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L2
Ventilation
29
Physiology
Professional
02/07/2013

Additional Physiology Flashcards

 


 

Cards

Term
How do you calculate ventilation?
Definition
volume x frequency
(volume per time)
ml/min
Term
The total volume of air in the lung is partitioned into what four primary volumes?
Definition
Tidal volume, inspiratory reserve volume, expiratory reserve volume, residual volume
Term
What is the average tidal volume?
Definition

Vt = 500 mL

tidal volume = volume of air inhaled and exhaled during one breath

Term
What is the average inspiratory reserve volume?
Definition

IRV = 3000 mL

IRV = the volume of air that can be inspired above tidal volume

Term
What is the average expiratory reserve volume?
Definition

ERV = 1300 mL

ERV = the volume of air that can be expired below tidal volume

Term
What is the average residual volume?
Definition

RV = 1200 mL -

RV = the volume of air remaining in the lung that cannot be exhaled

Term
What cannot be measured using a spirometer?
Definition
total lung capacity, functional residual capacity, residual volume
Term
What is the functional residual capacity?
Definition

FRC = the volume of air in lungs when you are not trying to inhale or exhale

FRC = ERV + RV = 2500 mL

Term
What is the vital capacity?
Definition
Vital capacity = the maximum range of volumes reached by inspiratory and expiratory efforts Vital capacity = IRV + Vt + ERV = 4800 mL
Term
What is total lung capacity and what is its average volume?
Definition

Total lung capacity is the maximum amount of air that can be voluntarily inspired.

TLC = IRV + Vt + ERV +RV = 6000 mL

Term
What are the four primary lung capacities?
Definition

functional residual capacity, inspiratory capacity, vital capacity, total lung capacity

 

 

Term
What is the inspiratory capacity?
Definition

IC is the maximum range of volumes reached by inspiratory efforts

IC = Vt + IRV = 3500 mL

Term
What two ways can you measure residual volume?
Definition

Helium gas dilution technique:

C1 x V1 = C2 x (V1 + V2)

 

Body plethysmograph:

P1V1 = P2V2 (Boyle's Law)

Term
What is Vdot?
Definition
V = volume and 'dot' stands for "per unit time" ... so it is referring to the total amount of air moved in or out of the lungs per unit time (usually one minute)
Term
What is total ventilation (VdotE) ?
Definition
total ventilation is equal to dead space ventilation plus alveolar space ventilation
Term
What is effective ventilation? ineffective ventilation?
Definition

effective = alveolar ventilation

ineffective = dead space ventilation

Term
How is alveolar ventilation related to concentration of CO2 in the exhaled air?
Definition
it is inversely related -- as CO2 increases, alveolar ventilation decreases
Term
What is the best clinical measure of effective ventilation?
Definition
arterial pCO2
Term
What pressure of CO2 in arterial blood is considered to be hypercapnia/acidosis?
Definition
>45 mmHg
Term
what is the capacity of the anatomical dead zone?
Definition
150 mL
Term
what is the clinical expedient for measuring anatomic dead space ?
Definition
pts weight in lbs = mL dead space
Term
What methods are used to measure anatomic dead space?
Definition
oxygen inhalation (Fowler's technique) or nitrogen washout
Term
how much of the normal tidal volume inspiration is "dirty" air?
Definition
150 mL
Term

What is the normal percentage of nitrogen concentration in the alveolar space?

What about after Fowler's method?

Definition

normal -- 80%

After Fowler's method -- 40%

 

Term
what is physiologic dead space?
Definition
it the volume of anatomic dead space plus the volume of alveolated airways that have poor pulmonary perfusion
Term
what is the volume of physiologic dead space?
Definition
160 mL
Term
which part of the lung has the greatest ventilation?
Definition
the basal lung
Term
what is the anatomical reason that the base of the lung receives the highest ventilation? physiological reason?
Definition
it has the most lung tissue; gravity
Term
where in the lung are alveoli most compliant?
Definition
at the base of the lung
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