Midterm 2 Flashcards
_______ requires measurement of gas volume or flow, and various instruments and measurement principles are used to make these measurements.
Pulmonary function testing
There are two general types of measuring instruments: _____ and ____
instruments that measure gas volume and instruments that measure gas flow.
Both types of instruments simultaneously measure time, and both compute various volumes and flow rates used in pulmonary function testing.
instruments that measure gas volume and instruments that measure gas flow.
The _____ is sometimes used as a generic term for all volume-measuring and flow-measuring devices.
spirometer
_______ are specifically called spirometers and include water-sealed, bellows, and dry rolling seal types.
Volume-measuring devices
These devices expand as they collect gas volumes.
Volume-measuring devices
The magnitude of the expansion is the _____ measured, and the speed of expansion represents the ____
volume and flow rate
In the absence of leaks and with low-momentum forces, _______ can be extremely accurate for measuring volumes, and with low inertia and friction forces, _____ can be extremely accurate when computing flow rates.
volume-measuring devices
_______ are commonly called pneumotachometers
Flow-measuring devices
Flow-measuring devices are commonly called pneumotach- ometers, although some practitioners reserve this term for only the device originally designed by _____.
Fleisch
These devices measure flow using a variety of unique principles.
Flow-measuring devices
The _____ measures the change in pressure as gas flows through it.
Fleisch-type pneumotachometer
Known as ___ or ____ , another type of flow-measuring device measures the temperature change created by gas flowing through it.
thermistors or mass flowmeters
There are also ______ , which use rotation of a fan or blades similar to a windmill.
turbinometers
Every measuring instrument has ______
capacity, accuracy, error, resolution, precision, linearity, and output.
The ideal instrument would have ______ to measure every pulmonary parameter, and it would have ____ and ____ over its entire measurement range.
unlimited capacity / perfect accuracy and precision
However, in real practice, there are no ______
ideal instruments
The _____ of an instrument refers to the range or limits of how much it can measure.
capacity
_____ is the combination of two or more lung volumes
capacity
Most instruments are designed with _____ to measure volumes and flow rates of all adults.
capacities
The ______ of a measuring instrument is how well it measures a known reference value.
accuracy
For volume measurements, standard reference values are provided by a graduated ____
3.0-L calibration syringe.
No measuring instrument is perfect, and there usually is an ____ difference between reference values and measured values. This difference is called the ____.
arithmetic / error
___ and ____ are opposing terms;
Accuracy and error
the greater the ____ , the smaller is the ____.
accuracy / error
Accuracy and error are commonly expressed as ____, with their sum always equaling ____
percentages / 100%.
To determine ____ and _____ , an object of known measurement (e.g., 3-L cylinder) is tested multiple times and the absolute value of the deviation from the known measurement (error) calculated. The average value of the error over multiple tests is then computed.
percent accuracy and percent error
______ is the smallest detectable measurement; instruments with high _____ can measure the smallest volumes, flows, and times.
Resolution
_____ is synonymous with reliability (repeatability) of measurements and the opposite of variability.
Precision
When multiple values are measured for a given test, the standard deviation of these values indicates the extent to which these values vary from the mean and is therefore an indication of the ____ of an instrument.
precision
A small standard deviation indicates low variability and ______.
high precision
_____ refers to the accuracy of the instrument over its entire range of measurement, or its capacity.
Linearity
Some devices may accurately measure large volumes or high flow rates but may be less accurate when measuring small volumes or low flow rates.
Linearity
To determine _____ , accuracy and precision are calculated at different points over the range (capacity) of the device.
linearity
____ includes the specific measurements made or computed by the instrument.
Output
Most volume-measuring and flow-measuring devices measure the ____ and _____ . Others calculate various forced expiratory flow (FEF) rates, and some measure tidal volume(VT) and minute ventilation (V̇E).
FVC and forced expiratory volume in 1 second (FEV1)
Diagnostic _____ usually measure and calculate vital capacity (VC), FVC, FEV1, peak expiratory flow (PEF) rate, and FEF rates. Some measure and calculate maximal voluntary ventilation (MVV). Some of these instruments may be a component of a laboratory system providing the _____ or ____ capability for other diagnostic tests of pulmonary function.
spirometers / volume-measuring or flow- measuring
Whether a spirometer or pneumo- tachometer is used in a diagnostic laboratory, a physician’s office, or at the bedside in a hospital, it should ___ or ____ the national performance standards for _____
meet or exceed / volume-measuring and flow- measuring devices.
In addition, the spirometer standards also require spirometers to have a thermometer or to produce values cor- rected for ___ , ___ and
body temperature, ambient pressure, and fully saturated with water vapor (BTPS).
For quality control, the standards include verifying volume accuracy at least ____ , although best practice in many laboratories is to verify accuracy ____ test subject.
daily / before each
Most modern pulmonary function laboratories use _____ for data acquisition and reproduction.
computers
______ decreases the time necessary to complete the tests and enhances the effectiveness of pulmonary function testing by increasing accuracy, increasing patient acceptance, and monitoring patient performance.
Computer-assisted testing
Although computer-assisted testing and interpretations of test results are often applied by a computer, pulmonary function testing always requires a ____ and ____ RT to administer the tests, and computer analysis should not replace ____.
trained and competent / human analysis.
In addition, both ____ (RT performing the test) and ____ (physician interpreting the test) should pay a close attention to grading the quality of PFTs.
technician and reviewer
The grading system recommended by the _____ includes typical _____ grading scale ( ______ ).
ATS guidelines / A through F
A being the highest and F being the lowest quality
It is recommended that tests achieving grades ____ are clinically useful and should be reported,
A through C
grades ___ may have limited value,
D and E
grade ____ should not be reported.
F
Unfortunately, many believe that ______ on grading the quality of tests are still needed.
stricter guidelines
The purpose of _____ is to provide the reviewer with possible limitations of test interpretation, and evaluate the possibility whether abnormal PFT results are due to underlying disease or suboptimal effort/performance.
quality grading
The _____ for PFTs, as for any other physiologic vari- able, are based for population studies and are, to some extent, arbitrary
reference values
the “normal” values for the PFT measurements are based on ____
height, age, gender, and race/ethnicity.
With all else being equal, taller, younger male patients tend to produce ____ and ____ than their shorter, older female counterparts.
greater volumes and flows
___ and ____ differences also exist.
Racial and ethnic
Large population-based studies have established the equations for reference values based on ____
height, age, gender, and race/ethnicity.
For individuals of mixed ethnic origin, or not represented by the major ethnic groups, ____ equations were developed.
composite
Along with the individual patient results, the ATS recommends routine reporting of the following reference values: ____, _____ and ____
predicted value, upper and lower limit of normal (ULN, and LLN, respectively), and z score.
The ____ is simply an average value derived from a large population of healthy subjects.
predicted value
____ and ___ are mathematically derived and encompass the range of “normal” values.
ULN and LLN
It is expected that 95% of healthy individuals fall between these two values.
ULN and LLN
The ____ is a statistical measurement that is used to show how much the patient’s result deviates from the predicted value.
z score
a z score of 0.5 would indicate that the test result is 0.5 standard deviations ____ than the predicted value
greater
______ are used to indicate that the test result is less than the predicted value
negative z scores
With the widespread use of computers for the measurement and reporting of PFTs, the _____ for given patient characteristics are the part of the computer ____, eliminating the need for manual calculation using _____ formulas.
reference values / software / cumbersome mathematical
Normal pulmonary function values are based on the subject’s ___ and sometimes ____
age, height, gender, ethnicity, and sometimes weight.
Normal pul- monary function predictably declines with age older than _____.
20 to 25 years
The presence of pulmonary disease is suspected when the test result ____ outside the upper limit of normal (ULN)/ lower limit of normal (LLN) range.
falls
The ____ of pulmonary impairment is assessed by comparison of each patient’s actual measurement with the predicted normal value for the patient.
severity
A common method of comparison is to compute a percentage of the predicted normal value according to the following equation:
Measured value
% Predicted = _______________ × 100
Predicted normal value
some clinicians and PFT laboratories still use ______ to identify the abnormality.
percent predicted values
arbitrary range of _____ predicted is used as the “normal” range.
80% to 120%
Any value less than 80% or greater than 120% predicted is there- fore considered ____.
abnormal
Although these two methods often produce similar results, the ____ is considered to be more accurate and is endorsed and recommended by the respiratory societies.
former
For tests of pulmonary function, these general principles should be considered: ____ and ____, ____ and ____
test sensitivity and specificity, validity, and reliability.
______ and ____ address the test’s ability to detect disease or absence of it, respectively.
Sensitivity and specificity
____ is high if the test is abnormal whenever disease is present.
Sensitivity
____ is high if the test is normal whenever disease is absent.
Specificity
Some tests are extremely ____, so that apparently healthy individuals may have an abnormal test result.
sensitive
some tests are not sensi- tive; individuals must be extremely sick to have an ______
abnormal test result
Most tests of pulmonary function are not ____ because several different diseases may cause the test result to be abnormal. This limitation of many PFTs explains why these tests identify a pattern of impairment rather than diagnose specific diseases.
specific
____ of the test relates to its meaningfulness or the ability to accurately measure what it is intended to measure.
Validity
When performing pulmonary function testing, strictly following testing procedures, ensuring patient effort and performance, and ensur- ing equipment accuracy and calibration establish test ____.
validity
____ of the test is its consistency.
Reliability
A ___ test produces consistent test results with minimal variability, when repeated.
reliable
To be reliable, each test must be performed ____
more than once
Ensuring test ____ and _____ is the most important role of the RT.
validity and reliability
Test results that are _____ and ____ can lead to misdiagnosis, treatment errors, and poor outcomes.
invalid or unreliable
A _____ test would be positive in patients with disease,
sensitive
_____ test would be negative in patients without disease.
specific
A ____ test would give results reflective of the individual’s true pulmonary function abilities, regardless of other factors such as effort or equipment faults.
valid
A ____ test would give the same, or very similar, results on multiple testing attempts.
reliable
