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Question 1
Incorrect
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Regarding dynamic compression of the airways, which of the following statements is CORRECT:
Your Answer: It is brought about by reflex activation of sympathetic nerves.
Correct Answer: It occurs during forced expiration.
Explanation:Dynamic compression occurs because as the expiratory muscles contract during forced expiration, all the structures within the lungs, including the airways, are compressed by the positive intrapleural pressure. Consequently the smaller airways collapse before the alveoli empty completely and some air remains within the lungs (the residual volume). Physiologically this is important as a completely deflated lung with collapsed alveoli requires significantly more energy to inflate. Dynamic compression does not occur in normal expiration because the intrapleural pressure is negative throughout the whole cycle.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 2
Correct
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Regarding V/Q mismatch, which of the following statements is CORRECT:
Your Answer: In a true shunt, increasing inspired oxygen has no effect on improving hypoxaemia.
Explanation:Both ventilation and perfusion increase towards the lung base, because of the effects of gravity, but the gravitational effects are greater on perfusion than ventilation and therefore there is a regional variation in V/Q ratio from lung apex (high V/Q) to lung base (low V/Q). In a pure shunt, there is normal perfusion but absent ventilation and the V/Q ratio = 0. In a true shunt increasing oxygen fraction has no effect because the oxygen-enriched air fails to reach the shunted blood. An increased A-a gradient is seen in V/Q mismatch.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 3
Incorrect
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Compliance is greater in all but which one of the following:
Your Answer: Elderly
Correct Answer: Pulmonary oedema
Explanation:Compliance changes at different lung volumes. Initially at lower lung volumes the compliance of the lung is poor and greater pressure change is required to cause a change in volume. This occurs if the lungs become collapsed for a period of time. At functional residual capacity (FRC) compliance is optimal since the elastic recoil of the lung tending towards collapse is balanced by the tendency of the chest wall to spring outwards. At higher lung volumes the compliance of the lung again becomes less as the lung becomes stiffer. At all volumes, the base of the lung has a greater compliance than the apex. Patients with emphysema have increased compliance. Compliance is affected by a person’s age, sex and height.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 4
Incorrect
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A 33 year old lady with a known nut allergy was having dinner at a Thai restaurant. She suddenly complained of lip and tongue swelling and difficulty breathing and is brought to ED by ambulance with suspected anaphylaxis. She received intramuscular adrenaline in the ambulance.The most appropriate doses of the second line treatments for anaphylaxis are which of the following?
Your Answer: 20 mg chlorphenamine and 400 mg hydrocortisone
Correct Answer: 10 mg chlorphenamine and 200 mg hydrocortisone
Explanation:Second line drugs to reduce the severity and duration of anaphylactic symptoms are intravenous or intramuscular chlorpheniramine and hydrocortisone. The recommended dose is 10 mg chlorpheniramine and 200 mg hydrocortisone in adults.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 5
Correct
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Which of the following is NOT an indication for a H1 receptor antihistamine:
Your Answer: Gastroesophageal reflux disease
Explanation:Antihistamines are competitive inhibitors at the H1-receptor (in contrast to H2 receptor antagonists used to decrease gastric acid secretion in gastroesophageal reflux disease).Indications: Allergic rhinitis and conjunctivitisUrticarial rashes, pruritus, insect bites and stingsAngioedemaAnaphylaxis (second line adjunct to adrenaline)Nausea/vomiting and prevention of motion sicknessInsomnia
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 6
Incorrect
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Which of the following drugs decreases plasma-theophylline levels:
Your Answer: Erythromycin
Correct Answer: Carbamazepine
Explanation:Examples of enzyme-inhibiting drugs (raise plasma theophylline level):ErythromycinClarithromycinCiprofloxacinFluconazoleVerapamilAllopurinolCimetidineExamples of enzyme-inducing drugs (lower plasma theophylline level):PrimidonePhenobarbitalCarbamazepinePhenytoinRitonavirRifampicinSt John’s Wort
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 7
Incorrect
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Which of the following statements is correct regarding the partial pressure of oxygen during respiration?
Your Answer: Exhaled PO 2 < Alveolar PO 2 < Inhaled PO 2
Correct Answer: Exhaled PO 2 > Alveolar PO 2
Explanation:Because of humidification, inspired PO2 in the airways is less than inhaled PO2. Because of gas exchange, alveolar PO2 is less than inhaled or inspired PO2.Because of mixing with anatomical dead space (air that has not taken part in gas exchange, exhaled PO2 is greater than alveolar O2, and therefore that has relatively higher PO2 on the way out, but is less than inhaled or inspired PO2.Typical values for a resting young healthy male (in kPa) are shown below:-Inhaled air: PO221.2, PCO20.0-Inspired air in airways (after humidification): PO219.9, PCO20.0-Alveolar air (after equilibrium with pulmonary capillaries): PO213.3, PCO25.3-Exhaled air (after mixing with anatomical dead space air): PO215.5, PCO24.3
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 8
Incorrect
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You are prescribing ipratropium bromide for a patient who has presented with an exacerbation of her COPD. What is the mechanism of action of ipratropium bromide:
Your Answer: Muscarinic agonist
Correct Answer: Muscarinic antagonist
Explanation:Ipratropium bromide is an antimuscarinic drug used in the management of acute asthma and COPD. It can provide short-term relief in chronic asthma, but short-acting β2agonists act more quickly and are preferred.The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) can be added to β2agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy.The aerosol inhalation of ipratropium can be used for short-term relief in mild chronic obstructive pulmonary disease in patients who are not already using a long-acting antimuscarinic drug (e.g. tiotropium).Its maximum effect occurs 30-60 minutes after use; its duration of action is 3-6 hours, and bronchodilation can usually be maintained with treatment three times per day.The commonest side effect of ipratropium bromide is dry mouth. It can also trigger acute closed-angle glaucoma in susceptible patients. Tremor is commonly seen with β2agonists but not with antimuscarinics. Ipratropium bromide should be used with caution in: Men with prostatic hyperplasia and bladder-outflow obstruction (worsened urinary retention has been reported in elderly men), People with chronic kidney disease (CKD) stages 3 and above (because of the risk of drug toxicity), People with angle-closure glaucoma (nebulised mist of antimuscarinic drugs can precipitate or worsen acute angle-closure glaucoma)
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 9
Incorrect
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Carbon dioxide is transported in the blood approximately:
Your Answer: 60% as bicarbonate ions, 20% as carbamino compounds and 20% dissolved in plasma
Correct Answer: 60% as bicarbonate ions, 30% as carbamino compounds and 10% dissolved in plasma.
Explanation:Carbon dioxide is transported in the blood from tissues to the lungs in three ways as bicarbonate ions (60%), as carbamino compounds with proteins (30%) or simply dissolved in plasma (10%).
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 10
Incorrect
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A 21 year old student presents to the emergency room with severe acute asthma. Salbutamol and ipratropium bromide nebuliser are prescribed. The most appropriate dose of salbutamol that should be prescribed initially for this patient is which of the following?
Your Answer: 0.5 mg every 20 - 30 minutes
Correct Answer: 5 mg every 15 - 30 minutes
Explanation:The first line treatment for acute asthma is high-dose inhaled short-acting beta2-agonists like salbutamol or terbutaline. Oxygen use should be reserved for hypoxemic patients in order to maintain oxygen saturations of 94 – 98%. In patients with moderate to severe asthma, a pressurised metered dose inhaler with spacer device is preferred (4 puffs initially, followed by 2 puffs every 2 minutes according to response, up to 10 puffs, whole process repeated every 10 – 20 minutes if necessary). For patients with life-threatening features or poorly responsive severe asthma, the oxygen-driven nebuliser route is recommended (salbutamol 5 mg at 15 – 30 minute intervals). In patients with severe acute asthma that is poorly responsive to initial bolus dose, continuous nebulisation should be considered (salbutamol at 5 – 10 mg/hour). For those in whom inhaled therapy cannot be used reliably, the intravenous route is usually reserved.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 11
Incorrect
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Cystic fibrosis patients have a weakened lung surfactant system. Which of the following cell types is in charge of surfactant secretion?
Your Answer: Type I pneumocytes
Correct Answer: Type II pneumocytes
Explanation:Alveolar type II cells are responsible for four primary functions: surfactant synthesis and secretion, xenobiotic metabolism, water transepithelial transport, and alveolar epithelium regeneration following lung injury.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 12
Correct
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Which of the following states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each of the gases in the mixture:
Your Answer: Dalton's law
Explanation:Dalton’s law states that when two or more gases, which do not react chemically, are present in the same container, the total pressure is the sum of the partial pressures of each gas.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 13
Incorrect
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Regarding pressures and airflow during the normal breathing cycle, which of the following statements is INCORRECT:
Your Answer: During expiration both intrapleural pressure and alveolar pressure rise.
Correct Answer: Negative intrapleural pressure causes dynamic compression of the airways.
Explanation:Dynamic compression occurs during forced expiration, when as the expiratory muscles contract, all the structures within the lungs, including the airways, are compressed by the positive intrapleural pressure. Consequently the smaller airways collapse before the alveoli empty completely and some air remains within the lungs (the residual volume).
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 14
Incorrect
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Regarding gas exchange at the alveolar-capillary membrane, which of the following statements is CORRECT:
Your Answer: The rate of diffusion across the membrane is governed by Darcy's law.
Correct Answer: The rate of diffusion in lungs can be estimated by measuring the diffusing capacity of the lungs for carbon monoxide.
Explanation:Gas exchange between alveolar air and blood in the pulmonary capillaries takes place by diffusion across the alveolar-capillary membrane. Diffusion occurs from an area of high partial pressure to an area of low partial pressure, thus the driving force for diffusion is the alveolar-capillary partial pressure gradient. Diffusion occurs across a membrane and is therefore governed by Fick’s law. Although CO2is larger than O2, it is is much more soluble and diffuses 20 times more rapidly. The diffusing capacity for oxygen (DLO2) cannot be measured directly but the rate of diffusion in the lungs can be estimated by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO).
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 15
Incorrect
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All of the following cause bronchodilation, EXCEPT for:
Your Answer: Muscarinic receptor antagonists
Correct Answer: Stimulation of irritant receptors
Explanation:Factors causing bronchodilation: Via beta2-adrenoceptorsSympathetic stimulation: Adrenaline (epinephrine)Beta2-adrenergic agonists e.g. salbutamolAnticholinergic and muscarinic antagonists e.g. ipratropium
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 16
Incorrect
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Stimulation of J receptors located on alveolar and bronchial walls results in all of the following EXCEPT for:
Your Answer: Hypotension
Correct Answer: Tachycardia
Explanation:Juxtapulmonary or ‘J’ receptors are located on alveolar and bronchial walls close to the capillaries. Their afferents are small unmyelinated C-fibres or myelinated nerves in the vagus nerve. Activation causes depression of somatic and visceral activity by producing apnoea or rapid shallow breathing, a fall in heart rate and blood pressure, laryngeal constriction and relaxation of skeletal muscles via spinal neurones. J receptors are stimulated by increased alveolar wall fluid, pulmonary congestion and oedema, microembolism and inflammatory mediators. J receptors are thought to be involved in the sensation of dyspnoea in lung disease.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 17
Correct
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Salbutamol should be used with caution in patients with which of the following:
Your Answer: Susceptibility to QT-interval prolongation
Explanation:Beta-2 agonists should be used with caution in people with: Cardiovascular disease, including arrhythmias and hypertension (beta-2 agonists may cause an increased risk of arrhythmias and significant changes to blood pressure and heart rate)Diabetes(risk of hyperglycaemia and ketoacidosis, especially with intravenous use)Hyperthyroidism(beta-2 agonists may stimulate thyroid activity)Hypokalaemia(potentially serious hypokalaemia may result from beta-2 agonist therapy; this effect may be potentiated in severe asthma by concomitant treatment with theophylline, corticosteroids, diuretics and by hypoxia)Susceptibility to QT-interval prolongationConvulsive disorders
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 18
Correct
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Ipratropium bromide should be used with caution in patients with which of the following conditions:
Your Answer: Prostatic hyperplasia
Explanation:Ipratropium bromide is an antimuscarinic drug used in the management of acute asthma and COPD. It can provide short-term relief in chronic asthma, but short-acting β2agonists act more quickly and are preferred.The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) can be added to β2agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy.The aerosol inhalation of ipratropium can be used for short-term relief in mild chronic obstructive pulmonary disease in patients who are not already using a long-acting antimuscarinic drug (e.g. tiotropium).Its maximum effect occurs 30-60 minutes after use; its duration of action is 3-6 hours, and bronchodilation can usually be maintained with treatment three times per day.The commonest side effect of ipratropium bromide is dry mouth. It can also trigger acute closed-angle glaucoma in susceptible patients. Tremor is commonly seen with β2agonists but not with antimuscarinics. Ipratropium bromide should be used with caution in: Men with prostatic hyperplasia and bladder-outflow obstruction (worsened urinary retention has been reported in elderly men), People with chronic kidney disease (CKD) stages 3 and above (because of the risk of drug toxicity), People with angle-closure glaucoma (nebulised mist of antimuscarinic drugs can precipitate or worsen acute angle-closure glaucoma)
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 19
Incorrect
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Regarding inhaled corticosteroids, which of the following statements is INCORRECT:
Your Answer: Side effects include paradoxical bronchospasm.
Correct Answer: Lower doses of inhaled corticosteroids may be required in smokers.
Explanation:Current and previous smoking reduces the effectiveness of inhaled corticosteroids and higher doses may be necessary.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 20
Incorrect
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Regarding antihistamines, which of the following statements is CORRECT:
Your Answer: The newer antihistamines have more of a sedating effect than older antihistamines.
Correct Answer: Elderly patients and children are more susceptible to side effects.
Explanation:Elderly patients and children are more susceptible to side effects. Antihistamines are competitive inhibitors at the H1-receptor. The newer antihistamines e.g. cetirizine cause less sedation and psychomotor impairment than the older antihistamines because they are much less lipid soluble and penetrate the blood brain barrier only to a slight extent. Antihistamines are used as a second line adjunct to adrenaline in anaphylaxis.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 21
Incorrect
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Regarding airway resistance, which of the following statements is INCORRECT:
Your Answer: Flow through airways is inversely proportional to airway resistance.
Correct Answer: In the lower respiratory tract, airway resistance is mostly determined by the smallest bronchioles.
Explanation:Airway resistance is primarily determined by the airway radius according to Poiseuille’s law, and whether the flow is laminar or turbulent. The major site of airway resistance is the medium-sized bronchi. The smallest airways would seem to offer the highest resistance, but they do not because of their branching parallel arrangement.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 22
Correct
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What is the appropriate dose of 1:1000 adrenaline solution for a 15-year-old patient with suspected anaphylactic shock?
Your Answer: 500 micrograms intramuscularly
Explanation:1: 1000 Adrenaline solution dosage for children above the age of 12 and adults, including pregnant women (over 50 kg) is 0.50 mL, which is equivalent to 500 mcg of adrenaline.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 23
Correct
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The following all cause a right shift in the oxygen dissociation curve EXCEPT for:
Your Answer: Foetal haemoglobin
Explanation:A decreased affinity of haemoglobin for oxygen (and hence increased ease of dissociation), shown by a right shift in the oxygen dissociation curve, is caused by a fall in pH, a rise in PCO2(the Bohr effect) and an increase in temperature. These changes occur in metabolically active tissues such as in exercise, and encourage oxygen release. The metabolic by-product 2,3-diphosphoglycerate (2,3 -DPG) also causes a right shift; 2, 3 -DPG may also be raised in chronic anaemia, chronic lung disease, or at high altitude. Foetal haemoglobin (HbF) binds 2, 3 -DPG less strongly than does adult haemoglobin (HbA), and so the HbF dissociation curve lies to the left of that for HbA, reflecting its higher oxygen affinity. This helps transfer oxygen from mother to foetus.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 24
Correct
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You suspect an anaphylactic reaction in a patient who is hypotensive, with trouble breathing after eating peanuts. Which of the following diagnostic tests will confirm this?
Your Answer: Mast cell tryptase
Explanation:The concentration of serum tryptase rises in anaphylaxis and anaphylactoid responses. Because tryptase is a significant component of mast cell granules, mast cell degranulation causes elevated tryptase levels in the blood. Although tryptase levels are not always high during anaphylaxis, it is considered a particular marker.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 25
Correct
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Regarding gas exchange at the alveolar-capillary membrane, which of the following statements is CORRECT:
Your Answer: Transfer of oxygen is usually perfusion-limited.
Explanation:Gas exchange between alveolar air and blood in the pulmonary capillaries takes place by diffusion across the alveolar-capillary membrane. Diffusion occurs from an area of high partial pressure to an area of low partial pressure, thus the driving force for diffusion is the alveolar-capillary partial pressure gradient. Diffusion occurs until equilibrium is reached, but random movement of particles continues to occur and this is known as dynamic equilibrium. The diffusing capacity for oxygen (DLO2) cannot be measured directly but the rate of diffusion in the lungs can be estimated by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO), not by measuring total lung capacity. The rate of transfer of a gas may be diffusion or perfusion limited; carbon monoxide transfer is diffusion-limited, oxygen transfer is usually perfusion-limited.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 26
Incorrect
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Question 27
Incorrect
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All of the following statements are correct regarding the management of acute asthma in adults except:
Your Answer: The dose of magnesium sulphate in acute severe asthma is 1.2 - 2 g intravenous infusion over 20 minutes.
Correct Answer: Intravenous aminophylline has been shown to result in significant additional bronchodilation compared to standard care.
Explanation:There usually isn’t any additional bronchodilation with intravenous (IV) aminophylline compared to standard care with inhaled bronchodilators and steroids. IV aminophylline may cause side effects such as arrhythmias and vomiting. However, some additional benefit may be gained in patients with near-fatal asthma or life-threatening asthma with a poor response to initial therapy (5 mg/kg loading dose over 20 minutes unless on maintenance oral therapy, then continuous infusion of 0.5 – 0.7 mg/kg/hr).
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 28
Correct
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Compliance is decreased by all but which one of the following:
Your Answer: Aging
Explanation:Factors increasing compliance:Old ageEmphysemaFactors decreasing compliance:Pulmonary fibrosisPulmonary oedemaAtelectasisExtremes of lung volumes (at higher lung volumes the compliance of the lung becomes less as the lung becomes stiffer)
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 29
Incorrect
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Which of the following is NOT a common side effect of antihistamines:
Your Answer:
Correct Answer: Tremor
Explanation:Common side effects of antihistamines may include:Anticholinergic effects (blurred vision, dry mouth, urinary retention)HeadacheGastrointestinal disturbancesPsychomotor impairment (sedation, dizziness and loss of appetite)These side effects are significantly reduced with second-generation agents.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 30
Incorrect
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Which of the following types of food is most commonly implicated in anaphylactic reactions:
Your Answer:
Correct Answer: Nuts
Explanation:Anaphylaxis can be triggered by any of a very broad range of triggers, but those most commonly identified include food, drugs, latex and venom. Of foods, nuts are the most common cause; muscle relaxants, antibiotics, NSAIDs and aspirin are the most commonly implicated drugs. Food is the commonest trigger in children and drugs the commonest in adults. A significant number of cases are idiopathic. Most reactions occur over several minutes; rarely, reactions may be slower in onset. The speed of onset of the reaction depends on the trigger e.g. intravenous medications will cause a more rapid onset than stings which in turn will cause a more rapid onset than ingestion of food.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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SESSION STATS - PERFORMANCE PER SPECIALTY
