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Question 1
Incorrect
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A 240 volt alternating current (AC) socket from a wall is used to charge a direct current (DC) cardiac defibrillator. Name the electrical component that converts AC to DC.
Your Answer: Step-up transformer
Correct Answer: Rectifier
Explanation:There are two types of defibrillators
AC defibrillator
DC defibrillatorAC defibrillator,
consists of a step-up transformer with primary and secondary winding and two switches. Since secondary coil consists of more turns of wire than the primary coil, it induces larger voltage. A voltage value ranging between 250V to 750V is applied for AC external defibrillator. And used to enable the charging of a capacitor.DC defibrillator,
consists of auto transformer T1 that acts as primary of the high voltage transformer T2. Is an iron core that transfers energy between 2 circuits by electromagnetic induction. Transformers are used to isolate circuits, change impedance and alter voltage output. transformers do not convert AC to DC.Diode rectifier composed of 4 diodes made of semiconductor material allows current to flow only in one direction. Alternating current (AC) passing through these diodes produces direct current (DC). Capacitor stores the charge in the form of an electrostatic field.
Capacitor is used to convert the rectified AC voltage to produce DC voltage but capacitors do not directly convert AC to DC.
Inductor induces a counter electromotive force(emf) that reduces the capacitor discharge value.
In step-down transformer primary coils has more turns of wire than secondary coil, so induced voltage is smaller in the secondary coil.
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This question is part of the following fields:
- Anaesthesia Related Apparatus
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Question 2
Correct
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You have always been curious about the effects of statins. While going through a study, something ticks you off and makes you think that they are way more common then the data suggests and are mostly under reported. In search of some concrete evidence, you decide to conduct a study of your own. While doing research, you come across a recent study that highlights the long term effects of statins. Which of the following types of study could that have been?
Your Answer: Clinical trial, Phase 4
Explanation:In general practice, majority of phase 3 trials and some of the trials conducted in phase 2 are randomized. Because phase 4 trials require a huge sample size, they are not randomized as much. The primal reason behind conducting phase 3 trials is to test the efficiency and safety in a significant sample population. At this point it is assumed that the drug is effective up to a certain extent.
During a case-control study, subjects that exhibit outcomes of interest are compared with those who don’t show the expected outcome. The extent of exposure to a particular risk factor is then matched between cases and controls. If the exposure among cases surpasses controls, it becomes a risk factor for the outcome that is being studied.
Pilot studies are conducted on a lower and much smaller level, to assess if a randomized controlled trial of the crucial components of a study will be plausible.
Phase 4 trials are the ones that are conducted after its established that the drug is effective and is approved by the regulating authority for use. These trials are concerned with the side effects and potential risks associated with the long term usage of the drug.
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This question is part of the following fields:
- Statistical Methods
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Question 3
Correct
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A laser is a device that stimulates atoms or molecules to emit light at particular wavelengths and amplifies that light, typically producing a very narrow beam of radiation. This can be of visible, infrared, or ultraviolet wavelengths. They have been widely utilized in theatre environment. Which of the following safety measures is most likely to reduce chances of eye injury to the theatre personnel?
Your Answer: Wearing laser protective goggles
Explanation:Eye damage is the most common potential hazard associated with laser energy. Everyone in the laser treatment room has the risk of eye exposure when working with a Class 3b or Class 4 healthcare laser system, and damage to various structures in the eye depending on wavelength of the laser if they are unprotected.
Red and near-infrared light (400-1400 nm) has very high penetration power. The light causes painless burns on the retina after it is absorbed by melanin in the pigment epithelium just behind the photoreceptors.
Infrared radiation (IR), or infrared light (>1060 nm), is a type of radiant energy that’s invisible to human eyes and hence won’t elicit the protective blink.
Ultraviolet light (<400 nm) is also a form of electromagnetic radiation which is can penetrate the cornea and be absorbed by the iris or the pupil and cause burn injuries or cataract occur due to irreversible photochemical retinal damage.
Safety eyewear is the best method of providing eye protection and are designed to absorb light specific to the laser being used. Laser protective eyewear (LPE) includes glasses or goggles of proper optical density (OD). The lenses should not be glass or plastic. The LPE should withstand direct and diffuse scattered laser beams.
The laser protection supervisor (LPS) or LSO is an individual who is responsible for any clinical area in which lasers are used. They are expected to have a certain level of equipment and determine what control measures are appropriate, for each individual system, but their presence does not guarantee the chances of having an eye injury.
Class 1 lasers are generally safe under every conceivable condition and is not likely to cause any eye damage. Class 3b or Class 4 medical laser systems are utilized in healthcare which have their own safety precautions.
Polarized spectacles can make your eyes more comfortable by eliminated glare, however, they will not be able to offer any protection against wavelengths at which laser act.
Using short bursts to reduce energy is also not correct as it would still be harmful to eye. -
This question is part of the following fields:
- Anaesthesia Related Apparatus
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Question 4
Correct
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The main site of storage of thyroid hormones in the thyroid gland is?
Your Answer: Thyroglobulin
Explanation:The follicle is the functional unit of the thyroid gland. The follicular cells surround the follicle which is filled with colloid. Suspended within the colloid is the is a pro-hormone complex thyroglobulin.
The synthesis and storage of thyroid hormones is done by follicular cells and the thyroglobulin within the colloid.
Iodide ions (Iˆ’) are actively transported against a concentration gradient into the follicular cell under the influence of thyroid stimulating hormone (TSH). It then undergoes oxidation to active iodine catalysed by thyroid peroxidase (TPO). The synthesis of thyroglobulin is in the follicular cells and it contains up to 140 tyrosine residues. The tyrosine residues of thyroglobulin and active iodine are merged to form mono- and di-iodotyrosines (MIT and DIT). The iodinated thyroglobulin is then taken up into the colloid where it is stored and dimerised. Two DIT molecules are joined to produce thyroxine (T4) while one MIT and one DIT molecule are joined to produce tri-iodotyrosine (T3) by a process catalysed by TPO.
Thyroglobulin droplets are taken up as vesicles into follicular cells by pinocytosis. This process is stimulated by TSH. When these vesicles fuse with lysosomes, hydrolysis of the thyroglobulin molecules and subsequent release of T4 and T3 into the circulation occurs.
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This question is part of the following fields:
- Pathophysiology
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Question 5
Correct
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A controlled retrospective study's level of evidence is?
Your Answer: Level 3
Explanation:Level 1 – High-quality randomised controlled trial with statistically significant difference or no statistically significant difference but narrow confidence intervals (prospective controlled)
Level 2 – Prospective comparative study (prospective uncontrolled)
Level 3 – Case-control study, retrospective comparative study (retrospective controlled)
Level 4 – Case series (retrospective uncontrolled)
Level 5 – Expert opinion.
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This question is part of the following fields:
- Statistical Methods
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Question 6
Correct
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Your manager asks you to inform patients that are suffering from a chronic pain about a trial that is going to be conducted in order to determine the efficacy of a novel analgesic. What phase is the trial currently in?
Your Answer: Phase 2
Explanation:Phase 0 trials assist the scientists in studying the behaviour of drugs in humans by micro dosing patients. They are used to speed up the developmental process. They have no measurable therapeutic effect and efficiency.
Phase 1 is associated with assessing whether a drug is safe to use or not. The process is extensive and can take up to several months. It also involves healthy participants (less than 100) that are paid to take part in the study. The side effects upon increasing dosage are also addressed by the study. The effects the drug has on humans including how its absorbed, metabolized and excreted are studied. Approximately 70% of the drugs pass this phase.
Phase 2 trials involve patients that are suffering from the disease under study and are associated with determining the efficiency and the optimum dosage of the drug.
Phase 3 also assesses the efficacy but at a higher scale with larger population sample.
Phase 4 trials are involved with the long term effects and side effects of the drug.
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This question is part of the following fields:
- Statistical Methods
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Question 7
Correct
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Of the stated laws, which is correct?
Your Answer: Boyle's law states that at constant temperature the volume of a given mass of gas varies inversely with absolute pressure.
Explanation:Boyle’s law is correctly stated as it states that the volume of a gas of known mass is inversely proportional with absolute pressure, at a constant temperature.
Beer’s law states that radiation absorption by a solution of known thickness and concentration is identical to that of a solution of double thickness and half concentration.
Bougner’s (or Lambert’s) law states that every layer with the same thickness will absorb the same amount of radiation as it passes through.
Graham’s law states that the diffusion rate of a gas is inversely related to the square root of its molecular weight.
Raoult’s law states that the reduction of a solvent’s vapour pressure is directly proportional to the solute’s molar concentration.
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This question is part of the following fields:
- Statistical Methods
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Question 8
Correct
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A 28-year-old man is admitted to the critical care unit. He has been diagnosed with adult respiratory distress syndrome and is being ventilated. His haemodynamic condition is improved using a pulmonary artery flotation. His readings are listed below: Haemoglobin concentration: 10 g/dL, Mixed venous oxygen saturation: 70%, Mixed venous oxygen tensions (PvO2): 50 mmHg. Estimate his mixed venous oxygen content (mL/100mL).
Your Answer: 9.5
Explanation:Mixed venous oxygen content (CvO2) is the oxygen concentration in 100mL of mixed venous blood taken from the pulmonary artery. It is usually 12-17 mL/dL (70-75%). It is represented mathematically as:
CvO2 = (1.34 x Hgb x SvO2 x 0.01) + (0.003 x PvO2)
Where,
1.34 = Huffner’s constant
Hgb = Haemoglobin level (g/dL)
SvO2 = % oxyhaemoglobin saturation of mixed venous blood
PvO2 = 0.0225 = mL of O2 dissolved per 100mL plasma per kPa, or 0.003 mL per mmHgTherefore,
CvO2 = (1.34 x 10 x 70 x 0.01) + (0.003 x 50)
CvO2 = 9.38 + 0.15 = 9.53 mL/100mL.
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This question is part of the following fields:
- Clinical Measurement
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Question 9
Correct
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A 50-year-old female, known case of diabetes, has come in for a check-up at the diabetic foot clinic. The pulses of her feet are examined. The posterior tibial pulse and dorsalis pedis pulses are palpated. Which of the following artery continues as the dorsalis pedis artery?
Your Answer: Anterior tibial artery
Explanation:At the ankle joint, midway between the malleoli, the anterior tibial artery changes names, becoming the dorsalis pedis artery (dorsal artery of the foot).
The dorsalis pedis artery is palpated against the underlying tarsals, immediately lateral to the tendon of extensor hallucis longus, from the midpoint between the malleoli to the proximal end of the first intermetatarsal space.
The popliteal artery forms the anterior tibial artery.
The tibioperoneal trunk is a branch of the popliteal artery.
The peroneal artery (also known as the fibular artery) supplies the lateral compartment of the leg.
The external iliac artery is formed from the common iliac artery at the level of the pelvis. -
This question is part of the following fields:
- Anatomy
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Question 10
Incorrect
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Regarding the carbon dioxide monitoring, which of the following statements is correct?
Your Answer: Is based on the principle of paramagnetism
Correct Answer: Carbon dioxide absorbs infrared radiation at 4.28 µm
Explanation:Carbon dioxide (CO2), is a carbonic gas made up of two dissimilar atoms, namely one carbon atom and two oxygen atoms. Capnography is a technique used to measure carbon dioxide during a respiratory cycle, and it consists in calculating the concentration of the partial pressure of CO2, through the absorption of the infrared light, namely that CO2 absorbs infrared radiation at a wavelength of 4.28 µm.
End-tidal CO2 (ETCO2), referring to the level of the carbon dioxide released at the end of an exhaled breath, is required to be continuously monitored, especially in ventilated patients, as it is a sensitive and a non invasive technique that provides immediate information about ventilation, circulation, and metabolism functions. ETCO2 is normally lower than the arterial partial pressure and varies between 0.6 and 0.7 kPa.
There are two methods used to measure carbon dioxide. The sidestream capnometer method samples gases at a set flow rate (150-200 mL/min) from a sampling area through small diameter tubing, and the mainstream analyser method that uses a direct measurement of the patient exhaled CO2 by a relatively large and heavy sensors. Sidestram method allows the analysis of multiple gases and anaesthetic vapours comparing to the mainstream method that does not allow the measurement of other gases.
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This question is part of the following fields:
- Anaesthesia Related Apparatus
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Question 11
Incorrect
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A patient under brachial plexus regional block complains of pain under the cuff after the torniquet is inflated. Which nerve was most probably 'missed' by the local anaesthetic?
Your Answer: Axillary nerve
Correct Answer: Intercostobrachial nerve
Explanation:The area described in the question is supplied by the intercostobrachial nerve, which provides sensory innervation to the portions of the axilla, tail of the breast, lateral chest wall and medial side of the arm.
It is a common for it to be ‘missed’ during administration of local anaesthesia because of its very superficial anatomic course. It may be anesthetized by giving an analgesia from the upper border of the biceps at the anterior axillary fold, to the margin of the triceps by the axillary floor.
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This question is part of the following fields:
- Pathophysiology
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Question 12
Incorrect
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Which of the following structures does the vertebral artery NOT traverse?
Your Answer: Vertebral canal
Correct Answer: Intervertebral foramen
Explanation:The vertebral artery originates from the subclavian artery and ascends through the neck in the transverse foramen of the C1-C6 vertebrae. C2 vertebra is called the axis vertebra. A part of the vertebral artery lies in a groove on the upper surface of the atlas’s (C1) posterior arch. It enters the vertebral canal below the inferior border of the posterior atlantooccipital membrane. The vertebral arteries then enter the skull via the foramen magnum.
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This question is part of the following fields:
- Anatomy
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Question 13
Correct
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The typical fluid compartments in a normal 70kg male are:
Your Answer: intracellular>extracellular
Explanation:Body fluid compartments in a 70kg male:
Total volume=42L (60% body weight)
Intracellular fluid compartment (ICF) =28L
Extracellular fluid compartment (ECF) = 14LECF comprises:
Intravascular fluid (plasma) = 3L
Extravascular fluid = 11LExtravascular fluids comprises:
Interstitial fluid = 10.5L
Transcellular fluid = 0.5L -
This question is part of the following fields:
- Physiology
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Question 14
Correct
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A 72-year-old long-term rheumatoid arthritis patient is having shoulder replacement surgery. He has chronic obstructive pulmonary disease with a limited exercise tolerance. He agrees to the procedure being performed with an interscalene brachial plexus block. Which of the following neurological complications puts this patient at the greatest risk?
Your Answer: Phrenic nerve block
Explanation:An ipsilateral phrenic nerve block will result from a successful interscalene block (ISB).
The phrenic nerve is the diaphragm’s sole motor supply, and ipsilateral hemidiaphragmatic paresis affects up to 100% of patients who receive ISBs. Phrenic nerve palsy is usually well tolerated and goes unnoticed by healthy people. However, forced vital capacity decreases by approximately 25%, which can produce ventilatory compromise in patients with limited pulmonary reserve, requiring assisted ventilation.
Vocal cord palsy occurs when the recurrent laryngeal nerve is inadvertently blocked, causing hoarseness and possibly acute respiratory insufficiency. Unless bilateral laryngeal nerve palsy occurs, which can cause severe laryngeal obstruction, this complication is usually of little consequence.
ISB can also cause cranial nerve X and XII palsy (Tapia’s syndrome). One-sided cord paralysis, aphonia, and the patient’s tongue deviating toward the block’s side are all symptoms.
When a local anaesthetic spreads to the stellate ganglion and its cervical sympathetic nerves, Horner’s syndrome can develop. Ptosis of the eyelid, miosis, and anhidrosis of the face are all symptoms. Horner’s syndrome, on the other hand, may not indicate that the brachial plexus is sufficiently blocked.
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This question is part of the following fields:
- Pathophysiology
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Question 15
Incorrect
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With regards to devices for temperature management, all of these are used EXCEPT:
Your Answer: Thermocouple works using the potential difference which is created when dissimilar metals are joined
Correct Answer: Thermistors use the resistance of a semiconductor bead which increases exponentially as the temperature increases
Explanation:There are different types of temperature measurement. These include:
Thermistor – this is a type of semiconductor, meaning they have greater resistance than conducting materials, but lower resistance than insulating materials. There are small beads of semiconductor material (e.g. metal oxide) which are incorporated into a Wheatstone bridge circuit. As the temperature increases, the resistance of the bead decreases exponentially
Thermocouple – Two different metals make up a thermocouple. Generally, in the form of two wires twisted, welded, or crimped together. Temperature is sensed by measuring the voltage. A potential difference is created that is proportional to the temperature at the junction (Seebeck effect)
Platinum resistance thermometers (PTR) – uses platinum for determining the temperature. The principle used is that the resistance of platinum changes with the change of temperature. The thermometer measures the temperature over the range of 200°C to1200°C. Resistance in metals show a linear increase with temperature
Tympanic thermometers – uses infrared radiation which is emitted by all living beings. It analyses the intensity and wavelength and then transduces the heat energy into a measurable electrical output
Gauge/dial thermometers – Uses coils of different metals with different co-efficient of expansion. These either tighten or relax with changes in temperature, moving a lever on a calibrated dial.
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This question is part of the following fields:
- Clinical Measurement
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Question 16
Correct
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All of the following statements about pH electrode are incorrect except:
Your Answer: A semi-permeable membrane reduces protein contamination
Explanation:Pulse oximeters combine the principles of oximetry and plethysmography to noninvasively measure oxygen saturation in arterial blood. A sensor containing two or three light emitting diodes and a photodiode is placed across a perfused body part, commonly a finger, to be transilluminated. Oximetry depends on oxyhaemoglobin and deoxyhaemoglobin, and their ability to absorb the beams of light produced by the light emitting diodes: red light at 660 nm and infrared light at 960 nm.
The isosbestic point is the point wherein two different substances absorb light to the same extent. For oxyhaemoglobin and deoxyhaemoglobin, the points are at 590 nm and 805 nm. These are considered reference points where light absorption is independent of the degree of saturation.
Non-constant absorption of light is often due to the presence of an arterial pulsation, whilst constant absorption of light is seen in non-pulsatile tissues.
Most pulse oximeters are inaccurate at low SpO2, but is accurate at +/- 2% within the range of 70% to 100% SpO2. All pulse oximeters demonstrate a delay in between changes in SaO2 and SpO2, and display average readings every 10 to 20 seconds, hence they are unable to detect acute desaturation episodes.
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This question is part of the following fields:
- Anaesthesia Related Apparatus
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Question 17
Incorrect
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An otherwise fit 7-year-old boy for an elective tonsillectomy is seen holding a bottle of sugared orange squash at anaesthetic assessment . He appears to have consumed 120 mL of the bottle's contents. What is the minimal safe fasting time prior to proceeding with a general anaesthetic in this patient?
Your Answer: 2 hours
Correct Answer: 1 hour
Explanation:The incidence of Pulmonary aspiration in children is about 0.07%€�0.1%.
The Association of Paediatric Anaesthetists of Great Britain and Ireland, The European Society of Paediatric Anaesthetists and L’Association Des Anesthésistes€�Réanimateurs Pédiatriques d’Expression Française produced a consensus statement in April 2018 with revised starvation times in children prior to elective surgery.
The preoperative fasting for elective procedures for children aged 0-16 years of age are:
Solid food/formula milk – 6 hours
Breast milk – 4 hours
Clear fluid – 1 hourA liberal clear fluid fasting regime does not affect the incidence of pulmonary aspiration in children as long as there are no specific contraindications (e.g. gastro-oesophageal reflux, cerebral palsy). Prolonged periods of fasting in children are associated with increase thirst and irritability and can lead to other adverse physiological and metabolic effects.
Clear fluids are defined as water, clear (nonopaque) fruit juice or squash/cordial, ready diluted drinks, and non-fizzy sports drinks.
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This question is part of the following fields:
- Pathophysiology
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Question 18
Incorrect
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A meta analysis takes into consideration five studies each of which is aimed at finding out the relation between a novel drug and upper gastro intestinal bleeding. The relative risk of getting an upper gastrointestinal bleed matched to a control population is recorded by each study. Which among the following studies provides the most compelling evidence that the bleeding is not caused by the new drug?
Your Answer: Fry et al
Correct Answer: Atkinson et al
Explanation:The research study conducted by Atkinson et al makes the most compelling case for the drug as it indicates the relative risk levels to be lower than 1. Also the study employs large square and a narrow confidence interval that are an indicative of a well performed study.
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This question is part of the following fields:
- Statistical Methods
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Question 19
Incorrect
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A balanced general anaesthetic including a muscle relaxant is administered at induction. It is observed that the train-of-four count is two after two hours, with no further doses of the muscle relaxant. What is most likely reason for this?
Your Answer: Rocuronium in renal failure
Correct Answer: Mivacurium with plasma cholinesterase deficiency
Explanation:Mivacurium is metabolised primarily by plasma cholinesterase at an In vitro rate of about 70% that of succinylcholine. Mivacurium is contraindicated in patients with genetic and acquired plasma cholinesterase deficiencies.
The clearance of atracurium is by Hoffman degradation and ester hydrolysis in the plasma and is independent of both hepatic and renal function.
Rocuronium is eliminated primarily by the liver after metabolises to a less active metabolite, 17-desacetyl-rocuronium. Its duration of action is not affected much by renal impairment.
Vecuronium undergoes hepatic metabolism into 3-desacetyl-vecuronium which has 50-80% the activity of the parent drug. It undergoes biliary (40%) and renal excretion (30%). The aminoglycoside antibiotics possess additional neuromuscular blocking activity. The potency of gentamicin > streptomycin > amikacin. Calcium can be used to reverse the muscle weakness produced by gentamicin but not neostigmine. When vecuronium and gentamycin are given together the effect on neuromuscular blockade is synergistic.
Significant residual neuromuscular block 2 hours after the administration of these drugs is unlikely In this scenario.
Any recovery from neuromuscular blockade with suxamethonium in a patient with deficiency of plasma cholinesterase demonstrate four twitches on a train of four count.
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This question is part of the following fields:
- Pharmacology
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Question 20
Incorrect
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A cannula is inserted into the cephalic vein of a 30-year-old man. Which of the following structures does the cephalic vein pass through?
Your Answer: Triceps
Correct Answer: Clavipectoral fascia
Explanation:The cephalic vein is one of the primary superficial veins of the upper limb. The superficial group of upper limb veins begin as an irregular dorsal arch on the back of the hand.
The cephalic vein originates in the anatomical snuffbox from the radial side of the arch and travels laterally up, within the superficial fascia to join the basilic vein via the median cubital vein at the elbow.
Near the shoulder, it passes between the deltoid and pectoralis major muscles. It pierces the coracoid membrane (continuation of the clavipectoral fascia) to terminate in the axillary vein’s first part.
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This question is part of the following fields:
- Anatomy
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Question 21
Correct
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International colour coding is used on medical gas cylinders. Other characteristics also play a role in determining the gas's identity within a cylinder. Which of the following options best describes a cylinder containing analgesics for obstetrics?
Your Answer: Blue body, blue/white shoulder, full cylinder; 13700 KPa, gas mixture, requires a dual stage pressure regulator
Explanation:The body of the Entonox cylinder is usually blue (occasionally white), with blue and white shoulders. Entonox contains a 50:50 mixture of oxygen and nitrous oxide, with a full cylinder pressure of 13700 KPa (137 bar). The cylinder is equipped with a two-stage pressure regulator for safe operation.
The cylinder body and shoulder of nitrous oxide are (French) blue.
In today’s anaesthetic workstations, carbon dioxide cylinders are no longer used.
The body of an oxygen cylinder is black, with a white shoulder.
The white Heliox (21 percent oxygen and 79 percent helium) cylinder has a brown and white shoulder. The administration of this gas mixture, which is less dense than air, is used to reduce turbulence (stridor) of inspiratory flow in patients with upper airway obstruction.
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This question is part of the following fields:
- Anaesthesia Related Apparatus
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Question 22
Correct
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Drug X, a new intravenous induction drug, is being administered as a bolus at regular time intervals, and the following data were observed: Time following injection (hours) vs Plasma concentration of drug X (mcg/mL) 2 / 400 6 / 100 10 / 25 14 / 6.25 Which of the following values estimate the plasma half-life (T½) of drug X?
Your Answer: 2 hours
Explanation:Half life (T½) is the time required to change the amount of drug in the body by one-half (or 50%) during elimination. The time course of a drug in the body will depend on both the volume of distribution and the clearance.
Extrapolating the values from the plasma concentration vs time:
Plasma concentration at 0 hours = 800 mcg/mL
Plasma concentration at 2 hours = 400 mcg/mL
Plasma concentration at 4 hours = 200 mcg/mL
Plasma concentration at 6 hours = 100 mcg/mL
Plasma concentration at 8 hours = 50 mcg/mL
Plasma concentration at 10 hours = 25 mcg/mL
Plasma concentration at 12 hours = 12.5 mcg/mL
Plasma concentration at 14 hours = 6.25 mcg/mL -
This question is part of the following fields:
- Statistical Methods
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Question 23
Correct
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Which one of the following causes vasoconstriction?
Your Answer: Angiotensin II
Explanation:Prostacyclin is a strong vasodilator. It is administered as an intravenous infusion for critical ischemia. Commercially, it is available as sodium epoprodtenol.
Atrial Natriuretic peptide (ANP) hormone secreted from the atria, kidney, and neural tissues. It primarily acts on renal vessel to maintain normal blood pressure and reduce plasma volume by: increasing the renal excretion of salt and water, glomerular filtration rate, vasodilation, and by increasing the vascular permeability. It also inhibits the release of renin and aldosterone.
Indoramin is an alpha-adrenoceptor blocking agent. which act selectively on post-synaptic-alpha adrenoreceptor, leading to decease in peripheral resistance.
Angiotensin II is a vasoconstrictor, causing high sodium retention. It also increases the secretion of antidiuretic hormone (ADH) and aldosterone level.
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This question is part of the following fields:
- Pharmacology
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Question 24
Incorrect
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Useful diagnostic information can be obtained from measuring the osmolality of biological fluids. Of the following physical principles, which is the most accurate and reliable method of measuring osmolality?
Your Answer: Change in osmotic pressure
Correct Answer: Depression of freezing point
Explanation:Colligative properties are properties of solutions that depend on the number of dissolved particles in solution. They do not depend on the identities of the solutes.
All of the above have colligative properties with the exception of depression of melting point.
The osmolality from the concentration of a substance in a solution is measured by an osmometer. The freezing point of a solution can determines concentration of a solution and this can be measured by using a freezing point osmometer. This is applicable as depression of freezing point is directly correlated to concentration.
Vapour pressure osmometers, which measure vapour pressure, may miss certain volatiles such as CO2, ammonia and alcohol that are in the solution
The use of a freezing point osmometer provides the most accurate and reliable results for the majority of applications.
Colligative properties does not include melting point depression . Mixtures of substances in which the liquid phase components are insoluble, display a melting point depression and a melting range or interval instead of a fixed melting point.
The magnitude of the melting point depression depends on the mixture composition.
The melting point depression is used to determine the purity and identity of compounds. EMLA (eutectic mixture of local anaesthetics) cream is a mixture of lidocaine and prilocaine and is used as a topical local anaesthetic. The melting point of the combined drugs is lower than that individually and is below room temperature (18°C).
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This question is part of the following fields:
- Physiology
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Question 25
Correct
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All of the following statements about that parasympathetic nervous system (PNS) are true except:
Your Answer: The PNS has nicotinic receptors throughout the system
Explanation:With regards to the autonomic nervous system (ANS)
1. It is not under voluntary control
2. It uses reflex pathways and different to the somatic nervous system.
3. The hypothalamus is the central point of integration of the ANS. However, the gut can coordinate some secretions and information from the baroreceptors which are processed in the medulla.With regards to the central nervous system (CNS)
1. There are myelinated preganglionic fibres which lead to the
ganglion where the nerve cell bodies of the non-myelinated post ganglionic nerves are organised.
2. From the ganglion, the post ganglionic nerves then lead on to the innervated organ.Most organs are under control of both systems although one system normally predominates.
The nerves of the sympathetic nervous system (SNS) originate from the lateral horns of the spinal cord, pass into the anterior primary rami and then pass via the white rami communicates into the ganglia from T1-L2.
There are short pre-ganglionic and long post ganglionic fibres.
Pre-ganglionic synapses use acetylcholine (ACh) as a neurotransmitter on nicotinic receptors.
Post ganglionic synapses uses adrenoceptors with norepinephrine / epinephrine as the neurotransmitter.
However, in sweat glands, piloerector muscles and few blood vessels, ACh is still used as a neurotransmitter with nicotinic receptors.The ganglia form the sympathetic trunk – this is a collection of nerves that begin at the base of the skull and travel 2-3 cm lateral to the vertebrae, extending to the coccyx.
There are cervical, thoracic, lumbar and sacral ganglia and visceral sympathetic innervation is by cardiac, coeliac and hypogastric plexi.
Juxta glomerular apparatus, piloerector muscles and adipose tissue are all organs under sole sympathetic control.
The PNS has a craniosacral outflow. It causes reduced arousal and cardiovascular stimulation and increases visceral activity.
The cranial outflow consists of
1. The oculomotor nerve (CN III) to the eye via the ciliary ganglion,
2. Facial nerve (CN VII) to the submandibular, sublingual and lacrimal glands via the pterygopalatine and submandibular ganglions
3. Glossopharyngeal (CN IX) to lungs, larynx and tracheobronchial tree via otic ganglion
4. The vagus nerve (CN X), the largest contributor and carries ¾ of fibres covering innervation of the heart, lungs, larynx, tracheobronchial tree parotid gland and proximal gut to the splenic flexure, liver and pancreasThe sacral outflow (S2 to S4) innervates the bladder, distal gut and genitalia.
The PNS has long preganglionic and short post ganglionic fibres.
Preganglionic synapses, like in the SNS, use ACh as the neuro transmitter with nicotinic receptors.
Post ganglionic synapses also use ACh as the neurotransmitter but have muscarinic receptors.Different types of these muscarinic receptors are present in different organs:
There are:
M1 = pupillary constriction, gastric acid secretion stimulation
M2 = inhibition of cardiac stimulation
M3 = visceral vasodilation, coronary artery constriction, increased secretions in salivary, lacrimal glands and pancreas
M4 = brain and adrenal medulla
M5 = brainThe lacrimal glands are solely under parasympathetic control.
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This question is part of the following fields:
- Physiology And Biochemistry
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Question 26
Incorrect
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Risk stratification is done prior to a major cardiac surgery using cardiopulmonary exercise testing. Given the following options, which one is most likely to have the highest risk for post-operative cardiac morbidity?
Your Answer: Oxygen saturation drop of 5%
Correct Answer: Anaerobic threshold (AT) of less than 11 mL/kg/minute
Explanation:The ventilatory anaerobic threshold (VAT), formerly referred to as the anaerobic threshold, is an index used to estimate exercise capacity. During the initial (aerobic) phase of CPET, which lasts until 50€“60% of Vo2max is reached, expired ventilation (VE) increases linearly with Vo2 and reflects aerobically produced CO2 in the muscles. Blood lactate levels do not change substantially during this phase, since muscle lactic acid production is minimal.
During the latter half of exercise, anaerobic metabolism occurs because oxygen supply cannot keep up with the increasing metabolic requirements of exercising muscles. At this time, there is a significant increase in lactic acid production in the muscles and in the blood lactate concentration. The Vo2 at the onset of blood lactate accumulation is called the lactate threshold or the VAT. The VAT is also defined as the point at which minute ventilation increases disproportionately relative to Vo2, a response that is generally seen at 60€“70% of Vo2max.
The VAT is a useful measure as work below this level encompasses most daily living activities. The ability to achieve the VAT can help distinguish cardiac and non€�cardiac (pulmonary or musculoskeletal) causes of exercise limitation, since patients who fatigue before reaching VAT are likely to have a non€�cardiac problem.
When VAT is detected, patients with PVo2 of ©½10€…ml/kg/min have a high event rate.
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This question is part of the following fields:
- Pathophysiology
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Question 27
Correct
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Which of the following best explains the statement Epinephrine is formulated as 1 in 1000 solution
Your Answer: 1000 mg per 1000 ml solution
Explanation:The statement Epinephrine is formulated as 1 in 1000 solution means 1 gm epinephrine is present in 1000 ml of solution.
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This question is part of the following fields:
- Pharmacology
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Question 28
Correct
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A 77-year-old woman is scheduled for day case cataract surgery under local anaesthesia. She has no cardiac or respiratory problems. Lisinopril is being used to treat her hypertension, which is under control. Which of the following preoperative investigations are the most appropriate for this patient?
Your Answer: No investigations
Explanation:Because the patient has mild systemic disease, he is ASA 2 and the procedure will be performed under local anaesthesia.
The following factors should be considered when requesting preoperative investigations:
Indications derived from a preliminary clinical examination
Whether or not a general anaesthetic will be used, the possibility of asymptomatic abnormalities, and the scope of the surgery.No special investigations are needed if the patient has no history of significant systemic disease and no abnormal findings on examination during the nurse-led assessment.
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This question is part of the following fields:
- Clinical Measurement
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Question 29
Correct
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Out of the following, which artery is NOT a branch of the hepatic artery?
Your Answer: Pancreatic artery
Explanation:The common hepatic artery arises from the celiac artery and has the following branches:
1. hepatic artery proper that branches into –
a. cystic artery to supply the gallbladder
b. left and right hepatic arteries to supply the liver
2. gastroduodenal artery that branches into
a. right gastroepiploic artery
b. superior pancreaticoduodenal artery
3. right gastric arteryThe pancreatic artery is a branch of the splenic artery.
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This question is part of the following fields:
- Anatomy
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Question 30
Incorrect
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Which of the following statements is true regarding the Wrights Respirometer?
Your Answer: May over-read at low flows
Correct Answer: Measures the minute volume to within an accuracy of +/- 10%
Explanation:A Wrights Respirometer measures the volume of air exhaled over the course of one minute of normal breathing
It is unidirectional and measures tidal volume and minute volume of gas flow in one direction. It is placed at the expiratory side (lower pressure than inspiratory side therefore lower chances of gas leaks)
Slits are arranged such that incoming gas will rotate the vane at a rate of 150 revolutions per litre of flowing gas
The Wright respirometer tends to over-read at high flow rates and under-read at low flows because of mechanical causes like friction and inertia and the accumulation of water vapour
The ideal flow for accurate readings is 2 L/min for the respirometer. The respirometer reads the tidal volume and minute volume with a ±5€“10% accuracy within the range of 4€“24 L/min.
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This question is part of the following fields:
- Anaesthesia Related Apparatus
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