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Flashcards in 1. Cell Injury Deck (35):
1

What do we use to measure oxygen in the body?

Hemoglobin, oxygen saturation (on the heme), partial pressure of arterial oxygen

2

What does it mean for oxygen saturation to be 100%?

All 4 spots on heme bound to oxygen

3

What is partial pressure of arterial oxygen?

Oxygen dissolved in PLASMA

4

What is the relationship between oxygen saturation and partial pressure of arterial oxygen?

Move in the SAME direction because oxygen saturation gets its oxygen from the oxygen dissolved in plasma

5

What is the most common cause of ischemia?

Thrombus in muscular artery

6

What is hypoxemia?

Decreased partial pressure of arterial oxygen

7

Whenever you have respiratory acidosis, what happens to partial pressure of O2?

Goes down - hypoxemia; there is always an inverse relationship between PCO2 and PO2

8

Patient with hypoxemia given 100% O2 and O2 doesn't increase - what's happening?

Shunt - perfusion but no ventilation (kids - hyaline membrane disease, adults - adult respiratory syndrome)

9

What happens when you give 100% O2 to someone with a perfusion defect?

O2 will increase because not every single alveoli is not perfused

10

Does anemia give you hypoxemia?

NO - it gives you decreased Hgb but PO2 and oxygen saturation are normal

You will have hypoxia (tissue lacks oxygen) but not hypoxemia (PO2 in the blood is normal)

11

Heater in the winter time, automobile exhaust, house fire - what should you think of?

CO poisoning

12

What else should you think of with house fire aside from CO poisoning?

Cyanide poisoning because of upholstery on furniture

13

What is the only lab value affected in CO poisoning?

Oxygen saturation is decreased because CO displaces O2 on the heme

14

How do we treat CO poisoning?

100% oxygen

15

What does cyanosis mean?

Decreased oxygen saturation

16

What is the first symptom of CO poisoning?

Headache

17

Why do we not see signs of cyanosis with CO poisoning?

It produces a cherry red pigment that can mask the blue

18

What is methemoglobin?

Hemoglobin with FE3+ instead of 2+ which makes it so that oxygen can't bind - decreased oxygen saturation

19

Dude coming out of the Rocky Mountains, cyanotic, give him 100% O2 and he's still cyanotic - diagnosis?

Methemoglobinemia because of drinking water with nitrites/nitrates which are oxidative agents

20

What is the main treatment for methemoglobinemia?

Methylene blue

21

What are 2 things that sulfa and nitro drugs (oxidizing agents) do?

1. Produce methemoglobin
2. Produce hemolytic anemia in G6PD deficiency

22

Why do we see methemoglobinemia in HIV patients?

They are usually on TMP-SMX for treatment of PCP

23

What shifts hemoglobin curve to the right?

CADET: CO2, acidosis, 23BPG, Elevation (causes increase in synthesis of 23BPG), Temperature

24

What shifts hemoglobin curve to the left?

CO, HbF, alkalosis

25

What inhibits cytochrome oxidase?

CO and cyanide (think 3 C's)

26

What does CO do?

1. decreases O2 sat
2. shifts hemoglobin curve to the left
3. inhibits cytochrome oxidase

this is why CO is so bad

27

What is one of the complications of salicylate poisoning?

Hyperthermia because salicylates are uncoupling agents

28

Acute respiratory acidosis - what happens to Hgb, oxygen sat, PO2?

Hgb - nothing, Oxygen sat and PO2 - both decreased

29

What can you give in addition to methylene blue for methemoglobinemia?

Ascorbic acid

30

What are the biggest problems in tissue hypoxia?

1. Decrease in ATP leading to anaerobic glycolysis and lactic acid build up
2. ATPase pumps broken
3.

31

What does the build up of lactic acid do in a cell?

Denature proteins and enzymes --> coagulation necrosis (grossly: infarction)

32

Why are cells swollen in tissue hypoxia?

Decreased ATP --> Na-K pump stops working --> Na stuck in cell --> cell swells

33

What happens to calcium in tissue hypoxia?

Enters cell because Ca-ATPase pump stops working - once it's in the cell calcium activates all kinds of enzymes (membrane damage, nuclear pyknosis)

34

When you have free radical damage what kind of pigment do you see in cells?

Lipofuchsin - can't break down lipids all the way

35

What is the most common cancer that comes from radiation?

Leukemia