SBA Paper 8 Flashcards
1
Q
- A 26-year-old man who suffered an isolated blunt force head injury a week ago, is
showing no clinical signs of improvement. He is ventilator dependent and his family
are aware of the situation. You are called to the neurointenbrainsive care unit to aid in the
performance of brainstem death testing as there are no consultants available.
Which factor is most likely to make testing inappropriate within the next hour?
A Recent cessation of an infusion of midazolam
B Hyperglycaemia
C Temperature of 34°C
D Administration of atracurium 25mg 40minutes ago
E Availability of two physicians to perform testing on this shift – an ST7
anaesthetist (yourself) and an ST7 respiratory physician
A
- E Availability of two physicians to perform testing on
this shift – an ST7 anaesthetist (yourself) and an ST7
respiratory physician
○ Brainstem death is confirmed when testing demonstrates irreversible loss of brainstem function in the event of brain damage with known, untreatable aetiology.
○ To ascertain the irreversibility of the patient’s state, certain criteria must be met as a pre-condition to testing.
Pre-testing criteria
• Confirmation of the absence of medications at a plasma level significant enough to cause central nervous system depression. Plasma levels may therefore be requested in anticipation – those of midazolam should be <1.0 µg/L
• Resolution of all primary circulatory, metabolic and endocrine disturbances. Blood glucose is accepted between 3–20mmol/L
• Temperature >34.0 °C. The patient may require active warming
• Ventilator dependence without residual muscle relaxation. Effects of recent
administration can be assessed with a nerve stimulator +/- reversed
Providing the above conditions have been met, brainstem testing may be carried out.
○ For this, 2 physicians are required.
° They should both have at least 5years
registration with the General Medical Council and one must be a consultant.
° Neither physician should be a member of an organ donation/transplant team.
○ There is no consultant available to assist with brainstem testing during this shift.
○ Even if all the other factors where managed to meet pre-testing criteria within the next hour, including bringing the temperature to above 34°C, reversal of neuromuscular blockade, corrrection of hyperglycaemia and a reduction in the plasma concentrations of midazolam, the tests would remain invalid.
2
Q
- A 70-year-old man with a history of well-controlled hypertension and smoking, has
a large meningioma resected. It is a 6-hour procedure during which the blood loss
is 600mL. He coughs briefly on extubation and is transferred to the recovery room
obeying commands. Half an hour later he rapidly drops his GCS to 3/15, becomes
bradycardic and hypoxic. His blood pressure is maintained.
Which of the following is the most likely cause for his deterioration?
A Myocardial infarction
B Air embolism
C Morphine analgesia
D Intracranial haematoma
E Hypovolaemia
A
- D Intracranial haematoma
Meningiomas are more commonly seen in women than men and account for 15% of
central nervous system (CNS) tumours. They arise from cells in the arachnoid mater
and often grow very slowly to a great size before symptomatic presentation. 90% are
benign, although even benign meningiomas can invade locally into the dura and
neighbouring bone. Fewer than 10% are multiple but they may be seen in patients
with neurofibromatosis and other genetic syndromes. Meningiomas can be highly
vascular and therefore confer an elevated risk of significant intraoperative bleeding.
Postoperative bleeding usually occurs within hours of surgery and subsequently,often reveals itself in recovery. Factors that may contribute to this event include size
and location of the tumour, coughing on extubation, postoperative vomiting and
inadequate pain relief leading to surges in hypertension and therefore intracranial
pressure.
Although postoperative myocardial infarction is possible with the co-morbidities,
acute onset bradycardia and reduced Glasgow coma score (GCS) makes this
diagnosis less likely. Venous air embolism in intracranial surgery is a recognised
complication due to the positioning of patients in the head up position. The most
common presentation is a reduction in end-tidal CO2 followed by cardiovascular
embarrassment. The timing of a postoperative course of deterioration following
a stable intraoperative course makes venous air embolism less likely as it often
presents acutely intraoperatively. A morphine overdosing may also present similarly
but the rapidity of the deterioration as well as the timing of it makes this less
likely. Hypovolaemia would be expected to present with the telltale signs of high
intraoperative blood loos, hypotension and tachycardia, which is not apparent in
this case. The rapidity of his neurological demise following this particular procedure
makes an intracranial haematoma therefore the most likely cause.
3
Q
- You are anaesthetising a 70 kg patient for coronary artery bypass grafting (CABG).
He suffered a non-ST elevation myocardial infarction (NSTEMI) 10 days ago
but has been becoming increasingly breathless on minimal exertion. Recent
angiography shows an 80% stenosis of the left main coronary artery. Baseline
blood pressure is 130/80 mmHg. Following induction with fentanyl, midazolam
and propofol, the systolic blood pressure drops to 65mmHg and there is anterior
ST elevation on the ECG. The blood pressure rises to 120/78 after 1.0mg of
metaraminol. The transoesophageal echo shows worsening anterior hypokinesis. What is the next most appropriate step?
A Give 500mL of colloid stat
B Give 30,000 units of heparin
C Give 1 mg of metaraminol and wait for 2 minutes
D Ask the surgeon to insert an intra-aortic balloon pump
E Commence milrinone
A
- B Give 30,000 units of heparin
This is a high-risk cardiac patient given his symptoms, recent non-ST elevation
myocardial infarction (NSTEMI) and the extent of left main coronary disease. Based
on the information given, it appears he is suffering from acute myocardial ischaemia,
which is persisting (as evidenced by worsening wall motion abnormalities on
transoesophageal echo (TOE)) despite restoration of perfusion pressures. Although
the dysfunction may be due to the negative inotropic action of the induction agents,
emergency institution of cardiopulmonary bypass may be indicated, therefore early
administration of heparin with the aim of fully anticoagulating the patient prior to
exposure to the bypass circuit is the best option here. The usual dose given is 300–
400IU/kg aiming for an activated clotting time (ACT) of over 480 seconds.
Further metaraminol may increase myocardial oxygen consumption by increasing
afterload. An inotrope such as milrinone would most likely be used following
revascularisation rather than before. Fluid administration may be warranted when
guided by real time TOE, but is not the best initial option here. Although insertion
of an intra-aortic balloon pump (IABP) may be beneficial, especially when weaning
from cardiopulmonary bypass (CPB) in this patient, it is unlikely that one can be
placed without slowing institution of CPB (unless there are a plethora of surgeons or
cardiologists available).
4
Q
- A 45-year-old woman presents for urgent repair of a LeFort III fracture with
involvement of the small bones of the nasal complex following a motor vehicle
accident. Her mandibular molar teeth are loose and she has poor mouth opening
and a clear cervical spine. It is anticipated she will be a difficult intubation and will
require postoperative ventilation.
Which route for airway control is the most appropriate to use in this scenario?
A Nasal intubation
B Retromolar intubation
C Surgical tracheostomy
D Oral intubation via direct laryngoscopy
E Submental intubation
A
- C Surgical tracheostomy
Maxillofacial trauma presents numerous airway challenges to the anaesthetist and a clear anatomical understanding of the types of fracture and corrective surgical approaches is needed to select the most appropriate airway.
○ The Le Fort classification is used to describe different patterns of mid-facial injury based on common fracture planes along lines of weakness (Figure 8.1).
○ A Le Fort I fracture traverses the maxilla horizontally above the apices of the maxillary teeth and allows the upper jaw to move in relation to the nose. ○ If the fracture line diverges superiorly, to create a pyramidal segment involving of the medial orbit as well as the nose, this becomes a Le Fort II fracture. This pyramidal segment can move as a block in relation to the frontal bone and zygoma.
○ A Le Fort III fracture denotes a complete
eparation of the mid-face from the skull base and involves fractures through the zygomatico frontal suture, floor of the orbit and the nasofrontal suture. ○ In an acute emergency, oral intubation is the route of choice whilst keeping cervical movements to a minimum (if this is yet to be cleared). However, it is not the most appropriate option in this scenario since temporary intraoperative dental occlusion will be required to aid surgical correction. An oral endotracheal tube will prevent
this. This is also a predicted difficult intubation, so performing an oral intubation
using direct laryngoscopy would not be appropriate.
In the above case, there is damage to the nasal complex of bones which increases the complexity since a nasotracheal tube will also interfere with their surgical correction. In scenarios where surgical access to the nose as well as intraoperative dental occlusion tests are needed, anaesthetists have historically switched from nasal to oral intubation intraoperatively. However, this is not ideal since there is a risk of losing a previously secure airway.
To accommodate nasal surgical access and temporary intraoperative dental
occlusion, the airway can be secured by retromolar and submental intubation or tracheostomy. The retromolar space is the gap between the last mandibular molar tooth and the anterior edge of the ascending ramus of the mandible. This space can accommodate an orotracheal tube and also allow dental occlusion tests to be performed without interference. The orotracheal tube can be guided into the space following conventional oral intubation or pass through the space en route to the trachea with the aid of a Bonfils or flexible fibre-optic scope in difficult airways. The tube is usually held in place by ties to the adjacent tooth which in the above scenario is loose. It is also not ideal for patients expected to need prolonged postoperative ventilation.
Submental intubation involves performing conventional oral intubation then
passing the endotracheal tube through a surgical incision in the floor of the mouth.
This keeps the mouth and nose free for the surgical access and avoids the need to perform a tracheostomy. Compared to a tracheostomy, it also leaves a more aesthetic scar and carries less serious complications. It is not the ideal airway for prolonged postoperative ventilation however.
An awake, formal tracheostomy prior to surgery is the most appropriate airway for the above scenario since surgical field interfere is avoided and a safe, stable airway for postoperative ventilation is provided
5
Q
- You are called to assist a junior colleague who has just topped-up an epidural to
enable an emergency Caesarean section for prolonged labour. The block level
was confirmed to be satisfactory. Upon securing the surgical drapes the patient
complained of a strange sensation around her mouth and double vision before
becoming unconscious followed by loss of cardiac output.
What is the most likely diagnosis?
A Concealed haemorrhage
B Local anaesthetic (LA) toxicity
C Amniotic fluid embolus
D Pulmonary embolus
E Total spinal block
A
- B Local anaesthetic (LA) toxicity
○ The rapid topping up of an epidural, following its prolonged use, is encumbered with the significant risk of reaching the threshold of local anaesthetic (LA) toxicity.
○ Presentation can occur almost immediately up to an hour after LA administration.
○ It classically begins with signs and symptoms of central nervous system (CNS) excitability followed by CNS depression and ultimately, cardiovascular instability.
○ A wide range of arrhythmias may ensue, resulting in cardiac arrest.
○ The other diagnoses should all be considered but, in light of her anaesthetic history during labour and systematic progression of signs and symptoms, LA toxicity is most likely and it should therefore be treated as such.
6
Q
- A 54-year-old woman is to undergo an abdominal hysterectomy with lymph node resection for endometrial adenocarcinoma. She has mild asthma, managed on inhalers, recently diagnosed diet controlled type II diabetes, and a body mass index (BMI) of 38. She admits to snoring and daytime sleepiness. Her exercise tolerance is reasonable.
The most appropriate analgesic plan would include:
A Gabapentin premedication. Simple analgesia and intravenous morphine
intraoperatively with transversus abdominis plane (TAP) blocks at the end of
the procedure. Postoperative PCA fentanyl in the high dependancy unit (HDU)
B Lumbar epidural with plain levobupivacaine and simple analgesia. Oral
morphine postoperatively
D Simple analgesia, lumbar epidural PCEA with
levobupivacaine/fentanyl mixture
A
- D Simple analgesia, lumbar epidural PCEA with
levobupivacaine/fentanyl mixture
○ Gynaecological surgery presents a number of challenges, and the added aspects of gynaecological oncology may provide further problems to the anaesthetist, especially in the era of more radical surgery for pelvic disease.
○ Good quality analgesia tailored to the patient is of paramount importance. ○ Chronic pain after abdominal hysterectomy may occur in up to 30% of patients, and poor perioperative pain control represents a modifiable risk factor.
○ Interestingly, much of the pain seems to relate to the visceral trauma of surgery, as there is no difference in rates of chronic pain when comparing open and laparoscopic approaches to hysterectomy surgery
○ Most recommendations for analgesia in hysterectomy involve categorising a patient’s risk of postoperative pain as high or low and then treating accordingly.
○ Risk factors for postoperative pain are:
• Chronic pain conditions and ambulatory opioid use
• Illicit intravenous drug abuse
• Previous chemo/radiotherapy
• Surgery with extensive tissue trauma
○ In a web review of procedure specific pain guidance (PROSPECT), recommendations in abdominal hysterectomy are for epidural analgesia for high risk patients, whereas in low risk, patients wound infiltration and opioids are deemed sufficient. Oral gabapentin is used by some for high risk patients, but side effects include sedation and dizziness, and thus this should not be given with other sedating agents.
○ It is often started pre-emptively as a premedicant before induction. Ketamine infusions, usually in combination with PCA opioids have also been used with success in high risk chronic pain patients.
○ In ovarian adenocarcinoma, patients with epidural anaesthesia have been shown to have improved rates of survival at 3 and 5 years. This is postulated to relate to preservation of immune function by avoidance of anaesthetic and analgesic drugs allowing for greater immunosurveillance and tumour cell clearance at the time of surgery.
○ The key points with this patient are that she is obese, and suffers with respiratory disease. Of significance, there is some evidence that she may suffer with obstructive sleep apnoea (OSA). Given the presence of OSA, the ideal postoperative environment is the high dependency unit (HDU) especially if patient controlled opiates are to be used. Gabapentin should be avoided. Given the respiratory picture, removing or minimising the need for systemic opioids would be beneficial, therefore an epidural is the best choice, in the first instance a low dose mixture should be tried, and other opiates avoided. A multimodal approach to managing this patient’s postoperative analgesia is required, therefore simple analgesia in combination
with patient controlled epidural analgesia (PCEA) with a levobupivacaine/fentanyl mixture is the ideal choice of analgesia for this patient.
7
Q
- A 27-year-old man is scheduled for surgical exploration and repair of his fractured mandible after being assaulted the previous night with injuries to the side of his face. After administration of 100μg fentanyl, 200mg propofol and 50mg rocuronium, his mouth will not open despite adequate force. He is afebrile with normal end tidal carbon dioxide levels.
What is the most likely cause of his persistent mouth closure?
A Pain
B Masseter spasm
C Sub-masseteric abscess
D Depressed zygomatic fracture
E Anterior dislocation of the mandible
A
- D Depressed zygomatic fracture
○ Airway management decisions for mandibular fractures are difficult due to the numerous and often co-existing causes of the associated trismus.
○ Trismus describes the inability to open the mouth and can occur as a result of pain, muscle spasm, swelling or any mechanical obstruction.
○ During the preoperative assessment, pain associated with mouth opening may mask other underlying contributors to trismus and also limit the airway examination. It is therefore important to communicate with
the surgeons if they have any concerns regarding the mechanics of mouth opening before induction.
○ With adequate depth of anaesthesia and neuromuscular blockade (as in the case above), it is expected that trismus secondary to purely pain will be reversed.
○ In cases where it is anticipated that mouth opening will be difficult despite anaesthesia, an awake fibre-optic intubation is warranted.
○ The masseter muscle is a powerful muscle of mastication which arises from the zygomatic arch and inserts on the ramus of the mandible. Masseter spasm will result in a clenched jaw, and can be an early presentation of malignant hyperpyrexia.
○ The normal carbon dioxide levels and temperature in the above case makes this diagnosis unlikely. Furthermore, although rocuronium has on very rare occasions been associated with malignant hyperpyrexia, the symptoms tend to be delayed.
○ Increased muscle rigidity affecting mouth opening can also be seen with propofol and fentanyl, although this would be expected to resolve following paralysis.
○ Failure of the mouth to open following anaesthesia and paralysis can be caused by a mechanical obstruction restricting the normal movement of the mandible across the temporomandibular joint. This can occur as a complication of a submasseteric
abscess where pus accumulates between the ramus of the mandible and the masseter muscle. These normally arise from molar infections, and when seen in the context of trauma, usually occur as late presentations of infected fractures. The absence of fever and the early presentation of the mandibular fracture in the above scenario make this diagnosis unlikely.
Dislocation of the temporomandibular joint (Figure 8.2) will also affect opening and closing of the mouth. The joint is formed by the articulation of the mandibular condyle with the mandibular fossa and the articular eminence of the temporal bone. An anterior dislocation occurs when the condyle travels along the articular eminence and becomes lodged anterior to it. This is the most common type of mandibular dislocation and can occur as a result of trauma, extreme mouth opening or dystonic reactions. Due to the associated locked position of the mandible, this type of dislocation results in a fixed open mouth with an inability to close. This does not fit with the clinical picture.
○ The most likely cause of the fixed mouth closure in the above case is a co-existing depressed zygomatic fracture which impinges on the coronoid process of themandible. This causes a mechanical obstruction preventing mandibular movement and therefore mouth opening which will not resolve after anaesthesia or paralysis.
○ Zygomatic arch fractures usually occur after blunt trauma to the side of the face and can be clinically difficult to diagnose. Signs include a dimple palpable on the arch which can be subtle and masked by swelling, and a limited mouth opening.
8
Q
- 48 hours following a severe traumatic brain injury, a 25-year-old man remains
intubated and ventilated and haemodynamically stable. Sedation was
discontinued 36 hours earlier but his GCS remains 3/15 and he continues to
make no respiratory effort. The critical care team believes the patient has suffered
irreversible traumatic brain injury.
What would be the next step in assessing the suitability of the patient to be an
organ donor?
A Apnoea testing
B CT scan of brain to confirm brainstem herniation
C Brainstem testing
D Cerebral circulation angiogram
E Sensory and motor evoked potentials measurement
A
- C Brainstem testing
○ Death is defined as an irreversible loss of consciousness and an irreversible loss of capacity to breath; severe traumatic brain injury is the commonest cause of death in young adults
○ In order to satisfy the criteria for organ donation it is essential to
demonstrate death by neurological criteria:
• The patient must be deeply unconscious, apnoeic and mechanically ventilated
• There is no doubt that the patient has suffered irreversible brain damage of a known aetiology
• There must be confidence that the effect of depressant drugs such as sedatives has been excluded and there are no reversible causes of apnoea.
• This patient fulfils the criteria for death by neurological criteria, and thus the next step is a formal assessment to confirm brainstem death by examining cranial nerves II – XI, followed by apnoea testing.
○ Once brainstem death has been confirmed by performing the examination twice by separate clinicians, the patient’s suitability for consideration of organ donation is confirmed.
○ As mentioned, apnoea testing is performed after brainstem testing. Brain imaging and cerebral angiograms are occasionally employed where there is doubt about the aetiology of brain damage, but are not essential tests.
○ Sensory evoked potentials (SEPs) or motor evoked potentials (MEPs) are used to monitor cerebral pathway integrity during spinal and neurosurgery and are not used in confirmation of brainstem death.
9
Q
- A 66-year-old man with a history of stable angina on exertion presents for revision of a left total hip replacement, his medications include a statin and low-dose aspirin. The primary joint has been cemented, and the surgeon is concerned that the procedure may be ’difficult‘. The patient had haemoglobin of 110g/L at his pre-assessment visit. You find a note from the pre-assessment nurse telling you that the patient is also a Jehovah’s Witness. The best blood conservation strategy, which is also likely to be acceptable to the patient would involve:
A Autologous pre-donation for one month with oral iron supplementation and recombinant erythropoeitin (EPO). Rescue therapy for severe bleeding with recombinant factor VIIB Autologous pre-donation for one month with intravenous iron supplementation. Rescue therapy for bleeding with recombinant factor VII
C Preoperative iron supplementation and EPO. Acute hypervolaemic
haemodilution during the procedure. Rescue therapy for bleeding with
recombinant factor VII
D Preoperative iron supplementation and erythropoietin (EPO). Acute
hypervolaemic haemodilution during the procedure. Rescue therapy for
bleeding with fresh frozen plasma and fibrinogen concentrate
E Preoperative iron supplementation and EPO. Acute normovolaemic
haemodilution, during the procedure. Rescue therapy for bleeding with
recombinant factor VII and platelets
A
- C Preoperative iron supplementation and EPO. Acute
hypervolaemic haemodilution during the procedure.
Rescue therapy for bleeding with recombinant factor VII
The Jehovah’s Witnesses (JW) have around 150,000 members of their movement
in the UK, and are of particular interest due to their stance on transfusion of blood
and its products. Their doctrine states that consumption of blood is forbidden, and
also that any blood removed from the body is unclean. This essentially means that the transfusion of blood or of major blood products is not accepted, and any forms
of blood removal and storage are generally not permitted. Therefore a number of
perioperative management plans must be instituted in this group of patients to
reduce the risks of anaemic morbidity and mortality.
Preoperative
The aim should be to assess and optimise the haemoglobin concentration (Hb).
Thus, anaemia should be investigated and treated vigorously, and any medications
which interfere with clotting, such as antiplatelets and non-steroidal anti-
inflammatory drugs (NSAIDs), should be discontinued if possible. Recombinant
erythropoietin (EPO) is useful in Jehovah’s witnesses and patients with anaemia who
are also unable to accept transfusion. EPO should be given with iron, and if deficient
or malnourished, B12 and folic acid, to prevent iron deficiency. Some regard
intravenous iron as superior when used with EPO. If time allows, allogenic donation
of blood could be considered, here a patient donates their own red cells for several
weeks prior to surgery. This reduces the risks of infection and blood incompatibility,
but will often be undertaken with EPO/ iron to stimulate regeneration and avoid
anaemia. Unfortunately, as this involves storage of blood this is not often acceptable
to Jehovah’s Witness patients.
Perioperative
It is important to remember that there are various techniques available other than
just drug treatments and cell salvage. Surgically, large procedures can be staged
and use of laser diathermy and haemostatic gels and glues may reduce blood
loss. From an anaesthetic technique viewpoint, a good principle to follow is to
avoid anything which increases venous pressure and thus blood loss, such as high
PEEP/intrathoracic pressures or hypercapnia. Lowering systemic pressures, using
deliberate hypotension can reduce blood loss, but this is offset by the risk to the
patient’s physiological status. Similarly, regional techniques have been shown to
reduce operative losses, but with neuraxial techniques, the risk of massive blood
loss and subsequent coagulopathy and propensity to form an epidural haematoma
has to be considered. General measures such as warming are mandatory to avoid
coagulopathy.
Haemodilution
Acute normovolaemic haemodilution is the perioperative removal of whole
blood, prior to the stage of surgery involving haemorrhage. This is replaced with
crystalloid or colloid, to maintain normovolaemic status, and thus when bleeding
does occur, the actual number of red cells lost per unit volume is lower. There is
also the attractive option of returning whole blood with a normal composition of
clotting factors and platelets at the end of the procedure to assist with haemostasis.
Again, due to the removal and storage considerations, this is often unacceptable
to Jehovah’s Witness patients. Acute hypervolaemic haemodilution is the
dilution of the circulating blood as above, but without removal and storage This technique is acceptable, clearly a balance has to be achieved between dilution for
haemodynamics and reducing red cell loss, and avoiding coagulopathy. A reduction
target in packed cell volume (PCV) of 30% was well tolerated in a study of Jehovah’s
Witness patients.
Cell salvage
Widely accepted by Jehovah’s Witness patients, this involves the centrifugal
separation, washing and re-suspension of red cells for transfusion. Importantly, the
circuit should remain in continuity with the patient to avoid the objections over
removal and storage. The washing stage produces red cells and is not designed
to recover platelets or clotting factors. There are several cautions to the use of
the cell saver, and these usually relate to the re-transfusion of undesirable agents
e.g. bacteria or tumour cells. Thus, use in sepsis, tumour beds or direct suction of
amniotic fluid is avoided.
Drugs/blood fractions/recombinant factors
Antifibrinolytics such as tranexamic acid are useful and acceptable to Jehovah’s
Witness patients. Fractionated components of blood such as fresh frozen plasma
(FFP), are usually not acceptable, although this is not universally the case. However,
the acceptance of recombinant factors is widespread such as with the established
use of recombinant Factor VII (NovoSeven). This is likely also the case with other
recombinant protein factors, but not certain with all newer compounds such
as fibrinogen concentrate. Indeed, the only way to be sure, is to ask the patient
explicitly about all eventualities, including their views on transfusion if all else fails
and they are close to death. This should be witnessed independently, and not by
family or Jehovah’s Witness advocates. Some Trusts now have useful and extensive
tick-box consent forms listing all agents especially for those with objections to
conventional allogenic transfusion.
The most important principle in clinical practice, also relevant in the examination
situation, is the individual nature of the patient’s decision. The patient has the choice
over what they are willing to accept, and this can vary in many cases, especially in
the grey area of fractionated products/recombinant agents. The discussion must
obviously take place in advance, and should be open and frank about the risks
involved including death or prolonged intensive care admission. Ideally, discussions
should take place in private, as patients may express different views in front of
relatives/other community members.
The first answer stems, A and B feature pre-donation, which is not an acceptable
practice for Jehovah’s Witness patients. D and E list rescue strategies involving blood
fractions not normally acceptable, but as aforementioned this does vary. Stem E also
features intraoperative normovolaemic dilution, which may also not be acceptable
as it involves blood storage. C remains as the combination of therapies most likely to
be found acceptable by Jehovah’s Witness patients.
10
Q
- A 45-year-old patient requires abdominal surgery to be supplemented by a
regional anaesthetic block.
In which one of the following operations is a unilateral transversus abdominis
plane (TAP) block most reliably able to provide perioperative analgesia?
A Laparoscopic inguinal hernia repair
B Open appendicectomy
C Paraumbilical hernia repair
D Open cholecystectomy
E Laparoscopic appendicectomy
A
- B Open appendicectomy
The transversus abdominis plane (TAP) block can provide good perioperative
analgesia when used for the appropriate operation. Its use can decrease opioid
consumption allowing patients to breath comfortably and speed mobilisation and
early discharge.
Innervation of the abdominal wall derives from the anterior rami of the lower six
thoracic nerves and the first lumbar nerve (T7-L1).
These nerves enter the transversus abdominis facial plane between the internal
oblique and transversus abdominis muscles.
The TAP block is essentially injecting a large volume of local anaesthetic (LA) in the
transversus abdominis plane targeting the T7 to L1 nerves. This block will provides
adequate analgesia for the abdominal wall but not for the abdominal viscera.
Although the early studies were able show blocks extending from T7 to L1, other
and more recent studies have unable to demonstrate a spread higher than T10.
Therefore, TAP blocks are currently recommended for infraumbilical surgery.
The injection can be done unilaterally or bilaterally depending on the type of the
surgery.
Unilateral block: Open appendicectomy and hernia repair below the umbilicus.
Bilateral block: abdominal hysterectomy, radical prostatectomy, Caesarean section,
midline incision and laparoscopic operations.
The addition of subcostal TAP block can achieve a higher block up to T7 and can
successfully be used with posterior TAP block for supraumbilical procedures such as
cholecystectomies.
In the above question, a right-sided TAP block can provide adequate analgesia for
open appendicectomy procedures. The other options require either bilateral TAP
block or an additional sub-costal block to achieve reliable analgesia.
The TAP block can be performed either by using ultrasound or a landmark technique.
The landmark technique, which was originally described by McDonnell et al, access
to the transversus abdominis plane is achieved through the triangle of Petit. The iliac
crest bound this triangular area inferiorly, anteriorly by the external oblique muscle
and posteriorly by the latissimus dorsi muscle (see Figure 8.3). After passing through
the skin, the needle should be advanced until two pops are felt, at which point
the needle lies in the transversus abdominis plane, immediately superficial to the
transversus abdominis muscle (see figure 8.3). A minimum of 20 mL LA is injected in
each side after aspiration.
In the ultrasound (US) technique, a linear high frequency probe is placed
transversely in the mid-axillary line between the iliac crest and the 12th rib.
The muscle layers and the transversus abdominis plane can easily be identified in this
area. A short bevel 100 mm needle is advanced with an in-plane approach until reaches
this plane, when 20 mL of LA is injected once again superficial to the transversusabdominis muscle. The LA spread in the plane will form an elliptical hypoechoic shape
between the transversus abdominis and the internal oblique muscles.
11
Q
- A 70-year-old man was admitted to your neurosurgical unit following a fall down flights of stairs. He sustained bilateral subdural haematomas and a C7 fracture. You are called to secure his airway as his GCS is 9 and he is agitated and confused.
What is the most appropriate method of applying cricoid pressure for the rapid
sequence intubation?
A Remove the collar completely and apply single handed cricoid pressure
B Double handed cricoid pressure application without the collar
C Keep the collar on and apply single handed cricoid pressure
D Do not use cricoid pressure as it worsens laryngoscopy
E Awake fiberoptic intubation without cricoid pressure
A
- B Double handed cricoid pressure application without
the collar
○ The use of cricoid pressure for rapid sequence induction (RSI) aims to prevent
regurgitation of gastric content, although the true aims of an RSI are to rapidly and
safely secure a definitive airway.
○ The utility and necessity of cricoid pressure has a very questionable evidence base currently, with many practitioners doing away with cricoid pressure completely as it is known to distort the view at direct laryngoscopy.
○ The pragmatic approach would be to utilise cricoid pressure carefully and advocate early release if laryngoscopic views are worsened by it.
○ Although the debate rages on, and is likely to do so for some time, the question
asked here is how to apply cricoid pressure assuming it will be used as part of your
standard RSI technique for a patient with an unstable cervical spine, therefore not
applying cricoid pressure at all is an incorrect answer.
○ An awake fibreoptic intubation
is inappropriate in a patient with a reduced GCS and agitation, thus is best avoided.
○ The aims here should be to ensure cervical spine stability and control without
sacrificing a safe RSI technique. Therefore removing the collar and having an
assistant provide manual in-line stabilisation (MILS) whilst another providing cricoid pressure is important.
○ Single-handed cricoid pressure is suitable should the posterior
component of a cervical collar be left in situ as this has been demonstrated to
produce minimal vertebral movement.
○ If the collar is removed completely, single-handed cricoid pressure leaves the patient at risk of vertebral instability.
○ However, the safest way to apply cricoid pressure would be with a bimanual approach with collar removed completely and MILS. This is thought to provide better laryngoscopic views, maintain the integrity of cervical flexion, and avoid excessive pressure being applied.
12
Q
- A 55-year-old man is admitted to your intensive care unit following an emergency laparotomy for faecal peritonitis secondary to a perforated sigmoid diverticulum. He
is paralysed and sedated, intubated and ventilated. His haemodynamic observations are as follows: heart rate 90 beats per minute sinus rhythm; mean arterial pressure (MAP) 62mmHg on 0.36µg/kg/min of noradrenaline; stroke volume index (SVI) is 19mL/m2/beat before, and 20mL/m2/beat after a 250mL bolus of Hartmann’s solution given over 150 seconds; haemoglobin concentration is 84 g/L; arterial blood lactate is 4.8mmol/L; central venous oxygen saturation (Scvo2 is 56%; central venous to arterial carbon dioxide difference is 1.4 kPa; highly sensitive cardiac troponin T (hs-cTropT) levels are 150 times the upper reference limit.
Given this information the best treatment strategy is:
A Increase the rate of the noradrenaline infusion to achieve a MAP of 75–85mmHg
B Give a 50mg bolus of hydrocortisone and repeat 6-hourly
C Give two units of packed red blood cells (pRBC)
D Request an urgent cardiology review as the patient needs an emergency
coronary angiogram and the insertion of an intra-aortic balloon pump
E Commence a titrated dobutamine infusion starting at 5µg/kg/min
A
- E Commence a titrated dobutamine infusion starting at 5µg/kg/min
○ The patient described is in septic shock despite fluid resuscitation and high dose
vasopressors.
○ The profound degree of shock is evidenced by the lactate, Scvo2 levels
and carbon dioxide gap, all of which are useful measures of global oxygen supply
demand imbalance.
○ The adequacy of fluid resuscitation is evidenced by the ~5% increase in stroke
volume index (SVI) following the rapid fluid bolus.
° As a general guide, a ≤10% increase in SVI is considered to be fluid unresponsive.
° A ≥15% increase in SVI is considered fluid responsive and should prompt the consideration of a further fluid bolus until the response is ≤10% (SVI maximisation). ° Changes in the 10–15% range are equivocal and further fluid boluses should balance the risks and benefits.
° However, the stroke volume index and hence cardiac index (HR x SVI) is low, despite optimal heart rate and rhythm, which is consistent with significant myocardial contractility impairment.
○ This may be due to septic cardiomyopathy and/or ischaemic
heart disease.
○ The highly sensitive cardiac troponin T (hs-cTropT) elevation does not differentiate between these two diagnoses.
○ A 12-lead ECG with acute/dynamic
changes consistent with ischaemia/infarction in a specific coronary territory, and echocardiogram showing new regional wall motion abnormalities would be highly suggestive of a type 1 myocardial infarction, and should be performed.
○ However, even if the clinical evidence points towards this diagnosis, the role and optimal timing of acute percutaneous coronary intervention and the use of mechanical support are highly controversial.
○ The best immediate management therefore is to commence a positive inotrope, such as dobutamine.
○ There is no definitive trial evidence to support the choice of one positive inotrope over any other.
○ In this scenario, the threshold for considering packed red blood cell transfusion should be <70 g/L and, as the patient is euvolaemic, the risk of fluid overload is very high hence pRBC transfusion is not indicated.
○ There is no value in increasing
the mean arterial pressures further as this is likely to have a negative impact on
myocardial function and worsen rather than improve both coronary and global
perfusion.
○ The role of ‘stress dose’ glucocorticoid therapy in this scenario as a treatment for functional hypoadrenalism remains controversial.
° It may be worth considering a therapeutic trial depending upon the patient’s response to the positive inotrope.
13
Q
- A 69-year-old woman with an established history of essential hypertension, type 2 diabetes mellitus and chronic renal impairment (baseline urea 9.8mmol/L and creatinine 142µmol/L), underwent elective, on-pump coronary artery bypass grafts yesterday. She successfully met all of her enhanced recovery cardiovascular and respiratory parameters and has consequently been extubated and not on any vasoactive drugs. Her fluid balance is + 2430 mL since arrival in the intensive care unit. Her urine output has been averaging 18mL/hour (actual body weight 92kg, ideal body weight 62.5kg). See Table 8.1 below for this patient’s blood results.On the basis of this information, the best renal treatment strategy is:
A Commence a dopamine infusion at 2.5mg/kg/hour
B Give 15 units of short acting insulin in 50mL of 50% dextrose in 15 minutes
C Give 500mL of 1.23% sodium bicarbonate over 1 hour
D Give 20mg of furosemide intravenously followed immediately by an infusion
at 5mg/hour
E Commence renal replacement therapy
A
- E Commence renal replacement therapy
○ In patients with normal renal function, on-pump cardiac surgery is associated with a 10-30% risk of acute renal injury and a <5% risk of needing acute renal replacement therapy.
○ These risks are significantly increased in patients with pre-existing renal impairment.
○ Other peri-procedural risk factors include on versus off-pump, longer bypass times, haemodynamic instability, need for high dose or protracted inotropes and/or vasopressors.
○ In the scenario described, the patient has clearly developed acute kidney injury (AKI), with oliguria, a metabolic acidosis, hyperkalaemia and uraemia.
○ There is no place for low dose dopamine or diuretics in either the prevention or management of AKI.
○ Given the rate of evolution of this patient’s metabolic derangement and apparently normal renal perfusion, temporising therapy to improve the acidosis and reduce the serum potassium are unlikely to prevent the need for renal replacement therapy, hence this is the best answer.
○ There are a number of considerations to take in to account when considering renal
replacement therapy in the acute setting:
• Most centres use bicarbonate based fluids for renal replacement therapy
• Although there is no universally agreed thresholds for commencing renal replacement therapy in ARF a reasonable suggestion would be:
• Hyperkalaemia (K+ >6.5mmol/L or o K+ >5.5mmol/L and rapidly rising at >0.25mmol/hr for 2 or more hours).
• Correction of severe/unresolving acidosis (pH <7.1); acidosis associated with cardiovascular compromise (end organ hypoperfusion)/high vasoactive drug requirements (noradrenaline >0.5µg/kg/min / dobutamine >10µg/kg/min).
• Uraemia (urea >40mmol/L or rising by >12mmol/24 hrs)
• Fluid overload causing severe hypertension and/or problematic oedema (e.g. abdominal compartment syndrome) and/or contributing to hypoxaemia / poor lung compliance.
• There is no evidence to support any specific modality over another in this setting
• The use of bolus insulin and dextrose mixtures is a poor practice as it is associated with a very high incidence of acute, severe dysglycaemia and rapid rebound hyperkalaemia. If temporisation of hyperkalaemia is required, continuous
infusions of insulin and dextrose are safer and more effective. Adjunctive use of nebulised salbutamol and intravenous bicarbonate can also be very helpful.
○ If cardiac toxicity is evident, acute protection is afforded by a slow bolus of intravenous calcium either as gluconate or chloride.
14
Q
- A 44-year-old woman presented with a grade 5 subarachnoid hemorrhage 7days
ago. Brainstem death testing conducted in the appropriate manner has revealed
intact gag and deep tracheal stimulation reflexes. The multi-disciplinary team
agrees that this patient has suffered a non-survivable brain injury.
What is the next most appropriate course of action?
A Monitor for deterioration and conduct brain stem testing at a later date
B Inform the family the results of the testing and approach the subject of heart-
beating organ donationC Escalate life support therapy to ensure end-organ perfusion is maintained in
case organ donation is accepted
D Contact the transplant coordinator
E Discuss the case with the coroner
A
- D Contact the transplant coordinator
When organ transplantation began all organs were retrieved from patients
immediately after cardiorespiratory arrest.
○ In 1976 brainstem testing allowed retrieval of heart-beating donor organs which has become the principal source of organs for transplantation for the last 25–30 years.
○ Non heart-beating organ donation (NHBOD) however is re-gaining popularity. ° This is partly because the demand for organs is increasing.
° In addition, the number of heart-beating donors is declining for two reasons: fewer younger people are dying as a result of severe injury or catastrophic cerebrovascular events, and improvements in diagnosis and management of severe brain injuries mean that fewer fulfill the brainstem testing criteria.
○ Suitability criteria for consideration for NHBOD include:
• A decision has been made to withdraw treatment
• They are expected to die within 2hours
• They have organs suitable for transplantation
○ The only absolute contra-indications are human immunodeficiency virus (unless
the recipient is also HIV positive) or Creutzfeldt–Jakob disease.
○ The final decision regarding suitability is made by the retrieval and transplant surgeons.
○ Comprehensive guidance from the Intensive Care Society and General Medical Council exist.
○ The decision to withdraw treatment must be separate from the one to donate organs.
○ A protocol may be useful to dictate a withdrawal of care approach, which ensures the interests of the dying patient remain the primary focus.
○ The family should first be made aware that further treatment is not in the patient’s best interests.
○ They can then be approached about donation after the transplant coordinator has been contacted, the organ donor register checked and consent obtained from the coroner.
○ The coordinator and senior clinician will ideally approach the family together.
○ The key consideration here is what is deemed to be in the patient’s best interests and does not cause harm or distress to them or their family. If they have expressed a wish to donate organs then blood testing and maintenance of life-sustaining treatment is acceptable (including escalation of treatment).
○ Similarly delaying withdrawal or moving the patient to facilitate transplantation is considered to be in the patient’s best interests if their wish to donate is known. Systemic heparinisation, femoral cannulation and CPR are not acceptable as they have a significant risk of harm.
○ Withdrawal of active treatment should not vary from local practice because organ donation is being considered and should proceed in accordance with the usual practice of the critical care unit.
○ Commencing treatment to ensure lack of distress prior to extubation, termination of ventilation or cardiovascular support is the usual practice.
○ After withdrawal of care the patient may continue to have a cardiac output for some time. If the patient is hypoxic or hypotensive for this period of time then the same physiological conditions that occur in warm ischaemic time are present. Therefore if the process of dying lasts more than 2–3hours the retrieval may be abandoned.
○ The ethical issues are numerous and include: the withdrawal of treatment,
appropriateness of ongoing treatment to facilitate donation, the method of
diagnosis of death and the time left between cessation of cardiorespiratory function and confirmation of death.
○Returning to the scenario above, the next step (which is what the question is asking for) is to contact the transplant coordinator. They will analyse the case and decide whether or not it is suitable to continue before putting the family in a position to make a decision. Breaking the news to the family that their relative will not survive and approaching the topic of organ donation should be separate conversations if possible. In addition the transplant coordinator should be present to answer logistical questions you may not be aware of.
15
Q
- A 42-year-old morbidly obese woman is admitted to the high dependency unit
(HDU) after an elective laparoscopic sleeve gastrectomy. Her background includes
type 2 diabetes, a previous deep vein thrombosis and obstructive sleep apnoea.
The patient had a grade 3 laryngoscopy view at intubation and had an internal
jugular central line and right radial arterial line inserted. Surgery was uneventful
but 2hours after admission the patient becomes agitated and breathless and
an arterial blood gas demonstrates hypercapnic respiratory failure. A trial of
non-invasive ventilation (NIV) was not tolerated and made her more agitated,
tachycardic and hypoxic.
What is the next immediate step?
A Intubate and ventilate
B Examine the respiratory system
C Request an urgent chest radiograph
D Request an urgent CT pulmonary angiogram
E Organise an urgent transthoracic echo
A
- B Examine the respiratory system
Obesity is a health epidemic facing Western countries.
○ Obesity is defined as a body mass index (BMI) >30kg/m2, ‘morbidly’ obese a BMI >35 and ‘super morbidly’ obese>55kg/m2.. ○ Recent figures suggest that up to 23% of men and 25% of women in the UK are obese.
○ Bariatric surgery presents many challenges intra-and postoperatively. ○ Management of the patient’s co-morbidities is often a reason for high-dependency care postoperatively as in this case.
○ Complications are increased in this group and this case explores the differential diagnosis of an immediate postoperative complication.
○ The list of differential diagnoses (which may not be exhaustive) include:
• Airway obstruction due to obstructive sleep apnoea (OSA), sedation, carbon
dioxide narcosis, anaphylaxis
• Breathing
• Hypoventilation resulting in hypercapnic respiratory failure
– OSA
– Residual anaesthesia or long-acting analgesia
– Abdominal splinting with residual pneumoperitoneum or sub-optimal
position in bed
• Aspiration of gastric contents at induction or extubation
• Pneumothorax as a result of the central venous cannulation or laparoscopic
surgery
• Pulmonary embolism
• Negative pressure pulmonary oedema
• Gas embolism
• Circulation
• Perioperative myocardial ischemic event
• Postoperative bleeding (may be seen in drain output)
• Disability
• Residual sedative drugs
• Focal deficit due to stroke
• Global deficit due to hypoperfusion (e.g. relative hypotension or prolonged
reverse-Trendelenburg position)
• Exposure
• Hypoglycemia
• Hypothermia
• Pain (not only operative, e.g. long standing back pain)
• Urinary retention
○ The best way to approach a complex patient is perform a rapid examination looking to exclude some of the dangerous causes above. ‘Agitated’ implies that the airway is patent for now and with a grade three laryngoscopy (in the optimum conditions present in theatre) caution and planning is required in order to re-intubate.
○ Hypercapnic respiratory failure is her main complaint and the focus of management should be to find a reversible cause of this deterioration in order to preventre-intubation. This could potentially avoid significant morbidity and mortality associated with a prolonged ventilatory period postoperatively.
○ The question requests the next immediate step and therefore a careful examination of the respiratory system would be of great use. Non-invasive ventilation (NIV)
could convert an undiagnosed simple pneumothorax (caused by a difficult central line insertion as in this case) to a tension pneumothorax and examination findings suggestive of this diagnosis would enable rapid decompression and resolution of the acute deterioration. ○ Aspiration of gastric contents or pulmonary oedema may
also be appreciated on clinical examination. As with all sick patients checking the electrocardiogram, the surgical drain output, the blood glucose level, the degree of residual neuromuscular blockade and the temperature are all part of the initial
survey.
Clinical examination should not be forgotten in the intensive care unit as it guides further investigation and management in a more focused and efficient manner.
16
Q
- A 56-year-old woman with a background of chronic kidney disease presents with a pulmonary embolism. She was admitted to the high dependency unit and commenced on an unfractionated heparin infusion for anticoagulation. Five days later she developed hypoxic respiratory failure and became cardiovascularly unstable. A repeat CT pulmonary angiogram demonstrated an extension of her pulmonary embolism.
What is the most useful investigation?
A Thrombophilia screen
B Full blood count
C Transthoracic echocardiogram
D Lower limb vein ultrasound
E Serotonin release assay
A
- B Full blood count
○ This scenario describes a case of Heparin Induced Thrombocytopenia (HIT), which is seen in 2.5% of patients treated with unfractionated heparin and 0.1% of those on low molecular weight heparin.
○ It presents with reduced platelets, arterial and venous thrombosis (30%), a systemic reaction consisting of anaphylactoid symptoms (25%)
and a skin rash, which represents dermal ischemia and necrosis as a result of emboli (4%).
○ The syndrome is further classified into two types.
• Type 1 HIT is a benign decrease in platelet numbers, which appears to be a physical interaction causing platelet aggregation. It results in a mild drop in the platelet count and may occur hours after treatment is commenced and usually recovers once heparin is stopped without any intervention. It is not associated with an increased risk of thrombosis.
• Type 2 HIT is an immune-modulated process caused by formation of
Immunoglobulin G (IgG) or rarely IgM antibodies, against heparin bound to a protein called Platelet Factor 4 (PF4). The onset is often delayed (day 5–10 after commencing treatment) but may present within hours if the patient has had previous exposure to heparin. The tail of the antibody binds to the Fcylla receptor on the platelet surface
resulting in activation, aggregation, clot formation and a consumptive decrease in
numbers. The platelet count usually drops below 50% of baseline values and a pro-
thrombotic state occurs and results in arterial and venous thrombi. The antibodies persist in the plasma for 2–3months.
○ The diagnosis of HIT is a 3-stage process. A scoring system is used to identify patients requiring further testing.
° This is called the 4T score and has been validated by Wakentin and Heddle in 2003.
• A low score (0–3 out of 8) has a negative predictive value of 0.998 whereas an intermediate (4–5) or high (5–8) score has a positive predictive value of 0.14 and 0.68 respectively, thus warranting further investigation (see Table 8.2)
• A score greater than 4 necessitates an enzyme-linked immune-sorbent assay (ELISA) test for the IgG against heparin-PF4 complex (termed the ‘HIT screen’).
• The false-positive rate is high due to the detection of other antibodies against this complex that do not cause HIT and therefore if positive, a second test is performed to confirm the diagnosis.
○ Serotonin release is measured in platelets mixed with patient’s own
plasma and heparin as a marker of platelet activation.
° This is called the Serotonin Release Assay (SRA).
○ In this scenario a full blood count would have revealed thrombocytopenia and
prompted the diagnosis of HIT.
○ This mandates immediate termination of heparin-containing products (including heparin in a renal replacement circuit) and confirmation of the diagnosis.
○ This patient obviously requires ongoing anticoagulation, and there are a number of options which are not heparin-based:
○ Lepirudin is a highly specific and irreversible inhibitor of thrombin principally metabolised by the renal system and danaparoid is a glycosaminoglycuronan Factor Xa antagonist principally metabolised by the liver.
18
Q
- The obstetric team wants to deliver a term baby by emergency Caesarean section
for foetal distress. A spinal anaesthetic was quickly established, and the baby was
delivered within minutes. However, the newborn appears floppy and pale. The
midwife asked for help with resuscitation the newborn. A neonatal crash call has
been put out, but the neonatal team has not yet attended. The mother is stable, and
you leave her under the care of a second anaesthetist to assist the midwife.
The first step in the resuscitation of a newborn is:
A Open the airway by maintaining the head in a neutral position
B Establish the Apgar score by assessing the newborn’s appearance, pulse,
grimace, activity and respiration
C Deliver five inflation breaths at 30 cmH2O airway pressure for a term baby
D Dry and stimulate the newborn with a towel, replace the wet towel and cover
the baby
E Assess the heart rate by auscultating over the precordium
A
- D Dry and stimulate the newborn with a towel, replace
the wet towel and cover the baby
Anaesthetists in the delivery suite are not infrequently asked to assist with the
resuscitation of newborns. It is important to be clear that the primary duty of
care of the obstetric anaesthetist is to the mother. However, if the mother is in a
stable condition, and her care can be delegated to another qualified person, the
anaesthetist should assist with the resuscitation of the newborn.
The Resuscitation Council UK has a consensus and evidence based newborn
resuscitation algorithm (Figure 8.4), which starts with drying and stimulating the
baby, removing any wet towels and covering the newborn. This is followed by
assessing the newborn for tone, colour, breathing and heart rate, and if necessary,
delivering five inflation breaths with sustained positive airway pressure of 30cmH2O
for 2–3seconds (20–25cm H2O in preterm babies). Assessing the Apgar score is not
part of the newborn resuscitation algorithm.
24
Q
- A 48-year-old man presents for an elective open rotator cuff repair. He is fit and
well and has no known allergies.
What would be the most appropriate perioperative analgesic plan?
A Interscalene block with 20mL 0.5% levobupivacaine and regular paracetamol and ibuprofen
B Suprascapular block with 20mL 0.5% levobupivacaine and regular paracetamol and ibuprofen
C Axillary brachial plexus block with 20mL 0.5% levobupivacaine and regular paracetamol and ibuprofen
D Regular paracetamol, ibuprofen and morphine patient controlled analgesia (PCA)
E Intra-articular injection with 10mg morphine and 20mL 0.5% levobupivacaine by surgeons at the end of surgery combined with regular paracetamol and ibuprofen
A
- A Interscalene block with 20mL 0.5% levobupivacaine and regular paracetamol and ibuprofen
○ Shoulder surgery is potentially very painful in the postoperative period.
○Early mobilisation and physiotherapy is important to ensure good return of function.
○ Effective perioperative pain management is therefore required to facilitate
this.
○ As with all pain management a multimodal approach should be adopted.
○ Regular paracetamol and ibuprofen should be prescribed provided there are no
known contraindications. Some surgeons may wish to avoid non-steroidal anti-
inflammatory drugs (NSAIDs) in the first 24hours due to the increased risk of
bleeding.
○ Interscalene blocks provide good analgesia for up to 15hours with minimal systemic
effects. Should the expertise be available a catheter technique could be employed.
○ A strong opioid should be prescribed for when the block wears off.
○Intra-articular analgesia (local anaesthetic + morphine) reduces postoperative
morphine requirements but is less effective than an interscalene block.
○ Suprascapular nerve blocks can be useful when an interscalene block is not
possible but only blocks a proportion of the pain afferents from the shoulder. It will
provide no cutaneous coverage so will need to be combined with local anaesthetic
infiltration to the skin.
○ An axillary block is not appropriate for shoulder surgery as blocking the brachial plexus at the level of the terminal branches will only provide good analgesia for surgery below the elbow. Table 8.3 summarises the various sensory effects of blocking the brachial plexus at different points along its course.
25
Q
- A 26-year-old woman developed a headache 36hours following a suspected dural
puncture with a 16G Tuohy needle whilst having an epidural for labour analgesia.
She had an epidural blood patch that was effective for 24hours, but the headache
has now returned. Neurological examination is normal and she is afebrile.
What step would most likely be beneficial in the management of this ongoing
headache?
A Sumatriptan
B 400mg caffeine intravenously twice daily
C Bed rest
D Intravenous fluids
E Second blood patch
A
- E Second blood patch
○ The risk of post-dural puncture headaches (PDPHs) following a labour epidural is
quoted up to about 10%.
○ The occipital/frontal headache usually develops in the first 72hours and has a clear postural element.
○ It is commonly associated with nausea, vomiting, neck stiffness and photophobia. It can also result in tinnitus and hearing loss.
○ Rarely abducens nerve palsies develop due to diminished cerebral spinal fluid
(CSF) volumes.
○ Headaches are common in the postpartum period and it is important to get a thorough history and examination to exclude more serious pathology.
Table 8.4 shows a list of potential differential diagnosis.
○ Once a diagnosis of PDPH has been made, treatment can be either conservative,
pharmacological or with an epidural blood patch.
• Conservative treatment comprises bed rest, good hydration, caffeinated drinks and simple analgesia.
• Pharmacological management includes caffeine or 5HT-agonists. These have both
been tried for their cerebral vasoconstrictor properties but with limited success and
in reality are seldom used.
• An epidural blood patch remains the gold standard and is thought to be most
effective if performed greater than 24 hours after the dural puncture.
-“Historically the efficacy of this treatment was exaggerated.
-“It is thought 50% of woman will recover completely after a single blood patch.
- However, 40% will go on to need a second.
- It is postulated to work by blocking the hole in the dura thereby preventing further
CSF leak.
27
Q
- The recovery nurses are concerned about a 74-year-old woman following a right
carotid endarterectomy under superficial cervical plexus block. They noticed
the right pupil is smaller than the left. The patient is asymptomatic but you also
observe ptosis of the right eye. The anaesthetic chart shows that the anaesthetist
used 20mL of 0.25% levobupivacaine for the block.What is the explanation you provide to the concerned patient and nurses?
A This is a surgical complication; need to contact the surgical team
B This is a regional anaesthetic related complication, reassure and continue to
observe the patient in recovery for resolution
C The patient had a stroke, alert the surgical team please
D Administer intralipid 20%, to the patient
E This is a congenital abnormality
A
- B This is a regional anaesthetic related complication, reassure and continue to observe the patient in recovery for resolution
○ Carotid surgery can be performed under either a regional anaesthetic block or
general anaesthesia.
○ In order to be performed awake, the second, third and fourth cervical dermatomes need to be blocked (C2–4).
○ Many suggest combining this with blockade of submandibular branches of the trigeminal nerve and infiltration of the carotid sheath by the surgeons.
○ Superficial cervical plexus blockade is often sufficient for this purpose, although some advocate combining a superficial with a deep cervical plexus block.
○ The superficial cervical plexus is blocked by infiltrating local anaesthetic in the subcutaneous plane along the posterior border of the sternocleidomastoid muscle.
○ It is a relatively safe procedure, although a rare complication includes a Horner’s
syndrome, comprising unilateral ptosis, miosis and anhydrosis due to sympathetic
blockade.
○ The patient exhibits the signs of Horner’s syndrome, and this is the most likely cause of the presentation.
○ The signs presented are unlikely to be due to a post-operative stroke. Intralipid is administered in the management of local anaesthetic toxicity, which is unlikely with 20mL of 0.25% levobupivacaine (50mg in total).
○ Congenital anisocoria is not associated with ptosis.
28
Q
- A 65-year-old man is listed for an elective total knee replacement.
What would be the most appropriate nerve block to manage his perioperative
analgesia?
A Femoral nerve block
B 3-in-1 block
C Fascia iliaca block
D Adductor canal block
E Sciatic and femoral nerve block
A
- D Adductor canal nerve block
○ The femoral nerve (FN) arises from the posterior divisions of the ventral rami of the
L2-L4 lumbar spinal nerves.
° It first descends within the bulk of psoas major muscle then emerges from its lower part, running downward in the fascial compartment plane between the psoas and the iliacus muscles.
° The femoral nerve then passes under the inguinal ligament into the thigh, where it lies lateral and slightly deeper to the femoral artery.
° The femoral artery and vein are contained in the femoral sheath, which lies above the fascia iliaca and underneath the fascia lata.
° Here the femoral nerve lies above the iliacus muscle and is sandwiched by the two layers of fascia iliaca to separate the nerve from the femoral sheath medially (Figure 8.5). ° In the thigh, the femoral nerve gives off anterior and posterior divisions. The anterior
division supplies the sartorius and pectineus muscles. It also gives off articular
branches to the hip joint and cutaneous branches to the anterior and the medial
surface of the thigh.
° The posterior division of the femoral nerve provides articular innervation to the
knee joint and muscular branches to the quadriceps muscles (rectus femoris, vastus
lateralis, vastus medialis and vastus intermedius).
° The posterior division continues downward to become the saphenous nerve, which is the largest sensory branch of the femoral nerve.
○ A femoral nerve block is indicated for operations on the anterior thigh (i.e. skin
graft, muscle biopsy and lacerations) and knee, and postoperative pain relief after
femur and knee surgery.
○ Additionally, femoral nerve blocks can be used to provide analgesia for hip dislocation and femoral neck fracture. When used in combination with a sciatic nerve block, femoral nerve blocks can be used for any procedures below the knee.
○ There are several approaches to block the femoral nerve, including a nerve stimulator guided nerve block, 3-in-1 block, fascia iliaca block and ultrasound guided femoral nerve block.
○ Nerve stimulator guided femoral nerve block: this block is performed at the
inguinal crease, where the femoral nerve is located below the inguinal ligament and
lateral to the femoral artery.
○ Femoral arterial pulsation is identified first in the middle of the line joining anterior superior iliac spine and pubic tubercle. The needle (50mm 22G block needle) is inserted at 60° cephalad, approximately 1–2cm lateral to the pulsation. The first twitch observed is the sartorius twitch, followed by the patellar twitch (quadriceps contraction) caused by stimulation of the posterior division of the femoral nerve. 15–20mL of local anaesthetic (LA) is injected at this point.
○ 3-in-1 nerve block: this block uses the same technique as nerve stimulator guided
nerve block. However, in a 3-in-1, a larger volume of LA (25–30ml) is injected and distal pressure is applied during injection to help the LA spread to the lateral femoral
cutaneous nerve and obturator nerve, in addition to the femoral nerve. The reliability
of this block, and the capacity to anaesthetise the obturator nerve, however, has
come in to significant question and it is not a recommended approach.
○ Fascia iliaca block: to perform this block, one must draw a line connection the
anterior superior iliac spine and the pubic tubercle. Next, this line is then divided
into thirds. The needle (50mm 22G block needle) is inserted 1–2cm below the
junction of the middle and lateral thirds. As the needle is advanced, two pops are felt
as the needle pierces the fascia lata and the fascia iliaca. The femoral nerve located in
this fascial plane, where 20-30 of LA is injected at this point. Fascia iliaca block is the
easiest way to block the femoral nerve. Ultrasound guided fascia iliaca block is also
described and is seen as a safer approach to performing this block.
○ Ultrasound guided femoral nerve block: a high frequency linear probe is used for
this block. This block is performed just below the inguinal crease where the nerve is
fairly superficial (<3cm from the skin) and usually has a triangular or flattened oval
shape just lateral to the femoral artery. A 50mm 22G needle is inserted in-plane
in a lateral to medial orientation to avoid puncture of femoral vessels. The needle
is advanced toward the femoral nerve and 10–20mL of LA is injected around the
nerve. Ultrasound guidance may reduce the onset time for the block and the volume
of the LA.
○ Adductor canal (sub-sartorial) block: Recently, the adductor canal block has been
used for perioperative analgesia for knee surgery. With the use of ultrasound, this
block becomes technically straightforward and a reliable approach to block the
saphenous nerve, which is a pure sensory nerve. The adductor canal block requires
injecting LA deep to the sartorius muscle in the adductor canal.
Anatomical examination of the adductor canal shows that, in addition to the
saphenous nerve, this canal also contains medial femoral cutaneous nerve, medial
retinacular nerve and articular branches from the obturator nerve. Thus injecting LA
in the adductor canal might produce sensory block of the whole of the anterior and
medial aspects of the knee without motor blockade. This is helpful in major knee
operations, such as total knee replacement (TKR).
Using a small volume of LA (5–10mL) will result in adequate analgesia for knee
arthroscopy, anterior cruciate ligament reconstruction and lower leg, foot and ankle
operations involving area covered by the saphenous nerve. Using a large volume of
LA (20–30mL), results in a proximal spread of the LA in the adductor canal leading to
reliable analgesia for major knee surgery, like TKR.
A high frequency linear ultrasound probe is used in this block. With the patient in
the supine position, the knee is slightly flexed and the leg is externally rotated. The
ultrasound probe is placed on the anterior aspect of the thigh, midway between
the medial epicondyle and the inguinal crease. Once the femur is identified, the
ultrasound probe is moved medially until the boat shape sartorius muscle is seen. At
this point, the femoral artery lies just underneath the sartorius in the adductor canal.
The saphenous nerve is usually too small to be visualised and the objective is to inject
LA around the femoral artery under the sartorius muscle. A 22G 100mm, short beveled
block needle is inserted ensuring that 20–30mL of LA spreads in the adductor canal. With enhanced recovery pathways gaining popularity, the addition of nerve blocks
to multimodal analgesic regimen provides optimum pain control in orthopaedic
surgery to improve patient outcomes and speed up a patient’s recovery.
Although many studies have shown that femoral nerve block provides superior
analgesia and causes fewer side effects when compared with intravenous
opioid, they also shown that femoral nerve block prolongs the motor blockade
and increases the risk of patient fall. This might delay the patient’s recovery and
discharge from hospital. )
Adequate pain control and preservation of motor activity has become the optimal goal
in TKR surgery to enhance patient recovery. Therefore, in the above clinical scenario, the
most appropriate option is to perform an adductor canal block as it results in a motor
sparing sensory blockade (no quadriceps weakness) with effective pain control.
