Oxygen Delivery Flashcards

1
Q

What is the definition of atmospheric pressure?

A

The total downward force of all the gases in the atmosphere.

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2
Q

What is the value of atmospheric pressure?

A

760mmhg

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3
Q

What is partial pressure?

A

Partial pressure, also referred to as the tension of a gas is the pressure a single gas in the atmosphere.

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4
Q

What is Dalton’s law?

A

The total pressure of a gas mixture is equal to the sum of the partial pressures of the component gases.

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5
Q

How do you calculate the partial pressure of a gas?

A

Multiple the total pressure (760mmhg) by the fraction of the gas you are trying to find.

I.e oxygen is 20.93%

760 x 0.2093 = 159.1mmhg

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6
Q

What are the 3 main components of atmospheric air?

A

Nitrogen, oxygen, carbon dioxide

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7
Q

What % of atmospheric air is nitrogen?

A

79.03%

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8
Q

What % of atmospheric air is oxygen?

A

20.93%

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9
Q

What % of atmospheric air is CO2?

A

0.0004%

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10
Q

What is the atmospheric pressure of nitrogen?

A

600.60mmhg

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11
Q

What is the partial pressure of oxygen in the atmosphere?

A

159.10mmhg

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12
Q

What is the atmospheric pressure of CO2?

A

0.3mmhg

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13
Q

What is the alveolar pressure of nitrogen?

A

569.24mmhh

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14
Q

What is the alveolar pressure of oxygen?

A

104mmhg

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15
Q

What is the alveolar pressure of CO2?

A

40.28mmhg

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16
Q

What is the alveolar pressure of water?

A

47.12mmhg

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17
Q

What is the % of nitrogen in alveolar air?

A

74.9%

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18
Q

What is the % of carbon dioxide in alveolar air?

A

5.3%

19
Q

What area of the lung does gas exchange occur?

A

The alveoli. Gas diffuses across the alveolar and capillary membrane.

20
Q

What are the 5 factors that affect diffusion across the alveolar capillary membrane.

A

Thickness of membrane

Surface area

Concentration of gases

Solubility of the gas in the fluid

Temperature of the fluid

21
Q

What is the average partial pressure of oxygen in VENOUS blood (PVO2)

A

40mmhg

22
Q

What is the average partial pressure of CO2 in venous blood?

A

46mmhg

23
Q

What are the 3 major factors that affect oxygen affinity to hemoglobin?

A

PH, CO2, temperature.

24
Q

What are 2 main ways Oxygen is carried in the body?

A

Hemoglobin, and transported in blood plasma.

25
Q

What are the 3 ways CO2 is transported in blood?

A

Carried as bicarbonate (65-70%)

Combined with hemoglobin (23-25%)

Dissolved in blood plasma (7-10%)

26
Q

What enzyme assists CO2 and H2O to create carbonic acid?

A

Carbonic anhydrase

27
Q

What does carbonic anhydrase do?

A

It joins CO2 and H2O together to create carbonic acid.

28
Q

What is the chemical name of carbonic acid?

A

H2CO3

29
Q

What does H2CO3 dissociate into?

A

Hydrogen + bicarbonate

H + HCO3

30
Q

What chemical moves into cells when bicarbonate moves in? And why?

A

Chloride. To maintain electrochemical neutrality within the cell.

31
Q

What happens to bicarbonate in the lungs?

A

It becomes H2O and CO2 and is expelled

32
Q

What is the Bohr effect

A

During exhalation CO2 is exhaled causing the body to become alkaline (creates a stronger O2 affinity at lung level). When blood reaches the tissue level CO2 diffuses from tissue to capillary blood making blood more acidotic (creates less O2 affinity). Bohr effect occurs on a breath by breath basis.

33
Q

What are the 4 types of hypoxia?

A

Hypoxic hypoxia
Hypemic hypoxia
Stagnant hypoxia
Histotoxic hypoxia

34
Q

What is hypoxic hypoxia?

A

Hypoxia due to breathing air with less than normal PO2.

Or due to decreased pulmonary ventilation from, pneumonia, pneumothorax, respiratory depression.

Anything that reduces the amount of oxygen available.

35
Q

What is hypemic hypoxia?

A

Hypoxia as a result of hemoglobin disruption or dysfunction.

Carbon monoxide poisoning, anemia

36
Q

What is stagnant hypoxia?

A

Hypoxia due to inadequate tissue perfusion. Can be caused by any shock state, blood flow deficit, thrombosis, embolus, vasoconstriction.

37
Q

What is histotoxic hypoxia?

A

When the body is able to acquire oxygen, transport oxygen adequately, but is unable to use it at the cellular level due to cellular disruption.

Example: cyanide poisoning

38
Q

Where are the CENTRAL chemoreceptors located?

A

Located on the Centerolateral surface of the medulla oblongata as well as other areas of the brainstem

39
Q

What chemical excites the central chemoreceptor causing increased respiration?

A

Hydrogen, produced from the break down of H2CO3.

40
Q

What are 7 things to consider when trouble shooting low SpO2? Fick principle

A

Adequate FiO2

Adequate diffusion across alveolar membrane

Adequate affinity for O2

Adequate O2 carrying capacity

Adequate perfusion

Adequate O2 release at tissues

Adequate ability to use O2

41
Q

What are the % O2 concentrations in a nasal cannula?

A

1Lpm = 24%
2 Lpm = 28%
3 Lpm = 32%
4 Lpm = 36%
5 Lpm = 40%
6 Lpm = 44%

42
Q

What are the O2 % in an NRB at 6-10lpm?

A

6 LPM = 60%
7 LPM = 70%
8 LPM = 80%
9 LPM = 90%
10 LPM = 95%+

43
Q

What is the calculation for oxygen tank duration?

A

PSI - safe residual pressure / flow rate
x constant

44
Q

What are the constant factors for D, E, M tanks

A

D = 0.16
E = 0.28
M = 1.56