Download Multiple Choice Answers

Multiple Choice Answers
128.
Glycoprotein IIb/IIIa inhibitors:
(a) True; (b) False; (c) True; (d) False; (e) False
(a) GP IIb/IIIa inhibitors block fibrinogen cross-links between platelets.
(b,c) They are not licensed with thrombolysis but have a role in stenting
during PTCA. (e) There is no specific reversal therapy available.
response. (c) Naloxone is a competitive antagonist. There is no
evidence for agonist activity. (d) This a characteristic of a competitive
antagonist. (e) Naloxone will reverse the effects of full, partial and
inverse agonists.
135.
129.
The troponins:
(a) True; (b) True; (c) False; (d) False; (e) True
(a) Elevated serum troponins may reflect an area of myocardial necrosis
weighing < 1.0 g. (b) Troponins may remain elevated for up to 10 days.
(c) This may reflect incomplete apoptosis as part of a non-ischaemic
inflammatory process (e.g. in sepsis). (d) Typically detected at 4--10 h.
(e) High TnT is associated with increased mortality in sepsis.
130.
Regarding reperfusion therapy:
(a) False; (b) True; (c) False; (d) True; (e) False
(a) rt-PA is associated with an increased risk of bleeding. (b) Most
benefit occurs in first 12 h. (c) PTCA is recommended in patients with
unstable CAD and after failed medical treatment. (d) Primary PTCA is
superior to thrombolysis in the early management of STEMI, especially
in the reduction of re-infarction and stroke. (e) STEMI-induced
cardiogenic shock is an indication for PTCA.
131.
The following are currently recommended
therapies in the treatment of unstable angina:
(a) True; (b) True; (c) True; (d) False; (e) True
(a) Reduces death or non-fatal MI by nearly 50% in UA. (b) b-Blockers
remain the most important anti-ischaemic drugs. (c) Efficacy probably
related to anti-factor Xa:IIa ratio. (d) Associated with increased mortality.
132.
In the diagnosis of MI:
(a) True; (b) False; (c) False; (d) False; (e) True
(a,b) May confirm MI in new LBBB, which itself is non-specific for
diagnosis. Echocardiography can also assess size of MI. (c) Refer to
diagnostic criteria for acute, evolving, recent or established MI.
(d) ST-depression occurs in leads V1 and V2 in posterior infarction.
(e) CK is usually used for this purpose.
133.
G-protein-coupled receptors:
(a) False; (b) False; (c) True; (d) True; (e) False
(a) Located on the plasma membrane. (b) It is the G-protein that is
composed of three subunits. (c) Directly via Ga (and indirectly via cross
talk). (d) Via b1-adrenoceptors (and M2 muscarinic receptors). (e) There
is almost no homology (similarity) to ligand-gated ion channels.
134.
Naloxone:
(a) False; (b) True; (c) False; (d) True; (e) True
(a) Naloxone is a competitive antagonist. (b) By reversing the effects of
endogenous opioids then naloxone could theoretically produce a pain
210
Concerning agonists and antagonists:
(a) False; (b) False; (c) True; (d) False; (e) False
(a) KD is a measure of ligand affinity and is usually obtained in a binding
experiment. (b) Efficacy is related to the strength or size of a response
produced. (c) EC50 is the concentration at which half the maximum
response occurs and hence estimates potency. (d) Potency is the dose
range over which a response is produced. (e) An inverse agonist has
negative efficacy. A partial agonist has (positive) efficacy that is lower than
that of a full agonist.
136.
During high intensity exercise, predominant
sources of ATP in the first minute of exercise are:
(a) True; (b) False; (c) True; (d) False; (e) False
(a,c) Phosphocreatine contains a high energy phosphate bond
similar to ATP and is available in limited supply in muscle for the first few
seconds at the start of exercise. Glycogen is broken down to
pyruvate, which is in turn converted to lactate in the absence of oxygen.
(b) Lactate is, therefore, a metabolite of the process rather than a
source of energy during high intensity activity. (d,e) Fatty acids
and amino acids with glucose combine to provide almost limitless
energy by oxidative phosphorylation and are very important in
endurance exercise.
137.
Type II muscle fibres are associated with:
(a) True; (b) False; (c) False; (d) True; (e) True
Recruitment of type II muscle fibres is associated with high intensity,
short-term exercise. They possess a poor blood supply and do not rely on
aerobic energy supplies. Hence, oxidative enzymes and myoglobin
levels are low in contrast to type I muscle fibres, which are more
important in endurance sports such as marathon running.
138.
During very strenuous exercise:
(a) False; (b) False; (c) True; (d) True; (e) False
(a) Oxygen consumption during vigorous exercise usually increases
about 20-fold from 250 ml min 1 to up to 5000 ml min 1. (b) How
respiration is stimulated during exercise is not completely understood.
It is thought to be a combination of motor centre activity, afferent
signalling from proprioceptors in muscles and joints as well as alterations
in the sensitivity of chemoreceptors to PO2 and PCO2. The changes
in PaO2 and PaCO2 are insufficient to account for the large increase in
respiration. (c,d) Cardiovascular function is the rate-limiting factor
in the delivery of oxygen to the muscles during strenuous
exercise. (e) Blood flow to muscles at rest is usually
2--4 ml 100 g muscle 1 min 1. During maximal exercise this increases
to about 100 ml 100 g muscle 1 min 1.
Continuing Education in Anaesthesia, Critical Care & Pain | Volume 4 Number 6 2004
ª The Board of Management and Trustees of the British Journal of Anaesthesia 2004
DOI 10.1093/bjaceaccp/mkh057
Multiple Choice Answers
139.
The following are indications for awake
craniotomy:
(a) False; (b) True; (c) True; (d) False; (e) False
(a) Posterior fossa lesions are a contraindication to awake surgery
because they often require the prone position. (b) Awake
techniques are increasingly used for stereotactic brain biopsy.
(c) Intraoperative cortical stimulation allows mapping of eloquent
cortical areas and allows accurate planning of resection
margins. (d) Because of the potential for significant pain during
resection. (e) Patient co-operation is crucial for the success
of awake craniotomy.
140.
During awake craniotomy:
(a) False; (b) False; (c) False; (d) False; (e) True
(a) Sedative may delay return to consciousness during the awake
phase and obtunded conscious level may mask intracranial
complications. (b) Noise levels in theatre must be kept to a minimum
but ear plugs should not be used because they would severely limit
communication with the patient. (c) Urinary catheterisation is required
for prolonged surgery. (d) Anticonvulsant medication should be
continued to minimize the risk of the development of intraoperative
seizures. (e) The patient should position themselves on the operating
table before administration of sedation or anaesthesia so that they
may lie in the most comfortable position.
(d) Loss of airway control is always a risk with any sedation technique.
(e) BIS monitoring may be used to guide depth of anaesthesia
in awake--asleep--awake techniques but has not been widely tested
during sedation for awake intracranial surgery.
143.
144.
In relation to local anaesthetic techniques
during awake craniotomy:
(a) False; (b) True; (c) False; (d) False; (e) False
(a) The provision of adequate local anaesthesia using regional, field and
dural blocks is essential for all awake intracranial procedures. (b) The
skin, scalp, pericranium and periosteum of the outer table of the skull
are all innervated by cutaneous nerves arising from branches of the
trigeminal nerve. (c) After anaesthesia of the periosteum of the outer
table, the skull can be drilled and opened without discomfort
because it has no other sensation. (d) Epinephrine containing local
anaesthetic solutions should not be deposited around the nerve trunk
associated with the middle meningeal artery. (e) The dura is innervated
by branches from all three divisions of the trigeminal nerve, the
recurrent meningeal branch of the vagus, and by branches of
the upper cervical roots and can only be adequately anaesthetized with
a field block around the edges of the craniotomy in addition to a
nerve block around the nerve trunk running with the middle
meningeal artery.
142.
In relation to the provision of sedation during
awake craniotomy:
(a) True; (b) False; (c) True; (d) False; (e) False
(a) a2-Adrenoreceptor agonists provide analgesia and sedation that
is easily reversed with verbal stimulation without risk of respiratory
depression. (b) Patient-controlled sedation with propofol during
awake epilepsy surgery has been associated with a higher incidence of
transient respiratory depression than other techniques. (c) Propofol
and remifentanil infusion is safe and easy to use and has a minimal
risk of respiratory depression. Changes in infusion rates are quickly
followed by changes in effect site concentrations, which correspond
well with the desired clinical changes in patient sedation and analgesia.
TURP syndrome:
(a) True; (b) False; (c) True; (d) True; (e) False
(a,b,d) Symptoms worsen with increasing volume of fluid absorbed,
longer duration of surgery, and failing to keep patients blood pressure
within normal limits. (e) Hypertonic saline may produce further
neurological symptoms.
145.
141.
Complications of awake craniotomy include:
(a) False; (b) True; (c) True; (d) True; (e) False
(a) The need to convert to general anaesthesia occurs in fewer than 1:20
patients. (b) There is a risk of intraoperative seizures particular during
cortical stimulation. (c) Airway obstruction or hypoventilation due to
excessive sedation may cause hypoxaemia. (d) Brain swelling may occur
because of raised PaCO2 secondary to sedation-related respiratory
depression. (e) Diabetes insipidus is caused by intracranial pathology or
neurosurgery (if > 80% of neurones synthesizing vasopressin are
destroyed or become temporarily non-functional) and is not related to
anaesthetic technique.
Concerning cataract surgery:
(a) True; (b) False; (c) False; (d) False; (e) True
(b) The procedure causes minimal postoperative pain. (c,d) Regional
anaesthesia accounts for 90% of cases, predominately using blunt
cannula techniques. (e) Confusion may be a contraindication as for all
regional techniques.
146.
Concerning regional anaesthesia in the elderly:
(a) False; (b) True; (c) False; (d) True; (e) True
(a) The elderly have a poor response to exogenous b-agonists therefore
a-agonists should be used. (b) Further volume loading may be detrimental.
(c) There is little evidence for long-term advantage. (d) Use of larger
spinal needles may facilitate performing the block. (e) The advantages
of regional anaesthesia with respect to postoperative cognitive
dysfunction are only maintained if sedation is avoided.
147.
Concerning anaesthetic drugs and the elderly:
(a) False; (b) True; (c) False; (d) False; (e) True
(a) Although there is reduced muscle mass, extrajunctional receptors offset
the reduction in dose that would otherwise be expected. (c) Increased
_ mismatch reduce uptake of volatile anaesthetic agents
shunt and V_ /Q
with low blood-gas solubility. (d) Reduced b-receptor activity means
a lesser increase in heart rate after atropine administration.
148.
In the elderly:
(a) False; (b) True; (c) False; (d) True; (e) True
(a) Fluid handling is impaired despite normal renal indices. Serum creatinine
is related to muscle mass, so a frail patient with renal dysfunction may still
have a serum creatinine that appears to be within normal limits.
(b,c) Although shivering may be ineffective at restoring body temperature,
it may still cause complications because of the reduction in
cardiorespiratory reserve.
Continuing Education in Anaesthesia, Critical Care & Pain | Volume 4 Number 6 2004
211
Multiple Choice Answers
149.
Controlled conventional ventilation using peak
inspiratory pressures of 14 cm H2O and a PEEP of
4 cm H2O in the anaesthetized normovolaemic
patient with pre-existing normal lungs induces the
following pulmonary changes:
(a) True; (b) False; (c) False; (d) True; (e) False
(a,d,e) Even the gentlest positive pressure ventilation activates the
inflammatory cascade releasing free radicals and produces shear-force
barotrauma. On CT scan the healthy anaesthetized patient develops
atelectasis and requires higher than normal PEEP to prevent dependant
atelectasis. (b) Preload depression of cardiac output is not seen in the
normovolaemic patient (except at extremely high pressures).
150.
High frequency oscillatory ventilation:
(a) False; (b) True; (c) False; (d) False; (e) False
(a) The majority of tidal movements is below dead space. (b,c) Alveolar
pressure swings are minimal owing to attenuation of the pressure
wave, maintaining stable inflation. Homogeneous pathologies have an
ideal pressure which HFO can achieve, and conventional cannot.
(d) HFO is best used early before conventional ventilation has caused
more lung damage. (e) Heavy sedation and NMB are rarely required
for comfort and worsen pulmonary mechanics.
152.
Antioxidants:
(a) True; (b) True; (c) True; (d) False; (e) False
(a,c,d) Critical illness is associated with high levels of free radical generation
and oxidative stress producing depletion of antioxidant defences.
212
153.
Nitric oxide:
(a) False; (b) True; (c) False; (d) False; (e) False
(a) Nitric oxide binds to the haem iron of guanylate cyclase stimulating
the production of cGMP. (b) When given as a gas it has marked
selective pulmonary vascular effects. (d) It has clear benefits in neonates
and other patients with severe pulmonary hypertension, but may not
be of benefit in the absence of pulmonary hypertension. (e) Tolerance
develops rapidly.
Safe ventilatory practice:
(a) True; (b) False; (c) True; (d) False; (e) True
(a,c) Overdistension of alveoli beyond their elastic limit associated
with excessive tidal volumes increases damage. (b,d) Cyclical collapse/
opening from inappropriately low PEEP (usually below the LIP of normal
alveoli) creates shear-force damage, worsening pulmonary function. In non
homogenous pathology the LIP reflects the inspiratory limb of the
abnormal/recruitable alveoli, not the normal ones, and therefore PEEP at or
above the LIP may lead to overdistension of the normal alveoli. (e)
Recruitment manoeuvres increasing the number of open recruitable
alveoli, maintained open on the deflation limb of the PV loop by appropriate
levels of PEEP improve outcome.
151.
(b,e) Vitamin E is a component of surfactant, and the lungs have a high
concentration of other antioxidants including glutathione and the
systems required to regenerate vitamin E and glutathione.
154.
Post-traumatic stress disorder:
(a) False; (b) False; (c) False; (d) False; (e) True
(a) This is chronic fatigue syndrome. (b) It is a normal reaction
to severe stress. (c) It is seen in about 15%, but in 30% of
patients recovering from ARDS. (d) Factual memory appears to
reduce the incidence.
155.
The following drugs may lead to erectile
dysfunction:
(a) True; (b) False; (c) True; (d) False; (e) True
(a) All b-blockers have been implicated. (d) This is the generic name for
Viagra. It is a phosphodiesterase (PDE5) inhibitor used to treat erectile
dysfunction. (e) As with other tricyclic antidepressants.
156.
Concerning patients treated in ICU:
(a) False; (b) True; (c) True; (d) False; (e) False
(a) Estimated incidence is 1%. (b) A characteristic obstructive
pattern is produced on Flow-Volume loop testing. (c) Very good
cosmetic results are obtained in the outpatient department by
experienced practitioners. (d) 70% of patients are unable to describe
anything about their ICU stay. Of those who remember
something, 28% describe nightmares and 5% hallucinations. (e) This
was attributable to the use of some earlier starch-based
preparations.
Continuing Education in Anaesthesia, Critical Care & Pain | Volume 4 Number 6 2004