Arterial Blood Gases–O2 Carriage/CO2 Carriage Flashcards

1
Q

There is about 26.4 mM of carbon dioxide in the blood. Of that, roughly ____ is in the form of HCO3-; the rest is split evenly as CO2 and carbamino proteins.

A

24 mM

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2
Q

Describe the Bohr effect.

A

CO2 binding to hemoglobin decreases the oxygen affinity of hemoglobin

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3
Q

What is the Haldane effect?

A

Oxygen binding decreases the CO2 affinity of hemoglobin

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4
Q

What factors decrease the oxygen affinity of hemoglobin?

A

Increased temperature, decreased pH, and increased CO2 concentration

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5
Q

What is D(O2)?

A

The delivery of oxygen to a tissue in one minute. It is given by the following formula: flow x C(a[O2]).

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6
Q

C(a[O2]) = _____________.

A

SaO2 x [Hb] x 1.39 ml O2/gm Hb + 0.003 x Pa(O2)

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7
Q

Define hypoxia.

A

Low O2 at tissues (P[O2]

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8
Q

What pathophysiologies can lead to hypoxia?

A

Low cardiac output; low arterial oxygen saturation (a syndrome called hypoxemia); or failure to deliver oxygen to the tissues (such as from anemia or carbon monoxide poisoning)

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9
Q

What five things can cause hypoxemia?

A

Decreased P(I[O2]); decreased P(A[O2]); diffusion problems; shunts; and V/Q mismatches

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10
Q

At high altitude, arterial CO2 _______, due to _________.

A

decreases; increased respiratory rate

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11
Q

What is the conversion between mM of CO2 and Torr?

A

0.03 mM/Torr

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12
Q

How does V(O2) differ from D(O2)?

A

D(O2) represents the amount of oxygen delivered to the tissues in one minute, while V(O2) represents the amount of oxygen consumed in one minute.

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13
Q

V(O2), which is the amount of blood consumed by the tissues in one minute, is given by ___________.

A

Q x ∆C(O2)

Also written Q x (Ca[O2] - Cv[O2])

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14
Q

Hypoxemia is defined as _______ in Denver and ________ at sea level.

A

Pa(O2)

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15
Q

What are some ramifications of carbon monoxide poisoning?

A

CO (1) decreases the Sa(O2); (2) increases O2 affinity, which decreases O2-offloading; and (3) binds tightly and won’t release

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16
Q

The A-a gradient is _________.

A

P(A[O2]) - P(a[O2])

17
Q

The normal A-a gradient is _________.

A

5-10 Torr

18
Q

What three hypoxemic conditions lead to increased A-a gradient?

A

V/Q mismatch, interstitial lung diseases, and consolidation pneumonias

19
Q

Those at high altitude produce more _______.

A

2,3-BPG (to decrease the oxygen affinity of hemoglobin and thus increase delivery)

20
Q

Ca(O2) is typically ______.

A

20.7 ml O2 / 100 ml blood

21
Q

Pulse-oximeters only give _________. To get an Pa(O2), you must get _________.

A

Sa(O2); an arterial blood gas

22
Q

Diseases such as __________ respond to 100% oxygen, while ______ do not.

A

asthma, bronchitis, and emphysema; diffusion disorders