Question Answer
When comparted to the normal, the following tracing represents fixed large airway obstruction, variable intrathoracic obstruction, variable extrathoracic obstruction, variable patient effort
When comparted to the normal, the tracing on the right represents; fixed large airway obstruction, variable intrathoracic obstruction, variable extrathoracic obstruction, variable patient effort
When comparted to the normal, the tracing on the right represents fixed large airway obstruction, variable extrathoracic obstruction, variable intrathoracic obstruction, variable patient effort
When comparted to the normal, the tracing on the right represents fixed large airway obstruction, vairable intrathoracic obstruction, variable extrathoracic obstruction, variable patient effort
After a baseline PFT a patient takes 2 puffs of albuterol and (post)testing is done immediately. The results do not improve much, what would you recommend? wait 15-20 minutes and repeat the post bronchodilator test
A patient has performed 2 flow-volume loops. As you compare the loops you notice the inspiratory flow curves were the same but the expiratory flow curve of the second loop was lower, based on this information you should; have the patient repeat the test and instruct him to blow out as hard as possible throughout the test
What % improvement during a pre and post bronchodilator study is considered significant? 15%
What is the purpose of ‘pre and post bronchodilator’ testing? To determine reversible airway disease
What are 3 indications for pre and post bronchodilator testing? 1. cough of unknown orgin, 2. known asthmatic condition, 3. anytime airway hyperreactivity is suspected
A patient just took 2 puffs of Vanceril, what should be done? proceed with the pre-post bronchodilator study
What is the minimum change in the post bronchodilator spirometry necessary to consider the reversibilty of Raw significant 15%
A methacholine challenge test determines: airway reactivity
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 are the limitations to PFT? how it is interpreted.
What part of the PFT is a static measurement? lung volume
What measures the mechanics of airflow; ability and speed of respiration? Spirometry
What assess reversibility of disease? bronchodilator response
What is a positive result that a disease is reversible? FEV1 or FVC >12% and 200ml improvement after bronchodilator
What test helps determine obstruction? Flow-Loop Volume
What test checks for interstitial lung disease? DLCO-diffusion capacity
What test checks for asthma response if pt has normal PFT? bronchoprovocation testing
List indications for PFT? 1. evaluated s/sx 2. screening at risk population 3. monitor pulmonary drugs 4. abd studies (CXR, EKG, ABG, hgb) 5. Preoperative assessment
What percentage of smokers have abn PFTs? 40%
What factors influence the PFTs normal results? age, race gender
What races have lower lung volume? Black, American Indian, oriental
What affects the quality of spirogram? artifact (cough, variable effort, leak, early termination) good start (pt needs to be physically capable of completing test) reproducibility
What is the normal decline of FEV1? 20-50ml/yr starting at age 35
What is the decline of FEV1 in COPD pts? 50-80ml/yrs
What type of lung disease decreases lung volume? Restrictive
What is the amount of air left in our lungs minus vital capacity? residual volume
What makes up vital capacity? Inspiratory capacity and expiratory reserve volume
What comprises Inspiratory capacity? tidal volume and inspiratory reserve volume
What is the tidal volume? regular breath
What is the reproducibility criteria for PFTs? the two largest FVC are within 200ml of each other and the 2 largest FEV1 are within 200ml of each other
What % predicted TLC indicates mild disease? <85% but > 70%
What % predicted TLC indicates moderate and moderately severe disease? moderate 70-60% severe <60%
What is FVC? Forced Vital Capacity (Tidal volume, inspiratory and expiratory reserve volume)
What does the spirometery assess?` 1. FEV1 2. FVC 3. FEV1/FVC 4. FEF 25-75
What disease process causes decreased FEV1? Obstructive
What is the normal % predictive FEV1? >/= 100%
What are the ranges for the abd predictive FEV1? mild: <100- >/= 70% moderate: <70 – >/= 60% mod. severe: <60 – >/= 50% severe: <50%- >/= 34%
What are differential diagnosis for obstructive lung diseases? asthma; COPD: chronic bronchitis, emphysema; Bronchiectasis; Bronchiolitis Upper airway obstruction
What are differential diagnosis for restrictive lung diseases? pleural parenchymal chest wall neuromuscular
What is a graphic display of the relationship between air flow and volume during a FVC (forced exhalation and inhalation)? Flow-Volume Loop
What is the purpose of checking the flow volume loop? Best reflection of the test acceptability
What kind of obstruction exist when the flow volume loop shows greater flow in exhalation than inspiration? variable extrathoracic upper airway obstruction
What kid of problem causes the flow volume loop to have greater inspiration than exhalation? variable intrathoracic upper airway obstruction
What are the criteria for PFT lung volume test according to Gladys, et al.(2003)? FVC < 85%, FEV1/FVC ratio >55% that indicates restrictive disease