Tidal Volume (TV)
amount of air inhaled or exhaled with each breath under resting conditions
Normal tidal volume of adult
Inspiratory Reserve Volume (IRV)
Amount of air that can be forcefully inhaled after a normal tidal volume inhalation
normal inspiratory reserve of adult
Expiraotry reserve volume
amount of air that can forcefully exhaled after a normal TV
normal expiratory reserve volume (ERV)
Residual Volume (RV)
Amount of air remaining in the lungs after a forced exhalation
normal residual volume
1200 mL (Females 1000 mL)
Vital Capacity (VC)
max amount of air exhaled after a maximal inspiration
normal vital capacity
4800ml (Female= 3200 mL)
the volume of air inhaled after a normal exhale
normal inspiratory capacity volume
M= 3600 mL
Functional Residual Capacity (FRC)
volume of air remaining in the lungs after a normal tidal volume expiration
normal functional residual capacity
Males: 2400 ml
Females: 1800 ml
Total Lung Capacity (TLC)
maximum amount of air contained in lungs after a maximum inspiratory effort
closed circuit helium dilution
way of measuring FRC. Closed circuit system where spirometer is filled w/ mixture of Helium and o2
Open circuit nitrogen washout method
Pt breaths 100% O2 for about 7 min or until all the nitrogen is washed out of pt's lungs while a PFT measures the exhaled nitrogen
Test calculations depend on fact: air is 79% nitrogen so amt of nitrogen exhaled should be 79% of TLC
Body Plethysmography (Body Box)
Individual is enclosed in a small, airtight chamber. The person's nostrils is clipped, and h/she is breathes against a mouthpiece. As the individual breathes, the air pressure and volume in the chamber change in accordance with the movements of the chest
forced expiratory volume in 1 second
FVC (forced vital capacity)
The amount of air forcefully expired after a maximal inspiration
The fraction of air exhaled in the first second relative to the total volume exhaled
FEF 25-75% (Forced Expiratory Flow)
-average flow that occurs during middle 50 of FVC measurement
-this measurement reflects the condition of the MEDIUM to SMALL airways
-decreases w/ age and obstructive lung disease
This measurement reflects the condition of medium to small airways
In which test would the patient be instructed to exhale as forcefully, rapidly, and completely as possible after taking in a maximal inspiration?
Which test is the most commonly performed pulmonary function measurement?
Which pulmonary measurement reflects the status of the medium to small airways?
How does the general shape of a flow-volume loop in restrictive lung disease compare to a normal pattern?
Shorter and narrower
Which of the following would you expect to be reduced during an acute asthma episode?
PEFR (peak expiratory flow rate)
Which gas law is the law of partial pressures?
When breathing FIO2 1.0 at seal level, what would the PN2 in the alveoli equal?
What does the PH2O equal in alveolar gas if the FIO2 is 0.21?
47 mm Hg
What is the normal value for the respiratory exchange ratio?
For a healthy adult at rest, what is the normal pressure gradient for oxygen across the alveolar-capillary membrane when breathing room air at sea level?
60 mm Hg
In a healthy adult at rest at sea level, what is the normal carbon dioxide gradient across the alveolar capillary membrane?
6 mm Hg
Which law states that the amount of gas that dissolves in a liquid is directly related to the partial pressure of the gas?
In a healthy 20 year old male, what would the FRC equal?
2.4 L or 2400 mL
In a healthy 20 year old male, what would the IRV equal?
In a healthy 20 year old male, what would the ERV equal?
In a healthy 20 year old male, what would the RV equal?
What is the best indicator of an obstructive lung disorder?
What device is most commonly used to monitor airway function at home?
peak flow meter
Which maneuvers form a flow-volume loop?
FVC and FIC
What portion of the FVC maneuver is considered to be effort dependent?
What would the partial pressure of oxygen equal in an air mixture at a depth of 99 feet under water?
159 x 4 or 636 mm Hg
At 99 feet under water, 4 atmospheres would be present so PO2 would equal 636 mm Hg.
-Good index of the integrity of large airway function
-Average flow rate that occurs between 200-1200 mL of FVC
"technically how fast we can get the first liter of the FVC out
max flow rate that can be achieved during FVC
-can be done bed side using peak flow meter hand held device
-measures a pts max speed of expiration
PEFR (peak expiratory flow rate)
During acute asthma the PEFR would be
largest volume of gas that can be breathed voluntarily in and out of lungs in 1 minute
MVV (maximum voluntary ventilation)
Flow volume loop
Flow on vertical axis
Volume on horizontal axis
Loop shows both exhalation/inhalation
Both curve and loop show PEFR/FVC at highest point
PIFR or PIF( peak inspiratory flow rate)
Highest insp flow generated during FVC
Maximum Inspiratory Pressure (MIP)
-125 cm H20 (Female -90 cm H20)
Maximum Expiratory Pressure (MEP)
230 cm H20 (Female 150cm H20)
Law of Partial Pressures
The total pressure of a mixture of gases is the sum of the individual pressures (Ptotal=P1+P2+P3...)
partial pressure of oxygen
partial pressure of nitrogen
atmospheric pressure _____ with increase in altitude
atmospheric pressure decreases w/ ______ in altitude
As density of atmospheric gases decrease
p.p exerted by each has also decreases
% of 02 always approx 21 both at sea level or on top of mt Everest
what changes is the barometric pressure
True or false
1 atm =
primary mechanism for moving in and out of lungs during ventilation
(movement of gas from area of high pressure/concentration to low)
Movement of INDIVIDUAL gas molecules from an area of high pressure to an area of low pressure
Ideal Alveolar Gas Equation
[PB-PH2O] FIO2 - PaCO2 (1.25)
fractional inspired oxygen concentration.
Essentially states that the rate of diffusion of a gas across a permeable membrane is determined by the chemical nature of the membrane itself, the surface area of the membrane, the partial pressure gradient of the gas across the membrane, and the thickne
less surface area=
less 02 gets transferred (through)
lower alveolar 02 levels
The transfer of gas across the alveolar wall is a function of the amount of blood that flows past the alveoli
When can the simplified alveolar gas equation be used?
When the PaCO2 less than 60 mm Hg and FIO2 0.6 or greater
Which law is represented by the equation below? V gas = [AD (P1-P2)] / T
In a healthy individual, which of the lung volumes is the largest?
Which of the following is derived from closed circuit helium dilution method?
In the open circuit washout method, what gas mixture does the patient breathe for the test?
a. 100% O2
b. 100% N2
c. room air
d. He-O2 mixture
a. 100% O2
Which test/method is considered most accurate for measuring RV?
a. open circuit nitrogen washout
c. closed circuit helium dilution
Which of the following can decrease the FEF 200-1200 ?
I. Obstructive disorders
II. Restrictive disorders
a. I only
b. II and III only
c. I and III only
d. I, II, and III
d. I, II, and III
At what age do pulmonary volumes and expiratory flow rates start to decrease?
What portion of the FVC cannot be influenced by further muscular effort?
a. first 70%
b. last 70%
c. first 30%
d. last 30%
b. last 70%
Which pulmonary function test in essence assesses the status of the alveolar-capillary membrane?
b. bronchial provocation test