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Flashcards in clinical assessment of respiratory disease Deck (22)
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1
Q

how to calculate respiratory quotient (respiratory exchange ratio)

A

CO2 production/oxygen consumption

2
Q

what is the respiratory quotient usually equal to

A

1

3
Q

how much O2 does the body consume (ml/min/kg) when sitting at rest, and what is the metabolic equivalent

A

3.5 ml/min/kg, with a metabolic equivalent of 1

4
Q

what are the metabolic equivalents of O2 consumption when standing, walking and running

A

1.5, 2, >7

5
Q

what are 2 forms of stored energy in muscles to generate muscular contraction

A

ATP, creatine phosphate

6
Q

what drives oxidative phosphorylation in muscles

A

inorganic phosphates, ADP, creatine

7
Q

what 2 processes increase during exercise in muscles

A

TCA, glycolysis

8
Q

effect on O2 consumption and CO2 production in muscles during exercise

A

oxygen consumption increases; initially CO2 production rises slowly as buffered, but then rises to match O2

9
Q

what happens to cardiac output, heart rate and oxygen consumption in the circulatory response to exercise

A

increases linerarly with intensity until plateaus as maximum reached

10
Q

what happens when heart rate is too fast in the circulatory response to exercise

A

filling time in diastole is reduced, reducing stroke volume after a peak

11
Q

what happens to tidal volume and ventilaton in the lung response to exercise

A

increases up to a peak where it plateaus, with breathing frequency increasing

12
Q

what is the most efficient fraction of vital capacity to breathe when exercising

A

1/2

13
Q

effect of exercise on ventilation perfusing matching

A

increases

14
Q

during incremental aerobic metabolism, what happens to oxygen flow, total body respiratory quotient and ventilation

A

oxygen flow matches demand, total body respiratory quotient rises, ventilation increases to match CO2 production

15
Q

during incremental aerobic metabolism, why does the respiratory quotient rise to 1

A

glucose becomes predominant fuel source

16
Q

describe the Bohr effect (including oxygen-dissociation curve)

A

as pH increases, Bohr shift of oxygen-dissociation curve to right, as at given PO2, Hb has less affinity to oxygen so offloads more to acidotic muscles

17
Q

what happens to lactate in acidosis

A

converted to protons

18
Q

how is the production of protons in acidosis buffered and what is the outcome

A

buffered by bicarbonate to increase CO2

19
Q

what is the outcome of the CO2 produced and effect on blood pH

A

increased ventilation of CO2 out, so pH remains relatively stable

20
Q

what happens if [H+] exceeds [HCO3-]

A

cannot buffer, so begin to hyperventilate to remove CO2 and reduce lactate

21
Q

describe cardiopulmonary exercise testing

A

patient on a bike has continuous ECG and gas exchange monitoring; power is slowly increased to put cardiopulmonary strain on the patient

22
Q

what can cardiopulmonary exercise testing be used for

A

detection of heart/lung conditions/restrictions on exercise