Midterm 1 Flashcards
There are two types of plethysmography systems.
Body plethysmography / Inductive plethysmography
____ Requires that the subject’s entire body be enclosed within a boxlike cabinet during testing.
Body plethysmography
A complex set of components is necessary for system operation and test performance.
Body plethysmography
____ involves the use of sensors strapped around the subject’s thorax and abdomen. The equipment is smaller and less complicated.
Inductive plethysmography
Body plethysmographs (BPs) are used for making two kinds of pulmonary function measurements.
The first is intrathoracic gas volume (VTG) / airway resistance (Raw)
This can be used to determine total lung capacity
Intrathoracic gas volume (VTG)
_____ air flow rakes during the subject’s breathing cycle.
Inspiratory and/or expiratory
____ changes inside the sealed cabinet that result from expansion and contraction of the subject’s thorax.
Air volume
Changes in air pressure at the subject’s ____.
mouth
Cabinet air volume changes are used to reflect changes in ____
lung volume.
Mouth pressure changes, when the subject’s airway is mechanically obstructed, are interpreted as changes in ____.
alveolar pressure
Readings of mouth alveolar pressure compared against changes in cabinet air volume are used to determine ___
lung volume.
Cabinet air volume changes compared against subject ventilatory air flow rates are used to determine ____
airway resistance.
The ____ has a volume of approximately 600 liters and is large enough for the subject to sit within
cabinet
In newer, well-designed models, the cabinet is constructed largely of ____. This allows for good visibility of the subject. It also reduces any claustrophobia that may be experienced by the subject.
plexiglass
Cabinets generally include an ____ system for easy communication between technologist and subject.
intercom
The cabinet may have a___ that can be opened or close by the operator as needed.
vent
Measuring systems are important to BP operation. A _______, _____, _____assembly is located within the cabinet.
pneumotachometer/ shutter /pressure transducer
The type of _____ used for measuring ventilatory air flow rates can vary with the brand of plethysmograph used.
pneumotachometer
The ____, when activated, occludes the mechanical airway of the pneumotachometer
shutter
___ It may be controlled by an electronic solenoid or by a pneumatic system. State-of-the-art BPs have automated ____ that close automatically at predetermined times in a test.
shutters
The ______ is located between the shutter and subject mouthpiece. it is used to measure pressure at the mouth.
pressure transducer
The method used for measuring cabinet air volume changes can vary considerably between ____ systems.
plethysmograph
There are two very different methods for measuring body plethysmograph cabinet volume changes. The two methods are based on using either:
- nonconstant-volume plethysmograph cabinet
-constant-volume, variable-pressure plethysmograph cabinet
Use either a primary volume or primary flow measuring spirometer system attached to the BPs outer wall. They are, as a result, referred to as _____
Nonconstant-volume plethysmographs / volume-or flow-type plethysmographs
These systems directly measure quantities of air that are forced to enter and leave the cabinet. This air movement occurs as a result of the subject’s thoracic volume increases and decreases during breathing. Both large and small changes in thoracic volume can be measured.
Nonconstant-volume plethysmographs
Conveniently, determination of other nonplethysmographic ventilatory parameters can be made with the subject still within the sealed cabinet. These parameters may include ____ and ____ flow rates. Systems of this type are rather complex and expensive.
inspiratory capacity and forced expiratory
______ ( pressure-type plethysmographs) Have a pressure transducer connected to an opening in the cabinet wall. The transducer directly measures changes in cabinet pressure during subject breathing.
Constant-volume, variable-pressure plethysmographs
The pressure changes can be interpreted as volume changes, as described by ____ (PI V1 = P2 V2).
Boyle’s law
For accurate assessment of cabinet air volume changes, temperatures within the cabinet must remain ___.
stable
Some systems have a small leak built into the cabinet to allow for temperature _____
equilibrium
If ____ breathing maneuvers are used by the subject, the leak does not present a problem
for pressure measurement.
panting - type
These systems provide an excellent frequency response to subject breathing maneuver. This is the most widely used type of plethysmograph. It is, however, limited strictly to traditional plethysmographic- type determinations
Constant volume, variable pressure plethysmograph (pressure type plethysmographs)
A ____ is an important BP component. It must be a biaxial (X-Y) recorder with a very good frequency response.
recording system
The ____ is used for plotting pressures measured by the plethysmograph against either ventilatory flow rates or cabinet volume changes.
recorder
Storage-type ____ or computer monitor perform well.
oscilloscopes
Real-time ____ can be used, but they may cause distortion of the graphic results at high subject breathing rates.
electronic recorders
A system for marking and measuring the tracing’s tangent angles is also
necessary.
recording system
A _____ rotating protractor overlay for the oscilloscope can be used.
clear plastic
____ can enable rapid assessment of the subject’s performance and test results.
Computers
Computers can also allow the operator to control the “ ____” tangent measurement for tracings generated during the tests.
best fit
_______ are used to make indirect measurement of ven-
tilatory parameters. They allow the operator to determine breathing volumes without a
physical connection to the subject’s airway.
Respiratory inductive plethysmographs (RIPs)
This is done by evaluating the changes in thoracic and abdominal girth that the subject experiences during breathing. These changes
are measured by a ____ and an ____
rib-cage strap (RC) and an abdominal strap (AB).
Attached to the straps
is a unit for producing a______(alternating) current through the wires.
high-frequency oscillating
A small _____ unit is also included for storing and processing the data and for
use in system calibration.
microprocessor
The straps consist of ____ wires that are coiled like a telephone receiver
cord. They are enclosed in an elastic material.
Teflon-insulated
The ____ produces a magnetic field around the wires. The field, in turn, causes a resistance to the current flow through the wires. This action is called ____.
alternating current
/ inductance
Changes in the number of coils per length of wire changes the ____ of the circuit.
inductance
