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Week 3 Alterations in Pulmonary Function
Advanced Pathophysiology (Chamberlain University)
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Week 3 Altera琀椀ons in Pulmonary Func琀椀on
Obstruc琀椀ve Lung Disease vs. Restric琀椀ve Disease
COPD
Asthma
Inters琀椀琀椀al Lung Disease
Weekly objec琀椀ves
1. WO3.3- Di昀昀eren琀椀ate between normal and abnormal respiratory structure and func琀椀on. (CO1)
2. WO3.1-Analyze pathophysiological mechanisms associated with altera琀椀ons in respiratory
processes. (CO1)
3. WO3.2- Describe outcomes of disrup琀椀ve or altera琀椀on in respiratory processes. (CO2)
4. WO3.4- Apply a clinical prac琀椀ce guideline in the management of a pa琀椀ent with altered
respiratory func琀椀on. (CO5).
Mechanics of Respira琀椀on: Pulmonary Func琀椀on Tests
Pulmonary func琀椀on tests (PFTs) are non-invasive tests that provide informa琀椀on about lung func琀椀on. PFTs
alone cannot di昀昀eren琀椀ate among the causes of respiratory abnormali琀椀es. Therefore, the pa琀椀ent’s
history, physical exam and other diagnos琀椀cs must be considered when making a diagnosis. The PFT can
help the NP determine the pa琀椀ent’s respiratory pa琀琀ern, speci昀椀cally if the abnormality is due to an
obstruc琀椀ve or restric琀椀ve problem. Once the pa琀琀ern is iden琀椀昀椀ed, PFTs allow the NP to determine the
severity of the disease. This data combined with other pa琀椀ent 昀椀ndings, leads to a diagnosis.
There are some indica琀椀ons to help the NP to determine when to order PFTs:
When signs and symptoms of a respiratory problem requires evalua琀椀on (cough, dyspnea,
cyanosis, wheezing, hypoxemia, hypercapnia and lung hyperin昀氀a琀椀on).
When disease progression needs to be determined.
When monitoring the e昀昀ec琀椀veness of drug therapy.
When monitoring for poten琀椀al toxic e昀昀ects of certain drugs.
Components of a Pulmonary Func琀椀on Tests
Spirometry: This measures air movement in and out of the lungs during various respiratory maneuvers.
The NP can also determine how much air the pa琀椀ent is breathing in and out and how fast the pa琀椀ent is
doing it. Think about the respiratory cycle in terms of lung volume and lung capaci琀椀es. The capacity is
just simply the sum of one of more volumes.
There are three important measures on which the NP focuses when reviewing spirometry results. These
are summarized in the table below:
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Measure De昀椀ni琀椀on Maneuver
Forced Vital The FVC measures the Pa琀椀ent inhales as deep as possible and then
Capacity (FVC); volume of air in the lungs exhales as long and as forcefully as possible.
Normal 80-120% that can be exhaled.
Forced Expiratory Amount of air forcefully The pa琀椀ent inhales and forcefully exhales as
Volume in 1 second exhaled from the lungs in the fast as possible.
(FEV1); Normal 80- 昀椀rst second.
120%
Determines if the pa琀琀ern is This is a calculated ra琀椀o that represents the
FEV1/FVC ra琀椀o obstruc琀椀ve, restric琀椀ve or propor琀椀on of a person's vital capacity that they
normal are able to expire in the 昀椀rst second of forced
expira琀椀on to the full, forced vital capacity.
Di昀昀using capacity: The di昀昀using capacity is simply how well the lungs are able to exchange gas. Gas
exchange is most e昀케cient in a lung that has high surface area because it’s easier for the blood to pick up
the gas that’s being exchange. An example of a condi琀椀on that decreases the pa琀椀ent’s di昀昀using capacity
because of a loss of surface area is emphysema. Condi琀椀ons that increase the lungs thickness can also
decrease di昀昀using capacity as in the case of pulmonary 昀椀brosis.
Residual volume (RV) and Total Lung Capacity (TLC): RV is the amount of air that remains in the lungs
a昀琀er a forceful exhala琀椀on. RV + FVC = TLC. Note that the RV cannot be measured by spirometry. Other
methods are used that require the pa琀椀ent to inhale an inert gas (helium) or sit in an air琀椀ght booth
where the pressure is measured during breathing. These measurements are also called sta琀椀c lung
volumes. The values add to the informa琀椀on obtained from spirometry. If the pa琀椀ent has an obstruc琀椀ve
disease, RV and TLC results will be elevated which reveals air trapping and hyperin昀氀a琀椀on. In restric琀椀ve
disease, the TLC is needed to con昀椀rm true restric琀椀on. It can also help in quan琀椀fying the degree of
restric琀椀on.
Steps to Analyze Pulmonary Func琀椀on Tests (PFTs)
First, the NP must understand how the results of the PFT is delivered. The results will yield measured
values and percentages of predicted values. Predicted values and lower limits of normal have been
standardized by popula琀椀on studies using individuals without lung disease. Each pa琀椀ent’s predicted
values depend on the age, height, and gender. This informa琀椀on is entered into a computer prior to the
PFT.
Once the results have been received, the NP looks at two factors: 1) the pa琀琀ern of the condi琀椀on; 2)
severity of the condi琀椀on.
Step 1: Determine the Pa琀琀ern
In order to classify the respiratory issue as either obstruc琀椀ve, restric琀椀ve or normal., the NP starts by
looking at the FEV1/FVC ra琀椀o.
Obstruc琀椀ve pa琀琀ern: If the FEV1/FVC ra琀椀o is less than 70% or less than the lower limit of normal for the
pa琀椀ent. FEV1 also falls to a greater degree than the FVC.
Restric琀椀ve pa琀琀ern: If the FEV1/FVC ra琀椀o is greater than 70% or greater than the lower limit of normal,
then the spirometry test is either normal, or a restric琀椀ve respiratory abnormality is present. To make this
Downloaded by youn sam ()
Week 3 Alterations in Pulmonary Function
Advanced Pathophysiology (Chamberlain University)
Scan to open on Studocu
Studocu is not sponsored or endorsed by any college or university
Downloaded by youn sam ()
, lOMoARcPSD|6353920
Week 3 Altera琀椀ons in Pulmonary Func琀椀on
Obstruc琀椀ve Lung Disease vs. Restric琀椀ve Disease
COPD
Asthma
Inters琀椀琀椀al Lung Disease
Weekly objec琀椀ves
1. WO3.3- Di昀昀eren琀椀ate between normal and abnormal respiratory structure and func琀椀on. (CO1)
2. WO3.1-Analyze pathophysiological mechanisms associated with altera琀椀ons in respiratory
processes. (CO1)
3. WO3.2- Describe outcomes of disrup琀椀ve or altera琀椀on in respiratory processes. (CO2)
4. WO3.4- Apply a clinical prac琀椀ce guideline in the management of a pa琀椀ent with altered
respiratory func琀椀on. (CO5).
Mechanics of Respira琀椀on: Pulmonary Func琀椀on Tests
Pulmonary func琀椀on tests (PFTs) are non-invasive tests that provide informa琀椀on about lung func琀椀on. PFTs
alone cannot di昀昀eren琀椀ate among the causes of respiratory abnormali琀椀es. Therefore, the pa琀椀ent’s
history, physical exam and other diagnos琀椀cs must be considered when making a diagnosis. The PFT can
help the NP determine the pa琀椀ent’s respiratory pa琀琀ern, speci昀椀cally if the abnormality is due to an
obstruc琀椀ve or restric琀椀ve problem. Once the pa琀琀ern is iden琀椀昀椀ed, PFTs allow the NP to determine the
severity of the disease. This data combined with other pa琀椀ent 昀椀ndings, leads to a diagnosis.
There are some indica琀椀ons to help the NP to determine when to order PFTs:
When signs and symptoms of a respiratory problem requires evalua琀椀on (cough, dyspnea,
cyanosis, wheezing, hypoxemia, hypercapnia and lung hyperin昀氀a琀椀on).
When disease progression needs to be determined.
When monitoring the e昀昀ec琀椀veness of drug therapy.
When monitoring for poten琀椀al toxic e昀昀ects of certain drugs.
Components of a Pulmonary Func琀椀on Tests
Spirometry: This measures air movement in and out of the lungs during various respiratory maneuvers.
The NP can also determine how much air the pa琀椀ent is breathing in and out and how fast the pa琀椀ent is
doing it. Think about the respiratory cycle in terms of lung volume and lung capaci琀椀es. The capacity is
just simply the sum of one of more volumes.
There are three important measures on which the NP focuses when reviewing spirometry results. These
are summarized in the table below:
Downloaded by youn sam ()
, lOMoARcPSD|6353920
Measure De昀椀ni琀椀on Maneuver
Forced Vital The FVC measures the Pa琀椀ent inhales as deep as possible and then
Capacity (FVC); volume of air in the lungs exhales as long and as forcefully as possible.
Normal 80-120% that can be exhaled.
Forced Expiratory Amount of air forcefully The pa琀椀ent inhales and forcefully exhales as
Volume in 1 second exhaled from the lungs in the fast as possible.
(FEV1); Normal 80- 昀椀rst second.
120%
Determines if the pa琀琀ern is This is a calculated ra琀椀o that represents the
FEV1/FVC ra琀椀o obstruc琀椀ve, restric琀椀ve or propor琀椀on of a person's vital capacity that they
normal are able to expire in the 昀椀rst second of forced
expira琀椀on to the full, forced vital capacity.
Di昀昀using capacity: The di昀昀using capacity is simply how well the lungs are able to exchange gas. Gas
exchange is most e昀케cient in a lung that has high surface area because it’s easier for the blood to pick up
the gas that’s being exchange. An example of a condi琀椀on that decreases the pa琀椀ent’s di昀昀using capacity
because of a loss of surface area is emphysema. Condi琀椀ons that increase the lungs thickness can also
decrease di昀昀using capacity as in the case of pulmonary 昀椀brosis.
Residual volume (RV) and Total Lung Capacity (TLC): RV is the amount of air that remains in the lungs
a昀琀er a forceful exhala琀椀on. RV + FVC = TLC. Note that the RV cannot be measured by spirometry. Other
methods are used that require the pa琀椀ent to inhale an inert gas (helium) or sit in an air琀椀ght booth
where the pressure is measured during breathing. These measurements are also called sta琀椀c lung
volumes. The values add to the informa琀椀on obtained from spirometry. If the pa琀椀ent has an obstruc琀椀ve
disease, RV and TLC results will be elevated which reveals air trapping and hyperin昀氀a琀椀on. In restric琀椀ve
disease, the TLC is needed to con昀椀rm true restric琀椀on. It can also help in quan琀椀fying the degree of
restric琀椀on.
Steps to Analyze Pulmonary Func琀椀on Tests (PFTs)
First, the NP must understand how the results of the PFT is delivered. The results will yield measured
values and percentages of predicted values. Predicted values and lower limits of normal have been
standardized by popula琀椀on studies using individuals without lung disease. Each pa琀椀ent’s predicted
values depend on the age, height, and gender. This informa琀椀on is entered into a computer prior to the
PFT.
Once the results have been received, the NP looks at two factors: 1) the pa琀琀ern of the condi琀椀on; 2)
severity of the condi琀椀on.
Step 1: Determine the Pa琀琀ern
In order to classify the respiratory issue as either obstruc琀椀ve, restric琀椀ve or normal., the NP starts by
looking at the FEV1/FVC ra琀椀o.
Obstruc琀椀ve pa琀琀ern: If the FEV1/FVC ra琀椀o is less than 70% or less than the lower limit of normal for the
pa琀椀ent. FEV1 also falls to a greater degree than the FVC.
Restric琀椀ve pa琀琀ern: If the FEV1/FVC ra琀椀o is greater than 70% or greater than the lower limit of normal,
then the spirometry test is either normal, or a restric琀椀ve respiratory abnormality is present. To make this
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