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68 Cards in this Set

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What is the O% in air?
21%
What is the CO2% in air?
0.03%
What is the N% in air?
78%
How much compressed air does an E tank hold?
1900psi(g)
14.3psi(a)
A full E cyclinder will evolve ____L of gaseous O2 at atm.
660L
If a tank pressure is 950 psig, the tank is ___% full. How many L will be left?
50% (950/1900)
330L
How much will 1L of compressed O2 yield of gaseous O2?
150L
How much will 1L of liquid O2 yield of gaseous O2?
850L
The concentration of O2 in alveoli AKA the driving end of O2 pp gradient is the ________ pp between _______ & ___________________________.
Alveolar (PAO2)
Alveolus & Pulm Cap blood (O2 diffuses down gradient into serum)
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!)
REVERSIBLY
Hgb
OxyHgb dissociation curve
What causes the rapid O2 exchange that evens out Hgb saturation in RBC's?
arterial pp (PaO2)
O2 DISSOCIATES from Hgb (per OxyHgb dis curve) down pp gradient into ??? (3)
Capillary wall
Cell
Mitochondria
What is the final step in the oxygen cascade? Where does it happen and at what torr?
O2 combines with free H+; H2O made!
MITOCHONDRIA LEVEL @ 0.5 torr
What does VO2 mean?
Oxygen consumption by the tissues.
What is the final electron acceptor?
Oxygen!
Where is CO2 produced?
Mitochondral Cytosol
***___ production is tightly coupled to ___ consumption***
CO2
O2
What is the normal A-aDO2 gradient?
10 torr (Room Air)
What an FiO2 of 100%, what is the A-aDO2 gradient? What is it due to?
30-50 torr
Anatomic shunt
What is the normal anatomic shunt? Via what veins?
2-5%
Bronchial, pleural, and thebesian veins
What is the A-aDO2 equation?
A-aDO2 = PAO2 - PaO2
Solve for PAO2 =
(PB - PH2O)FiO2 - PaCO2/0.8
What is the Resp Exchange ratio?
Fraction of oxygen consumption(VO2) used for:
Oxidative phosphorylation &
Associated CO2 production
What is the equation for the resp exchange ratio? What does it equal?
VCO2 / VO2
=0.8
The resp exchange ratio compensates for ______ CO2 transferred into the alveolus than _____ removed from.
LESS CO2 transferred than O2 removed
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?
a-ADO2
Nl > 0.75
O2 is carried in combination with _____ AND dissolved in __________
Hgb
Plasma
O2 transport is a fxn of: (3)
CO
Hgb
Hgb affinity for O2
1 gm of Hgb carries ________ mL O2
1.34
O2 is not dissolved nor yielding a pp when its?
Bound to Hgb
What does the OxyHgb curve show?
Varying O2 tensions in correlation with O2 saturation.
During a L shift, what does Hgb do to O2?
HOLDS onto it!
When can blood exchange large amounts of O2 with small changes in O2 tension?
B/t 20-80 torr
This maintains the driving pressure b/t bld & tissues
What is the definition for P50?
O2 tension at which 50% of Hgb is saturated
(37 C, 40 torr, pH 7.4)
What does oxygen content involve?
O2 dissolved & bound to Hgb
What is the value to O2 in plasma?
0.003mL O2/dl plasma/torr

1dL = 100mL
What is the nl O2 content in arterial blood(CaO2)?
20gm %
What is the nl O2 content in venous blood (CvO2)?
15 gm %
What is the OXYGEN CONTENT equation?
CaO2 = (Hgb x 1.34 x SaO2) -Oxygen attached to Hgb + (PaO2 x 0.003) - Oxygen dissolved in plasma
What is the equation for O2 transport?
TO2 = CaO2 x CO
(TO2 may exceed DO2)
ex: AV fistula
What is the equation for O2 delivery?
DO2 = CO x CaO2
ex: Taken up by tissues
What is the equation for O2 consumption?
VO2 = CO x C(a-v)O2
Assuming no shunt
NL = 250 ml/min
(~3mg/kg/min)
Nl venous O2 = ?
40 torr
70% saturation
O2 content = 15 gm %
Anesthesia affects oxygenation by ?
~10-15% CO shunt
Atelectasis
VQ mismatch worse when low TV.
During GA, what is the lowest acceptable FiO2?
30%
If 1L NC is 24% FiO2, what is 4L NC?
36%
What are the advantages of O2 use in Anesthesia?
Dec inc of post-op infxn
Dec PONV
Improved oxygenation of marg perf tissues
Red risk of liability in hypoxia-related injuries
What does the HBO do?
Inc HP, O2 tension, N gradient & O2 supply, tissue oxygenation, slows clostridea growth D/T PO2 > 250 torr
HBO uses?
Decompression sickness
Crush injuries, skin grafts
Chr. Osteomyelitis
Is bacteriostatic
CO poisoning, cyanide tox, acute severe anemia
HBO Toxicity D/T
Superoxides
Singlet O2
Hydroxyl radical
Hydrogen peroxide
Key point for CO poisoning
CO reversibly binds to Hgb 200x > O2
CARBOXYHGB interferes w/ BINDING & DISSOCIATION of O2 & Hgb
How is CO poisoning dx'd?
Co-oximeter (Diff. carboxy & oxy Hgb)
S/sxs of CO poisoning?
HA,NV, NO cyanosis, PaO2 NORMAL on ABG, pulse ox FALSELY HIGH
CarboxyHgb cause what kind of shift on the dissociationn curve?
LEFT
What is the early warning of hypoxemia?
O2 sat < 90%
PaO2 of 60 torr or less.
What is the ETCO2 in vol %? torr?
4-6 vol %
35-45 torr
At rest, how much CO2 do we produce?
2/5mL CO2/kg/min
What is hypoxia?
Red of oxygen supply to a tissue
RESULT: CYANOSIS
Cessation of oxid. phosphorylation @ mito level =
LACTATE/PYRUVATE RATIOS RISE
ATP/ADP RATIOS FALL!
Hypoxia causes what kind of damage?
IRREVERSIBLE damage
Occurs w/i 4-5 minutes
What is a major effect of hypoxia?
INTRACELLULAR ACIDOSIS
What is hypoxemia? What is it D/T?
Deficient oxygenation of the blood.
PaO2 <60 torr, PvO2 < 30 torr
Dec PAO2 or true pulm shunt
When venous blood from bronchial, thebesian, and the L heart enter the LA & LV, it is called what?
Anatomic shunt
R heart blood enters the L heart WITHOUT exchanging alveolar gas D/T?
True (Absolute) Shunt
What does NOT improve a true shunt? What causes it?
Increasing the FiO2
Atelectasis, Pulm edema, Bilat pneumonia
What are the compensating factors in a true shunt?
Inc CO
Dec O2 utilizaton which causes:
Inc A-aDO2 systemic shunt

Pulm distribution perf changes DECREASE shunt
What is the most common cause of hypoxemia?
Relative shunt (VQ mismatch)
What is the nl V/Q?
>0.75
What helps differentiate b/w VQ mm & true shunt?
O2
What is the Intrapulm Shunt Fraction?
Qs/Qt =
A-aDO2 (0.003) / (CaO2 - CvO2) + (A-aDO2)(0.003)

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