Question Answer
_______ _______ is one aspect of quality assurance. quality control
what often determines the specific procedures that are required for calibration and QC? type of equipment used
what does the type and complexity of instrumentation for a specific test determine? long/short term maintenance (replacing disposable items)
what are 2 other kinds of maintenance? preventative and corrective
what are essential for a comprehensive maintenance program? procedure manual; accurate records
a _______ is any known test signal for an instrument that can be used to determine its accuracy and precision. _________ _______ are test subjects for whom specific variables have been determined. control; biologic controls
what is a primary means of ensuring data quality? control procedures by which data are obtained
what are the 2 concepts that are central to quality assurance? accuracy; precision
_______is defined as the extent to which measurements of a known quantity results in a value approximating that quantity. accuracy
_______ is defined as the extent to which repeated measurements of the same quantity can be reproduced. precision
the _______ observed value, rather than the _____, is often reported as the best test. largest; mean
_________ _______is accuracy determined by measuring an unknown control and comparing the results with a large number of laboratories using similar equipment and methods. proficiency testing
_________ is the process in which the output signal from an instrument is adjusted to match a known input. calibration
in computerized systems, th signal produced by the spirometer is often corrected by applying a software __________ ______. calibration factor
syringes used for calibration should be accurate to within +/-___ ml or +/-___% of the stated volume. 15; 0.5
what is an important distinction of QC with calibration? calibration may not be needed, QC always is
a syringe of at least __-L volume should be used to generate a control signal for checking spirometers. 3
what is maximum acceptable error for spirometers? +/- 3.5% or +/- 65 ml (whichever is larger)
volume-displacement spirometers should be checked in __-L increments across their volume range. 1
___________ ________ are also available for assessing the accuracy of commonly measured parameters such as FEV1 and FEF 25%-75%. computerized spirometry
________ _______ are healthy subjects who are available for repeated tests. biologic controls (lab personnel or others)
what is a disadvantage of biologic controls? pulmonary function varies from day to day
to provide useful statistics, ___-___ sets of measurements should be recorded. 10-20
the __________ ___ _________ may be calculated by dividing the SD by the mean; __________ ___ __________ may also be calculated. coefficient of variation; coefficient of repeatability
____-____ ______ _____ produce a biphasic volume signal. what does it do? sine-wave rotary pumps; checks volume/flow accuracy for I and E
what devices incorporate large-volume syringes with a computer-controlled motor drive? computer-driven syringes
_________ ___________ _______ simulates the exponential flow pattern of a forced expiratory maneuver. what is a the primary advantage? explosive decompression devices; flow/volume signals reproduced
_____ ______ should also be performed on volume-based spirometers daily before assessing volume accuracy. leak checks (>30 mL/min significant)
the _____ _______ from a spirometer should be <1.5 cmH2O up to flows of 14 L/sec. back pressure
__________ ________ refers to the spirometer’s ability to produce accurate volume and flow measurements across a wide range of frequencies. what is this most critical for? frequency response; PEF and MVV maneuvers
a ________ may be used in conjunction with an adjustable compressed gas source to supply a gas at a known flow to the device. rotameter (water-seal type does this too)
______ _______ or _________-__________ ______ of spirometry are required for diagnostic functions, validation, or when waveforms are to be measured manually. printed records; computer-generated displays
analyzers should be calibrated to match the __________ _______ over which measurements will be made. physiologic range
what is the most common technique for analyzer calibration and what does it involve? two-point calibration; introducing 2 known gases
what are the two points for? 1. “zero” – low end 2. “span” – high end
the nonlinearity of each of the analyzers should be ___% or less of the full scale. 0.5
what must be included when calculating the dilution of the test gas? volume of air in the syringe connectors (dead space)
what are 2 methods for verifying analyzer performance? 1. as dilution is analyzed, meter reading recorded, plotted against expected % 2. simulate lung volume or DLCO tests
a _____ _______ is simply an airtight container of known volume. lung analog
a _____ ________ uses precision gas mixtures to allow repeatable DLCO measurements at different levels. DLCO simulator (3rd method)
what is the 4th method of evaluating gas analyzers? testing biologic controls (simplest means of checking systems that depend on accurate analysis)
how is calibration of mouth pressure transducer done? connect it to water manometer or similar device that generates accurate pressure (+/-50 cmH2O, freq 8 hz or mroe)
what is an accurate measure of pressure in a box pressure transducer? +/- 0.2 cmH2O
what is ideal for box calibration? adjustable sine-wave pump connected to small syringe
how may the pneumotachometer (flow sensor) be calibrated? apply known flow or known volume
with what is QC of plethysmographs accomplished? isothermal lung analog, fixed resistors, biologic controls
what is measured to have a simple but effective mean of checking plethysmograph function? VTG, RAW, both from biologic control subjects
what is another method of checking plethysmograph accuracy? compare VTG w/ FRC determined by gas dilution (0.90; >10% – equipment malfunction)
a “____” gas is used to zero or balance each electrode. a “____” gas is used to adjust the gain of the electrode’s amplifier. low; high
the PO2 electrode is usually calibrated over a range of ______ mmHg. PCO2 range: _______; pH uses buffers with values or _____ (low) and _____ (high). 0-150; 40-80; 6.84; 7.38
the difference in calibration is termed ____ and indicates an electrode’s stability. drift
systemic errors can sometimes be masked by _________ _________. ___________ of the calibration gases or buffers is a common example. automatic calibration; contamination
________ ______ are sufficient for ensuring proper functioning of sensors such as optodes, spectrophotometers, or fluorescence quenching devices. electronic checks
what are the 2 methods of QC for blood gas analysis? 1. tonometry of whole blood 2. commercially preparded controls
______ is ideal for QC of gas electrodes because its viscosity and gas exchange properties are the same as those of pt samples. blood
tonometry is the most precise control of the ____ _______. PO2 electrode
what are the complications of tonometry? contamination, improper temp control, inadequate gas flow
what are the 2 types of commercially prepared controls? 1. aqueous 2. fluorocarbon-based emulsions
what is one problem with aqueous controls? poor precision of PO2
what is necessary to detect blood gas analyzer malfunction? interpreting “control runs”
a QC value that falls within +/-__ SDs of the mean is usually considered to be “in control.” 2
the normal variability that occurs when multiple measurements are performed is called _______ _____. random error
a widely used set of rules is that proposed by ________. this approach to QC is termed the _________-____ ______. westgard (detects errors); multiple-rule method
rules 1 and 2 detect marked changes in electrode performance, sometimes called a _____, by examining how far from the mean a single control value falls. shift
when using the multiple-rule method, always keep a ________ _______. Control history
how many levels of control materials are normally used to provide adequate QC for a blood gas analyzer? 3
_____________ _________ _________ consists of comparing unknown control specimens from a single source in multiple laboratories. interlaboratory proficiency testing
what is the three primary uses of criteria of acceptability of PFT? 1. basis for decision making 2. evaluate validity 3. score/evaluate technologist
how should you examine tracings or graphics? compare the observed tracing with the characteristics of acceptable curve/pattern
the decision to perform additional maneuvers is usually based on __________. Repeatability
what are the key indicators for spirometry? start-of-test and duration of effort
what are the key indicators for gas dilution lung volumes? absence of leaks and test duration
what are key indicators for DLCOsb? inspired vols and breath-hold times
what is an important component of quality assurance for PFT? scoring/grading the quality of the test
what is a key component for obtaining valid data, particularly in tests that require pt instruction and encouragement? well-trained and high motivated technologist
what also should be provided from the technologist? feedback
what are the standard precautions that should be applied in the pulmonary function and/or blood gas lab? 1. treat ALL as contaminated 2. exercise care to prevent injuries 3. protective barriers 4. wear gloves 5. wash hands


Question Answer
What are the 5 chronic obstructive disorders? 1. CF. 2. Bronchitis, 3. Asthma, 4. Bronchiectasis, 5. Emphysema
What is the range for % predicted for a mild restriction? 60-79%
Contraindications to pulmonary function testing? Hemoptysis of unknown orgin, pneumothorax, unstable hemodynamic status, Thoracic abdominalor cerebral aneurysms, Recent eye surgery, Pt unable to cooperate, Acute disease that would affect performance, Recent surgery of thorax or abdomen
A RCP asking the patient to take a maximal deep breath and rapidly exhale to maximum exhalation would be measuring the patient’s FVC
Which values can be determined from a forced expiratory spirogram? Flowrates- FEV1, FEF 25-75, FEF 200-1200, etc
Question Answer
what is diffusing capacity also referred to as? transfer factor
what is DLCO used to assess? gas-exchange ability of lungs, specifically oxygenation of mixed venous blood
what is the most common DLCO method and most standardized method? single-breath DLCO
what does DLCO measure? transfer of diffusion-limited gas (CO) across the alveolocapillary membranes
what is DLCO reported in? mL of CO/min/mm of mercury at 0 degree C, 760 mmHg, dry
CO combines with hemoglobin approximately ____ times more readily than O2. 210
in the presence of normal amounts of Hb and normal ventilatory function, what is the primary limiting factor to diffusion of CO? status of the alveolocapillary membranes
what are the 2 components that the process of conductance across the membranes can be divided into? 1. membrane conductance (DM) 2. chemical reaction b/t CO and Hb
what does DM reflect? and what does the uptake of CO by Hb depend on? process of diffusion across alveolocapillary membrane; reaction rate/pulm capillary blood vol
what factors can diffusing capacity be affected by? factors that change the membrane component, alterations in Hb, capillary blood volume
basically, what is the pressure gradient causing diffusion? alveolar pressure
what is the equation that all methods of DLCO are based on? DLCO = VCO/(PACO-PCCO)
what does the pt do in the single-breath technique? exhales to RV, inspires a VC breath (“IVC” or “VI”)
what does the diffusion mixture usually contain? 0.3% CO, “tracer” gas, 21% O2, balance is N2
what is usually the tracer gas? insoluble, inert gas (He, methane, neon)
what are used to detect changes in CO? rapidly responding infrared analyzers; gas chromatography
how much should the pt ideally inhale of the VC? 90% within 2.5-4 secs
after inspiring the VC breath, how long does the pt hold the breath at TLC? 10 secs, exhales within 4 secs
after a suitable ________ _______ (750-1000 mL) has been discarded, a sample of _________ ____ is collected in a small bag or by continually aspirating a sample of the exhaled gas. washout volume; alveolar sample
what is the sample analyzed to obtain? fractional CO and tracer gas concentrations in alveolar gas, FACO2, and FAtracer
the concentration of CO in the alveoli at the beginning of the _______ _____ must be determined as well. breath hold
what does the change in the tracer gas concentration reflect? dilution of inspired gas by the gas remaining in the lungs (RV)
what is this change used to determine? CO concentration at beginning of breath hold, before diffusion from alveoli into pulm capillaries
what are the two times the dilution of the tracer gas is used? 1. CO concentration at beginning of breath hold 2. determine lung vol where breath hold occurs
what is the difference in the amount of the CO between inspiration and expiration? diffusion of gas thru the alveolocapillary membrane
the tracer gas and CO analyzers may be calibrated to real ____ ______ when sampling the diffusion mizture, and to read _____ when sampling air. full scale; zero
if the analyzers have a linear response to each other, the fractional concentration of the tracer gas in the alveolar sample is equal to the ______. FACO0
systems that use the same detector for both CO and the tracer gas also need to provide _______ _______. the linearity of the system should be within ____% of full scale. linear output; 0.5%
_______ _______ uses specialized infrared analyzers capable of detecting several gases simultaneously. what do these systems use as a tracer gas? multigas analysis; methane
what is one advantage of multi-gas analysis? CO and CH4 (methane) are measured rapidly and continuously
what tracer gas is used for gas chromatography? carrier gas? neon; helium
gas chromatography is slow (60-90 secs), but is extremely __________. accurate
what should the resistance of the breathing circuit be? <1.5 cmH2O/L/sec, at a flow of 6 L/sec
what is used instead of a reservoir bag for the test gas? what should the maximal inspiratory pressure to maintain flow at 6 L/sec be in a demand-flow system? demand valve; <10 cmH2O
the ______ method of timing the breath hold hsould be used. what does this method measure? jones; breath-hold time from 0.3 of the I time to the midpoint of the alveolar sample collection
what should anatomic dead space be calculated as? 2.2 mL/kg IBW
instrument VD should not exceed _____ mL for adult subjects. 350
what is anatomic and instrument VD subtracted from before the alveolar vol is calculated? inspired volume
all gas volumes must be corrected from _____ to _____ for DLCO calculations. ATPS; STPD
accurate measurement of inspired vols during the maneuver requires that the spirometer have an accuracy of ____% over a range of __ L. 3.5%; 8
what is absorption of CO2 usually accomplished with? chemical absorber using baralyme or soda lyme (each produce water vapor)
__________ _____ is commonly used to remove water vapor. what is also used to establish water vapor content? anhydrous CaSO4; selectively permeable tubing
when should DLCOsb maneuvers be performed? after pt has been seated for 5 minutes
why should pt refrain from exertion immediately before the test? exercise increases CO (increases DLCO)
how long should expiration to RV be? how should inspiration to TLC be? usually 6 secs or less; rapid but not forced
healthy subjects and pts with airway obstruction should be able to inspire at least ___% of their VC within __ seconds. 85%; 4
what does the single-breath calculation assume? instantaneous filling of the lung
what should the pt avoid excessiveness of? positive intrathoracic pressure (valsalva maneuver) or negative intrathoracic pressure (muller maneuver)
what might the valsalva/muller maneuver cause the DLCO to do? valsalva – decrease DLCO; muller – increase DLCO
exhalation should take less than __ secs and alveolar gas sampling should occur in less than __ secs. 4; 3
how long should the breath-hold time, measured using the hones method be? 10 secs +/- 2 secs
what is one of the most common problems encountered when performing the DLCOsb maneuver? failure to inspire 85% of previously measured VC
to obtain an alveolar sample, _____ _____ gas needs to be washed out. what is usually a sufficient washout time? what about with small VCs? dead space; 0.75-1.0 L; 0.5 L
what is the sample volume size? 0.5-1.0 L
alveolar sampling may be adjusted to begin at the point where the tracer gas and CO indicate an “________ ________.” alveolar plateau
____ or more DLCOsb maneuvers should be averaged. duplicate determinations should be within __ mL CO/min/mmHg of each other, or within ___% of the largest value obtained two; 3; 10%
why should no more than 5 repeated maneuvers be performed? b/c of the effect of increasing COHb from inhalation of the test gas.
how long of a delay should be b/t repeated maneuvers to allow for washout of the tracer gas from the lungs? 4-minute
the predicted DLCO should be corrected so that it reflects the DLCO at an Hb value of ____g% for adult and adolescent males, and to an Hb value of ____g% for women/children of either sex younger than 15. 14.6; 13.4
what does DLCO vary inversely with? changes in alveolar O2 pressure (PAO2)
what does the pt do during the rebreathing technique? rebreathes from a reservoir containing 0.3% CO, tracer gas, and air; 30-60 secs at 30 breaths/min
the rebreathing method can be used during ________. exercise
what happens during the slow exhalation single-breath-intrabreath method? pt inspires a VC breath of test gas containing 0.3% CO, 0.3% CH4, 21% O2, & balance N2
what does the pt do during this method? exhales slowly and evenly at approximately 0.5L/sec from TLC to RV
____ is used as the tracer gas because it can be rapidly measured using an infrared analyzer. CH4
the _________ _______ can also be used during exercise. intrabreath method
what is done during the membrane diffusion coefficient and capillary blood volume method? pt performs 2 DLCOsb tests, each at a different level of alveolar PO2
what can measurement of diffusion of CO at different levels of alveolar PO2 be used for? distinguish resistance caused by alveolocapillary membrane from resistance caused by RBC membrane/Hb reaction rate
the membrane component of resistance to gas transfer can also be estimated by measuring the rate of uptake of ______ ______. nitric oxide
what is DLNO a direct measure of? conductance of alveolocapillary membrane
NO combines with Hb approximately ____ times faster than CO. 280
DLNO reflects the ________ __________ to gas diffusion in the lungs. membrane resistance
the avg DLCO value for resting adult pts by the single-breath method is approximately ___ mL CO/min/mmHg (STPD) with significant variability. 25
DLCO is often decreased in _________ lung disorders, particularly pulmonary fibrosis. resistrictive
what are other causes of decreased DLCO? pulmonary edema; medical/surgical intervention for cardiopulmonary disease; radiation therapy; chemo drugs; inhalation of toxic gases
what is DLCO in CHF? early stage – normal or increased; most times decreased
what is an exception to the extent of reduction being directly proportional to the vol of lung removed? lung volume reduction surgery and bullectomy
DLCO is commonly used to monitor _____ ________. drug toxicity
DLCO may be helpful in evaluating disorders such as ____________ syndrome. hepatopulmonary
decreases in DLCO are termed _________ _______. diffusion defect
what is the steady state (filey) technique? breath a gas mixture of 0.1%-0.2% CO in air for 5-6 mins; last 2 mins expired gas collected in bag/balloon; ABG drawn
what is exhaled volume measure and analyzed for? CO, CO2, O2
what is the calculation of steady diffusing? DLCOss= VCO/PACO
DLCO may be decreased in both acute and chronic ____________ lung disease, like __________. obstructive; emphysema
DLCO measurements at rest have been suggested to estimate the probability of ___ ___________ during exercise. O2 desaturation
what is DLCO directly related to in healthy individuals? lung volume
what can analysis of this relationship help to determine? whether a decrease is due to loss of lung volume (restriction) or from uneven V/Q (obstruction)
in healthy subjects, DL/VA is __-__ mL of CO transferred/min/L of VA. 4-5
how is VA measured? by the dilution of the tracer gas used
what is the advantage of the intrabreath method? not requiring a breath hold at TLC
what indicates a restrictive cause of decreased DLCO? obstructive cause? decreased without a reduction in VA; if DLCO and DL/VA are decreased
what are 7 other physiologic factors that can influence the observed DLCO? 1. Hb/Hct 2. COHb (increases reduce DLCO) 3. alveolar PCO2 4. pulmonary capillary blood vol 5. body position (supine increases DLCO) 6. altitude about sea level 7. asthma/obesity
what are the 3 methods to measure breath-hold time? 1. jones method 2. epidemiology standardization project method (midpoint of I to beginning of alveolar sampling) 3. ogilvie method (beginning of I to beginning of alveolar sampling)
a ______-_________ _______ has been proposed that uses separate equations for the three phases of the maneuver. three-equation method
Question Answer
Tidal Volume TV The amount of air inhaled and exhaled with each breath during quiet breathing. Average 500mL
Inspiratory reserve volume IRV The amount of air that can be forcibly inhaled beyond the TV. Average 3100mL
Expiratory reserve volume ERV The amount of air that can be forcibly exhaled after a normal TV. Average 1200mL
Residual volume RV The amount of air still in the lungs after a forced ERV. Average 1200mL
Vital Capacity VC The maximum volume of air that can be exhaled after a maximal inspiration. Average 4800mL
Inspiratory capacity IC The volume of air that can be inhaled after a normal exhalation. Average 3600mL
Functional residual capacity FRC The volume of air remaining in the lungs after a normal exhalation. Average 2400mL
Total lung capacity TLC The maximum amount of air that the lungs can accommodate. Average 6000mL
Obstructive lung disorder RV, TV and FRC are increased. VC, IC, IRV and ERV are decreased
Restrictive lung disorder VC, IC, RV, FRC, TV and TLC are decreased
Trouble getting air out Obstructive
Trouble getting air in restrictive
Question Answer
TLC, RV and RV/TLC ratio is used to define the pattern and extent of air trapping and hyperinflation? True or False True
Which is not a contraindication for pulmonary function testing? cardiac arrhythmia, chronic cough, untreated pneumothorax, active chest pain, untreated PE Chronic Cough
Spirometry can be used to evaluate disability for Social Security? T or F True
DLCO is used to assess pulmonary involvement in systemic diseases? T or F True
Which test is used to differentiate between emphysema & Chronic Bronchitis? FVC, SVC, DLCO, Lung Volumes DLCO
Cardiopulmonary stress testing is used to determine the level of cardiac fitness? T or F True
Which is not an indication for spirometry? smoking, abnormal CXR, fatigue, working in hazardous environment, dyspnea Fatigue
Lung volumes are used to assess the severity of restrictive lung disease? T or F True
Cardiopulmonary stress tests can be used in the determination of heart failure in the workup process for heart transplantation?T or F True
Spirometry does not consist of which of the following? SVC, Lung volumes, FVC, MVV Lung Volumes
Body Plethsymography uses which gas law? Charles, Boyles, Howes, Venture principle Boyles Law
Which is considered the “gold standard” for spirometers? body box, dry rolling seal, water seal, bellows or wedge Water Seal
Wright respirometer is considered what type of pneumotachometer? pressure differential, heated wire, turbine, pitot tube Turbine
Which of the following can alter the calibration of a spirometer that uses a pressure differential pneumotachometer? moisture on flow sensor, heating element not working, not properly scaled, bellows are sticking Moisture on the flow sensor or restrictive element
Which of the following can be used to analyze multiple gases simultaneously? thermal conductivity, gas chromatography, emission spectroscopy, infrared absorption Gas chromatography
Which type of analyzer can be used for breath-by-breath measurement of CO2? thermal imaging, polargraphic, zirconium fuel cell, thermal conductivity Zirconium fuel cell
Which of the following is not a volume displacement spirometer? water seal, bellows, pitot tube, dry rolling seal Pitot Tube
Which gas is used as a carrier gas when using a gas chromatography? nitrogen, oxygen, helium, neon Helium
Zirconium fuel cell is used in exercise testing. Why? similar to blood gas electrode, fast response time, separates gases, utilizes a ionization chamber Fast response time
Which of the following is considered a pneumotach? water seal, bellows, pitot tube, dry rolling seal pitot tube
When a patient is in a sitting position for spirometry, they should be sitting straight with both feet on the floor? T or F True
When doing a SVC, how many tidal breaths should be performed before the actual SVC maneuver? 2, 3, 4, doesn’t matter 3
how many acceptable FVC maneuvers need to be performed? 2, 3, 4, 1 3
A patient with CF has the following FVC results: FVC 3.01L 2.99L 3.12L FEV1 1.99L 2.01L 1.95L Which of the following should be done? report the largest FVC and FEV1
When performing a MVV, the patient breaths should be larger than tidal breaths and at a rapid pace? T or F True
When a patient exhales for 6 seconds with no obvious plateau the test is automatically stopped? T or F False
A back extrapolated maneuver is never acceptable? T or F False
SVC & FVC results should differ by what volume in healthy patients? 50ml, 100ml, 200ml, 250ml 200ml
A patient with a FEV1/FVC ratio of 55% is an indication of what disease process? It is a normal ratio, restrictive disease, obstructive disease obstructive disease
The MVV can be approximated by which formula? 35 x FEV1
Patients with restrictive lung disease can have a normal FEV1/FVC ratio? T or F True
Conversions from ATPS to BTPS need to be done if the spirometer does not perform this calculation? T or F True
When calculating the FEV1/FVC ratio, the ratio must be done after the BTPS correction? T/F False
When performing a FVC, testing can be stopped after 2 repeatable efforts and 3 acceptable efforts are performed? T of F True
Sprirometry is the most common of all the PFT’s? T or F True
According to ATC standards, if the patient is unable to perform an acceptable effort, testing may be stopped after how many? 10, 8, 3, 20 8
A FVC is considered repeatable when which criteria is met? cough before 1st sec, 2 best FVC w/i 150ml, 2 best FEV1s w/i 150ml, efforts are at least 6 sec long & obvious plateau All of the above
A blunted or flat inspiratory curve on the flow volume loop is an indication of what? COPD, restrictive lung disease, sleep apnea, upper airway obstruction Upper airway obstruction
When performing an SVC, tidal breathing before and/or after the efforts s/b w/i 100ml. Which calculation is not effected by the tidal breathing? ERV, SVC, TLC, RV SVC Calculation
FEV1 can be measured directly from the flow volume loop? T or F False
What ethnic origin does not receive a race correction? African American, Native American, Asian, Hispanic Native American
Normal range for predicted values is? 95-105%, 90=110%, 80-120%, 75-120% 80-120%
All FVC & VC maneuver need to be corrected to BTPS? T or F True
What is not considered in the calculation of predicted values? Age, height, weight, gender Weight
Women have typically larger lung volumes than men of the same age & Height? T or F False
The VC, SVC and FVC are the most widely used of the pulmonary function test? T or F True
BTPS corrections can be manually calculated if necessary? T or F True
Predicted values generally plateau about the age of 20-25 then decrease at a predictable rate using an acceleration curve? T or F False
Which of the following author is recommended to be used for predicted values by ATS? Kory, Morris, NHANES III, Knudsen NHANES III
The difference between a VC & FVC is the speed and force in which the maneuver is performed? T or F True
MVV stands for what? Maximum Voluntary Ventilation
When performing a MVV, instruct the patient to take breaths that are larger than TV and smaller than VC? T or F True
If the volumes are not corrected to BTPS, the values reported will be higher than actual? T or F False
All reported values are corrected to ATPS? T/F False
When performing a SVC, how many tidal breaths need to be performed prior to the actual SVC maneuver? 2, 3, 5, 1 3
When the LLN is used, it denotes what? midrange for predicted values, upper limit of the normal range, lower limit of normal range, values are out of normal range & considered abnormal The lower limit of the normal range
The MVV can be approx. by which formula? 37.5 x FEV1
Conversions from ATPS to BTPS need to be done if the spirometer does not perform this calculation? T or F True
IRV and ERV are the subdivision of SVC? T or F True
When calculating the BTPS a correction factor is given to correct for the barometric pressure? T or F False
What is the percentage given for race correction? 15%
TGV is the measurement of what lung compartment? TLC, RV, FRC, VT FRC
When reporting Raw/Gaw, these efforts can be averaged? T or F True
When performing a Raw/Gaw maneuver, the patient pants against what?Open shutter, closed shutter Open Shutter
Which of the following can increase the Raw? acute asthmatic episode, bronchospasm, advanced emphysema, all of the above all of the above
TGV is considered the gold standard in lung volume testing? T or F True
TGV is often compared to gas dilution methods and can be useful as an index of air trapping? T or F True
When performing a TGV maneuver, mouth pressure is theoretically equal to what? pressure at mouth, alveolar pressure, atmospheric pressue, barometric pressure Alveolar Pressure
When performing a TGV maneuver, the patient pants against what?Open shutter, closed shutter Closed Shutter
A small air leak in the seal of thh box is acceptable? T or F False
TGV is corrected to BTPS? T or F True
TGV is based on what law? Boyle’s Law
The most common methods of measuring FRC is He Dilution, N2 washout or plethsymography? T/F True
When performing a He dilution in a healthy patient, approx. how long before equilibrium is reached? 2 minutes, 3 min, 4 min, 10 min 3-4 minutes
The term hyperinflation refers to abnormally high TLC? T or F True
When performing either a He dilution or N2 washout the breathing s/b regular tidal breathing w/o large tidal volumes? T or F True
Along with the IC what else is required to calculate the TLC? RV, FRC, ERV, VC FRC
When performing a N2 washout, the test can be stopped when the exhaled concentration is between 1 & 2% exhaled? T or F True
When performing a N2 washout in a normal Pt, approx. how long for N2 to washout & the test can be stopped? 1-2 min, 2-3, 3-4, >10 3-4 minutes
Both the N2 washout & He dilution values are corrected to BTPS? T or F True
In patients with COPD, the TLC can be normal? T or F True
If multiple efforts are performed using either method they should agree w/i 10% and can then be averaged? T or F True
The term air trapping refers to an abnormally high RV? T or F True
The TLC is calculated combining other lung volumes. Write one equation TLC = IC + FRC
FRC values of > 120% predicted generally represent hyperinflation? T or F True
Patients with restrictive lung patterns, the FRC is generally elevated? T or F False
In patients with asthma the FRC is generally elevated but can be reversible? T or F True
Vocal cord dysfunction mimics what disease? Asthma
FEF 25-75 is represented by what Curve? Volume-Time Curve
Which is not a bronchoprovication test? methacholine, exercise challenge, bronchodilator response, cold air inhalation Bronchodilator response testing
Acceptability of efforts needs to be met for all challenge testing? T or F True
Warm up periods are recommended for exercise challenge testing? T or F False
When performing a Methacholine challenge, when is testing stopped? 10% or > decrease in FEV1, 20% or > decrease in FVC, 20% or > decrease in FEV1, all levels of methacholine are administered regardless if decrease A 20% or greater decrease in the FEV1 occurs
Bronchial challenge testing can be used to screen individuals who may be at risk from invironmental & occupational exposures? T/F True
When performing a methacholine test, inhaled bronchodilators, inhaled steroids, antihistamines & caffiene s/b helf only for the day of the test? T or F False
Performing an exercise challenge test will rule out the presence of vocal cord dysfuction? T/F False – it rules out asthma
Exercise challenge testing can be used to determine if the patient has vocal cord dysfunction, exercise induced bronchospasm or both? T or F True
When determining if a patient has a positive response to bronchodilators, which values are used? FVC, FEV1, FEV1 & FVC FEV1 and FVC
A FEV1 of less than 80% predicted is a relative contraindication for methacholine testing? T/F True
Exercise challenge testing is used with patients that have shortness of breath on exertion but have normal PFTs? T or F True
When performing a Methacholint test on a Pt with suspected vocal cord dysfunction, the methacholine will show a positive response? T or F False
When performing an exercise challenge test, the patient needs to exercise for a minimum of 10 minutes? T or F False
A potential problem with exercise testing is that the level and type of exercise will not mimic real life triggers? T or F True
According to ATS standards, what needs to occure for apositive response to bronchodilators? Increase of 12% & 200ml in FVC, Increase 10% & 150ml in FEV1, Increase of 10% & 150ml in both FEV1 & FVC, Increase of 12% & 200ml in both the FEV1 & FVC Increase of 12% and 200 ml in both the FEV1 and FVC
Which of the following are uses for cardiopulmonary stress testing (CPXT)? to guide therapies for heart failure Pts, to evaluate unexplained dyspnea, formulated individualized exercise programs, all above All of the above
At maximal exercise, there is a build up of lactic acid? T or F True
Which are potential limitations of maximal O2 consumption? muscle metabolism, oxygen carrying capacity, the heart, All of above All of the above
VO2max obtained during exercise indicates whether or not a patient has a normal heart, lungs, circulatory system & exercise capacity? T or F True
Which are factors affecting VO2max? type of exercise, gender, natural endowment, age, all of the above All of the above
Which of the following is not generally used for CPXT testing? treadmill, cycle ergometer, 6 minute walk 6 minute walk
Max VO2 obtained at peak exercse can indicate if the Pt had normal exercise capacity or if they are limited by the heart, lungs or circulatory system? T or F True
Key measurements also include METS & anaerobic threshold? T or F False
A VO2 of 16 ml/kg/min is an indication of which of the following? Mild to moderate impairment
VO2 measures the maximal reserve of the pulmonary system? T or F False
VO2 max is not limited by pulmonary function, but instead measures cardiovascular systems maximal reserve? T or F True
What RER indicates a maximal test? 0.78, 0.91, 1.01, 1.10 1.10
Hyperventilation will decrease the RER? T or F False – it will increase the RER RER = relation of CO2 to O2
Lactic acid will begin to accumulate after the patient reaches a RER of 0.8? T or F False – Lactic acid is only released after anaerobic threshold
RER stand for what? respiratory exhalation ratio, ratio exchange respiratory, respiratory exchange ratio Respiratory Exchange Ratio
In cardiopulmonary stress testing the VO2 is usually expressed as? mg/min, L/min, ml/kg/min, mg/kg/hr ml/kg/min – it is the only PFT test where body weight comes into play
What are the uses for Cardiopulmonary stress testing? individual exercise programs, guide therapy for heart Pts, risk stratify potential transplant pts, differentiate between cardiac/pulmonary pts, all of above All of the above
MVV is performed prior to cardiopulmonary stress testing to determine a pts respiratory reserve? T or F True
RER uses what parameters? Vo2 & VCO2, RR & VCO2, RR & VO2, RR & HR VO2 and VCO2
Generally a RER of 1.0 is an indication that an aerobic threshold has been met? T or F True
Testing equipment must be both accurate & precise? T or F True
A syringe is generally used to calibrate & is used as a method for QA? T or F True
What is the accuracy range for a calibration syringe? +/- 1.5%, 2.5%, 3.5%, 4.5% +/- 3.5%
If a 3L syringe is used what is the accuracy range? 2.85-3.15, 2.50-3.50, 2.90-3.10, exactly 3L 2.90L – 3.10L
What can be common problems when calibrating spirometers? cracked/sticking bellows, faulty computer/software signals, leaks in tubing/connectors, all of the above All of the above
Biological controls can be used in repeat testing for QA? T or F True
Disposable mouthpieces should be used for spirometry testing, if not, these mouthpieces need to be sterilized between patients? T/F True
While calibrating a spirometer with a 3L syringe, teh measured volumes are 3.35, 3.40, and 3.39. What should be done to correct the problem? remove bacteria filter, recheck with 1L syringe, locate & repair leak, turn off BTPS correction Turn off BTPS correction
Using a biological control is recommended to be part of the Quality Assurance program? T or F True
Bacteria filters can be used on pulmonary function equipment to help prevent cross contamination? T or F True
Question Answer
How many lung volumes are there 4
how many lung capacities are there 4
what are lung volumes distinc measurements that do not overlap each other
what are lung capacities measurements containing two or more lung volumes
what volumes and capacities cannot be measured directly RV, FRC and TLC
how do we measure RV, FRC and TLC indirectly using helium dilution, nitrogen washout, body plethysmograph or radiologic estimation
Calculating TLC IRV+VT+ERV+RV or VC+RV or IC+FRC
Calculating VC IRV+VT+ERV or IC+ERV or TLC-RV
Calculating IC IRV+VT or TLC-FRC or VC-ERV
Calculating FRC ERV+RV or TLC-IC
TLC total lung capacity, sum of VC and RV, based on age size and gender, increased w/obstructive and decreased with restrictive
VC vital capacity, max exhaled volume after a deep breath (if forced it is called FVC)
what is the most important part of the FVC coaching, bad coaching is bad results
the 3 phases of the FRC are max inspiratory effort, initial expiratory blast, forceful emptying of the lungs
why do we not continue coaching and yelling during the forceful emptying portion of the FRC may lead to airtrapping in obstructive pts
can a VC be to high? no, the higher the better, just to low
how does obstructive disease cause a decrease in FRC by causing a slow rise in the RV
IC inspiratory capacity, measured with spirometer
FRC functional residual capacity, (RV+ERV is FRC) resting volume in lungs following exhalation of VT
what volume represents the the force of the expanding chest wall and the contractile rebound of the lung tissue(elastic equilibrium) FRC
what kinds of diseases cause a <FRC pneumothorax, restrictive diseases, age, obesity
what kinds of diseases cause an >FRC emphysema, any disease that causes a loss of lung tissue, obstruction
IRV inspiratory reserve volume, measured with routine spirometer
VT tidal volume, exhaled or inhaled in each breath, can be reduced in both restrictive or obstr
a decrease in VT with no change in RR will result in what hypoventilation and >CO2
What is the normal RR for a pt with restrictive disease increased, because VT’s are shallow, RR must be increased to proportional to loss of VT
SVC slow vital capacity, test performed by having pt blow everything out slowly after max inspiration, allows for less airtrapping
what is the most important measurement for a preop pt VC, significant reduction in VC indicates pt is at high risk for resp failure after surgery
ERV expiratory reserve volume, (FRC-RV is ERV) max exhaled following passive exhalation, < obesity, poor performance and restrictive (limited clinical use)
RV residual volume, amount left in lung after pt exhales all that is physically possible, < in restrictive and >in obstructive as airtrapping occurs
RV/TLC, what percent of TLC is normally RV 25%
RV/VC, what percent of VC is normally RV 33%, >33% COPD is present
What is the significance of a reduced RV/VC none, there are no clinical states that reduce RV/VC only increase as with COPD (will be in normal range with restrictive disease state)
VE RRxVT, best index of ventilation when used in conjunction with ABG. Should be up with exercise, fever, pain, hypoxia and acidosis
What does the expiratory side of the FVC curve provide contractile state of the airways, FEV1, FEV3, FEF25-75, PEF (peak flow)
FEVt forced expiratory volume timed in liters (t is commonly expressed in .5, 1, 2, 3 seconds) norm is relative to his FVC
FEV1 max forced exhalation during 1st second, best indicator of obstructive disease, reflects the flow in larger airways, best express as a % of FVC (FEV1/FVC is FEV1%), norm is 75% of VC, <in acute or chronic COPD, norm in restrictive
FEV3 looks at the 3 second point on the curve.
FEV.5 and FEV1 used along with FEV200-1200 to assess the flow rates and disorders of the large airways, will be < with airway obstruction
FEV% FEVT/FVC reduced with obstructive disorders
FEV1% 75-85% <65% is is airway obstruction
FEV3% 95%
FEF25-75% sensitivity test expressed in L/sec (measures flow or speed of exhalation), middle 50% of the exhalation (not 50% point but total 50%) and reflects patency of airways, best early indicator of obstructive disease
PEF max flow rate during PFT maneuver, steepest part of FVC, can be measured with spirogram or hand-held device at home or ER. Often used by asthmatics to measure severity of asthma obstruction
PEF measurements <100 L/min is sever obstruction, 100-200 L/min is mod to severe obstruction, >200 is mild
Once treatment has been started in an asthma pt, what test can be given to help determine response to TX PEF
spirometer positive displacement-volume, used to measure volumes and flow rates
water-seal spirometer measures volume and time
what is the best indicator of a restrictive disease? Vital Capacity
how do we measure obstructive diseases flow rates, FEV1, FEF200-1200, FEF25-75, PERF and FVC
what is the best indicator of obstructive disease FEV1
what is the best indicator of large airway obstruction FEF200-1200
what is the best indicator of a small airway obstruction FEF 25-75
what is the best indicator of airtrapping FVC that is smaller than SVC
what is a PFT determines the functional status of the lungs
what can PFT’s be used for presence of pulm disease, esp which pts will be harmed by smoking, evaluating pts before surgery, eval effectiveness of therapy, documenting progression of pulm disease, effects of exercise on lung function, measures degree of airway hyper-responsiveness
what is bronchoprovocation testing PFT that measures degree of airway hyper-responsiveness
contraindications of PFT’s recent ab, thoracic or eye surgery, hemodynamic instability, symptoms indication acute sever illness, recent hypoptysis, pneumothorax, recent hx of ab thoracic or cerebral aneurysm
what tis the most important factor influencing lung size and predicted values height
at what age does a persons lung size begin to shrink 20yrs
what is the primary instrument used in PFT’s spirometer
what does a spirometer measure the lung volume compartments that exchange gas with the atmosphere
spirograph attaches to spirometer to graphically record PFT’s
spirogram the graphic tracing of the PFT
body plethysmograph for total lung capacity and airway resistance studies
what are the 2 main categories of PFT abnormalities obstructive and restrictive defects
how do obstructive disease present on PFT’s if expiratory flow is below normal
how do restrictive diseases present on PFT’s if lung volume is reduced
Upper airway obstruction will show up where on PFT reduced flow rate in initial 25% of FEC
what portion of the flow/volume curve is effort Dependant the first 1/3
what portion of the flow/volume curve is effort independent the later 2/3
a restrictive disease is present when PFT lung volumes are reduced to less than 80% of predicted levels
what are the two most common causes of restrictive disease atelectasis and obesity
what are two examples of combined obstructive/restrictive disease sarcoidosis and emphysema
sarcoidosis unknown cause characterized by deposition of cicronodules called noncaseating granulomas throughout the body and lungs
what is the easiest way to distinguish between obstructive and restrictive diseases on a PFT obstructive causes reduced expiratory flows, restrictive causes reduced lung volumes
3 ways to measure TLC body plethysmograph (body box), open-circuit nitrogen washout, or closed-circuit helium dilution
why is body box more accurate it measures communicating and non-communicating/poor communicating spaces (volumes)
what are non communicating or poor communicating lung volumes airtrapping (COPD, Asthma) or pneumothorax
(open-circuit) nitrogen washout air in lungs is 79% nitrogen just like atmosphere, pt breaths 100% O2 for approx 7 mins, nitrogen is measured during exhalation for volume measurements
(closed-circuit) helium dilution pt breaths helium for 7 minutes, when equilibrium is reached, helium is measured and lung volumes are calculated
why is helium used as a measuring gas helium is an inert gas so not significantly absorbed
what PFT equipment uses an open-circuit system nitrogen washout
what PFT equipment uses a closed-circuit system helium dilution
what is the most accurate determination of gas volumes in the chest plethsmograph/body box
MVV, max voluntary vent rapid & full as possible for 12-15 seconds, total exhaled is obtained,repeat 4 or 5 times and multiplied to get a max volume for 1 minute (15×4 is 60), measures status of resp muscles, compliance and resistance, used prior to surgery, not generally useful
Flow volume loops (FLOOP) flow and volume on a graph paper, V is horizontal, F is vertical, Inspiration is below horizontal, expiratory is above
how are FLOOPs used to show if response to medications two flow volume curves superimposed on each other, one before bronchodilator and one after
FLOOPs are best used to look for patterns in what diseases restrictive (<volume), large airway obstruction (<flow, norm volume), severe COPD (hockey stick or boot)
PFT’s before and after bronchodilator 2 of 3 must improve, FVC >10%, FEV1 15%, or FEV25-75 20-30%, best in asthmatics, misleading in COPD
DLCO diffusion capacity of the lungs, <with emphysema and pulm fibrosis
RAW normal w/out ETT tube .5-3.0 cmH2O/L/sec, as airways narrow, pressure of resistance increases
compliance volume change per unit of pressure change, measured with balloon catheter
Dynamic compliance measured when gas is flowing
static compliance measured with no flow of gas
Total CL lung tissue compliance + chest wall compliance, <CL as lungs become stiff, the more non-compliant the more stiff,
what is a flat top of the curve represent on a floop stiff lungs-<CL, (less volume, more pressure)
what does a round top of the curve represent on the floop emphysema, <elastance (more volume and less press)
RQ respiratory quotient, norm is .8-.85, ratio of CO2 produced to O2 consumed. Fatty diet RQ is .7 and RQ is 1 for carbs, best used during weaning to adjust pt diet and <WOB
Bronchoprovocation pt inhales histamine or methacholine, cold air and exercise, used to test pt for hyperactive airways
methacholine challenge parasympathomimetic used to induce bronchospasm
most useful PFT tests as seen in table 8-1 1-VC, 2-FEV1 and FEV1%, 3-TLC, FRC, RV, RR, VE, FEV3, FEV25-75, DLCO, RAW and CL
Do PFT’s measure the ability of the lungs to exchange resp gases no, DLCO does and it is done in a closed circuit helium test with carbon monoxide
which of the following is least use PFT-A)documenting disease progression B) eval probability of getting a pulm disease C) exercise eval D) weaning from mech ventilation B is
The tracing obtained from a PFT is called spirogram
which is the most important factor in predicting PFT measurement age, weight, height, gender height
PFT’s are effort dependent T/F True
What piece of equip is used to measure TLC and RAW body plethysmography
which of the following are consistent with obstructive disease? > exp flows, <exp flows, <vol and flows, or >volumes and flows <exp flow
an obstruction in the upper airway will affect which portion of the spirometric tracing all of it, the initial the middle and the end, it is flat
which is true regarding restrictive disease-<volumes on PFT, can be caused by obesity, exp flow are usually normal all (not sure on the flow)
VT can be > or < with restrictive or obstructive disease VT is < with both restrictive and obstructive
what PFT is useful in determining the need for mech ventilation FVC
Question Answer
TLC Normal total lung capacity 6000ml
VT Normal tidal volume 500 ml
VC normal vital capacity 4800
RV normal residual volume 1200
Volumes that cannot be directly measured in a PFT RV, FRC, TLC
Tests used for RV, FRC, and TLC Helium dilution, Nitrogen washout, body box (most accurate)
PFT Equipment for measuring volume water sealed spirometer (uses bell) bellows spirometer (most popular) dry rolling seal spirometer
Infection Control in PFT’s standard precautions fluids-hand washing, gloves, barrier filters. Infectious disease- personal respirator or close fitting mask (N-95 for TB). safe disposal, sterilize or disinfect equip between patients.
Why PFT’s identify and quantify changes in pulm function, epidemiological surveillance for pulm disease, assessment of post op risk, determine pulm disability, evaluate and quantify therapeutic effectiveness
Patient instructions for FVC effort dependent, careful instructions, be sure Pt understands and will cooperate, demonstrate, enthusiastic coaching, sitting standing ok, nose clips on or off ok, 3 tests, best 2 must be within 5% ( convert atps to btps)
ATPS to BTPS since ATPS can be 5 to 15% different that BTPS, adjustments must be made or test will be invalid.
FEV1 forced exp volume in 1 second, Normal is 4.2 L…(<80%=obstructive), measured as volume it is considered a flow. Used as a measure of general severity with airway obstruction
FEV2 forced exp volume in 2 seconds, normal is 4.6L
FEV3 forced exp volume in 3 seconds 4.8L
PEFR Peak exp flow rate, steepest point on curve on the “FLOOP”, normal is 9.5L/sec (best identified on a flow-volume loop
FEF200-1200 forced exp press between 200 and 1200, normal 8.5ml/second, measures large airway flow
FEF25-75 forced exp flow between 25 and 75, normal is 4.5L/second, measures small airways
Measuring RV Residual Volume, normal 1200, like the FRC & TLC it cannot be directly measured. alternative tests are, 1.Body box 2. Helium dilution 3. Nitrogen washout
Body Box best method to measure RV, uses Boyles Law to calc RV, larger values because more accurate information
PFT Contra-indications hemoptysis, pneumothorax, cardio problems, thoracic, abdominal or cerebral aneurysm, recent eye surgery, acute disease that may cause nausea or vomiting, recent ab or chest surgery
FVC Validity/Reliability 3 acceptable tests must be given, best 2 should not vary by more than 5%, no cough, swallow or disruptions, smooth, continuous and complete, exhalation must be a minimum of 6 seconds
M V V Max voluntary ventilation, normal is 160L/min, tested with Spirogram, fast and hard for at least 12 seconds, 2x-use best results, tests for strength of muscles, flow and capacity, tested pre-op/ make sure patient can get of vent post op
PFT Severity normal 80 – 120, moderate 50-64, very severe <35
Obstructive severity check FEV1 & FEV1%
Restrictive Severity check FVC, TLC & VC
DLCO Diffusion of Lung Carbon Monoxide, normal is 40ml/min/mmHg, 0.3%CO & 10% He in air held in a single breath for 10 seconds.
Restrictive Disease ↓ volumes & capacities, affects lung parenchyma and thoracic pump, ↓ inspiration, ↓CL, more vertical slope on PFT tracing than obstructive, restriction+diffusion=fibrosis
Obstructive Disease ↓ Flows, ↑ CL, flatter curve on PFT tracing, affects airways, obstruction+diffusion=emphysema
FVC Forced Vital Capacity, normal is 480 ml
FEV1% FEV1/FVC, normal is 75 to 85 % (<70%=obstruction)
VC/TLC% VC is normally 80% of TLC
Spirometery Value Factors height, age, gender, ethnicity, sometimes for extreme weight and altitude (may be reduced 12 to 15 % for non-white)
FVC Tracings obstructive curve is flatter, restrictive curve is more vertical
Conditions that ↓ DLCO ↓ DLCO is associated with emphysema , Fibrosis, restrictive diseases, carbohemoglobin polycythemia, CHF, anemia, pulm embolism, exercise
Airway Obstruction Tests FEF200-1200, normal is 8.5 L/sec, <80%=large airway disease. FEF25-75, normal is 4.5 L/sec,<80%=small airway disease. (FRC or RV >120%=airtrapping)
Patient Effort Patient efforts insures validity and reliability of tests. Tests that are not valid or reliable, can lead to misdiagnoses, mistreatments and poor outcomes
Reversibility of airway obstruction before and after treatment studies, FEV1 >15% indicates effective treatments
PFT categories (test types) lung vol and cap, flow rates through airways, ability of lungs to diffuse gases (DL)
Nitrogen washout test open circuit (non-re breather), exhaled gas measured for N2, Patient breaths until little N2 remains, 2-5 mins normal, COPD longer (perforated ear drum will scew test)
Helium Dilution test measures RV,FRC,TLC…closed circuit, helium and O2, CO2 is absorbed by soda lime and )2 is added, Pt breaths until gas concentration is equalized 3-5 mins (20 mins in copd)
Fibrosis restriction + diffusion
bronchoprovocation testing methocholine induced asthma attack, positive response is FEV1 falls more than 20%, reversed with svn or mdi treatment
Question Answer
IC – Inspiratory Capacity Volume of air that is inhaled after a normal exhalation. (Vt=IRV)
IRV – Inspiratory Reserve Volume Maximum volume of air that can be inhaled after a normal tidal volume. inhalation.
ERV – Expiratory Reserve Volume Maximum volume of air that can be exhaled after a normal tidal volume.
FRC – Functional Residual Capacity Volume of air remaining in the lungs after a normal exhalation. (ERV + RV)
TLC – Total Lung Capacity Maximum amount of air that the lungs can hold.
Capacity 1 or more volumes combined
Vt – Tidal Volume Volume of air that normally moves into and out of the lungs in one calm breath.
Obstructive Lung Disease RV TLC & FRC – Increase IRV & IC – Decrease
Restrictive Lung Diseases All volumes & capacities decrease.
RV – Residual Volume The amount of air remaining in the lungs after a maximal exhalation.
VC – Vital Capacity Maximal volume of air that can be exhaled after a maximal inspiration.
SVC – Slow Vital Capacity Diagnostic for restrictive lung disease.
FVC – Forced Vital Capacity Diagnostic for obstructive lung disease.
FEV 1 The volume of gas that can be exhaled after 1 second of time. Most used from an FVC. Normal is 83%
FEF – Forced Expiratory Flow 25%-75% Reflects medium to small airways. Normal is approx. 4.5 L/Sec. Decreased in Obstructive Diagnosis
FEF – Forced Expiratory Flow 200- 1200 Reflects condition of larger airways. “Effort Dependent”
MVV – Maximum Voluntary Ventilation Deep and Fast breathing for 15 seconds. Normal ranges: Men 170 L/min Women 110 L/min
Flow-Volume Loop Forced Vital Capacity (FVC) manuever followed by a forced inspiratory volume manuever.
Flow-Volume Loop Important Measurements PEFR, PIFR, FVC, FEVt, FEV1/FVR Ratio, FEF 25%, FEF 50%, FEF 75%
DLco – Diffusion Capacity of Carbon Monoxide Test that measures the amount of CO diffused across the A-C Membrane.
DLco – Diffusion Capacity of Carbon Monoxide Normal Ranges Normal Range Male = 25 ml/min/mmHg Identifies a diagnosis of AC Membrane thickening.
MIP – Maximum Inspiratory Pressure Normal Range Normal range (NIF) Males – 125 cmH2O Females – 90 cmH2O
MEP – Maximum Expiratory Pressure Normal Range Normal range Males – 230 cmH2O Females – 150 cmH2O
NIF – Negative Inspiratory Force The ability to take a deep breath and to generate a cough strong enough to clear secretions. The patient’s should be at least –20 cm H20.
SVC Acceptable Value – Bedside Test Acceptable value = 20ml/kg IBW
NIF Acceptable Value – Bedside Test Acceptable Value = -20 cmH2O or >
VT Acceptable Value – Bedside Test Acceptable Value = 7-9 ml/kg IBW
PF Acceptable Value – Bedside Test Acceptable Value = 300 lpm or >
Spirometer An apparatus for measuring the volume of air inspired and expired by the lungs. It records the amount of air and the rate of air that is breathed in and out over a specified period of time.
Respirometer A device used to measure the rate of respiration of a living organism by measuring its rate of exchange of oxygen and/or carbon dioxide.
NIFometer A disposable single patient monitor that indicated for use in measuring Negative Inspiratory Force.
FEV1 Normal Value 83% Normal Value
Question Answer
what is assessment of ventilatory responses closely related to? measurement of resting ventilation
___________ _________ is usually assessed by measuring the change in ventilation that occurs with elecated CO2 or decreased O2. ventilatory response
______ ________ is the volume of gas inspired of expired during each respiratory cycle. tidal volume
the total volume of gas expired per minute is ________ __________. minute ventilation (alveolar/dead space ventilation)
where are VT, f, VE performed at? VD and VA? ventilatory response tests for CO2 & O2? bedside/PFT lab; critical care areas/PFT lab; PFT lab
how is VT measured? simple spirometry via vol displacement system or flow-sensing device
VT may also be measured from an ___________ _____ ________. integrated flow signal
what is the exchange difference termed that shows that VI and VT are greater than VE b/c at rest the body produces a slightly lower vol of CO2 than the vol of O2 consumed? what is the normal for resting pts? respiratory exchange ratio; 0.8
VT may also be estimated by means of a ___________ __________ ______________. respiratory inductive plethysmography
what is the most common way to determine respiratory frequency? measuring flow changes while pt breathes through a flow-sensing spirometer
how is the most accurate rate measured? over several minutes and divided by the # (avg)
what is it called when prolonged measurement of VT and rate with a volume-displacement spirometer requires a means of removing CO2? rebreathing system; uses CO2 absorber
what are commonly used to scrub CO2 from rebreathing system? sodasorb or baralyme
how is the VE measured? pt breathes into or out of a vol-displacement or flow-sensing spirometer for a least 1 min
what gives an accurate avg of VE? measuring expired gas vol for several mins and dividing by the time
what is the avg VT for healthy adults at rest? 400-700 ml
when does decreased VT occur? restrictive disorders; pulmonary fibrosis, neuromuscular diseases; changes in CL/RAW
what are decreases in VT and f often associated with? respiratory center depression
low VT and rate usually result in ________ ___________. alveolar hypoventilation
the VT alone is not a good indicator of the adequacy of ________ ____________. alveolar ventilation
from the equipment/noseclip alone, some pts will exhibit _______ VT than normal. larger
what is the normal RR? 10-20 breaths/min
what are indications of a change in the ventilatory status? increases/decreases in the RR
what can cause increased RR? exercise, hypoxia, hypercapnia, metabolic acidosis, decreased CL
what is decreased breathing freq common in? CNS depression and CO2 narcosis
what is the normal VE? 5-10 L/min
what is VE the sum of? VA and VD
what might a large VE (>20 L) result from? enlarged VD
what can cause increases in VE? hypoxia, hypercapnia, metabolic acidosis, anxiety, exercise
what can cause decreases in VE? hypocapnia, metabolic alkalosis, resp center depression, neuromuscular disorders
___________ _____ _____ is the lung volume that is ventilated but not perfused by pulmonary capillary blood flow. what can this be divided into? respiratory dead space (VD); anatomic dead space and alveolar dead space
what is VA? what can VA be expressed as? vol of gas that participates in gas exchange in the lungs; VA = VT – VD
how is VA calculated? VA = f(VT-VD)
what is anatomic dead space (VD) esimated from? individual’s body size as 1 ml/lb of IBW
how is VD calculated? VD = PaCO2 – PeCO2/(PaCO2 x VT) (PeCO2 – mixed gas sample)
what is it called if expired volume is not measured, and only a dilution ratio can be determined? VD/VT ratio
when can the VD/VT ratio be calculated? if arterial and mixed-expired PCO2 values are known
____-_____ ____ can be used to estimate PaCO2. what is the main advantage of this method? end-tidal PCO2; no arterial blood sample
how is VD/VT calculated? (PETCO2-PECO2)/PETCO2
anatomic dead space is larger in ______ than in ______ because of differences in body size. men; women
when does VD increase? exercise; certain forms of pulm disease (bronchiectasis)
when is VD decreased? asthma or disease characterized by bronchial obstruction or mucous plugging
of greater clinical significance is the measurement of respiratory dead space, which is accomplished well by applying the _____ ________. bohr equation
what is the normal value of VD/VT in adults and the range? 0.3; 0.2-0.4 (percentage – 30% is normal)
when does VD/VT ratio decrease? exercise
as CO increases, perfusion of the alveoli at the lung apices increases; this is called ___________. recruitment
when is VD/VT increased? pulmonary embolism; pulmonary HTN
what is the VA at rest in healthy adults? what can the adequacy of VA be determind by? 4-5 L/min; ABGs
low VA associated with acute resp acidosis defines ____________. hypoventilation
excessive VA defines _____________. hyperventilation
what is ventilatory response to CO2 a measurement of? increase/decrease in VE caused by breathing concentrations of CO2 under normoxic conditions (PaO2 = 90-100)
what is ventilatory response to O2 a measurement of? increase/decrease in VE caused by breathing concentrations of CO2 under isocapnic conditions (PaCO2 = 40 mmHg)
__________ ________ is the pressure generated at the mouth during the first 100 msec of an inspiratory effort against an occluded airway. occlusion pressure
what are the 2 ways the response to INCREASING levels of CO2 can be measured? 1. open-circuit technique 2. closed-circuit or rebreathing technique
what is the open-circuit technique? (increasing levels of CO2) pt breaths various concentrations of CO2 (1-7%) until a steady state is reached
what parameters can be measured? PECO2, PaCO2, P100, VE
what is the closed-circuit technique? (increasing levels of CO2) pt rebreathes from a circuit (7% CO2 in O2) for 4 mins or until the PetCO2 >9%
what do valves and pressure taps allow the acquisition of? and a pneumotach for measuring ___. P100/PECO2 samples; VE
what is the open-circuit technique? (decreasing levels of O2) pt breaths gas mixture of O2 concentration from 12-20% to which CO2 is added to maintain PCO2 levels
what is the closed circuit technique? (decreasing levels of O2) pt rebreathes from a system similar to closed-circuit CO2, but contains CO2 scrubber
how is response to decreasing FiO2 monitored? via VE or P100 and the PO2/SpO2 via pulse ox
what is a constant level of CO2 called? isocapnia
what is the CO2 response? appropriate conc of CO2 must be used; SpO2 >95%
what is the O2 response? FiO2 appropriate to induce hypoxic response; isocapnia demonstrated by monitoring PetCO2
what is P100? pressure transducer and monitor capable of recording up to 50 cm and 50-100 mm/sec
ventilatory response should be reproducible within ___%. 10
reported P100 should be the avg of ______ or more occlusions at each level. three
the response to an increase in PaCO2 in a normal individual is a ______ increase in VE of approximately __ L/min/mmHg. what is the normal range of response? linear; 3; 1-6 L/min/mmHg PCO2
what type of pts have a blunted response to CO2? COPD
the normal response to a decrease in PO2 appears to be exponential once the PO2 has fallen to the range of ___-___. 40-60
what type of conditions falls in this category? COPD, myxedema, obesity-hypoventilation syndrome, OSA, idiopathic hypoventilation
_____ has been suggested as a measurement of ventilatory drive independent of the mechanical properties of the lungs. P100
what is the range for normal P100 values? 1.5-5 cmH2O
what does P100 increase in? hypercapnia, hypoxia
Question Answer
How can you estimate the patient’s minimum effort when perfroming the MVV test? FEV-1 x 35
Briefly describe the ‘MVV’ and list it’s typical value 1. Have patient breath deep/fast for 12 seconds (x5) 2. Typical value 170 l/min
Briefly describe the ‘FEF 25-75’ and list it’s typical value 1. The flow rate during the middle 50% of exhalation. 2. typical value = 4-5 L
Briefly describe the ‘peak expiratory flowrate’ and list it’s typical value 1. Maximum flow generated during expiration. 2. 300 l/min
Briefly describe the ‘FEF 200-1200’ and list it’s typical value 1.The flowrate during the liter after the first 200 ml have been discarded. 2. typical value 6 l/min
After performing a PFT on a 48 year old, the MVV is 55% of predicted and the FEV-1 is 76% of predicted; your intrepretation is the patient’s effort should be questioned
Which test would you use to measure small airway function? FEF(25-75)
When performing an MVV test, the position of the spirometer bell on the Collins water-seal spirometer should be; in the mid-position
Why is it important to have pulmonary function values that are reproducible? The only way that values are reproducible is from maximum effort
Term Definition
Indications for (PFT) – presence of lung disease – how much of the lung is damaged – the amount of damage due to the disease – progress of the disease – nature of the disease – evaluate the therapy given – response to therapy
Pulmonary Function Equipment – Spirometer – Electronic Spirometer – Pneumotachometer – Peak Flow Meter
Spirometer are used to MEASURE FLOWS and FLOW RATES
Pneumotachometers measures flow, and volume
Peak Flow Meters – measured at bedside – patient exhale forcefully which moves the indicator – read directly from the device –
Peak Flow Meter Values Low Range: 300-400 L/min Typical: 10L/sec= 600L/min High Range: 600-800 L/min
Peak Flow Meters Personal Best – record peak flow everyday morning and noon for 2-3 weeks when asthma is under control. – should be recorded after (SABA)
Plethysmograph (Body Box) – Boyles Law – Measure Thoracic Volume = FRC ( more accurately) Raw (airway resistance)
Calibration and Quality Control of Equipment must meet ATS-ERS standards tests are done by large volume syringe( Super Syringe) 3.0L Accuracy +/- 3.5% (2.895-3.105) L using flow = 2 and 12 L/sec
To Calibrate Flow use rotameter
Gas Analyzer calibration are calibrated = 0 = running a gas that doesn’t contain the gas you are calibrate (i.e. 100% oxygen reads 0 on a He/ N2 analyzer)
Gas Analyzer Troubleshooting Galvanic- fuel cell Polarographic : replace batteries
Pressure Manometer MIP/ MEP MIP= < -20 = inspiratory muscle weakness MEP=< + 40 = poor ability to clear airway secretions
PFT Testing and Procedure (VC)vital capacity,(SVC) slow vital capacity patient is instructed to take a maximal inspiration followed by maximal expiration WITHOUT force
(SVC) Identify slow vital capacity Restrictive look at SVC for restrictive disease DECREASED = RESTRICTIVE
Vital Capacity indicator Vital capacity is the BEST for RESTRICTIVE DISEASE INDICATOR
Forced Vital Capacity The volume of air that can be expired as forcefully and as rapidly as possible after a max inspiration
Forced Vital Capacity Identify Identifies= FLOW RATES OBSTRUCTION
Forced Vital Capacity maneuver and procedure will provide important FLOW RATES to identify OBSTRUCTIVE DISEASES
Flows that can be measured FEV 1.0 FEF 200-1200 FEF 25-75 PEFR
FEV 1.0 The amount of gas expired in the 1st sec A decrease indicates OBSTRUCTIVE
FEV/FVC Value given as a ratio
Decreased FEV/FVC 1.0 The BEST indicator of OBSTRUCTIVE DISEASE
Measurements and Minimum Accepted FEV/FVC fev 0.5 = 60% fev 1.0 = 70% fev 2.0 = 94% fev 3.0 = 97%
FVC The FVC is not a FLOW its a VOLUME
MVV The largest volume and rate that can be breathe per minute voluntary effort performed for 12-15 secs
Pre and Post Bronchodilator Testing used to measure reversibility of an obstructive pattern Minimum increased 12% and 200mL All bronchodilators should be held 8 hours prior to test
FRC measures RV, TLC
FRC can be measured by He dilution N2 was out (Open method) Plethysmograph (Body Box) (closed)
DLCO measures carbon monoxide NV = 25mL CO/min/mmHg/ (STPD)
Decreased DLCO All restrictive + Except Emphysema The only Obstructive
Flow Volume Loops A normal flow volume loop should look like a football
Flow Volume Loop Obstructive short and wide = Obstructive
Flow Volume Loop Restrictive skinny and tall
Predicted Normal Values All measured values are compared with the predicted normal values for that individual. Based on Age, Height, Gender
Important Evaluation look at the % predicted
Classification of Interpretation Normal = 80-100% Mild = 60- 79% Moderate = 40 – 59% Severe = < 40%
Obstructive Disease CBABE Cystic Fibrosis, Bronchitis, Asthma, Bronchiectasis, Emphysema
Restrictive EVERYBODY ELSE e.g. neuromuscular, pleural disease, thoracic deformities