Math Stuff

Question 1

Calculation for RQ

Answer 1

RQ= CO2 produced
———————
O2 consumed

Question 2

RQ for average diet

Answer 2

0.8

Question 3

RQ for all Carbs diet

Answer 3

1.0

Question 4

RQ for all fat diet

Answer 4

0.7

Question 5

RQ for all protein diet

Answer 5

0.8

Question 6

Fick’s Law (Rate of Diffusion)

Answer 6

D x A x 🔺P
Vx= —————-
🔺X

D= Diffusion coefficient

A= surface area

P= partial pressure diff

X= membrane thickness

Question 7

Inspiratory capacity

IC=

Answer 7

IC= Vt + IRV

Question 8

Vital Capacity

VC=

Answer 8

VC= IRV + Vt + ERV

Question 9

Functional Residual Capacity

FRC=

Answer 9

FRC= ERV + RV

Question 10

Total Lung Capacity

TLC=

Answer 10

TLC= VC+ RV

Question 11

RV
—— should normally equal=?
TLC

What is it in obstructive?
WHat is it in restrictive?

Answer 11

Should be .25 or less

Increases with both restrictive and obstructive

Question 12

FEV1
——- should normally equal ?
FVC

How does it change in obstructive?
How does it change in restrictive?

Answer 12

Normally 0.8

Obstructive= lower

Restrictive= higher

Question 13

Physiological Dead Space (Vd)

2 ways

Answer 13

Vd= anatomical dead space + functional dead space in alveoli

Vd= Vt x PaCO2 - PECO2
———————
PaCO2

PECO2= CO2 in expired air
PaCO2= CO2 in arterial blood
Vt= tidal volume

Question 14

Minute ventilation

Answer 14

=Vt x #breaths/min

Question 15

Alveolar ventilation (Va)

2 ways

Answer 15

Va= (Vt-Vd) x #breaths/min

Or
VCO2 x K
Va= ————-
PACO2

VCO2=rate of CO2 production
K= constant (will be given)

Question 16

Transmural Pressure

Answer 16

Tp= Alveolar Pressure-Intrapleural Pressure

Question 17

Compliance

Answer 17

🔺V
C= ——
🔺P

(Or you can measure the slope on a graph (rise over run)

Question 18

Lap of Laplace (Collapsing Pressure of alveolus)

Answer 18

2T
P=——
r

P=collapsing pressure
T= surface tension
r= alveolar radius

Question 19

Airflow (Q)

Answer 19

🔺P
Q= ——
R

Q= airflow rate
R= airway resistance

Question 20

Poiseuille’s Law (Resistance)

Answer 20

8 η x L
R=———
πr^4

η= viscosity of inspired air
L= length
r=airway radius
R=resistance

~~note that Resistance is Inversely proportional to r^4~~

Question 21

Henry’s Law (Concentration of a dissolved Gas, Cx)

Answer 21

Cx= P x solubility

P= partial pressure of the gas

Solubility constant will be given

Question 22

Dalton’s Law of Partial Pressure of a Gas (Px)

Not corrected for humidified air

Answer 22

Px= Pb x F

Pb= barometric Pressure

F= fractional concentration of a gas

F=0.21 for oxygen!!

Question 23

What does F= if you are dealing with oxygen

Answer 23

F=0.21

F is the fractional concetration of a gas

Question 24

Dalton’s Law of Partial Pressure of a gas (Px)

Corrected for humidified air

Answer 24

Px= (Pb- 47) x F

47 is the Pressure of H2O
F will be 0.21 if you’re asked about oxygen

Question 25

O2 binding capacity

Answer 25

Amount O2 bound to Hb
= ——————————-
100mL

Question 26

What is the normal concentration of Hb?

Answer 26

15g/dL

1 dL is the same thing as 100mL

Question 27

How much oxygen will one g of Hb bind?

Answer 27

1.34mL

                                                                                                20.1mL oxygen Normal O2 binding capacity of blood  15 x 1.34= ——————-——-
                                                                                                      100mL

Question 28

What is a normal V/Q

Answer 28

0.8

This means that alveolar ventilation is 80% of pulmonary blood flow

Question 29

A-a gradient

2 ways

Answer 29

=PAO2-PaO2 (Alveolar- arterial)

Or

= PIO2- PACO2
———- -PaO2
RQ

(This one was hard to format and it’s not quite right. There should be brackets around the PIO2 and the fraction)