Oxygen

Front 1

What is the O% in air?

Back 1

21%

Front 2

What is the CO2% in air?

Back 2

0.03%

Front 3

What is the N% in air?

Back 3

78%

Front 4

How much compressed air does an E tank hold?

Back 4

1900psi(g)
14.3psi(a)

Front 5

A full E cyclinder will evolve ____L of gaseous O2 at atm.

Back 5

660L

Front 6

If a tank pressure is 950 psig, the tank is ___% full. How many L will be left?

Back 6

50% (950/1900)
330L

Front 7

How much will 1L of compressed O2 yield of gaseous O2?

Back 7

150L

Front 8

How much will 1L of liquid O2 yield of gaseous O2?

Back 8

850L

Front 9

The concentration of O2 in alveoli AKA the driving end of O2 pp gradient is the ________ pp between _______ & ___________________________.

Back 9

Alveolar (PAO2)
Alveolus & Pulm Cap blood (O2 diffuses down gradient into serum)

Front 10

How does O2 bind when it is in serum and it enters the RBC? Wht does it bind to? Based on what? (Hope this last question makes sense to ya'll!)

Back 10

REVERSIBLY
Hgb
OxyHgb dissociation curve

Front 11

What causes the rapid O2 exchange that evens out Hgb saturation in RBC's?

Back 11

arterial pp (PaO2)

Front 12

O2 DISSOCIATES from Hgb (per OxyHgb dis curve) down pp gradient into ??? (3)

Back 12

Capillary wall
Cell
Mitochondria

Front 13

What is the final step in the oxygen cascade? Where does it happen and at what torr?

Back 13

O2 combines with free H+; H2O made!
MITOCHONDRIA LEVEL @ 0.5 torr

Front 14

What does VO2 mean?

Back 14

Oxygen consumption by the tissues.

Front 15

What is the final electron acceptor?

Back 15

Oxygen!

Front 16

Where is CO2 produced?

Back 16

Mitochondral Cytosol

Front 17

***___ production is tightly coupled to ___ consumption***

Back 17

CO2
O2

Front 18

What is the normal A-aDO2 gradient?

Back 18

10 torr (Room Air)

Front 19

What an FiO2 of 100%, what is the A-aDO2 gradient? What is it due to?

Back 19

30-50 torr
Anatomic shunt

Front 20

What is the normal anatomic shunt? Via what veins?

Back 20

2-5%
Bronchial, pleural, and thebesian veins

Front 21

What is the A-aDO2 equation?

Back 21

A-aDO2 = PAO2 - PaO2
Solve for PAO2 =
(PB - PH2O)FiO2 - PaCO2/0.8

Front 22

What is the Resp Exchange ratio?

Back 22

Fraction of oxygen consumption(VO2) used for:
Oxidative phosphorylation &
Associated CO2 production

Front 23

What is the equation for the resp exchange ratio? What does it equal?

Back 23

VCO2 / VO2
=0.8

Front 24

The resp exchange ratio compensates for ______ CO2 transferred into the alveolus than _____ removed from.

Back 24

LESS CO2 transferred than O2 removed

Front 25

Since the A-aDO2 changes with varying conc of FiO2, what is used instead D/T its staying relatively constant regardless of FiO2? What is the normal value?

Back 25

a-ADO2
Nl > 0.75

Front 26

O2 is carried in combination with _____ AND dissolved in __________

Back 26

Hgb
Plasma

Front 27

O2 transport is a fxn of: (3)

Back 27

CO
Hgb
Hgb affinity for O2

Front 28

1 gm of Hgb carries ________ mL O2

Back 28

1.34

Front 29

O2 is not dissolved nor yielding a pp when its?

Back 29

Bound to Hgb

Front 30

What does the OxyHgb curve show?

Back 30

Varying O2 tensions in correlation with O2 saturation.

Front 31

During a L shift, what does Hgb do to O2?

Back 31

HOLDS onto it!

Front 32

When can blood exchange large amounts of O2 with small changes in O2 tension?

Back 32

B/t 20-80 torr
This maintains the driving pressure b/t bld & tissues

Front 33

What is the definition for P50?

Back 33

O2 tension at which 50% of Hgb is saturated
(37 C, 40 torr, pH 7.4)

Front 34

What does oxygen content involve?

Back 34

O2 dissolved & bound to Hgb

Front 35

What is the value to O2 in plasma?

Back 35

0.003mL O2/dl plasma/torr

1dL = 100mL

Front 36

What is the nl O2 content in arterial blood(CaO2)?

Back 36

20gm %

Front 37

What is the nl O2 content in venous blood (CvO2)?

Back 37

15 gm %

Front 38

What is the OXYGEN CONTENT equation?

Back 38

CaO2 = (Hgb x 1.34 x SaO2) -Oxygen attached to Hgb + (PaO2 x 0.003) - Oxygen dissolved in plasma

Front 39

What is the equation for O2 transport?

Back 39

TO2 = CaO2 x CO
(TO2 may exceed DO2)
ex: AV fistula

Front 40

What is the equation for O2 delivery?

Back 40

DO2 = CO x CaO2
ex: Taken up by tissues

Front 41

What is the equation for O2 consumption?

Back 41

VO2 = CO x C(a-v)O2
Assuming no shunt
NL = 250 ml/min
(~3mg/kg/min)

Front 42

Nl venous O2 = ?

Back 42

40 torr
70% saturation
O2 content = 15 gm %

Front 43

Anesthesia affects oxygenation by ?

Back 43

~10-15% CO shunt
Atelectasis
VQ mismatch worse when low TV.

Front 44

During GA, what is the lowest acceptable FiO2?

Back 44

30%

Front 45

If 1L NC is 24% FiO2, what is 4L NC?

Back 45

36%

Front 46

What are the advantages of O2 use in Anesthesia?

Back 46

Dec inc of post-op infxn
Dec PONV
Improved oxygenation of marg perf tissues
Red risk of liability in hypoxia-related injuries

Front 47

What does the HBO do?

Back 47

Inc HP, O2 tension, N gradient & O2 supply, tissue oxygenation, slows clostridea growth D/T PO2 > 250 torr

Front 48

HBO uses?

Back 48

Decompression sickness
Crush injuries, skin grafts
Chr. Osteomyelitis
Is bacteriostatic
CO poisoning, cyanide tox, acute severe anemia

Front 49

HBO Toxicity D/T

Back 49

Superoxides
Singlet O2
Hydroxyl radical
Hydrogen peroxide

Front 50

Key point for CO poisoning

Back 50

CO reversibly binds to Hgb 200x > O2
CARBOXYHGB interferes w/ BINDING & DISSOCIATION of O2 & Hgb

Front 51

How is CO poisoning dx'd?

Back 51

Co-oximeter (Diff. carboxy & oxy Hgb)

Front 52

S/sxs of CO poisoning?

Back 52

HA,NV, NO cyanosis, PaO2 NORMAL on ABG, pulse ox FALSELY HIGH

Front 53

CarboxyHgb cause what kind of shift on the dissociationn curve?

Back 53

LEFT

Front 54

What is the early warning of hypoxemia?

Back 54

O2 sat < 90%
PaO2 of 60 torr or less.

Front 55

What is the ETCO2 in vol %? torr?

Back 55

4-6 vol %
35-45 torr

Front 56

At rest, how much CO2 do we produce?

Back 56

2/5mL CO2/kg/min

Front 57

What is hypoxia?

Back 57

Red of oxygen supply to a tissue
RESULT: CYANOSIS
Cessation of oxid. phosphorylation @ mito level =
LACTATE/PYRUVATE RATIOS RISE
ATP/ADP RATIOS FALL!

Front 58

Hypoxia causes what kind of damage?

Back 58

IRREVERSIBLE damage
Occurs w/i 4-5 minutes

Front 59

What is a major effect of hypoxia?

Back 59

INTRACELLULAR ACIDOSIS

Front 60

What is hypoxemia? What is it D/T?

Back 60

Deficient oxygenation of the blood.
PaO2 <60 torr, PvO2 < 30 torr
Dec PAO2 or true pulm shunt

Front 61

When venous blood from bronchial, thebesian, and the L heart enter the LA & LV, it is called what?

Back 61

Anatomic shunt

Front 62

R heart blood enters the L heart WITHOUT exchanging alveolar gas D/T?

Back 62

True (Absolute) Shunt

Front 63

What does NOT improve a true shunt? What causes it?

Back 63

Increasing the FiO2
Atelectasis, Pulm edema, Bilat pneumonia

Front 64

What are the compensating factors in a true shunt?

Back 64

Inc CO
Dec O2 utilizaton which causes:
Inc A-aDO2 systemic shunt

Pulm distribution perf changes DECREASE shunt

Front 65

What is the most common cause of hypoxemia?

Back 65

Relative shunt (VQ mismatch)

Front 66

What is the nl V/Q?

Back 66

>0.75

Front 67

What helps differentiate b/w VQ mm & true shunt?

Back 67

O2

Front 68

What is the Intrapulm Shunt Fraction?

Back 68

Qs/Qt =
A-aDO2 (0.003) / (CaO2 - CvO2) + (A-aDO2)(0.003)

CaO2 - CvO2 = 5
0.003 = Sol coefficient O2 in plasma