General Primary MCQ2 Flashcards
(30 cards)
P50:
a) is normally 5.5 kPa
b) is increased at high altitude
c) is an indicator of the position of the oxygen dissociation curve
d) is increased in foetal blood
e) is increased in banked red blood cells
FTTFF
The work of breathing:
a) is inversely related to lung compliance
b) increases during exercise
c) normally requires 15% of total body oxygen consumption
d) is increased when the subject breathes heliox instead of room air
e) is calculated by integration of a pressure/volume loop
TTFFT
Alveolar - arterial oxygen difference (A-a DO2):
a) is normally 2-3 kPa while breathing room air
b) is increased under anaesthesia due to increased V/Q mismatch
c) is decreased in one lung ventilation
d) is increased in the presence of right to left intracardiac shunts
e) is decreased in severe exercise
TTFTF
Lung compliance:
a) is normally 0.2 L/cm H2O
b) is decreased with loss of pulmonary surfactant
c) is increased in emphysema
d) is decreased after induction of general anaesthesia
e) is different at the apices and bases of lungs
TTTTT
An arterial blood sample has the following values:
pH 7.25, PCO2 4 kPa, PO2 8 kPa, base excess -5.6 mmol/L, standard bicarbonate 20 mmol/L
These could result from:
a) an intracardiac left to right shunt
b) Acute respiratory distress syndrome
c) chronic obstructive airways disease
d) aspirin overdose
e) diabetic ketoacidosis
FTFTT
The Magill (Mapleson A) breathing system:
a) is the most efficient system for spontaneously breathing patients
b) will work with minimal rebreathing at a fresh gas flow of 70% of minute volume
c) makes scavenging of exhaled gases easier
d) co-axial version is the Lack system
e) is also efficient during controlled ventilation
TTFTF
The respiratory centre in the brain stem receives input from:
a) the aortic and carotid bodies
b) bronchiolar stretch receptors via vagal afferents
c) oxygen-sensitive chemoreceptors in the medulla
d) receptors which respond to the hydrogen ion concentration in the cerebrospinal fluid
e) mechanoreceptors of the larynx
TTFTT
The carotid bodies:
a) have cells which respond only to decrease in PaO2
b) have the highest blood flow (ml/unit weight) in the body
c) maximally stimulate the respiratory centre between 4-8 kPa
d) increase the respiratory drive when mean arterial pressure decreases below 70 mmHg
FTTT
Concerning pulmonary function tests:
a) FEV1 is low in small airway disease
b) FEV1 is also effort dependent
c) The flow-volume loop can indentify the source of airway obstruction
d) the diffusing capacity of the lung for carbon monoxide is decreased in emphysema
e) FEV1 and PEFR can be used to assess the reversibility of airway obstruction
TTTFT
Mixed venous oxygen saturation:
a) is normally between 65-80%
b) is essential in calculations of shunt and oxygen extraction ratio
c) is increased in hypothermia
d) is decreased in low cardiac output states and in thyrotoxicosis
e) can be continuously monitored with an oximetric Swan Ganz catheter
TTTTT
With a decrease in body temperature:
a) P50 and PaCO2 are decreased
b) pH is increased
c) arrhythmias are increasingly common at temperatures below 30 degrees C
d) blood becomes more viscous
e) the EEG becomes isoelectric at about 20 degrees C
TFTTT
Concerning the pharmacokinetics of inhalational agents:
a) agents with a high blood:gas partition co-efficient will keep alveolar to inspired gas (FA/FI) ratio low
b) alveolar partial pressure rises faster in adults than in children
c) high cardiac output slows the rate of rise of alveolar partial pressure (FA)
d) diffusion hypoxia is due to the second gas effect
e) the second gas effect slows the rate of rise of alveolar partial pressure (FA)
TFTTF
The following statements regarding inhalational agents are correct:
a) the blood gas partition co-efficient of desflurane is 0.42
b) desflurane can cause sympathetic stimulation
c) sevoflurane can degrade to compound A in soda lime
d) desflurane is suitable for inhalational induction
e) desflurane can be used in halothane vaporiser
TTTFF
Nitrous oxide (N2O):
a) has a blood:gas partition coefficient of 0.47
b) is 34 times less soluble than N2
c) may be associated with postoperative hearing loss
d) inactivates methionine synthetase after prolonged administration
e) when inhaled at 66% can double a pneumothorax in 10 minutes
TFTTT
The speed of induction with inhalational agents:
a) is quicker in patients with very high functional reserve capacity
b) is quicker if the agent is very soluble in blood
c) is slower in the presence of right to left shunt
d) is unchanged in the presence of left to right shunt with normal systemic flow
e) is quicker when used with nitrous oxide
FFTTT
With reference to the skeletal muscle myofilaments:
a) actin is the major constituent of thin filaments
b) myosin and tropomyosin combine to form the thick filaments
c) troponin is a constituent of thin filaments
d) tropomyosin prevents the interaction between actin and myosin in the resting state
e) troponin C has 4 calcium binding sites
TFTTT
The following receptors are part of a ligand-gated ion channel:
a) opioid m receptor
b) muscarinic cholinoceptors
c) nicotinic cholinoceptors
d) GABA A receptor
e) GABA B receptor
FFTTF
Drugs with anti-emetic activity:
a) must cross the blood-brain barrier to be effective
b) include agents which are selective dopamine D1 receptor antagonists
c) include histamine H1 receptor agonists
d) are ineffective orally
e) include propofol
FFFFT
- metoclopramide and domperidone are D2 antagonists
Concerning the rate of diffusion of a gas:
a) it is a result of the random movement of the gas molecules
b) it is proportional to the tension gradient
c) it depends upon the gas temperature
d) it is inversely related to the square root of the gas density at constant temperature
e) carbon dioxide diffuses more rapidly than oxygen
TTFFT
Graham’s Law:
“The rate of diffusion is inversely proportional to the square root of its molar mass at identical pressure and temperature”
Fick’s law gives us a number of factors that affect the diffusion rate of a gas through fluid:
- The pressure difference across the diffusion barrier
- The solubility of the gas
- The cross-sectional area of the fluid
- The distance molecules need to diffuse
- The molecular weight of the gas
- The temperature of the fluid – not important within the lungs and can be assumed to be 37oC
Concerning the use of lasers:
a) most lasers use light of wavelengths in the visible and infrared spectrum
b) the CO2 laser is strongly absorbed by water, blood and tissues
c) the Nd-Yag laser is absorbed mostly by pigments
d) nitrous oxide should be avoided during the use of a laser near the airway
e) endotracheal tube cuffs should be inflated with saline or water
TTTTT
Concerning pacemakers:
a) AOO is a fixed rate type of pacemaker
b) VVI is the most common type of synchronous pacemaker
c) failure to capture is never seen with hyperkalaemia
d) unipolar electrocautery is prefered in patients with a pacemaker
e) the ground plate of the electrocautery should be placed as far as possible from the pacemaker
TTFFT
Regarding defibrillation:
a) the greater the time interval between onset of ventricular fibrillation and defibrillation, the less the success of defibrillation
b) 5-40 joules should be applied to the heart if the chest is open
c) paddles should be of 13 cm in diameter in adults
d) defibrillation is most effective when the electric shock is delivered during inspiration
e) the myocardium is refractory to defibrillation in hypothermia
TTTFT
Regarding acid-base balance:
a) chronic obstructive airways disease patients have high serum bicarbonate levels
b) the normal anion gap is 20-25 mmol/L
c) mixed venous pH is always lower than arterial pH
d) the pKa for bicarbonate buffer is 6.1
e) kidneys cannot produce urine with a pH <4.4
TFTTT
Baroreceptors:
a) in the carotid sinus are innervated by the vagus nerve
b) are stretch receptors
c) reset the threshold for firing in chronic hypertension
d) are made less sensitive by volatile agents
e) also respond to the changes in blood pH and PaCO2
FTTTF
