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Flashcards in Environment Deck (31):
1

At steady state,
1. Lung O2 uptake rate=
2. Cell CO2 production rate=

1. Cell O2 utilization rate
2. Lung CO2 release rate

2

Alveolar Air is a mixture of ___

Fresh air from environment
Used are leaving from blood (tissues)

3

Alveolar CO2 and O2 pressures:
____ O2 than inspired air
___ CO2 than inspired air

Less
More

4

1. O2 from alveolar air dissolves into ____
2. CO2 leaves the ____ and enters alveolar air.

Pulmonary capillary plasma (both answers)

5

Alveolar air represents best case for ____.
Most ___
Least ___

Arterial blood
O2
CO2

6

Primary symbols in respiratory phys:
Describe

Designates variable being measured
Dot over main symbol
Upper case letters
First derivative with respect to time

7

What are the standard primary symbols?

P= pressure
V= volume (gas)
Q= volume (or qty blood)
C= content (ml/gas/dl blood)
F= fractional concentration (no units)
S= saturation (% or fraction)

8

Secondary symbols in respiratory phys:
Describe

Designated site where first symbol was measured
Bar over symbol: a mean or mixed sample
Prime after symbol: end of a structure or respiratory maneuver

9

What are the standard secondary symbols?

I= inspired air
E= expired air
A= alveolar gas
a= arterial blood
v= venous blood
c= capillary blood
T= tidal gas
D= dead space

10

Tertiary symbols in respiratory phys:
Describe

Designated the respiratory gas
Usually O2, CO2, or N3
Sub-script (or original line)

11

Partial pressure is ___

The pressure exerted by each gas in a mixture, independent of other gases present
Equal to the pressure that would exist if that gas alone occupied the whole volume

12

fractional composition of dry atmosphere:
1. Nitrogen
2. Oxygen
3. Argon
4. Carbon Dioxide
5. Other
(Calculated by adding pressure of each)

1. 0.78
2. 0.209
3. 0.009
4. 0.0005
5. 0.0015

13

Pgas x= ____

Fgas x • PB

14

PB =

PN2 + PO2 + PAr + PCO2 + PH2O (temp dependent)

15

What is the vapor pressure in mmHg for a temp of 37 C (body temp)?

47
So PH2O=47 mmHg

16

What is the ideal gas law?

PV=nRT

17

Ambient Temp and Pressure Saturate (ATPS) conditions:

Temp= room temp
Pressure= ambient pressure
Saturated at room temp
Exists in equipment
*Never use on patients chart

18

Body temp and pressure saturated (BTPS) conditions

Temp= 37 C
Pressure= ambient pressure corrected for H2O (PB-47)
Saturated with water vapor=47 mmHg
*used to chart almost all volumes and flow
EXCEPT:
-VO2
-VCO2
-diffusing capacity

19

Standard temp and pressure dry (STPD) conditions:

Temp= 0 C (273 K)
Pressure = 760 mmHg
No water vapor
*Always use to chart:
-oxygen uptake, VO2
-CO2 production, VCO2
-diffusing capacity, DLCO

20

What is Henry's Law?

The concentration of a dissolved gas is directly proportional to the partial pressure of that gas in the gas phase
- [gas] dissolved = alpha • Pgas

21

Solubility coefficient (alpha) for CO2 and O2 in physiological units
(ml gas/dl blood) / mmHg

CO2= 0.075
O2= 0.003

22

Diffusivity (D) =

Solubility of gas / the square root of molecular weight

23

True or false:
Each gas has a unique value for Diffusivity(D).
It depends on membrane A or T.
It is essentially a diffusion coefficient.

First statement is true
Second is false. Doesn't depend on those
Third is true

24

Diffusing capacity of the lung (DL) =

(A•D)/T
Also
Vgas/(P1-P2)

Where A is area
T is thickness

25

Strategy for measuring DL clinically

Determine uptake rate of a gas at a given partial pressure gradient
Gas specific
Use carbon monoxide? (DLCO)

26

What is the advantage to using DLCO (Carbon Monoxide Diffusing Capacity)?

Virtually no back pressure
Hb binding with high affinity
Low solubility

27

Describe single breath DLCO

Single inspiration of a dilute CO mixture (0.2%)
10 second breath hold
Normal value is 25 ml/min/mmHg (increases with exercises)

28

DLCO (increases/decreases) with
1. loss of surface area
2. increasing membrane thickness.
3. Increase ventilation/perfusion mismatching

Decreases
Decreases
Decreases

29

True or false.
DLCO is a better index of overall lung function than of diffusion capabilities

True

30

Normal values for each of the following:
1. PO2 inspired air
2. PO2 alveolar air
3. PO2 arterial blood
4. PO2 mixed venous blood

1. 150 mmHg
2. 100 mmHg
3. 80-95 mmHg
4. 40 mmHg

31

Normal values for each of the following:
1. PCO2 inspired air
2. PCO2 alveolar air
3. PCO2 arterial blood
4. PCO2 mixed venous blood

1. 0 mmHg
2. 40 mmHg
3. 40 mmHg
4. 45 mmHg