Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Sp: PMI > 8. Pulse Oximetry > Flashcards

8. Pulse Oximetry Flashcards

1
Q

how many hemoglobin per RBC

A

300 million

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

hemoglobin subunits

A

4 subunits
each subunit contains a heme group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

heme group

A

porphyrin ring
iron (site of oxygen binding)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how may oxygen molecules can 1 hemoglobin bind?

A

4 subunits
each bind 1 oxygen

= 4 total oxygen per hemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how many oxygen molecules per RBC

A

over 1 billion oxygen molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

hematocrit
(Hct)

A

percentage of blood that is red blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

blood components

A

plasma
white blood cells (thrombocytes)
red blood cells (RBCs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

normal male hematocrit

A

45%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

normal female hematocrit

A

39%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

hematocrit vs hemoglobin lab values

A

Hct = 3xHb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

hematocrit units

A

percentage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

hemoglobin units

A

concentration (g/dL)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

anemia

A

decrease in hemoglobin and/or hematocrit

  • decr Hct will result in decr Hb (directly proportional)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

anemia Hb

A

<6.5 g/dL
<65 g/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

anemia Hct

A

<20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Causes of anemia

A

fluid administration
- dilutes [Hb]
blood loss
- decr Hb
lysed RBCs
- destroyed Hb
renal insufficiency/failure
-decr erythropoietin (EPO) production. –> less RBCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

PAO2

A

partial pressure of O2 in the alveoli

cannot measure
can calculate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

PAO2 factors

A

primarily determined by pt FiO2
- incr FiO2 = incr PAO2
- decr FiO2 = decr PAO2

barometric pressure
- higher alt: decr press = decr FiO2

minute ventilation (minimally)
- changing breathing rate does not really help

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

PaO2

A

partial pressure of O2 in the arteries

portion of O2 that dissolves in blood

1.5% of all O2 in body

measured by blood sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what percentage of O2 in the body is bound to hemoglobin?

A

98.5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

PaO2 factors

A

determined by PAO2
- decr PAO2 = decr PaO2 (room air)
- incr PAO2 = incr PaO2 (supp O2)

not affected by Hct (RBC levels) or SaO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

normal PaO2

A

80-100 mmHg (room air)

decreases w/age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

normal PaO2 for healthy pts calculation

A

PaO2 ~ 5x FiO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

low PaO2 causes

A

lung disease
problems w/alveolar capillary gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
PaO2 can be a quick indicator of
if the pt has healthy or unhealthy lungs
26
SaO2
% of Hb that is saturated w/O2 directly measured: blood sample indirect measure: pulse ox
27
SaO2 factors
Primarily determined by PaO2 - lower PaO2 = lower SaO2 - higher PaO2 = higher SaO2
28
supplementary O2 impacts to SaO2
supp O2 incr PAO2 (incr FiO2) incr PAO2 = incr PaO2 (incr diffusion of O2 into blood) incr PaO2 = incr SaO2 ( Hb can soak up more O2)
29
Other factors that impact SaO2
pH Co2 Temp Anemia 2,3 DPG Carboxyhemoglobin levels Methemoglobin levels these alter the way Hb soaks up O2
30
A-a Gradient
difference in PAO2 and PaO2 - PAO2 (lungs) vs PaO2 (blood) should be small in healthy pts w/good lung diffusion
31
normal A-a Gradient
room air: 5-15mmHg 100% FiO2: 10-110mmHg
32
widened A-a Gradient
expected w/lung disease -impaired alveolar/capillary diffusion PAO2 = normal - O2 can still get into alveoli PaO2 = decreased - more difficult to get O2 into blood
33
Oxyhemoglobin Dissociate Curve (HbO2)
shows how PaO2 determines SaO2
34
PaO2 = 60 mmHg
SaO2 = 90%
35
PaO2 = 27 mmHg
SaO2 = 50%
36
Right Shift HbO2
Hb less affinitive f/O2 - wants to release O2 to tissues - better tissue perfusion Same level of O2 in blood -- Pa O2 no change Hb unable to saturate as much w/O2 -- SaO2 lower If you want to incr SaO2 with a right shift, you need to increase PaO2
37
Right Shift HbO2 causes
acidosis (decr pH) hypventilation (incr CO2) incr 2,3-DPG anemia hyperthermia **when you want better O2 delivery to tissues**
38
Bohr effect
right shift PaCo2 incr O2 displaced from Hb
39
Left Shift HbO2
Hb more affinitive f/O2 - worse tissue perfusion Same level of O2 in blood -- PaO2 no change It does not take much O2 to achieve same SaO2
40
Left Shift HbO2 causes
alkalosis (incr pH) hyperventialtion (decr CO2) decr 2,3-DPG hypothermia CO poisoning (carboxy Hb) CN poisoning (cyano Hb) methemoglobinemia (metheoglobin)
41
P50
the PaO2 which will cause a SaO2 of 50%
42
P50 of 27
when the PaO2 is 27mmHg the SaO2 of an adult is 50%
43
High P50
right shift Hb less affinitive for O2 better tissue perfusion
44
Low P50
left shift Hb more affinitive for O2 worse tissue perfusion
45
P50 Sickle Cell anemia (HbS)
31 mmHg want to be less affinitive for O2 to increase tissue perfusion
46
P50 Pregnancy
30 mmHg want mom to be less affinitive for O2 to donate more O2 to the baby
47
P50 fetal
19 mmHg baby is more affinitive for O2 to steal more O2 from mom
48
P50 packed RBC
18 mmHg low due to depleted 2,3-DPG
49
SaO2 Direct Measurement
draw arterial blood sample - blood gas - ABG
50
SaO2 Indirect Measurement
SpO2 pulse oximetry not always accurate
51
SpO2 monitor
plethysmography - finger volume changes SpO2 pulse rate
52
what indicates adequate pulse measurement in SpO2?
adequate waveform
53
Oxyegenated Hb light absorption
absorbs more IR (940 nm) allows more RED to pass (660nm)
54
De-oxygenated Hb light absorption
absorbs more RED (660 nm) allows more IR to pass (940nm)
55
when is the pulse oximeter accurate?
if it has a good waveformc
56
Causes of bad SpO2 waveform
blood pressure cuff on same side - flattens SpO2 wave on inflation conditions that decr BF to fingers - hypotension - vasoconstriction (NE infusion) - cold extremities (hyperthermia) - low cardiac output motion/shivering
57
SpO2 probe placement
Best: opposite arm as BP cuff (same side as IV)
58
NIBP cuff placement
opposite side as IV
59
alternative pulse ox placements
ear clip nose clip closer to heart = respond more quickly to SpO2 changes (more accurate)
60
SpO2 accuracy
95% accurate when SpO2 >70% (more inaccurate as SpO2 decreases)
61
bad SpO2 waveform treatment
ear/nose probe treat hypotension (if present) warm up extremities
62
SpO2 HR and ECG HR relationship
should be equal if not equal, look for the bad waveform. Trust the one with the good waveform.
63
Low SpO2 Normal SaO2 Causes
**false low reading** bade waveform diagnostic IV dye (MB,indigo carmine) dark nail polish
64
Low SaO2 Normal SpO2
**false normal reading** CO poisoining CN toxicity
65
CO poisoning
CO binds to Hb - CO is 230x more affinitive for Hb displaces O2 - decr SaO2 caboxyhemoglobin forms (COHb) CO absorbs light in same was as O2 - normal SpO2 reading
66
COHb Formation Causes
smoking/smoke inhalation - nonsmokers: 1% - smokers: 8-10% (SpO2: 90%) dried out CO2 absorbant (old type)
67
CO2 absorbant old type fun facts
degradation of VA can produce CO risk increases w/dried out absorbant new CO2 absorbant doesnt degrade VA into CO or compound A
68
CO Poisoning Diagnosis
SaO2: decreased (hypoxic) SpO2: normal or elevated - COHb absorbs same RED as O2 - SpO2 thinks COHb is O2 PaO2: no change No cyanosis - Hb is still bound (skin pink/red)
69
2 methods to confirm CO poisoning
arterial blood gas lab - SaO2 - carboxyhemoglobin saturation - % methemoglobin co-oximeter - special pulse ox for CO detection
69
what has a higher effect on tissue perfusion: SaO2 or PaO2?
SaO2
70
CO poisoning treatment
administer 100% O2 - awake: mask - unconscious: intubate (mech)
71
CN- poisoning
CN- bind to Hb displace O2 creates cyanohemoglobin (CNHb) decreased SaO2 (hypoxia)
72
CN- poisoning diagnosis
SaO2: decreased SaO2 (hypoxia) PaO2: normal SpO2: normal No cyanosis
73
2 methods to confirm CN- poisoning
arterial blood gas Co-oximeter
74
causes of CN- poisoning
high nitroprusside (nipride) smoke inhalation
75
CN- poisoning treatment
Sodium nitrate Sodiam thiosulfate
76
Methemoglobinemia
formation of methemoglobin MetHb iron is oxidized - Fe2+ to Fe3+
77
Causes of MetHb
high dose nitroprusside high dose nitroglycerine local anesthetic in pharynx - benxocaine - cetacaine chemical workers - factory/mine/pesticides
78
nitroprusside
extremely potent vasodilator infusion light sensitive so covered w/ bag
79
nitroglycerin
vasodilator less potent than nipride more common can be bolused
80
MetHb diagnosis
SaO2: decreased (hypoxia) - unable to bind O2 SpO2 reading: 85% PaO2: no change cyanosis
81
Why does the SpO2 read 85% for MetHb
absorbs identical amounts of Red (660nm) and IR (940nm) light
82
MetHb treatment
methylene blue

Sp: PMI (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions