Pulse OX ppt what what bitches Flashcards Preview

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Flashcards in Pulse OX ppt what what bitches Deck (20):
1

Arterial blood oxygen saturation SaO2 is determined by what

by the ratio of oxygenated (Sat Hgb) to deoxygenated hgd

2

A SPO1 of 90 is what PaO2

60

3

what if the main goal in reading the pulse ox

find out what teh pts PaO2 is and if SPO2 is not 100% or things do not match find out why! don't just give O2

4

SpO2 does what to VQ mismatch at higher doses

Mask it

5

This higher the FiO2 the more you mask what

VQ mismatch

6

Oxyhemoglobin absorbs what light

infra red (940 nm)

7

deoxyhemogobin absorbs what light

Visible light (660 nm)

8

how does the pulse OX work?

-Prob with 2 lights one red, one infrared
- sensor detects the ratio of red/infra red absorption ratios
-detection of absorption during pulsatile flow several times/sec
-calc is done from the Beer-Lambert law

9

Isobestic point

means absorbs at the same point, and represents the worst site to measure (uses with beer-lambert) this is why each oxygenated and de-oxygenated hgb is measured at different numbers

10

Advantages of Pulse OX

non-invasive
easy to apply
Continuous monitoring
early detection of desat
Inexpensive

11

SPO2 of 85% = PaO2 what? and will you see cyanosis?

55mm
nope

12

SPO2 of 20% = PaO2 what? and will you see cyanosis?

40 mm
yes

13

Disadvantages of Pulse OX

artifact
Inaccurate below SPO2 70%
rare risk of burns in poor perfusion states

14

Lag times
ear
finger
toe

ear- 7-20 sec
finger- 20-35 sec
toe- 40-70 secs

15

What type of low flow or low pulsatile flow states cause inaccuries in pulse ox

Cardiac bypass
hypotension
b/p cuff inflation
tourniquets
vasoconstriction

16

a Hgb < ___ gives an underestimation of SPO2

<10

17

What dyshemoglobins cause pulse ox inaccuracies

Carboxyhemoglobin
Methemoglobin

18

what dyes cause pulse ox Inaccuracies

methylene blue
indigo carmine (lesser degree)

19

What other things can make Pulse OX inaccurate

ambient light
deep skin pigment
electrocautery
excessive motion
Fingernail polish

20

Ficks law states what

Diffusion rate of gas is directly
proportional to:
–Partial pressure gradient
–Membrane area
–Solubility of gas in membrane

Diffusion rate of gas is inversely
proportional to:
–Membrane thickness
–Square root of the molecular weight