of venous thromboembolism
in the absence of pharmacological thromboprophylaxis.

variations in practice within different modes of anaesthesia accounts for some of the difficulty in generating evidence to guide practice

It is also possible that anaesthesia has less of an impact than receiving timely surgery, high-quality orthogeriatric care and appropriate rehabilitation

Although there is little evidence to favour either mode of anaesthesia, accumulating evidence suggests that the aims and techniques of anaesthesia (of either mode) are important in hip fracture repair.

Question 16

Intraoperative surgical and anaesthetic roles to reduce the risk of BCIS. Reproduced from the Association of Anaesthetists/BOA/BGS guideline.

Question 17

Evidence based Anaesthesia

Proceed with surgery?

Answer 17

Proceeding with anaesthesia and surgery

Patients may have been told they are ‘not fit’ for elective hip surgery.

the risk of proceeding must be weighed against the risk of adopting a non-operative approach

risks of not operating are even higher, and non-operative management involves several weeks of painful immobilisation

NHFD data, Johansen and colleagues
48.6% of patients with hip fracture who did not undergo surgical repair died in a hospital, compared with 6.6% of patients who underwent surgery.

provides effective analgesia, we suggest that it is reasonable to proceed even when the procedure is deemed to be palliative, unless the patient is felt to be likely to die imminentl

Question 18

Enabling timely hip fracture repair

Answer 18

Enabling timely hip fracture repair

Irish Hip Fracture Database adopting a standard of 48 h
Fragility Fracture Network.
sing NHFD data, Sayers and colleagues demonstrated a 9.4% relative increase in 30-day mortality risk when hip fracture repair was undertaken >24 h after hospital admission

mongst patients with mild-to-moderate cognitive impairment, delaying surgery for more than 1 day increases the risk of delirium two-fold.

(HIP ATTACK) study, a large international RCT comparing complication rates when ‘accelerated’ hip fracture repair was undertaken (median: 6 h from diagnosis) with standard care (median: 24 h),

However, the risk of delirium and the times to mobilisation and discharge were all significantly lower in the ‘accelerated’ group

Question 19

Avoiding hypotension

Answer 19

The ASAP-2 study used NHFD outcome data to compare anaesthetic techniques as recorded in the ASAP.

No mortality benefit was found to either spinal anaesthesia or GA, but a statistically significant increase in 5- and 30-day mortality was associated with incremental decreases in the lowest recorded MAP.

Bone cement implantation syndrome (BCIS) is an important cause of cardiovascular (and respiratory) collapse during cemented hemiarthroplasty and total hip replacement, and to a lesser extent in any procedure involving instrumentation of the femoral canal (e.g. femoral nail).

RF
male sex,
the use of diuretics,
significant cardiopulmonary disease
and increasing age

Question 20

Intraoperative surgical and anaesthetic roles to reduce the risk of BCIS. Reproduced from the Association of Anaesthetists/BOA/BGS guideline.

Answer 20

Conduct of surgery

1 Ask the anaesthetist to confirm that he/she has heard your instruction to the theatre team that you are about to prepare the femoral canal for cement and prosthesis insertion.

2 Carefully prepare, wash, and dry the femoral canal. Use of a pressurised lavage system is recommended to clean the endosteal bone of fat and marrow contents.

3 Use a distal suction catheter on top of an intramedullary plug. Insert the cement from a gun in retrograde fashion on top of the plug and pull the catheter out as soon as it is blocked with cement.

4 Do not use excessive manual pressurisation or pressurisation devices in patients at higher risk of cardiovascular events.

_____________________________________________

Conduct of anaesthesia

1 Ensure that the patient is adequately hydrated before induction of and during anaesthesia.

2 Maintain vigilance for possible cardiovascular events once the femoral head is removed and the surgeon has verbally indicated his/her intent to instrument the femoral canal.

3 Confirm to the surgeon that you are aware of preparation of the femoral canal for cement and prosthesis insertion.

4 Aim to maintain the systolic blood pressure within 20% of preinduction values throughout surgery, using vasopressors and/or fluids. Invasive blood pressure monitoring is indicated for patients at higher risk.

5 Be ready to give vasopressors, e.g. metaraminol/adrenaline in case of cardiovascular collapse.

Question 21

Peripheral nerve block

Answer 21

Peripheral nerve block
The fascia iliaca compartment block (FICB), femoral nerve block and 3-in-1 block provide effective but incomplete analgesia in patients with hip fracture

hip joint arises from both the lumbar and sacral plexuses.

(LCNT) should be blocked for surgery, as it supplies the skin that is incised, although additional local anaesthetic infiltration is required if a posterior surgical approach

Association of Anaesthetists advises that peripheral nerve blocks for hip fracture patients can be repeated after 6

FICB in the perioperative period even if it has been undertaken earlier, to reduce quadriceps femoris muscle spasm, facilitate positioning for anaesthesia and provide postoperative pain relief

Question 22

Avoiding cognitive complications

Answer 22

Avoiding cognitive complications

1 Delirium affects a quarter of people with hip fracture
and is associated with increased rates of adverse outcomes,
including mortality and the need for residential or nursing care.

Timely hip fracture surgery appears to mitigate the risk of delirium,

f brain hypoperfusion attributable to hypotension may have a protective effect

Drugs and delirium,

including opioids and
drugs with central anticholinergic activity,
such as cyclizine, prochlorperazine and atropine

. A multidisciplinary ‘care bundle’ approach focused on the provision of FICB and the avoidance of long-acting opioids, antihistamines, antipsychotics and anticholinergics, maintained through staff education and continuous audit, appears to be effective in preventing delirium

Question 23

Controversies

Answer 23

‘Delay’ vs ‘optimisation’

delaying surgery may be appropriate if effective optimisation is undertaken during this time.

1. Anaemia and blood transfusion
   target of 9 g dl−1 should be adopted for frailer patients
   to 10 g dl−1 for patients with a history of ischaemic heart disease,
   use of tranexamic acid.

Question 24

Controversies

Answer 24

‘Delay’ vs ‘optimisation’

delaying surgery may be appropriate if effective optimisation is undertaken during this time.

1. Anaemia and blood transfusion
   target of 9 g dl−1 should be adopted for frailer patients
   to 10 g dl−1 for patients with a history of ischaemic heart disease,
   use of tranexamic acid.
2. Undiagnosed cardiac murmur
   However, surgery should not be delayed pending the results of echocardiography for undiagnosed murmurs; anaesthesia should instead proceed with invasive blood pressure monitoring and particular attention paid to maintaining cardiovascular stability through the use of lower doses of anaesthesia, i.v. fluids and vasoactive drugs as appropriate.
3. Anti-platelets, anticoagulants and spinal anaesthesia
   ragmatic approach to anticoagulation when spinal anaesthesia is deemed superior to GA (e.g. severe chest disease)
4. Single antiplatelet therapy, including clopidogrel, is not a contraindication to spinal anaesthesia. Spinal anaesthesia may be appropriate for patients taking dual antiplatelet therapy for who are unsuitable for GA, on a risk/benefit basis
5. )
   For patients taking vitamin K antagonists, spinal anaesthesia can be undertaken once the international normalised ratio (INR) is ≤1.5.
   if
   INR of >1.5 should receive an initial dose of vitamin K as soon as possible (i.e. in the emergency department), with further vitamin K or prothrombin complex concentrate if the INR remains >1.5 after 4–6 h.
6. )
   Direct-acting oral anticoagulant (DOAC) activity cannot be reliably assessed using standard coagulation tests. However, unless the patient has severe renal dysfunction (i.e. creatinine clearance <30 ml min
   provided after two half-lives have elapsed.
   last dose of DOAC should therefore be confirmed, and spinal anaesthesia can usually be undertaken on the following day

Question 25

Conduct of spinal

Answer 25

ASAP adopted a standard dose of bupivacaine ≤10 mg for use in spinal anaesthesia, and stated that, if used, intrathecal opioids should be limited to fentanyl e ASAP found that a median dose of 2.5 ml bupivacaine 0.5% (12.5 mg) was used, bupivacaine 4 mg plus fentanyl 20 μg, diluted with saline 0.9% to a total volume of 2 ml (described as ‘mini-dose’ spinal), and 2 ml glucose-free bupivacaine 0.5% (10 mg) without opioid are sufficient for hip fracture surgeries lasting up to 110 min after injection, with fewer interventions for hypotension required in the mini-dose group. hese findings suggest that lower doses are both practical and desirable, particularly when used in combination with FICB, analgesia in the event that surgery is prolonged

Question 26

Conduct of spinal

Answer 26

ASAP adopted a standard dose of bupivacaine ≤10 mg for use in spinal anaesthesia, and stated that, if used, intrathecal opioids should be limited to fentanyl e ASAP found that a median dose of 2.5 ml bupivacaine 0.5% (12.5 mg) was used, bupivacaine 4 mg plus fentanyl 20 μg, diluted with saline 0.9% to a total volume of 2 ml (described as ‘mini-dose’ spinal), and 2 ml glucose-free bupivacaine 0.5% (10 mg) without opioid are sufficient for hip fracture surgeries lasting up to 110 min after injection, with fewer interventions for hypotension required in the mini-dose group. hese findings suggest that lower doses are both practical and desirable, particularly when used in combination with FICB, analgesia in the event that surgery is prolonged ocedures requiring fracture reduction before incision may require the anaesthetic to last substantially longer than the operating time itself he predicted operating time, and the time taken to position the patient and prepare the surgical field, should be communicated effectively during the ‘team brief’. When surgery is unexpectedly prolonged, additional infiltration of local anaesthetic, cautious administration of systemic analgesics and conversion to GA are all acceptable strategies for maintaining the patient's comfort sedation ver sedation in patients with hip fracture is common, and the role of sedative and analgesic medications in postoperative delirium is well described. In one comparison of ‘lighter’ vs ‘heavier’ sedation (assessed clinically) during hip fracture repair, heavier sedation doubled the risk of postoperative delirium in patients with a low burden of comorbidity, many patients fall asleep once spinal anaesthesia has been established, sedative drugs can be avoided in most cases. We therefore suggest that sedatives should be used with caution and limited to short-acting, titratable agents; propofol by target-controlled infusion is ideal

Question 27

Conduct of GA

Answer 27

The aims of GA are similar to those of spinal anaesthesia: hypotension and deliriant drugs should be avoided if possible, and anaesthetic doses should be sympathetic to the limited physiological reserve of patients with hip fracture. Strategies to optimise anaesthetic dose include depth of anaesthesia monitoring, using age-adjusted minimum alveolar concentration values for volatile anaesthesia, and carefully titrating induction agents against clinical and EEG-based assessments of anaesthetic depth. Peripheral nerve blocks help to minimise the required dose of both anaesthetic agents and opioids by reducing nociception during surgery and providing effective postoperative analgesia, and should be performed before or shortly after the induction of anaesthesia. Maintaining spontaneous respiration minimises the risk of atelectasis, barotrauma and any hypotension associated with positive-pressure ventilation inhalational or titrated i.v. induction, either manually or by using a target-controlled infusion There is an argument for adopting a low threshold for tracheal intubation. This can be achieved in combination with spontaneous breathing by using deep inhalational induction or topical anaesthesia of the airway. n is deemed to be not required, using a second-generation supraglottic airway that provides additional protection against aspiration is an appropriate approach.

Question 28

Postoperative recovery

Answer 28

hip fracture should receive high-dependency care after surgery, as would now routinely be the case for patients with a similar predicted mortality risk after emergency abdominal surgery. Adopting this approach on a universal basis would require resources that, at present, are unavailable in many healthcare systems ctors in the critical care unit (e.g. monitors, alarms and frequent night-time interruptions), which may make delirium more likely in susceptible patients by-case for the management of specific reversible conditions, after risk assessment and in consultation with the multidisciplinary team. management pathway, aiming for early remobilisation, rehabilitation and maintenance of the patient's prior cognitive function thogeriatricians, occupational therapists and physiotherapists is important, and postoperative screening for delirium as specified in the English BPT naesthetists should be mindful of enabling postoperative recovery through their anaesthetic technique. To this end, there is an argument for providing anaesthesia in a consistent way on an institutional basis, so that those involved in recovery and rehabilitation after hip fracture are better able to anticipate patients' postoperative needs.

Question 29

Consent

Answer 29

Informed consent for hip fracture anaesthesia presents several challenges; cognitive impairment is commonplace and mental capacity may fluctuate. Patients may not always wish to engage in a comprehensive discussion of risk, as this may provoke unnecessary anxiety at an already stressful time.8 It is often appropriate to involve family members or other advocates in the consent process, and to establish how much the patient wishes to know at an early point in the discussion. aterial risks’ (i.e. those important to the patient), being mindful of the specific complications associated with hip fracture surgery (e.g. the high rate of postoperative cognitive complications).28 Risk stratification tools, such as the Nottingham Hip Fracture Score, may be useful, including by providing a basis for reassurance in lower-risk cases.29 Patients should be offered a choice of the ‘reasonable options’ for their management (and the option to do nothing).28 This may involve a discussion of both general and spinal anaesthesia, and peripheral nerve blocks and sedation. Whilst patients should have a free choice, we suggest it is reasonable for the anaesthetist to explain what technique is usually provided at their institution, and the benefits that this may offer in terms of integrating peri- and postoperative care. The patients' experience of hip fracture anaesthesia has been studied, and qualitative research suggests that postoperative complications (e.g. pain, delirium and reduced mobility) are more important to patients than the mode of anaesthetic itself. erhaps by measuring their experience of anaesthesia using tools, such as the Bauer questionnaire, and screening for complications, so that anaesthetists are able to optimise their practice accordingly.

Question 30

a) Outline the basic physical principles involved in the formation of an ultrasound image.

Answer 30

The formation of an ultrasound image is based upon sound waves that are transmitted from, and received by, an US transducer. It utilises frequencies of 2-15MHz (human hearing operates at 1-20kHz).

Question 31

b) What is piezoelectrical activity and how is it utilised in ultrasound?

Answer 31

Ultrasound transducers have piezoelectric properties: ● When current is applied across the crystal, it expands and contracts as the polarity of the voltage changes. This produces a series of pressure waves (sound waves). ● In reverse, when the sound wave returns, it squeezes and stretches the crystal and generates a voltage change across its surface. This is amplified and forms the receiving signal.

Question 32

c) What governs the reflection of sound waves and the formation of an ultrasound image?

Answer 32

● The reflectivity of sound waves depends on the difference in the acoustic impedance of the two media at an interface. ● The higher the difference in acoustic impedance, the greater the reflection, thus obscuring the deeper tissues, e.g. a tissue-air interface has a reflection coefficient of 0.999 and 99% of the sound waves are reflected

Question 33

d) List the patient factors that influence ultrasound image quality.

Answer 33

1 ● Increased Body Mass Index. 2 ● Tissue oedema. 3 ● Muscle atrophy. 4 ● Anatomical abnormalities.

Question 34

e) What acoustic artefacts may influence the ultrasound image quality?

Answer 34

1 ● Post cystic enhancement — fluid-filled structures like a cyst provide increased brightness behind them. 2 ● Acoustic shadowing — caused by highly reflective surfaces such as bone. 3 ● Anisotropy — image quality is affected by the angle at which the ultrasound beam hits the target. 4 ● Air — air does not allow the passage of ultrasound beams.

Question 35

f) Which two needling techniques are commonly used in ultrasound-guided nerve blocks

Answer 35

● In-plane needling technique or long-axis technique. ● Out-of-plane needling technique or short-axis technique

Question 36

g) List the advantages and disadvantages of one of these techniques.

Answer 36

In-plane needling technique: ● Advantages: - able to visualise the entire length of the needle; - able to visualise the proximity of the nerve to the needle. ● Disadvantages: - difficulty in keeping the needle in view; - the needle entry point may be unusual; - longer distance from the skin entry point to the nerve.

Question 37

A 19-year-old patient has suffered a complete transection of the spinal cord at the first thoracic vertebral level due to a fall but has no other injuries. a) What is the pathophysiology of neurological injury subsequent to the fall in this patient?

Answer 37

Primary injury: ● From direct cord compression. ● Haemorrhage. ● Traction forces. Secondary injury: ● Haemorrhage in the central grey matter damages the axons and neuronal cell membrane. ● This leads to spinal cord oedema and subsequent spinal cord ischaemia. ● Loss of autoregulation contributes to neurogenic shock. ● A persistent drop in the systemic arterial pressure may lead to further cord hypoperfusion causing a spread in the damaged zone (penumbra). ● Cord ischaemia extends bidirectionally. ● Secondary spinal cord injury ensues further.

Question 38

b) What is the cause of neurogenic shock in this patient and how does it present?

Answer 38

Neurogenic shock — interruption of autonomic pathways leading to hypotension and bradycardia.

Question 39

c) How would spinal shock present in this patient and what are the phases?

Answer 39

Spinal shock: ● Loss of reflexes below the level of the spinal cord injury. ● Results in the clinical signs of flaccid areflexia. ● Usually combined with hypotension of neurogenic shock. ___________________ Stages of spinal shock: ● Areflexia (days 0-1). ● Initial reflex return (days 1-3). ● Early hyperreflexia (days 4-28). ● Late hyperreflexia (1-12 months).

Question 40

d) What disturbances may occur subsequently in the cardiovascular system?

Answer 40

● An initial massive release of catecholamines leads to dramatic hypertension and tachycardia. ● A loss of sympathetic tone leads to vasodilatation and hypotension. ● Bradycardia from unopposed vagal tone also contributes to hypotension as does negative inotropism. ● Pulmonary capillary integrity is lost which predisposes this patient to pulmonary oedema.

Question 41

e) What effects may be seen in the respiratory system?

Answer 41

● Loss of inspiratory intercostal muscle and abdominal muscle contribution to the work of breathing. ● Vital capacity reduced to 30-80% of normal. ● Normal to weak cough. ● Short-term ventilation may be needed. ●Long-term ventilation may be needed if the patient has other comorbidities

Question 42

f) When and why may suxamethonium be contraindicated in this patient?

Answer 42

● Suxamethonium should be avoided from 72 hours post-injury and for up to 6 months after the injury. ● Acute denervation causes the development of extrajunctional acetylcholine receptors. Due to this, the use of suxamethonium in this patient can lead to life-threatening hyperkalaemia.

Question 43

g) Give the advantages of a regional anaesthetic technique for a patient having elective lower limb surgery 2 years after a high thoracic spine transection.

Answer 43

This patient may safely have a spinal anaesthetic for elective lower limb surgery 2 years post-spinal cord injury. Advantages: ● Abolishes autonomic dysreflexia. ● Avoids the development of spasms perioperatively. ● Reduces the incidence of thromboembolism. ● Avoids the risks from airway manipulation for general anaesthesia. ● Avoids the need for ventilation in this patient who may already have respiratory compromise due to the spinal cord injury.

Question 44

Q5 — Wrong-side block and never events a) List the implications for the patient of an inadvertent wrong sided peripheral nerve block.

Answer 44

● Nerve injury from siting the wrong block. ● Local anaesthetic toxicity while siting the block. ● Delayed hospital discharge from reduced mobility. ● Implications for the patient’s dexterity. ● May lead the team to continue with the wrong-site surgery.

Question 45

b) Summarise the recommendations of the “Stop Before You Block’’ campaign. .

Answer 45

● Perform the WHO checklist sign in as usual. ● Extra vigilance under the following circumstances: - delay between sign in and doing the actual block; - when the patient has been moved/turned; - the presence of distractions in the anaesthetic room; - when performing lower limb blocks; - when less experienced personnel are performing the block. ● The anaesthetist and anaesthetic assistant should perform a “STOP” moment just before needle insertion. The surgical site marking and the site of the block should be confirmed.

Question 46

c) List the factors that have been identified as contributing to the performance of a wrong-side block.

Answer 46

● Distractions in the anaesthetic room. ● Time lag between the WHO sign in and the siting of the block. ● Covering up of the surgical marking with blankets to avoid the patient getting cold.

Question 47

d) Define the term “never event”.

Answer 47

Never events are defined as “serious, largely preventable patient safety incidents that should not occur if relevant preventive measures have been put in place”.

Question 48

e) List any five drug-related never events

Answer 48

● Mis-selection of a strong potassium solution. ● Administration of medication by the wrong route. ● Overdose of insulin due to abbreviations or an incorrect device. ● Overdose of methotrexate for non-cancer treatment. ● Mis-selection of high-strength midazolam during conscious sedation.

Question 49

Q6 — Ankle block A 32-year-old patient is scheduled for hallux valgus surgery. a) What anaesthetic options are available for anaesthetising this patient?

Answer 49

● General anaesthesia. ● Regional anaesthesia: - spinal anaesthesia; - popliteal sciatic block; - ankle block. ● A combination of the above techniques.

Question 50

b) List the nerves supplying the ankle joint.

Answer 50

1 ● Posterior tibial nerve. 2 ● Deep peroneal nerve. 3 ● Superficial peroneal nerve. 4 ● Saphenous nerve. 5 ● Sural nerve.

Question 51

c) Describe the origin and sensory innervation from the posterior tibial nerve.

Answer 51

Posterior tibial nerve: ● Terminal branch of the tibial nerve. ● Mixed sensory and motor nerve. ● Enters the foot posterior to the medial malleolus. ● Commonly lies posterior to the posterior tibial vessels. ● Divides into medial and lateral plantar branches. ● Supplies the majority of the sole of the foot.

Question 52

d) Describe the origin and sensory innervation from the deep peroneal nerve.

Answer 52

Deep peroneal nerve: ● Branch of the common peroneal nerve. ● Enters the foot underneath the extensor retinaculum between the tendons of extensor digitorum longus and extensor hallucis longus. ● Lies lateral to the dorsalis pedis artery. ● Supplies the skin of the first web space.

Question 53

e) Describe the origin and sensory innervation from the superficial peroneal nerve.

Answer 53

Superficial peroneal nerve: ● Branch of the common peroneal nerve . ● Enters the superficial fascia in the dorsal aspect of the foot after piercing the deep fascia between extensor digitorum longus and peroneus brevis. + ● Sensory to the majority of the dorsum of the foot.

Question 54

f) List the disadvantages of using an ankle block for this patient

Answer 54

● Multiple injections may be uncomfortable especially if the patient is awake ● An inability to use a proximal tourniquet for an extended duration. ● Time consuming. ● Risk of vascular injection. ● Failure/inadequate block

Question 55

You are called to resuscitate a 26-year-old male who had a major accident while driving a motorcycle. He is diagnosed with a pelvic fracture. a) How would you classify pelvic fractures?

Answer 55

The Young and Burgess classification (based on the direction of force causing the injury): ● AP compression — head-on collision; the pubic symphysis widens. ● Lateral compression — hit from one side; internal rotation of one side of the pelvis and anterior pubic rami fracture. ● Vertical shear — fall from height or axial loading of an extended limb on collision; complete disruption of the pelvic ring with superior displacement of the hemipelvis. ● A combined mechanism — a combination of the above forces. Pelvic ring fractures can be stable or unstable: ● Stable — low-energy mechanism of injury, heals well. ● Unstable — secondary to a high-impact injury, associated with haemorrhage; two types: - with rotational instability only; - with rotational and vertical instability.

Question 56

b) How would you initially manage and resuscitate this patient?

Answer 56

● ATLS® approach — ABCDE approach. ● Mostly presents to major trauma centres. ● Team approach. ● Identify and manage life-threatening injuries. ● Pelvic binder application, and skeletal traction if there is also vertical instability. ● Usually multiple injuries have been sustained — care in assessing and managing. ● Do not stress the pelvis mechanically as it can destabilise clot formation. ● Avoid log rolling. ● Haemodynamic stability determines what radiological investigations could be undertaken. ● CT scan or contrast CT scan. ● If the patient is unresponsive to resuscitation, rapid intervention is needed with multi-specialty involvement and consultant-led decision making. ● The immediate options are angiography and embolisation if available, or pelvic packing after an emergency laparotomy. ● Analgesia — IV morphine titrated; ketamine can be used as a second line analgesic. Intranasal diamorphine can be used if there is no IV access. ● Bleeding should be controlled.

Question 57

c) How would you apply a pelvic binder in this patient and how long would you leave it?

Answer 57

● The early use of a pelvic binder improves the outcome. ● The aim is to approximate the fracture ends, to reduce bleeding, to reduce pain and to stabilise the pelvis temporarily. ● The binder can be placed over the greater trochanters, making sure there is exposure available if a laparotomy is needed. ● The disadvantages of using a pelvic binder are that it will not reduce vertical displacement and it can worsen the deformity in lateral compression fractures. It can also cause pressure sores, nerve damage, tissue necrosis, etc. ● Remove within 24 hours of application

Question 58

d) What are the surgical options that are available in this patient?

Answer 58

1 Surgical stabilisation/fixation in two stages: ● Initial stabilisation. ● Definitive fixation. 1 Stabilisation: ● External fixator. ● Skeletal traction. ● Pelvic packing. ● Radiological embolisation, etc. 2 Fixation: ● Approach to the anterior ring — common, pubic diastasis plate. ● Approach to the posterior ring — posterior ilium, sacrum. ● Approach to the acetabulum — anterior or posterior column.

Question 59

e) What are the anaesthetic considerations in this patient with a traumatic pelvic fracture?

Answer 59

Preoperative: ● Communication, MDT approach. ● Urological input. ● Prepare cell salvage, correct coagulopathy and cross-match for red cells. ● Electrolyte abnormalities corrected. ● Book a critical care bed. Intraoperative: ● Two large-bore IV cannulae. ● Arterial line. ● Full AAGBI monitoring. ● Reinforced tracheal tube if a prone posture is used. ● Take care not to dislodge any chest drains, suprapubic catheters, extraventricular drains, etc. ● Prophylactic antibiotics. ● Tranexamic acid 1g loading dose and 1g infusion. ● Active mechanical compression devices for preventing VTE. Postoperative: ● Multimodal analgesia. ● Local wound infiltration. ● Epidural analgesia (if continuous passive motion devices are used in acetabular surgeries). ● Intensive or high dependency care unit. Thromboprophylaxis: ● Mechanical prophylaxis as soon as admitted. ● Chemical prophylaxis once haemodynamically stable, clotting corrected. ● If a high-risk patient, consider a IVC filter prophylactically.

Question 60

A 78-year-old patient is undergoing an elective total hip replacement. a) During the surgery, when can the patient present with bone cement implantation syndrome (BCIS)?

Answer 60

● At the time of cementation. ● Insertion of prosthesis. ● Reduction of joint. ● Limb tourniquet deflation.

Question 61

b) What clinical features would make you suspect a BCIS?

Answer 61

● Transient/sustained desaturation. ● Hypotension. ● Cardiac arrhythmias. ● Cardiac arrest

Question 62

c) How would you grade the severity of BCIS?

Answer 62

● Grade 1 — moderate hypoxia (SaO2 <94%) or a reduction in systolic arterial pressure of >20%. ● Grade 2 — severe hypoxia (SaO2 <88%) or a reduction in systolic arterial pressure of >40%) or unexpected unconsciousness. ● Grade 3 — cardiovascular collapse needing CPR.

Question 63

d) What is the pathophysiology of BCIS?

Answer 63

There are two probable theories: ● Mechanical effects — high intramedullary pressure causes embolisation of debris (marrow, fat, cement particles, air, bone particles, platelet aggregates, fibrin aggregates) to the right atrium/right ventricle/pulmonary artery. This leads to an increased pulmonary vascular resistance (PVR). ● Mediator effects — systemic embolisation of bone cement causes release of vasoactive/pro-inflammatory mediators which directly increase the PVR.

Question 64

e) What are the risk factors for the development of BCIS?

Answer 64

Patient-associated risk factors: ● ASA III or IV. ● Significant cardiovascular disease. ● Pre-existing pulmonary vascular hypertension. ● Osteoporosis. Surgical risk factors: ● Aetiology of fracture — pathological fracture. ● Site of fracture — intertrochanteric fracture. ● Type of prosthesis — long-stem arthroplasty.

Question 65

f) How can surgeons minimise the risk of development of BCIS?

Answer 65

● Consider using a cementless hip prosthesis. ● Adequate lavage of the intramedullary canal of the shaft of the femur to ensure removal of debris. ● Ensure good haemostasis. ● Drilling a venting hole on the distal shaft of the femur to act as a pressure relieving opening during intramedullary reaming. ● The use of a bone-vacuum cementing technique. ● Retrograde insertion of cement by a cement gun.

Question 66

You are part of the in-patient pain ward round. You are asked by ward staff to review a 38-year-old female who had a femoral nerve block followed by general anaesthesia for an external fixator of her lower leg 2 days ago. She complains of symptoms related to nerve injury in the particular dermatome since the nerve block. a) What is the incidence of peripheral nerve injury after surgery?

Answer 66

● 3 in 10,000. ● Peripheral nerve injury is nine times more related to surgical or patient factors rather than to a nerve block. ● Persistence of symptoms — 0-2.2% at 3 months, 0-0.8% at 6 months, 0-0.2% at 1 year.

Question 67

b) Explain the anatomy of peripheral nerves in general.

Answer 67

● Peripheral nerves — numerous fascicles are held together by connective tissue epineurium. ● Perineurium — multi-layered epithelial sheath around each fascicle. ● Inside each fascicle, axons and capillary blood vessels are embedded in the endoneurium. ● Vasa nervorum — blood supply (extrinisic and intrinsic).

Question 68

c) How would you classify the severity of nerve injury?

Answer 68

Seddon classification — according to disruption of the axon: ● Neuropraxia — damage limited to the myelin sheath only; the best prognosis. ● Axonotmesis — intact endoneurium, but loss of axonal continuity. ● Neurotmesis — complete transection of the nerve, usually requiring surgical intervention; the worst prognosis.

Question 69

d) What are the mechanisms of nerve injury?

Answer 69

Four categories: ● Mechanical. ● Pressure. ● Chemical. ● Vascular. Anaesthetic, surgical and patient factors: ● Anaesthetic — needle placement, pressure of injection, chemical and additives. ● Surgical — patient positioning, traction, stretch, compression, ischaemia, contusion, transection, post-surgical inflammatory neuropathy, double-crush theory (already susceptible patients). ● Patient — metabolic (diabetes), entrapment, toxic, hereditary, demyelination, ischaemic neuropathies, anticoagulant therapy, peripheral vascular disease, smoking, hypertension, vasculitis.

Question 70

e) What factors would you consider to reduce nerve injury in your practice?

Answer 70

● Nerve localisation techniques — triple monitoring — nerve stimulation, ultrasound and pressure monitoring. ● Paraesthesia is not reliable, but if elicited, the injection should be stopped. ● Peripheral nerve stimulation — a current intensity of 0.2-0.5mA with a pulse duration of 0.1ms is safe for placement of local anaesthetic — it is not reliable and nerve damage could already have occurred. ● Electrical impedance — extraneural vs. intraneural components. ● Ultrasound — visualisation of spread, reduced dose need, decreased intravascular puncture, reduced local anaesthetic systemic toxicity (LAST). ● Injection pressure monitoring — highly sensitive for an intrafascicular intraneural injection, but lacks specificity; <15psi indicates an extrafascicular injection. ● Equipment-related factors: - needle design — blunt short bevelled needles (45°) cause less trauma; - adjuvants — avoid neurotoxic additives; amides are safer. Ropivacaine has the lowest potential for neurotoxicity. Local mediated vasoconstriction occurs more often with levobupivacaine than lignocaine. ● Patient selection — avoid metabolic or neuropathic conditions. ● Awake better than asleep.

Question 71

f) How would you evaluate the above patient and what diagnostic tests could be used?

Answer 71

● Early recognition and prompt risk stratification to prioritise those needing urgent attention (imaging +/- neurological consultation). ● Early surgical and/or medical consultation to be sought. ● Patient evaluation — a thorough history and examination. ● Rule out other signs of infection (especially if a catheter is inserted). ● Diagnostic tests — neurophysiological studies to assess the function of nerves and muscles — EMG, NCS or both.

Question 72

g) How would you manage this patient? Explain the RA-UK guidelines where appropriate in this management plan

Answer 72

Mild or resolving symptoms or sensory deficits: ● Reassure the patient and review in 4 weeks. ● If persistent refer to neurology; consider MRI and other imaging, NCS, EMG. ● Definitive diagnosis, treatment, surgery, informing the patient and team, follow-up Complete or progressive neurological deficit or the presence of motor deficit: ● Surgical cause to be assessed and intervention as appropriate (e.g. haematoma, cut, stretch injury — decompression, reconstruction, etc.). ● Further imaging and intervention (e.g. space-occupying lesion). ● Immediate neurological referral. ● NCS, EMG. ● Definitive diagnosis, treatment — drugs, physiotherapy, etc. ● Surgical intervention if required. ● Follow-up as appropriate.

Question 73

Q10 — Local anaesthetic toxicity a) What are the clinical features of local anaesthetic systemic toxicity (LAST)?

Answer 73

Neurological: ● Two stages — an initial excitatory phase followed by a depressive phase. ● Perioral tingling, tinnitus, slurred speech, lightheadedness, tremor, agitation. ● Toxicity can occur without these symptoms also. ● Generalised convulsions. ● Coma, respiratory depression Cardiovascular: ● Three phases. 1 ● Initial hypertension, tachycardia. 2 ● Intermediate — hypotension. 3 ● Terminal phase — peripheral vasodilatation, fall in BP severe, arrhythmias, asystole.

Question 74

b) What are the mechanisms of LAST?

Answer 74

● Systemic absorption or accidental IV injection. ● Lipophilic local anaesthetic. ● Crosses the cell membrane and causes toxicity — various sites including inotropic, metabotropic and other targets. ● Affects balance between excitatory and inhibitory pathways. ● Conduction blocks on sodium, potassium and calcium channels. ● Disrupts signals at metabotropic receptors, reduced cyclic AMP concentration, reduced contractility

Question 75

c) What are the risk factors for LAST?

Answer 75

Related to local anaesthetic: ● Type of local — bupivacaine is more toxic than levobupivacaine; levobupivacaine and ropivacaine have vasoconstrictor effects; the CC/CNS ratio is the ratio to produce cardiovascular collapse to that needed for seizures — bupivacaine has a ratio of 2 whereas lignocaine has a ratio of 7. ● Dose of local — the maximum dose of bupivacaine is 2mg/kg and for lignocaine this is 3mg/kg. Related to the block: ● The risk of vascular injection is high with an interscalene or a stellate ganglion block. ● There is a risk of high absorption — scalp, bronchial mucosa, pleura. ● Single vs. continuous infusion. ● Conduct — frequent aspiration, incremental, test dose, ultrasound use. Patient factors: ● Renal, liver or cardiac disease — reduced clearance. ● Elderly patients — low clearance. ● Children — low alpha-1 acid glycoprotein (AAG), increases elimination half-life. ● Pregnant — low AAG levels, increased perfusion and absorption.

Question 76

d) List a few steps that you could take to prevent LAST.

Answer 76

● Pre-procedure — risk/benefit, communication, monitoring, labelling syringes. ● During the procedure — frequent aspiration, slower injection, communication with the patient, ultrasound use, Luer connectors. ● Post-procedure — catheters labelled correctly, documentation, ongoing monitoring

Question 77

e) How would you manage LAST once it has occurred?

Answer 77

AAGBI guidelines, 2010: ● Early diagnosis and suspicion. ● Immediate management: - stop injecting; - resuscitation — 100% oxygen, CPR; - control seizures. ● Treatment: - IV lipid emulsion (ILE); - continue CPR. ● Follow-up: - intensive care monitoring; - patient care for future.

Question 78

f) ) What are the mechanisms of action of intravenous lipids in LAST

Answer 78

● Lipid sink hypothesis — lipid expands intravascularly and draws down local anaesthetic. ● Enhanced fatty acid metabolism — bupivacaine inhibits fatty acid oxidation, affecting the heart; IV lipids provide fatty acids. ● Others — fatty acids inhibit local anaesthetic binding to cardiac sodium channels; There is a cytoprotective effect by activating protein kinase B; an inotropic effect by increasing intracellular calcium; altered kinetics and shunting to sequestering organs; a cardiotonic effect by positive inotropy and lusitropy (relaxation of cardiac muscle).