Rakesh 6 Flashcards
1
Q
- A 53-year-old woman was admitted following a subarachnoid
haemorrhage. Two days after her admission, the ALERT team informs
you that she is hyponatraemic. On assessment she is not thirsty and is
euvolaemic. Her blood test shows plasma sodium 129 mmol/L, urine
sodium 29 mmol/L, and plasma osmolality 270 mOsm/kg. What is the
most likely diagnosis?
A. Iatrogenic hyponatraemia.
B. Syndrome of inappropriate ADH secretion (SIADH).
C. Cerebral salt wasting syndrome (CSWS).
D. Severe dehydration.
E. Drug-related hyponatraemia.
A
C
- Answer: B
The diagnostic criteria for SIADH are:
hypotonic hyponatraemia (serum sodium < 135 mmol/L) and serum osmolality < 280 mOsm/kg
urine osmolality > serum osmolality
urine sodium concentration > 18 mmol/L
normal thyroid, adrenal, and renal function
clinical euvolaemia — absence of peripheral oedema or dehydration.
The most common neurological causes of SIADH are subarachnoid haemorrhage (SAH), traumatic
brain injury (TBI), brain tumour, and meningitis/encephalitis. The absence of dehydration in SIADH
is very important as this is the key feature diff erentiating it from CSWS, in which clinical signs
of dehydration will always be present. It is important to distinguish between SIADH and CSWS
because the treatment of the two conditions is diametrically opposed.
2
Q
- Concerning the Bain anaesthesia breathing circuit, which of the
following is the correct statement?
A. Fresh gas fl ow is along the inner tube.
B. The minimum length is 2 m.
C. During controlled ventilation the minimum fresh gas fl ow is 6 L/min.
D. End tidal CO 2 concentration cannot be altered by changing the fresh gas fl ow.
E. It is a co-axial Mapleson A circuit.
A
a.
- Answer: A
The Bain circuit is a modifi cation of the Mapleson D system. It is a co-axial system in which the
fresh gas fl ows through a narrow inner tube within the outer corrugated tubing. Essentially, the
Bain circuit functions in the same way as the T-piece, except that the tube supplying fresh gas to the
patient is located inside the reservoir tube.
The circuit has three phases.
Inspiration: the patient inspires fresh gas from the outer reservoir tube.
Expiration: the patient expires into the reservoir tube. Although fresh gas is still fl owing into
the system at this time, it is wasted, as it is contaminated with expired gas.
Expiratory pause: fresh gas from the inner tube washes the expired gas out of the reservoir
tube, fi lling it with fresh gas for the next inspiration.
Spontaneous ventilation: normocarbia requires a fresh gas fl ow of 200–300 mL/kg.
Controlled ventilation: a fresh gas fl ow of only 70 mL/kg is required to produce normocarbia.
Bain and Spoerel have recommended:
2 L/min fresh gas fl ow in patients <10 kg
3.5 L/min fresh gas fl ow in patients 10–50 kg
70 mL/kg fresh gas fl ow in patients > 60 kg.
The recommended tidal volume is 10 mL/kg and respiratory rate is 12–16 breaths/min.
3
Q
- A 36-year-old male had a bike accident and was admitted to critical care
with isolated severe head injury. After 24 h his condition is still critical,
with no signs of brain stem activity, he is polyuric and his plasma sodium
is 154 mmol/L, his condition does not improve despite aggressive fl uid
therapy. Which of the following is the correct diagnosis and treatment
of this condition?
A. Diabetes insipidus and small titrated doses of 1-deamino-8- d -arginine vasopressin.
B. Diabetes insipidus and administration of dextrose saline fl uids.
C. Cerebral salt wasting syndrome (CSWS) and normal saline fl uids.
D. Severe dehydration and oral fl uids replacement.
E. Syndrome of inappropriate ADH secretion (SIADH) and small doses of vasopressin.
A
A
- Answer: A
Diabetes insipidus is associated with damage to the pituitary gland or hypothalamus, most
commonly due to surgery, a tumour, an illness (such as meningitis), infl ammation, or a head injury.
In some cases the cause is unknown. This damage disrupts the normal production, storage and
release of ADH. The incidence of DI can be as high as 35 % after traumatic brain injury, when it is
associated with more severe injury and increased mortality.
DI results from a failure of ADH release from the hypothalamic–pituitary axis. The ability to
concentrate urine is impaired, resulting in the production of large volumes of dilute urine.
This inappropriate loss of water leads to an increase in serum sodium and osmolality and a
state of clinical dehydration.
There are two aims in the management of DI: replacement and retention of water and replacement
of ADH. Conscious patients are able to increase their own water intake and this is often suffi cient
treatment if the DI is self-limiting. In unconscious patients, fl uid replacement is achieved with
water administered via a nasogastric tube or IV 5 % dextrose. If urine output continues > 250 mL/h,
synthetic ADH should be administered. This is usually in the form of small titrated doses of
1-deamino-8- d -arginine vasopressin, which can be given intranasally (100–200 mg) or IV (0.4 mg).
4
Q
- A 32-year-old pregnant woman is admitted to the labour ward for
induction of labour due to reduced foetal movement. She suffers from
multiple sclerosis, with her last exacerbation 3 years ago. Her pregnancy
had been unremarkable throughout. The CTG shows foetal bradycardia
requiring emergency caesarean section (category I). What is the most
appropriate method to induce the patient for general anaesthesia?
A. GA is contraindicated and she should have a spinal.
B. Rapid sequence using thiopental, suxamethonium, and alfentanil.
C. Thiopental, rocuronium, and remifentanil.
D. Modifi ed rapid sequence using thiopental and rocuronium.
E. Propofol and rocuronium.
A
D
- Answer: D
Multiple sclerosis does not contraindicate either regional or general anaesthetic. In this case the
foetus has severe bradycardia and GA is the most common practice.
In multiple sclerosis there is up-regulation of nicotinic acetylcholine receptors, and sensitivity to
depolarizing neuromuscular blocking agents is increased. Therefore, their administration can result
in hyperkalaemia and cardiac arrest. Although this eff ect may be more signifi cant in patients with
a severe neurological defi cit, it is advisable to avoid succinylcholine in even mild conditions unless
clinically indicated. Rocuronium is now considered an alternative for rapid sequence induction in
obstetric anaesthesia.
Opioids — even those with short duration of action — should be avoided unless the maternal
condition warrants their use (e.g. to dampen the hypertensive response to intubation in
pre-eclampsia).
5
Q
- A 14 year-old boy is brought to A&E following a car accident. He has
suff ered head injury, with fl uctuating level of consciousness. He requires
general anaesthesia for urgent CT scan and possible craniotomy.
His mother is abroad and his father is an hour’s car journey away.
What is the most appropriate step regarding consent?
A. It would be appropriate to proceed with emergency treatment without consent.
B. Without consent from the mother the proposed treatment is considered battery.
C. The team can wait for the father to arrive.
D. Legal advice must be sought urgently before proceeding.
E. A social worker can sign the consent.
A
A
- Answer A
It is clear in this situation that it is in the child’s best interests to have appropriate treatment for
a head injury as quickly as possible. Using the doctrine of emergency (which assumes a person’s
consent to medical treatment when he or she is in imminent danger and unable to give informed
consent; also known as implied consent), it would be appropriate to proceed with emergency
treatment without consent. Best practice would include making sure attempts were being made to
contact the child’s parents, documentation in the medical records of the reasons for proceeding
under the doctrine of emerg
6
Q
- A young patient is brought to A&E by the air ambulance and has an
isolated head injury with GCS 8/15 at the scene. She is intubated and
ventilated with an end tidal CO 2 of 3.1 kPa. Profound hypocarbia should
be avoided in traumatic brain injury in order to prevent:
A. Respiratory alkalosis.
B. Metabolic acidosis.
C. Cerebral vasoconstriction with diminished perfusion.
D. Neurogenic pulmonary oedema.
E. Shift of the oxyhemoglobin dissociation curve.
A
c
- Answer C
Ventilation targets in traumatic brain injury include a P aO 2 of 13 kPa and a P aCO 2 of 4.0–4.5 kPa.
Excessive hyperventilation ( P aCO 2 < 4 kPa) should be avoided because it has been associated with
worsening of cerebral ischaemia secondary to excessive cerebral vasoconstriction.
7
Q
- A 78-year-old male patient was admitted to critical care after
emergency repair of abdominal aortic aneurysm. He has been anuric
for the last 2 h. Which is the most correct statement pertaining to
acute kidney injury?
A. Perioperative renal failure is a rare complication of major surgery.
B. Dopamine has been shown to prevent acute renal failure.
C. Perioperative manitol provides renal protection.
D. Postoperative renal dysfunction is associated with mortality of up to 60 % .
E. By the nature of the pathophysiolgy, perioperative renal failure is not associated with
cardiac dysfunction.
A
D
- Answer: D
Acute kidney injury is defi ned when one of the following criteria is met:
serum creatinine rises by ≥ 26 μ mol/L within 48 h or
serum creatinine rises ≥ 1.5-fold from the reference value, which is known or
presumed to have occurred within 1 week or
urine output is < 0.5 mL/kg/h for over 6 consecutive hours.
Acute kidney injury (AKI) occurring around the time of surgery is a common complication of major
surgery and is associated with considerable morbidity and mortality. Perioperative AKI accounts
for 20–25 % of cases of hospital-acquired renal failure. The incidence varies between 1 and 25 %
depending on the type of surgery and on the defi nition of renal failure.
At present there is no evidence to suggest that the use of any pharmacological treatment provides
perioperative renal protection. The key renal protective strategies include:
ensuring adequate hydration and renal perfusion
avoid nephrotoxic agents
careful glycaemic control
managing post operative complications promptly and aggressively.
Renal dysfunction after surgery is often associated with multiple organ dysfunction syndrome and
may result in a mortality of up to 60 % . It is also associated with a high risk of infection, prolonged
intensive care unit (ICU) and hospital stay, progression to chronic renal failure (CRF), and dialysisdependent
end-stage renal disease (ESRD). The chance of full recovery from an episode of AKI
in the surgical setting is only 15 % — many patients progress to develop varying degrees of chronic
renal dysfunction.
A number of postoperative complications are known to be associated with renal dysfunction.
Prompt diagnosis and management of acute cardiac dysfunction, haemorrhage, sepsis,
rhabdomyolysis, and intra-abdominal hypertension are essential to prevent the development of AKI
8
Q
- A 27-year-old woman is admitted to the labour ward at 40 weeks with
early onset labour. Her midwife informs you that the patient is known to
suff er from benign intracranial hypertension and her BMI is 35. Which of
the following is the best way to manage her?
A. Avoid any regional anaesthesia.
B. She could have an epidural but spinal should be avoided.
C. She could have any regional anaesthesia.
D. Remifentanil PCA is the best option.
E. Entonox and opioid IM.
A
C
- Answer: C
Benign intracranial hypertension is a diagnosis of exclusion described as raised ICP in the absence
of an intracranial lesion, hydrocephalus, or infection, and normal cerebrospinal fl uid (CSF)
composition. The condition is more common in obese women, while symptoms often worsen
during pregnancy and improve after delivery. Dural puncture is not contraindicated, but due to the
altered CSF circulation, spinal anaesthesia may be unpredictable. There have been reports using
combined spinal–epidural anaesthesia and intrathecal catheters for operative delivery, both of
which allow augmentation of anaesthesia if required.
9
Q
- A 57-year-old man had laparoscopic cholecystectomy. In recovery his
heart rate is 110/min, blood pressure is 210/110 mmHg, and oxygen
saturation is 98 % . His past medical history includes hypertension treated
with enalapril, and he has a BMI of 35. The recovery nurse asks you to
review the patient. What would be your next step?
A. Treat the blood pressure with sublingual nifedipine 5 mg.
B. Reassure the patient, repeat the blood pressure, and check the pain score.
C. Reassure the patient and give titrated dose of intravenous morphine.
D. Give intravenous atenolol, titrating with the blood pressure.
E. Assess the patient, repeat blood pressure, and then consider titrated dose of 5 mg/mL
labetalol.
A
B
- Answer: E
Postoperative hypertension can occur due to coughing on emergence of anaesthesia, postoperative
pain, bladder distension, or anxiety or due to a residual eff ect of muscle relaxants. It is also
important to remember some patients will be confused and disorientated after anaesthesia and this
may worsen blood pressure values. This highlights the importance of the recovery room being a
suitably calm environment, with staff trained to anticipate and treat these problems.
The important steps would be to reassess the patient and continue monitoring, which should
include ECG, blood pressure, and S pO 2 . It is important to treat the reversible causes: fi rst pain and
urine retention followed by the treatment of continuing hypertension. Although there is no cut-off
value for treatment, a persistently elevated systolic blood pressure reaching 200 mmHg would
suggest treatment is appropriate.
This patient is severely hypertensive postoperatively, which may be due to multiple causes. Exclude
pain, urinary retention, hypoxia, and anxiety. Repeat the blood pressure measurement if the
pressure is persistently high, then consider labetalol 5 mg/mL, which should be titrated to normal
blood pressure for that patient. Keep the patient in recovery
10
Q
- A 59-year-old male is scheduled for left parotidectomy. He has a past
medical history of CABG, after which he had an automatic implantable
cardioverter-defi brillator (AICD) sited due to recurrent episodes of VT.
He has a LVEF of 35 % , with trivial mitral regurgitation and cardiomegaly
on chest X-ray. With regards to AICD, what would be your fi rst step
before induction of anaesthesia?
A. Check for preoperative electrolyte level.
B. Ensure only bipolar diathermy is used and prepare the emergency drugs.
C. Invasive monitoring with transoesophageal echocardiography.
D. Arrange for magnet along with the resuscitation trolley.
E. Programmer available to deactivate antitachycardia and defi brillation response and have external pads placed on chest.
A
E
- Answer: E
An automatic implantable cardiac defi brillator is a (AICD) system that consists of a pulse
generator and leads, and is used for detection and therapy of tachyarrhythmias. It may provide
antitachycardia, antibradycardia pacing, synchronized or nonsynchronized shocks, telemetry, and
diagnostic storage. Many devices use adaptive rate pacing to modify the pacing rate for changing
metabolic needs. The ICD batteries contain up to 20 000 J of energy. Cardioversion with energy
exceeding 2 J results in skeletal and diaphragmatic muscle depolarization and is painful to the
conscious patient. High energy discharges of 10–40 J, delivered asynchronously, are used to treat
ventricular fi brillation (VF). AICD terminates VF successfully in almost 98 % of cases.
For any patient with a pacemaker, it is essential to identify the device so that its response to
electrocautery is known. In particular, the backup mode should be determined. If extensive
close-proximity electrocautery is required and loss of AV synchrony may compromise the patient
haemodynamically (for example, heart failure patients), then it is advisable that a telemetric
programmer and an experienced operator is present during surgery.
During surgery, bipolar electrocautery should be used whenever possible; if not, then the anode
plate should be positioned as far away from the pacemaker generator as possible. Similarly, the
cathode should be kept as far away from the device as possible. the lowest possible amplitude should
be used and the operator should apply electrocautery in short bursts rather than continuously.
Careful monitoring of the pulse, pulse oximetry, and arterial pressure is essential during
electrocautery, as ECG monitoring can also be aff ected by interference. For the patient with an
implanted defi brillator, facilities for external defi brillation should be available immediately after the
device is disabled. If possible, remote pads should be used and applied in a suitable orientation.
11
Q
- A 28-year-old primigravida is admitted to the labour ward at 32 weeks’
gestation with a mild frontal headache and increasing swelling of her
ankles. Her blood pressure is 170/120 mmHg, urine dip stick testing
shows 3 + protein, and there is pitting oedema to the mid-calf.
The most common maternal complication of severe pre-eclampsia is:
A. Acute renal failure.
B. Disseminated coagulopathy or HELLP syndrome.
C. Eclampsia.
D. Liver failure or haemorrhage.
E. Pulmonary oedema or aspiration.
A
E
- Answer: B
Pre-eclampsia complicates up to 8 % of pregnancies in the developed world. Pre-eclampsia is
associated with widespread endothelial dysfunction, leading to placental ischaemia and multi-organ
dysfunction. Maternal complications of severe pre-eclampsia include:
DIC or HELLP syndrome (10–20 % )
pulmonary oedema or aspiration (2–5 % )
abruptio placentae (1–4 % )
acute renal failure (1–5 % )
eclampsia (1 % ), liver failure or haemorrhage (1 % ), and rarely stroke and death.
There is an association with long-term cardiovascular disease.
12
Q
- A 77-year-old male is admitted to intensive care with an intrabdominal
bleed. He has chronic atrial fi brillation, for which he is on longterm
warfarin. On admission his INR is 3.5. Which of the following
management is most appropriate in this situation?
A. Administration of 50 mL/kg fresh frozen plasma.
B. Administration of intravenous vitamin K 2 mg.
C. Administration of recombinant factor VIIa.
D. Replacement of clotting factors II, VII, IX, and X.
E. Administration of protamine.
A
D
- Answer: D
Warfarin is the oral anticoagulant of choice for atrial fi brillation. Nicoumalone and phenindione are
licensed in the UK but are potentially more toxic than warfarin and are seldom used. All currently
available oral anticoagulants act by antagonizing the eff ect of vitamin K by preventing the reduction
of oxidized vitamin K required for carboxylation of clotting factor precursors, resulting in reduced
hepatic production of active coagulation factors II, VII, IX, and X, and hence in prolongation of the
prothrombin time and INR. This usually takes 48–72 h to develop fully.
The management of warfarin overdose, following initial resuscitation and stabilization includes
administration of prothrombin complex concentrate (PCC), which contains the necessary
factors but is expensive. Therefore 15 mL/kg of fresh frozen plasma (FFP) is often administered,
but presents a risk of anaphylaxis and transmission of blood-borne pathogens, and is the most
common cause of transfusion-related acute lung injury (TRALI). Recombinant factor VIIa (rFVIIa) is
increasingly being used in uncontrollable haemorrhage. The Israeli Multidisciplinary Task Force have
recommended its use where the platelet count is 50–109/L, pH > 7.2, and fi brinogen > 0.5; it has
been shown to work in oral anticoagulant overdose.
13
Q
- Regarding the elimination half-life of a drug, which of the following
statements is correct?
A. It is half the time taken to totally eliminate the drug from the body.
B. It is the time taken for the initial plasma concentration to fall by half.
C. It is used to calculate the maintenance infusion rate of a drug.
D. It is used for dosing intervals.
E. It is always a constant in an individual.
A
B
- Answer: D
The elimination half-life is the time taken for the plasma concentration to drop by half during the
elimination phase. The time taken for the initial plasma concentration to fall to half its value is also
called as distribution half-life. The removal of a drug from the plasma is known as clearance and the
distribution of the drug in the various body tissues is known as the volume of distribution. Both of
these pharmacokinetic parameters are important in determining the half-life of a drug. For most
of the drugs, initial plasma concentration reduces by the process of distribution or drug uptake by
tissues. To maintain steady plasma concentrations, the maintenance infusion rate is determined by
the amount of drug that has been eliminated from the body.
14
Q
- On your elective list for general paediatric theatre there is a 5-year-old
boy with muscular dystrophy for insertion of PEG. He suff ers from
recurrent chest infections and the paediatrician thinks he probably
silently aspirates overnight. His chest is clear and his oxygen saturation
overnight was 97 % . The most important reason for monitoring core
temperature in the perioperative period is:
A. Children with this condition are at risk of hypothermia.
B. Muscular dystrophies are associated with malignant hyperthermia.
C. If hypothermia develops the patient can manifest rhabdomyolysis.
D. If the temperature in recovery is less than 36 ° C the child has to stay longer in recovery.
E. Changes in core temperature can aff ect neuromuscular block.
A
C
- Answer: B
Temperature measurement and control is extremely important. Patients with neuromuscular
disorders can be vulnerable to both hypo- and hyperthermia. A high index of suspicion should exist
for patients with muscular dystrophies and myotonias for concomitant malignant hyperthermia.
Unexplained tachycardia with an increase in end-tidal carbon dioxide concentration should alert
the anaesthetist to a potential hyperthermic complication, which should be treated aggressively.
Hyperthermia may occur due to increased muscle activity seen in myotonias, iatrogenic causes, or
malignant hyperthermia.
15
Q
- A 20-year-old builder fractured his radius 2 months ago and was in a
synthetic cast for 6 weeks. Despite his fracture healing and his cast being
removed, over the last 2 weeks he has been experiencing continuous
pain, described as burning, shooting, and aching. He has noticed that the
arm fl uctuates in colour and temperature, and his arm is weaker than
when his cast was removed. What is the possible diagnosis?
A. Neuropathic pain.
B. Complex regional pain syndrome I.
C. Complex regional pain syndrome II.
D. Phantom limb pain.
E. Compartment syndrome
A
C
- Answer: B
In complex regional pain syndrome I (CRPS I) the symptoms are preceded by tissue injury, most
commonly limb trauma (absence of nerve injury). Diagnostic criteria for CRPS fall into four
categories: sensory, vasomotor, sudomotor, and motor/trophic changes.
The exact pathogenesis of CRPS is unclear. Theories can be divided into peripheral and central
mechanisms, with central nervous system abnormality predominating.
Diagnostic criteria
The International Association for the Study of Pain proposed formal diagnostic criteria in 1995.
The diagnostic criteria for CRPS I are as follows.
Following an initiating noxious event:
spontaneous pain or allodynia/hyperalgesia occurs beyond the territory of a single peripheral
nerve and is disproportionate to the inciting event
there is or has been evidence of oedema, skin blood fl ow abnormality, or abnormal
sudomotor activity in the region of the pain since the inciting event.
The diagnosis is excluded by the existence of conditions that would otherwise account for the
degree of pain and dysfunction
