NR 507 Exam- Pulmonary System &
Function
Pulmonary Function Testing Case Questions and Answers
Abbreviations: *** -FVC / Forced Vital Capacity
-FEV1 / Forced Expiratory Volume in One Second
-TLC / Total Lung Capacity
-RV / Residual Volume
-DLCO / Diffusion Capacity for Carbon Monoxide
-BD / Bronchodilator
Mechanics of Respiration: Pulmonary Function Tests *** Pulmonary function tests (PFTs) are non-
invasive tests that provide information about lung function. PFTs alone cannot differentiate among the
causes of respiratory abnormalities. Therefore, the patient's history, physical exam and other
diagnostics must be considered when making a diagnosis.
The PFT can help the NP determine the patient's respiratory pattern, specifically if the abnormality is
due to an obstructive or restrictive problem. Once the pattern is identified, PFTs allow the NP to
determine the severity of the disease. This data combined with other patient findings, leads to a
diagnosis.
There are some indications to help the NP to determine when to order PFTs: *** 1. When signs and
symptoms of a respiratory problem require evaluation (cough, dyspnea, cyanosis, wheezing, hypoxemia,
hypercapnia, and lung hyperinflation).
2. When disease progression needs to be determined.
3. When monitoring the effectiveness of drug therapy.
4. When monitoring for potential toxic effects of certain drugs.
,Components of a Pulmonary Function Tests
Spirometry *** Spirometry: This measures air movement in and out of the lungs during various
respiratory maneuvers. The NP can also determine how much air the patient is breathing in and out and
how fast the patient is doing it. Think about the respiratory cycle in terms of lung volume and lung
capacities. 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:
There are three important measures on which the NP focuses when reviewing spirometry results: 1.)
FVC *** Measure
Forced Vital Capacity (FVC); Normal 80-120%
Definition
The FVC measures the volume of air in the lungs that can be exhaled.
Maneuver
Patient inhales as deep as possible and then exhales as long and as forcefully as possible.
There are three important measures on which the NP focuses when reviewing spirometry results: 2.)
FEV1 *** Measure
Forced Expiratory Volume in 1 second (FEV1); Normal 80-120%
Definition
Amount of air forcefully exhaled from the lungs in the first second.
Maneuver
The patient inhales and forcefully exhales as fast as possible.
,There are three important measures on which the NP focuses when reviewing spirometry results: 3.)
FEV1/FVC ratio *** Measure
FEV1/FVC ratio
Definition
Determines if the pattern is obstructive, restrictive or normal
Maneuver
This is a calculated ratio that represents the proportion of a person's vital capacity that they are able to
expire in the first second of forced expiration to the full, forced vital capacity.
Components of a Pulmonary Function Tests:
Diffusing capacity *** The diffusing capacity is simply how well the lungs are able to exchange gas. Gas
exchange is most efficient 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 condition that decreases the patient's diffusing capacity
because of a loss of surface area is emphysema. Conditions that increase the lungs thickness can also
decrease diffusing capacity as in the case of pulmonary fibrosis.
Components of a Pulmonary Function Tests:
Residual volume (RV) and Total Lung Capacity (TLC)
RV + FVC = TLC *** RV is the amount of air that remains in the lungs after a forceful exhalation. RV + FVC
= TLC.
Note that the RV cannot be measured by spirometry. Other methods are used that require the patient
to inhale an inert gas (helium) or sit in an airtight booth where the pressure is measured during
breathing. These measurements are also called static lung volumes. The values add to the information
obtained from spirometry.
, If the patient has an obstructive disease, RV and TLC results will be elevated which reveals air trapping
and hyperinflation. In restrictive disease, the TLC is needed to confirm true restriction. It can also help in
quantifying the degree of restriction.
Steps to Analyze Pulmonary Function 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 population studies using
individuals without lung disease. Each patient's predicted values depend on the age, height, and gender.
This information is entered into a computer prior to the PFT.
Once the results have been received, the NP looks at two factors:
1) the pattern of the condition;
2) severity of the condition.
Step 1 - Determine the pattern *** In order to classify the respiratory issue as either obstructive,
restrictive or normal., the NP starts by looking at the FEV1/FVC ratio.
Obstructive pattern: If the FEV1/FVC ratio is "less than 70%" or less than the lower limit of normal for
the patient. FEV1 also falls to a greater degree than the FVC.
Restrictive pattern: If the FEV1/FVC ratio is "greater than 70%" or greater than the lower limit of normal,
then the spirometry test is either normal, or a restrictive respiratory abnormality is present.
To make this distinction, the NP must look at the TLC. In restrictive disorders, the percent predicted of
TLC is <80%, where 80-120% represents a normal range.
Measurement: Forced vital capacity (FVC) *** Obstructive -Decreased or normal
Restrictive- Decreased
Function
Pulmonary Function Testing Case Questions and Answers
Abbreviations: *** -FVC / Forced Vital Capacity
-FEV1 / Forced Expiratory Volume in One Second
-TLC / Total Lung Capacity
-RV / Residual Volume
-DLCO / Diffusion Capacity for Carbon Monoxide
-BD / Bronchodilator
Mechanics of Respiration: Pulmonary Function Tests *** Pulmonary function tests (PFTs) are non-
invasive tests that provide information about lung function. PFTs alone cannot differentiate among the
causes of respiratory abnormalities. Therefore, the patient's history, physical exam and other
diagnostics must be considered when making a diagnosis.
The PFT can help the NP determine the patient's respiratory pattern, specifically if the abnormality is
due to an obstructive or restrictive problem. Once the pattern is identified, PFTs allow the NP to
determine the severity of the disease. This data combined with other patient findings, leads to a
diagnosis.
There are some indications to help the NP to determine when to order PFTs: *** 1. When signs and
symptoms of a respiratory problem require evaluation (cough, dyspnea, cyanosis, wheezing, hypoxemia,
hypercapnia, and lung hyperinflation).
2. When disease progression needs to be determined.
3. When monitoring the effectiveness of drug therapy.
4. When monitoring for potential toxic effects of certain drugs.
,Components of a Pulmonary Function Tests
Spirometry *** Spirometry: This measures air movement in and out of the lungs during various
respiratory maneuvers. The NP can also determine how much air the patient is breathing in and out and
how fast the patient is doing it. Think about the respiratory cycle in terms of lung volume and lung
capacities. 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:
There are three important measures on which the NP focuses when reviewing spirometry results: 1.)
FVC *** Measure
Forced Vital Capacity (FVC); Normal 80-120%
Definition
The FVC measures the volume of air in the lungs that can be exhaled.
Maneuver
Patient inhales as deep as possible and then exhales as long and as forcefully as possible.
There are three important measures on which the NP focuses when reviewing spirometry results: 2.)
FEV1 *** Measure
Forced Expiratory Volume in 1 second (FEV1); Normal 80-120%
Definition
Amount of air forcefully exhaled from the lungs in the first second.
Maneuver
The patient inhales and forcefully exhales as fast as possible.
,There are three important measures on which the NP focuses when reviewing spirometry results: 3.)
FEV1/FVC ratio *** Measure
FEV1/FVC ratio
Definition
Determines if the pattern is obstructive, restrictive or normal
Maneuver
This is a calculated ratio that represents the proportion of a person's vital capacity that they are able to
expire in the first second of forced expiration to the full, forced vital capacity.
Components of a Pulmonary Function Tests:
Diffusing capacity *** The diffusing capacity is simply how well the lungs are able to exchange gas. Gas
exchange is most efficient 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 condition that decreases the patient's diffusing capacity
because of a loss of surface area is emphysema. Conditions that increase the lungs thickness can also
decrease diffusing capacity as in the case of pulmonary fibrosis.
Components of a Pulmonary Function Tests:
Residual volume (RV) and Total Lung Capacity (TLC)
RV + FVC = TLC *** RV is the amount of air that remains in the lungs after a forceful exhalation. RV + FVC
= TLC.
Note that the RV cannot be measured by spirometry. Other methods are used that require the patient
to inhale an inert gas (helium) or sit in an airtight booth where the pressure is measured during
breathing. These measurements are also called static lung volumes. The values add to the information
obtained from spirometry.
, If the patient has an obstructive disease, RV and TLC results will be elevated which reveals air trapping
and hyperinflation. In restrictive disease, the TLC is needed to confirm true restriction. It can also help in
quantifying the degree of restriction.
Steps to Analyze Pulmonary Function 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 population studies using
individuals without lung disease. Each patient's predicted values depend on the age, height, and gender.
This information is entered into a computer prior to the PFT.
Once the results have been received, the NP looks at two factors:
1) the pattern of the condition;
2) severity of the condition.
Step 1 - Determine the pattern *** In order to classify the respiratory issue as either obstructive,
restrictive or normal., the NP starts by looking at the FEV1/FVC ratio.
Obstructive pattern: If the FEV1/FVC ratio is "less than 70%" or less than the lower limit of normal for
the patient. FEV1 also falls to a greater degree than the FVC.
Restrictive pattern: If the FEV1/FVC ratio is "greater than 70%" or greater than the lower limit of normal,
then the spirometry test is either normal, or a restrictive respiratory abnormality is present.
To make this distinction, the NP must look at the TLC. In restrictive disorders, the percent predicted of
TLC is <80%, where 80-120% represents a normal range.
Measurement: Forced vital capacity (FVC) *** Obstructive -Decreased or normal
Restrictive- Decreased
