Anatomy And Physiology Of Respiratory System

Front 1

What constitutes a lobular unit?

Back 1

Interlobular septa (pulm veins and lymphatics)

Centrilobular (pulm artery and bronchioles)

Lobular (lung acini)

Front 2

What is surfactant composed of?

Back 2

Lipid (90%) DPCC

Protein (10%)

-SP-A, , SP-D: innate immunity of the lung

- SP-B, SP-C: reduces surface tension

-ABCA3: role in transport surfactant

-TTF-1: role in surfactant regulation

Front 3

What are the surfactant dysfunction disorders?

Back 3

Neonatal ARDS

Pulmonary alveolar proteinosis

Front 4

What factors can increases total PVR?

Back 4

Lung compression

Increased lung volume

Gravity

Increase interstital pressure

Increase blood viscosity

Positive pressure ventilation

Hypoxia

Sympathetic nerve stimulation

Front 5

how to calculate PAO2?

Back 5

PAO2 = FiO2 (barometric pressure - water vapor partial pressure) -PaCO2/R

Front 6

How to calculate alveolar ventilation?

Back 6

VA = Minute ventilation - dead space

Front 7

How to calculate physiologic dead space?

Back 7

VDCO2/VT = (PaCO2- Endtidal CO2)/PaCO2

Front 8

How to calculate Arterial O2 content CaO2?

Back 8

CaO2 = (1.34 x Hb x SpO2) + (0.003 x PaO2)

Front 9

How to calculate O2 delivery DO2?

Back 9

DO2 = cardiac output x arterial O2 content

Front 10

What is the normal V/Q ratio?

Back 10

0.6-3.0

Front 11

How to calculate shunt fraction?

Back 11

1. Need to put patient on 100% O2 for 20-30minutes

2. obtain ABG and mix venous O2 and calculate PAO2 ( a substitute for end-capillary O2 content.

3. Qs/Qt = (CcO2- CaO2)/ (CcO2- CvO2)

Front 12

How to get the most accurate pulmonary artery pressure?

Back 12

To minimize influences of the pressure differences in the 3 lung zones, need to acquire data when alveolar pressure is the lowest

-catheter tip needs to be in zone 3

-acquire data at end expiration

Front 13

What factors limits gas diffuse/transfer?

Back 13

diffuse surface

molecular weight/ hb binding

the pressure gradient across membranes

perfusion.

Front 14

Wha are the two general limitations for gas transfer?

Back 14

Perfusion limited: example O2 and CO2 and nitrous Oxide

Diffusion limited: example carbon monoxide

Front 15

How to do an internal validation of the blood gas?

Back 15

H+ (nmol) = (24 x PCO2)/bicarb

every 1 change of H+ = 0.01 pH change

40nmol = 7.40

Front 16

How does lung volume changes during pregnancy?

Back 16

Reduced RV and FRC.

TLC is only mildly decreased in the third trimester.

Tidal volume increases due to increased progesterone.

Front 17

What ABG changes are expected during pregnancy?

Back 17

Increased PO2 and decreased PCO2

Front 18

How does PFT changes when aging?

Back 18

FEV1 decreases

VC decreases

RV increases

Front 19

What's considered an acceptable spirometry?

Back 19

Good start: extrapolated volume < 5% or FVC < 150cc

Exhalation to RV, time > 6s

Absence of artifact

Front 20

What's considered an reproducible spirometry?

Back 20

Two largest FEV1 and FVC within 150cc of each other

Front 21

What's the prerequisites before doing a bronchodilator response test?

Back 21

Avoid SABA > 4hrs

Avoid LABA > 12hrs

Front 22

What's the limitation of body plephysmography?

Back 22

Expensive, and space consuming

Exceeding 1 pant/sec results in overestimation of FRC

Front 23

What's the limitation of gas dilution techiques, nitrogen washout, helium rebreathing?

Back 23

It doesn't measure the trapped air, underestimate lung volume.

Front 24

What's considered a good single breath test for DLCO?

Back 24

Inhaled gas < 4 seconds

Breath hold 8-12seconds

Exhaled rapidly < 4 second

Exhaled volume is >85% of largest VC.

Front 25

True/False:

DLCO is the highest in the mornings.

Back 25

True

Front 26

True/False:

DLCO is elevated in the premense period

Back 26

True

Front 27

What are the contraindications for methocholine challenge?

Back 27

ABSOLUTE:

Severe airflow limitation (FEV1 < 50%)

MI or CVA within in the last 3months

Uncontrolled HTN (>200/100)

Known aortic aneurysm

RELATIVE:

FEV1 <60%

Pregnancy/Nursing/

On myasthenia gravis meds.

Front 28

What medications to hold prior to methocholine challenge?

Back 28

SABA: 8hrs

SAMA 24hrs

LABA: 48hrs

LAMA: 7 days

Theophyline (short acting): 24hrs

Theophyline (long acting): 48hr

Front 29

What's consider + exercise challenge test?

Back 29

15% decreased FEV1

Front 30

How does DLCO changes with pregnancy?

Back 30

Increase in the first trimester, then decreases

Front 31

What are the absolute contraindication for CPETs?

Back 31

uncontrolled cardiac issues

DVTs

Osat < 85% at rest

Front 32

How does cardiac output changes with exercises?

Back 32

Initially increased through increased SV and HR. As the work rate increased, CO increases almost exclusively with increased HR.

Front 33

How does BP changes with exercise?

Back 33

Systolic pressure increases

diastolic pressure stay the same

Front 34

How does ventilation changes with exercises?

Back 34

At low exercise, tidal volume increases at the expenses of IRV.

At peak exercise, increased ventilation is largely driven by increased RR.

Front 35

What's the considered normal anaerobic threshhold?

Back 35

>40% of Vo2Max

Front 36

How to calculate maximum heart rate?

Back 36

220-age

Front 37

What's an abnormal ventilatory reserve?

Back 37

VeMax is > 70% of MVV

Front 38

What to think about if there is cyclical flutuation in minute ventilation during exercise?

Back 38

congestive heart failure.

Front 39

What is the normal Ve/Vco2 at AT?

Back 39

32-34

Front 40

Usually end-tidal O2 increases before end-tidal CO2 during exercise, what is the explaination when end-tidal CO2 does not increase?

Back 40

Increased dead space.

Front 41

What is acetozalmide good for in high altitude?

Back 41

prevention, usually advise to take one day prior to rapid ascend

Front 42

What can cause elevated Ve/Vco2?

Back 42

Early AT (due to elevated Vco2)

Hyperventilation syndrome

Increased deadspace

can be seen in CHF, COPD, ILD, PH (very high level)

Front 43

What does end-expiratory lung volume do during exercise?

Back 43

It decreases, to recruit inspiratory volume.

Front 44

What's the reason why EELV may sometime increased during exercise, in diseased patients?

Back 44

At low EELV, breathing are limited by low expiratory flow. Subject increases EELV in order to avoid expiratory flow limitations.

Front 45

What's the reason why EILV (end inspiratory lung volume) are increased during exercises?

Back 45

To increase Tidal volume. In diseased lung where EILV cannot be increased, respirate rate is increased to maintain minute ventilation.

Front 46

Back 46

Obesity

Front 47

Back 47

Restrictive lung disease

Front 48

Back 48

COPD

Front 49

Back 49

Normal

Front 50

True/False:

A-a gradient remains normal during pregnancy

Back 50

False, there is an increase in A-a gradient during pregnancy