6. Vascular & General Flashcards
1
Q
. You anaesthetize a patient for laparoscopic nephrectomy which has
now been converted to an open procedure. You recommend that the
patient should receive a continuous local anaesthetic wound infiltration
catheter. The surgeon asks where is best to place it?
A. Subcutaneously
B. Between external oblique and internal oblique muscle layers
C. Between internal oblique and transversus abdominis muscle layers
D. Preperitoneal
E. Intraperitoneal
A
- C
The innervating nerves run between the muscle layers internal oblique and transversus abdominis,
which is the best site for catheter placement, similar to the anatomy of a TAP block. There remains
some controversy over the exact placement of wound catheters at various surgical sites. Placing the
catheter between muscle layers requires a layered wound closure by the surgeon.
2
Q
- Regarding patient positioning under general anaesthesia. The most commonly reported nerve injury postoperatively is:
A. Ulnar nerve
B. Common peroneal nerve
C. Lateral cutaneous nerve of thigh
D. Median nerve
E. Sciatic nerve
A
- A
More than a quarter of all perioperative nerve injuries involve the ulnar nerve. The classic site of
injury is in the ulnar groove behind the medial epicondyle of the humerus. At this point, the nerve is
quite exposed to both direct trauma from the sides of the operating table and indirect trauma from
stretch. It is three times more common in males than females.
3
Q
- You anaesthetize a 71- year- old woman for day surgery laparoscopy. She has a history of early Parkinson’s disease which is well controlled. Her drug therapy includes ropinirole. The best choice of antiemetic is:
A. Prochlorperazine
B. Metoclopramide
C. Droperidol
D. Ondansetron
E. Domperidone
A
- D
Parkinson’s disease is a common neurodegenerative disorder due to loss of dopaminergic neurones in the substantia nigra.
Ropinirole is a dopamine agonist.
A number of anti- emetics are
contraindicated in Parkinson’s disease due to their dopamine antagonist effects. 5- HT3 receptor
antagonists (e.g. ondansetron) and H1- receptor antagonists have fewer side effects.
4
Q
- You anaesthetize a 66- year- old man for open cholecystectomy. He has moderate chronic obstructive pulmonary disease (COPD). His current ventilation settings are FiO2 of 0.5, P insp of 25 cmH2O, PEEP 6 cmH2O, I:E ratio of 1:2 with a RR 12 bpm giving a tidal volume of around 500 mL. You notice his blood pressure has dropped to 90/ 42 and his tidal
volume has dropped to 390 mL. The expiratory flow does not return to zero prior to inspiration. He is adequately paralysed. What is the best
ventilatory management at this point?
A. Switch to volume controlled ventilation
B. Increase the I:E ratio to 1:4
C. Increase the P insp to 30 cmH2O
D. Decrease the respiratory rate to 8
E. Decrease the PEEP to 0
A
- B
This clinical scenario suggests ‘breath stacking’ when airway narrowing limits expiratory flow causing
inspiration to occur before expiration is complete. This leads to development of intrinsic PEEP, raised
intrathoracic pressure, and potential cardiovascular instability due to decreased venous return.
Allowing more time for expiration either by increasing the I:E ratio or decreasing the respiratory
rate would allow more time for exhalation and reduce the likelihood of breath stacking. However,
decreasing the respiratory rate too much may cause hypercapnia, acidosis, and hypoxia so a balance
needs to be achieved. A respiratory rate of 8 is probably too low.
Increasing the P insp would increase the chance of barotrauma.
Switching to volume- controlled ventilation would cause an increase in peak pressure again with a
risk of barotrauma.
Increasing PEEP rather than decreasing it could be beneficial by keeping small airways open during
exhalation but again at risk of cardiovascular compromise if too high.
5
Q
- An ASA 1 42- year- old- female patient had an uneventful laparoscopic cholecystectomy. In recovery she develops inspiratory stridor and tachypnoea and has desaturated to 90% on 6 L of oxygen via a Hudson
mask. You have called for help and performed a jaw thrust with no improvement. What is the next most appropriate management?
A. Give propofol
B. Give suxamethonium
C. Give nebulized salbutamol
D. Application of CPAP with 00% oxygen with Mapleson C system
E. Perform a rapid sequence induction and re- intubate
A
- D
The symptoms of stridor, tachypnoea, and desaturation postoperatively suggest laryngospasm,
which requires prompt recognition and treatment. As this patient has no airway device in place the
initial step would be to apply CPAP with 00% oxygen and potentially the laryngospasm will resolve.
If this fails you may need to progress to treatment with propofol ± suxamethonium and may need
to secure the airway with an endotracheal tube.
6
Q
- A 54- year- old lady in the HDU is receiving an amiodarone infusion for fast atrial fibrillation. You review her 3 hours later because she is complaining of pain in her arm around the cannula site where the
amiodarone is being infused. You note the area is swollen, tense, and red. You immediately stop the infusion and aspirate as much as you can from the cannula and elevated her arm. What is the most useful
secondary management to reduce tissue injury?
A. Stellate ganglion block
B. Intravenous hydrocortisone
C. Saline washout
D. Phentolamine injection
E. Hyaluronidase injection
A
- C
Extravasation of amiodarone can lead to tissue necrosis. Saline washout under local or general
anaesthesia is probably the most effective treatment to remove and dilute the drug from the site of
injury and has been shown to reduce tissue injury.
Steroids have been used historically but there is little evidence to support their use after
extravasation injuries.
Hyaluronidase has a temporary effect of making tissues more permeable when injected at the site
which could help dispersion of extravasated amiodarone. It could therefore aid a saline washout but
is of no benefit alone.
Phentolamine injected at the site can relax smooth muscle and cause vasodilatation. Early use is
only recommended after extravasation of vasopressors.
Stellate ganglion block can again cause vasodilatation and may have a role after the extravasation of
vasopressors and thiopentone only. The procedure also has risks and side effects to be considered
7
Q
- A 58- year- old male presents for carotid endarterectomy (CEA) after an episode of amaurosis fugax in the right eye. He has been commenced
on clopidogrel. He is awaiting three vessel coronary artery bypass graft (CABG) for angina which is stable. He also has hypertension and hypercholesterolaemia. His other medications are aspirin, amlodipine,
ramipril, simvastatin, isosorbide mononitrate, nicorandil, and glyceryl trinitrate (GTN) spray as required. What is the single most appropriate
action plan?
A. Cancel CEA until CABG, continue clopidogrel
B. Proceed with right CEA and continue clopidogrel
C. Cancel CEA and proceed with CABG but stop clopidogrel
D. Proceed with left CEA and stop clopidogrel
E. Proceed with right CEA and stop clopidogrel
A
- B
Proceed with right CEA and continue clopidogrel.
In terms of which procedure first, CABG is a major cardiovascular risk procedure. CEA is
intermediate. Therefore, performing CEA before CABG is overall the most cardiovascular
protective strategy. With the symptom of Amaurosis fugax, the carotid lesion is ipsilateral.
A number of studies have shown that stopping antiplatelet therapy prior to CEA increases the risk
of stroke while presenting only a moderate bleeding risk.
8
Q
- Regarding monitoring of non- depolarizing neuromuscular blockade, which statement is the most accurate?
A. A train of four >0.8 is a reliable indicator of return of safe motor function
B. Should commence pre- induction and continue until a reversal agent is given
C. Can be done using the isolated forearm procedure
D. Total paralysis is evidenced by continued apnoea
E. Is accurate using a quantitative monitor of measurement
A
- E
The muscular response to ulnar nerve stimulation is best but the facial or peroneal nerves can also
be used. Monitoring of neuromuscular blockade using a peripheral nerve stimulator is essential for
all stages of anaesthesia when neuromuscular drugs are administered. It should be commenced at
induction to ensure adequate relaxation prior to intubation and continued until return of consciousness.
Awareness is most common at induction and during transfer from the anaesthetic room to theatre
(50% cases), and around 20% of cases occur during emergence, commonly related to inadequate
reversal of neuromuscular block
The isolated forearm technique is a monitor of awareness, not neuromuscular block.
Train of four (TOF) monitoring must be quantitative to be accurate. Trials have shown marked
inadequacy of qualitative assessment methods, even with experienced anaesthetists.
9
Q
- A 26- year- old female presents with neuropathic pain and paraesthesia along the lateral border of her hand for six months. On examination she has wasting of the abductor pollicis brevis, the hypothenar eminence, and the interossei muscles of the hand. There is no history of trauma.
The most likely diagnosis is:
A. Radial nerve palsy
B. Carpal tunnel syndrome
C. Thoracic outlet syndrome affecting C8 and T1 nerve roots
D. Raynaud’s disease
E. Median nerve palsy
A
- C
This description describes neurogenic thoracic outlet syndrome involving C8 and T1 nerve roots
with pain, paraesthesia, and muscle wasting in an ulnar distribution. This is the most common
neurogenic type although radial nerve symptoms and referred pain to chest, neck, ear, and upper
arm from C5, C6, and C7 involvement can also be present sometimes. Thoracic outlet syndrome
most commonly affects young females between the ages of 20 and 40 years.
10
Q
- A 62- year- old man with COPD and hypertension is recovering from a laparotomy for a perforated duodenal ulcer. He can now eat and drink
and is to convert from his patient- controlled anaesthesia morphine to oral analgesia. He has used 40 mg IV morphine in the last 24 hours.
What would be the most appropriate oral analgesia regimen?
A. Six hourly co- codamol 30/ 500
B. Six hourly tramadol 100 mg
C. MST 40 mg bd with 10 mg sevredol for breakthrough and regular paracetamol
D. MST 20 mg bd with 5 mg sevredol for breakthrough and regular paracetamol
E. Regular co- codamol 30/ 500 mg with tramadol 00 mg for breakthrough
A
- D
This gentleman has had the oral equivalent of 80 mg of morphine in the last 24 hours and is likely
to need stronger opioids than just co- codamol and tramadol initially. It is reasonable as a starting
measure to prescribe half this dose in a modified release opioid form. Half this should be given in
the morning and half in the evening. Extra doses of short- acting opioids must be available regularly
for breakthrough.
Conversion of IV to oral morphine is a 1ː2 ratio.
11
Q
- A 34- year- old female with myotonic dystrophy requires a laparoscopic cholecystectomy. She has a body mass index (BMI) of 38. She has a normal airway and no symptoms of reflux. She has had her usual
medications. The surgeon requests muscle relaxation for the operation.
What would be the best option for muscle relaxation?
A. Use a reduced dose of rocuronium with sugammadex for reversal
B. Use an increased dose of rocuronium with sugammadex for reversal
C. Use usual dose of suxamethonium with no reversal agent
D. Use a reduced dose of rocuronium with glycopyrrolate/ neostigmine for reversal
E. Use an increased dose of vecuronium with glycopyrrolate/ neostigmine for reversal
A
- A
Myotonic dystrophy is an autosomal dominant disorder. Multisystem signs and symptoms usually
manifest in early adulthood. They have myotonia which is incomplete muscle relaxation, especially
the inability to ‘let go’ after a hand grip. They may also have muscle wasting, cardiac and respiratory
abnormalities, endocrine dysfunction, and intellectual impairment.
Depolarizing neuromuscular blocking agents and anticholinesterase drugs may induce generalized
muscle contractures and should be avoided.
Non- depolarizing neuromuscular blocking agents are not associated with myotonia but patients
with this disease may show increased sensitivity to them. If they are absolutely required, they
should be given in reduced doses with careful monitoring and sugammadex to ensure complete
reversal.
12
Q
- You anaesthetize a 71- year- old man for elective abdominal aortic aneurysm repair. He is stable following epidural insertion and induction
of anaesthesia. The surgeon tells you he is about to cross clamp the aorta. What is the next step in your anaesthetic management of this patient?
A. Administer a bolus of local anaesthetic epidurally
B. Have a noradrenaline (norepinephrine) infusion ready for immediate use
C. Start volume loading the patient
D. Deepen anaesthesia
E. Increase the FiO2 to 1.0
A
2. D
Cross- clamping the aorta increases the afterload to the heart and causes a sudden increase in
arterial pressure proximal to the clamp. Measures to deal with this include use of short acting
vasodilators such as a GTN infusion, additional opioids, and deepening anaesthesia.
Increasing the FiO2 is of no benefit.
Most would advocate not using the epidural until the cross clamp is removed and haemostasis
achieved as hypotension could be exacerbated and more difficult to treat.
13
Q
- A 72- year- old man requires an emergency laparotomy. A CT scan has
shown a perforated diverticulum. He has a past medical history of atrial
fibrillation and hypertension. His heart rate is AF 110, blood pressure
97/ 63, and temperature 38.5°C. The surgeons are keen to proceed. The
most appropriate risk assessment tool is:
A. ASA grade
B. Lee’s RCRI
C. P- POSSUM score
D. HES procedure group
E. APACHE- II score
A
- C
The details of the case describe a patient with advanced age and comorbid disease requiring major
urgent non- cardiac surgery.
Based on this alone they are likely to be at high risk of perioperative death (mortality >5%) and therefore should be managed as ‘high risk’.
Recommendations from the
National Emergency Laparotomy Audit state that objective and formal risk assessment should be
carried out routinely; ASA alone is not detailed enough.
Lee’s revised cardiac risk index (RCRI) is
more recent than Goldman’s Original Cardiac Risk Index. It describes six independent risk variables
for patients undergoing major non- cardiac surgery. It is validated in predicting cardiovascular risk
factors only.
P- POSSUM is freely available on the internet and is possibly the best validated method.
Its scoring includes 12 physiological and six operative details.
Hospital Episode Statistics (HES)
contains details of all admissions at NHS hospitals in England and may also be linked to mortality
data. APACHE II was derived in the general ICU population and is used to estimate ICU mortality
14
Q
- A 72- year- old female patient with chronic renal failure has notoriously
difficult peripheral and central IV access. She had multiple central lines
over the last 20 years. She requires an upper body central line. The gold
standard test to check catheter tip position is:
A. Chest X- ray
B. Ultrasound/ echocardiography
C. Arterial blood gas analysis
D. Fluoroscopy with contrast
E. Monitored pulse waveform
A
- D
Upper body central venous catheters (CVCs) should be positioned with the tip parallel to the
vessel wall, usually in the lower superior vena cava (SVC) or the upper right atrium (RA). Common
sites for tip misplacement include being too high in the superior vena cava, in the internal jugular
vein, angled toward the wall of the vein, too low in the RA, in the right ventricle, in the innominate
vein, and finally the subclavian vein.
Ultrasound can confirm catheter position with supraclavicular, transthoracic, and transoesophageal
echocardiographic views. Electrocardiograpy and electromagnetic guidance are increasingly used
to guide catheter tip positioning. Chest X- ray is most commonly used to check position due to its
simplicity but cannot be described as a gold standard. Fluoroscopy with X- ray contrast in real time
remains the gold standard for imaging in the difficult patient.
15
Q
- A 77- year- old man is recovering well after an anterior resection. His
epidural catheter has been removed after providing successful analgesia
for 72 hours. He has chronic atrial fibrillation and is on rivaroxaban.
What is the safe minimum time interval to recommence his rivaroxaban
after the epidural catheter has been removed?
A. hour
B. 6 hours
C. 2 hours
D. 24 hours
E. 48 hours
A
- B
Rivaroxaban is a direct inhibitor of factor Xa. The current guidelines suggest waiting 6 hours to
commence or recommence rivaroxaban after central neuraxial block or removal of the epidural
catheter to minimize the risk of vertebral canal haematoma.
It is also recommended to wait 12– 18 hours after a dose of rivaroxaban before performing a
central neuraxial block or removing an epidural catheter.
