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Question 1
Correct
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Many of the processes we deal with in anaesthesia are exponential.
What is the underlying mathematical principle of an exponential process?Your Answer: The rate of change of x is dependent on the magnitude of x
Explanation:The magnitude of x determines the rate of change of x. First-order drug kinetics is a good example. Most drugs’ plasma levels are controlled by an exponential process. The rate of change in drug metabolism is proportional to the current plasma concentration (so-called non-linear kinetics).
A tear-away function is just one type of exponential relationship (y = ex), in which e is Euler’s number, x is the power, and e is the base. Natural logarithms rely on Euler’s number.
Euler’s number is a mathematical constant, not a mathematical principle. It’s referred to as an irrational number. This is a number that cannot be expressed as a simple fraction or a ratio.
A line or curve that acts as the limit of another line or curve is known as an asymptote. A washout exponential curve, for example, where the value y represents the plasma concentration of a drug in a single compartment model against time on the x axis. This descending curve approaches but never touches the x axis. This curve is asymptotic to the x axis, which is the curve’s asymptote. An asymptote isn’t just a characteristic of exponential curves.
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This question is part of the following fields:
- Basic Physics
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Question 2
Correct
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Suppose the afterload and myocardial contractility remain unchanged, which of the following factors in the pressure-volume loop indicates an increase in the preload of the left ventricle?
Your Answer: Increased end-diastolic volume
Explanation:If the afterload and myocardiac contractility remains unchanged, an increase in the preload can be attributed to an increase in end-diastolic volume.
Preload can be defined as the initial stretching of the cardiac myocytes prior to contraction. Preload, therefore, is related to muscle sarcomere length. Because sarcomere length cannot be determined in the intact heart, other indices of preload are used such as ventricular end-diastolic volume or pressure. When venous return to the heart is increased, the end-diastolic pressure and volume of the ventricles are increased, which stretches the sarcomeres, thereby increasing their preload.
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This question is part of the following fields:
- Basic Physics
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Question 3
Correct
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Anaesthetic gas concentrations can be measured using a refractometer. The main principal which allows it to be used for this purpose is which of the following?
Your Answer: Refraction
Explanation:Refractometers measure the degree to which the light changes direction, called the angle of refraction. A refractometer takes the refraction angles and correlates them to refractive index (nD) values that have been established. Using these values, you can determine the concentrations of solutions.
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This question is part of the following fields:
- Basic Physics
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Question 4
Incorrect
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What makes the ultrasound nebulizer efficient?
Your Answer: Humidification of inspired gas by up to 100%
Correct Answer: Reduction in gas flow resistance
Explanation:Smallest drops reach not only the upper but also the lower respiratory tracks. As a result, the ultrasonic nebulizer is most efficient for the therapy of pulmonary diseases and stands out as a robust and reliable support within the clinical setting.
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This question is part of the following fields:
- Basic Physics
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Question 5
Incorrect
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Which of the following statements is true regarding oxygen?
Your Answer: Has a critical temperature of 183°C
Correct Answer: Forms molecules containing either two or three atoms
Explanation:Oxygen is formed by a molecule of oxygen and two molecules of hydrogen with a molecular formula of H2O
The critical temperature is defined as a temperature above which the substance cannot be liquefied, no matter how much pressure is applied.
Water has a critical temperature of -118.6oC. So, it cannot be liquified at room temperature.Medical oxygen cylinder is stored in a cylinder with a white shoulder and black body. Meanwhile, medial air is stored in cylinders with a white and black shoulder and a French grey body.
The partial pressure of air at a high altitude is less but the relative concentration remains constant.
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This question is part of the following fields:
- Basic Physics
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Question 6
Incorrect
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Very large SI units are easily expressed using mathematical prefixes.
One terabyte is equal to which of the following numbers?Your Answer: 1,000,000,000 bytes
Correct Answer: 1,000,000,000,000 bytes
Explanation:To denote large measured units, the following SI mathematical prefixes are used:
1 deca = 10 bytes (101)
1 hecto (h) = 100 bytes
1 kilo (k)= 1,000 bytes
1 mega (M) = 1,000,000 bytes
1 giga (G) = 1,000,000,000 bytes
1 Tera (T) = 1,000,000,000,000 bytes
1 Peta (P) = 1,000,000,000,000,000 bytes -
This question is part of the following fields:
- Basic Physics
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Question 7
Correct
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The half-empty cylinder weighs 4.44 kg.
The tare weight of a nitrous oxide cylinder is 4 kg.
The molecular weight of nitrous oxide is 44gm.
Based on the data, how many litres of nitrous oxide remains in the cylinder for use?Your Answer: 224 litres
Explanation:The Tare weight of a cylinder is the weight when it is empty. So,
Weight of cylinder – tare weight = weight of remaining N2O (g).
4.44 kg – 4 kg = 0.44 kg
Here,
0.44 kg of nitrous oxide remains in the cylinderSince the molecular weight of nitrous oxide is 44 g and one mole of an ideal gas will occupy a volume of 22.4 litres at STP
Therefore amount left in the cylinder is several (gN2O/44) x 22.4 litres of N2O.(440/44) x 22.4 = 224 litres.
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This question is part of the following fields:
- Basic Physics
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Question 8
Incorrect
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Question 9
Incorrect
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General anaesthesia is administered to a patient in a hospital in Lhasa which is one of the highest cities in the world (at 11,975 feet). An Anaesthetic rotameter is normally calibrated at 20 C and 1 bar pressure and is known to be underread at altitude. The temperature of the theatre was 10 C.
Which one of the following physical properties is responsible for the rotameter inaccuracy in these conditions?Your Answer:
Correct Answer: Density of the gas
Explanation:Since the gas is less dense at higher altitudes, the density of a gas influences flows when passing through the orifice. Due to this reason, for a given flow rate, the bobbin will not be forced as far up the rotameter tube.
At higher altitudes, the volume of a fixed mass of gas increases, and therefore the molecules of gas are widely spaced resulting in a decrease in density with an increase in altitude.
Viscosity is simply termed as friction of gas. The viscosity of a gas is important only at low flow rates when the flow characteristic of the gas is laminar.
Charle’s law stated that the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature (T) provided the pressure remains constant.
Boyle’s law for a fixed amount of gas at constant temperature, the pressure (P) and volume (V) are inversely proportional.
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This question is part of the following fields:
- Basic Physics
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Question 10
Incorrect
SESSION STATS - PERFORMANCE PER SPECIALTY
