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Flashcards in Lung Volumes Deck (13)
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1
Q

Vt
TLC
RV

A

Volume inhaled or exhaled each breath

Volume in lung after max inspiration

Volume remained in lung after max exp

2
Q

VC

FRC

A

Max volume that can be exhaled after max inspiration

Volume remaing in lung after normal expiration

3
Q

IRV
ERV
IC

A

Max volume inhaled starting at end of normla inspiration

Max volume exhaled starting at end of normal expiration

Max volume that can be inhaled starting at end of a normal expiration

4
Q

What influences lung volume (non-postural)

A

Age, height and gender…as age and heigh increase, vital capacity decreases

5
Q

What cannot be measured by spirometry?

A

RV, TLC, and FRC

6
Q

Postural influences on LVs

A

Difference generated by weight of abdominal contents and more exaggerrated in obese patients

Sitting or standing has lower IRV with higher ERV…TLC and VC are the same…this makes IC lower in sitting and standing and FRC higher

7
Q

Equation TLC

A

TLC = FRC + IC = VC + RV

8
Q

Lung dz effects

A

Restrictive - lower everything…change in elastic property of the lung…TLC and FRC lowered with VC

Obstructive - increase in airway resistance…higher TLC and FRC…but VC compromised

9
Q

FRC determination helium

A

Helium dilution method

Helium not taken up by pulmonary blood circulation

Inital amount of helium in system - C1 * V1

After = C2 * (V1+FRC)

FRC=(V1(C1-C2))/C2

10
Q

Body plethysmograph method

A

Uses Boyle’s law

P*V=constant

Patient instructed to exhale against a closed shutter at the mouthpiece…pressure in lung will increase and pressure in box will decrease

11
Q

Difference of measurement methods

A

SHould not be different in healthy

If individual has a portion of the lung obstructed, then they are not exposed to helium…technically still part of FRC but cannot be detected by helium…body pleythysmoraphg method CAN detect this

12
Q

FRC by body plethysmograph also called

A

Thoracic gas volume

13
Q

Why is body plethysmograph method often higher than helium?

A

Alveoli distal to obstruction cannot be reached by helium gas…bc of compressibility of tthe air, it can still be changed so included with body plethysmograph

Difference between two can suggest obstruction in the intra-pulmonary airways