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Question 1
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 2
Incorrect
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At a pH of 7, pure water has an hydrogen ion concentration of?
Your Answer: 0 nanomol/L
Correct Answer: 100 nanomol/L
Explanation:pH is the negative log to the base 10 of hydrogen ion concentration:
So, what power produces the answer?
pH = – log10 [H+]
Making [H+] the subject:
[H+] = 10-pH
Substituting, [H+] = 10-7
One nanomole = 1 x 10-9 or 0.000000001
10-7 = 1x 0.0000001 or 10 x 0.00000001 or 100 x 0.000000001
100 nanomole
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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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The child-Pugh scoring system can be used, if risk classifying a patient with chronic liver disorder earlier to anaesthesia.
Which one is the best combination of clinical signs and examinations used within the Child-Pugh scoring system?Your Answer: Ascites, grade of encephalopathy, albumin, bilirubin and INR
Explanation:In the Child-Pugh classification system, the following 5 components are determined or calculated in order:
Ascites
Grade of encephalopathy
Serum bilirubin (?mol/L)
Serum Albumin (g/L)
Prothrombin time or INR
Raised liver enzymes are not the component of the classification system.
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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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Which of the following is the smallest value of pressure?
Your Answer: 2.0265 bar
Correct Answer: 14.69 psi
Explanation:The SI unit of pressure is the pascal (Pa) and it is equal to one newton (N) per square meter (m2) or N/m2.
1 atmosphere (atm) is the equivalent of:
101325 Pa760 mmHg
1.01325 bar
1033.23 cmH2O.
14.69 pounds per square inch (psi)
1013.25 millibar (mbar) or hectopascals (hPa), and14.69 psi is equal to one atmosphere. The other values are equal to two atmospheres of pressure.
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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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A patient admitted to the hospital is on oxygen via a venturi mask.
The air entrainment ratio is 1:9 i.e. 1 litre of 100% oxygen from the source entrains 9 litres of air from the atmosphere). The flow rate of 100% oxygen is 6L/minute.
Based on the given data which of the following value approximates the oxygen concentration delivered to the patient?Your Answer: 35%
Correct Answer: 28%
Explanation:The formula for calculating air: oxygen entrainment ratio is given as :
100% − FiO2 = air/oxygen entrainment ratio
Since FiO2 − 21% and the entrainment ratio is already known. Substituting the values in the equation: x = FiO2.100 − x = 9
x − 21
100 − x = 9(x − 21)
100 − x = 9x − 189
10x = 289
x = 289/10
x = 28.9% -
This question is part of the following fields:
- Basic Physics
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Question 6
Incorrect
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Fixed performance devices like high air flow oxygen enrichment (HAFOE) masks have large volumes of air entrained into a flow of 100% oxygen.
The term that best describes the physics behind air entrainment is?Your Answer: Coanda effect
Correct Answer: Bernoulli's principle
Explanation:Bernoulli’s principle states that as the speed of a moving fluid increases, there is a simultaneously decrease in static pressure or a decrease in the fluid’s potential energy.
This is seen in the simultaneous increase in speed and kinetic energy and fall in pressure that causes entrainment of large volumes of air into a flow of 100% oxygen in the nozzle of HAFOE masks.The reduction in fluid pressure that happens when a fluid flows through a constriction in a tube is the Venturi effect.
When a flow of gas or liquid attaches itself to a nearby surface and remains attached even when the surface curves away from the initial direction of flow, this is the Coanda effect.
The branch of engineering and technology that is concerned with the building of devices that use the flow and pressure of a fluid for functions usually performed by electronic devices is Fluidics . Fluidic logic is used to power some ventilators.
The branch of engineering that utilises pressurised gases is Pneumatics.
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This question is part of the following fields:
- Basic Physics
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Question 7
Incorrect
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Question 8
Incorrect
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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: It is a tear-away function
Correct 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 9
Incorrect
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Regarding thermocouple, which of the following best describes its properties?
Your Answer: Can be used as a switch in a thermostat
Correct Answer: The electromotive force at the measuring junction is proportional to temperature
Explanation: -
This question is part of the following fields:
- Basic Physics
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Question 10
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 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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SESSION STATS - PERFORMANCE PER SPECIALTY
