8. Regional / Trauma Flashcards
Q1 — Nerve block for shoulder surgery
a) List the specific nerves that need to be blocked to achieve
effective analgesia for shoulder surgery.
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.
b) Name any six possible complications of an interscalene block.
● Subarachnoid/epidural injection.
● Stellate ganglion block.
● Pneumothorax.
● Phrenic nerve palsy — ipsilateral hemidiaphragmatic paralysis.
● Horner’s syndrome.
● Local anaesthetic toxicity.
● Accidental intravenous injection.
c) What positioning is needed for shoulder surgery?
The deck chair (modified sitting position) is most commonly used for
shoulder surgeries.
d) List any three complications of positioning for shoulder surgery.
● 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.
e) What postoperative advice would you give to a patient who has
received an interscalene block
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
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?
.
● 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.
b) What is the nerve supply of the skin overlying the hip joint?
● 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.
c) What regional nerve blocks can be used to provide
preoperative analgesia?
● Femoral nerve block.
● Fascia iliaca block.
● Lateral cutaneous nerve of the thigh block.
● Psoas block.
d) What nerves are blocked by the fascia iliaca block?
● Lateral femoral cutaneous nerve.
● Femoral nerve.
● Obturator nerve.
e) List the scoring systems that can be used to predict 30-day
mortality in this patient.
● 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).
f) List the AAGBI recommendations regarding unacceptable
reasons for delaying surgery
● Lack of facilities or operating theatre space.
● Awaiting echocardiography.
● Unavailable surgical expertise.
● Minor electrolyte abnormalities.
Key Points
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.
Intro
comorb
30 day mortality changes
BPT in ireland
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
POCD / delirium
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
Evidence-based anaesthesia for hip fracture repairp
Spinal GA
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.
Intraoperative surgical and anaesthetic roles to reduce the risk of BCIS. Reproduced from the Association of Anaesthetists/BOA/BGS guideline.
Evidence based Anaesthesia
Proceed with surgery?
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
Enabling timely hip fracture repair
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
Avoiding hypotension
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
Intraoperative surgical and anaesthetic roles to reduce the risk of BCIS. Reproduced from the Association of Anaesthetists/BOA/BGS guideline.
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.
Peripheral nerve block
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
Avoiding cognitive complications
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
Controversies
‘Delay’ vs ‘optimisation’
delaying surgery may be appropriate if effective optimisation is undertaken during this time.
- 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.
Controversies
‘Delay’ vs ‘optimisation’
delaying surgery may be appropriate if effective optimisation is undertaken during this time.
- 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. - 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. - Anti-platelets, anticoagulants and spinal anaesthesia
ragmatic approach to anticoagulation when spinal anaesthesia is deemed superior to GA (e.g. severe chest disease) - 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
- )
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. - )
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
Conduct of spinal
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
Conduct of spinal
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
Conduct of GA
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.
Postoperative recovery
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.
Consent
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.
a) Outline the basic physical principles involved in the formation
of an ultrasound image.
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).
b) What is piezoelectrical activity and how is it utilised in
ultrasound?
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.
c) What governs the reflection of sound waves and the formation
of an ultrasound image?
● 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
d) List the patient factors that influence ultrasound image quality.
1 ● Increased Body Mass Index.
2 ● Tissue oedema.
3 ● Muscle atrophy.
4 ● Anatomical abnormalities.
e) What acoustic artefacts may influence the ultrasound image
quality?
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.
f) Which two needling techniques are commonly used in
ultrasound-guided nerve blocks
● In-plane needling technique or long-axis technique.
● Out-of-plane needling technique or short-axis technique
g) List the advantages and disadvantages of one of these
techniques.
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.
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?
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.
b) What is the cause of neurogenic shock in this patient and how
does it present?
Neurogenic shock —
interruption of autonomic pathways leading to
hypotension and bradycardia.
c) How would spinal shock present in this patient and what are
the phases?
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).
d) What disturbances may occur subsequently in the
cardiovascular system?
● 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.
e) What effects may be seen in the respiratory system?
● 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
f) When and why may suxamethonium be contraindicated in this
patient?
● 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.
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.
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.
Q5 — Wrong-side block and never events
a) List the implications for the patient of an inadvertent wrong sided peripheral nerve block.
● 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.
b) Summarise the recommendations of the “Stop Before You
Block’’ campaign.
.
● 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.
c) List the factors that have been identified as contributing to the
performance of a wrong-side block.
● 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.
d) Define the term “never event”.
Never events are defined as
“serious, largely preventable patient safety
incidents that should not occur if relevant
preventive measures have been put in place”.
e) List any five drug-related never events
● 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.
Q6 — Ankle block
A 32-year-old patient is scheduled for hallux valgus surgery.
a) What anaesthetic options are available for anaesthetising this
patient?
● General anaesthesia.
● Regional anaesthesia:
- spinal anaesthesia;
- popliteal sciatic block;
- ankle block.
● A combination of the above techniques.
b) List the nerves supplying the ankle joint.
1 ● Posterior tibial nerve.
2 ● Deep peroneal nerve.
3 ● Superficial peroneal nerve.
4 ● Saphenous nerve.
5 ● Sural nerve.
c) Describe the origin and sensory innervation from the posterior
tibial nerve.
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.
d) Describe the origin and sensory innervation from the deep
peroneal nerve.
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.
e) Describe the origin and sensory innervation from the
superficial peroneal nerve.
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.
f) List the disadvantages of using an ankle block for this patient
● 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
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?
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.
b) How would you initially manage and resuscitate this patient?
● 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.
c) How would you apply a pelvic binder in this patient and how
long would you leave it?
● 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
d) What are the surgical options that are available in this patient?
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.
e) What are the anaesthetic considerations in this patient with a
traumatic pelvic fracture?
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.
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)?
● At the time of cementation.
● Insertion of prosthesis.
● Reduction of joint.
● Limb tourniquet deflation.
b) What clinical features would make you suspect a BCIS?
● Transient/sustained desaturation.
● Hypotension.
● Cardiac arrhythmias.
● Cardiac arrest
c) How would you grade the severity of BCIS?
● 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.
d) What is the pathophysiology of BCIS?
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.
e) What are the risk factors for the development of BCIS?
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.
f) How can surgeons minimise the risk of development of BCIS?
● 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.
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?
● 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.
b) Explain the anatomy of peripheral nerves in general.
● 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).
c) How would you classify the severity of nerve injury?
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.
d) What are the mechanisms of nerve injury?
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.
e) What factors would you consider to reduce nerve injury in your practice?
● 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.
f) How would you evaluate the above patient and what diagnostic tests could be used?
● 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.
g) How would you manage this patient? Explain the RA-UK
guidelines where appropriate in this management plan
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.
Q10 — Local anaesthetic toxicity
a) What are the clinical features of local anaesthetic systemic
toxicity (LAST)?
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.
b) What are the mechanisms of LAST?
● 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
c) What are the risk factors for LAST?
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.
d) List a few steps that you could take to prevent LAST.
● 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
e) How would you manage LAST once it has occurred?
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.
f) ) What are the mechanisms of action of intravenous lipids in
LAST
● 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).
