Indication for pulmonary function testing

What role does PFT testing have for the RT?

It is a lab science and diagnostic role for the RT

Where would you expect full PFT testing versus spirometry only?

Full PFTs are found in hospitals; physician offices and clinics may perform spirometry only

Who obtains the PFT and who interprets it?

A physician

Can PFT testing be done on inpatients or in the ER?

Yes

Who is associated with the early development of spirometry in 1846?

John Hutchison

What was Hutchison trying to measure with his early spirometer?

Lung volumes and how they changed with different disease processes

In the 1850 spirometer described in your notes, what happened when the patient blew into the tube?

The upside-down bucket in water moved upward

What basic principle did the 1850 spirometer use?

An underwater seal

What did the kymograph allow clinicians to graph?

Volume and flow

How could the kymograph be used to calculate flow?

It rotated at a fixed speed so volume could be related to time

What organizations are major references for PFT standards?

ATS and ERS

What does the ATS/ERS task force address?

Laboratory setup, patient considerations, test performance, and interpretation

A patient has suspected pulmonary disease. What can a PFT help determine?

The presence and amount of change in pulmonary function caused by disease

A patient has started therapy. How can PFTs help?

They can evaluate the effectiveness or response to therapy

Why might PFTs be ordered before surgery?

To assess the risk of postoperative complications

Can PFTs be used to evaluate pulmonary disability?

Yes

What common symptoms in your notes may lead to PFT testing?

Shortness of breath and cough

Can a PFT tell you exactly what disease the patient has?

No. It can classify the pattern as normal, obstructive, or restrictive

A PFT result shows abnormal lung function. Why is history still important?

PFTs cannot definitively diagnose a disease and must be supported by history and other diagnostics

What are the two major categories of pulmonary disease in your notes?

Obstructive and restrictive

What is the primary abnormality in obstructive disease?

Increased airway resistance

What is the primary problem in restrictive disease?

Decreased lung compliance, which reduces lung volumes

Can a patient have both obstructive and restrictive abnormalities?

Yes. Some pulmonary diseases create a mixed pattern

Which structure does your notes associate with obstructive disease?

The “tubes” or airways

Which structure does your notes associate with restrictive disease?

The alveoli

A patient has COPD. Which pattern would it fall under?

Obstructive

Are emphysema and chronic bronchitis classified as obstructive or restrictive?

Obstructive

What pattern is asthma classified as?

Obstructive

What pattern is bronchiectasis classified as?

Obstructive

What pattern is interstitial lung disease classified as?

Restrictive

What pattern are fibrosis and sarcoidosis classified as?

Restrictive

What pattern are kyphosis and scoliosis associated with?

Restrictive

What pattern is obesity associated with in the classification provided?

Restrictive

What pattern are ALS and muscular dystrophy associated with?

Restrictive

A patient has abnormal symptoms, signs, or lab results. Why might you order PFTs?

To help evaluate them diagnostically

Why would you perform PFTs on someone with a known disease?

To measure the physiologic effect of the disease or disorder

Can PFTs be used in someone who has no diagnosis but is at risk for pulmonary disease?

Yes

Why might PFTs be ordered before an operation?

To assess preoperative risk

Can PFTs help assess prognosis?

Yes

A patient has started a new pulmonary treatment. Why repeat PFTs?

To assess response to the therapeutic intervention

Why would a chronic pulmonary patient have repeated PFTs over time?

To monitor disease progression

How can PFTs be used around an exacerbation?

To monitor the exacerbation and recovery from it

Someone works around an injurious substance. Why might PFTs be repeated?

To monitor for adverse effects from exposure

Why might a patient taking a drug with known pulmonary toxicity need PFTs?

To monitor for adverse pulmonary reactions

Why might someone in pulmonary rehabilitation have PFTs?

As part of a disability/impairment or rehabilitation assessment

Can PFTs be used for insurance or legal evaluations?

Yes

What non-clinical uses of PFTs are listed?

Research, clinical trials, epidemiological surveys, and deriving reference equations

Why might an at-risk worker have PFT testing?

For pre-employment and lung-health monitoring

Why might PFTs be done before someone begins a high-risk physical activity?

To assess health status beforehand

Why can cardiovascular problems make spirometry risky?

Forced testing can increase myocardial demand or cause blood-pressure changes

A patient had an acute MI 5 days ago. Is this a relative contraindication?

Yes. Acute MI within 1 week is a contraindication

Would severe hypertension or systemic hypotension make you cautious about PFT testing?

Yes

Why would a significant atrial or ventricular arrhythmia be concerning?

It is listed as a relative contraindication due to myocardial demand/BP changes

What heart-failure condition is listed as a contraindication?

Noncompensated heart failure

Is uncontrolled pulmonary hypertension a relative contraindication?

Yes

Is acute cor pulmonale a relative contraindication

Yes

A patient has a clinically unstable pulmonary embolism. Should you be cautious about PFT testing?

Yes

A patient previously fainted during forceful coughing. Why is that important?

A history of syncope related to forced expiration/cough is a relative contraindication

Why can recent brain or eye problems be concerning during spirometry?

Forced maneuvers can increase intracranial or intraocular pressure

A patient had brain surgery 2 weeks ago. Is that within the contraindication window?

Yes. Brain surgery within 4 weeks

A patient had eye surgery 5 days ago. Is that a relative contraindication?

Yes, within 1 week

Why might recent sinus or middle-ear surgery matter?

Forced testing increases sinus and middle-ear pressures

A patient currently has a pneumothorax. Should PFT testing raise concern?

Yes

How long after thoracic or abdominal surgery is listed as a relative contraindication period?

Within 4 weeks

Why is late-term pregnancy listed as a relative contraindication?

It falls under conditions affected by increased intrathoracic and intraabdominal pressure

Why might active tuberculosis prevent routine PFT testing?

It creates an infection-control risk

What patient findings may increase infection-transmission risk during PFTs?

Hemoptysis, significant secretions, oral lesions, or oral bleeding

Why is hemoptysis of unknown origin concerning during forced expiration?

The maneuver may aggravate the underlying condition

Why are thoracic, abdominal, or cerebral aneurysms concerning?

Increased thoracic pressure may risk rupture

A patient has severe nausea or vomiting. Why might testing be delayed?

Acute illness or symptoms can interfere with test performance

What patient factors can make following PFT directions difficult?

Confusion, dementia, young age, or a language barrier

What are the four major potential-harm factors associated with PFT testing?

High thoracic pressures, large BP swings, chest/lung expansion, and communicable disease

What are the two general types of PFT measuring devices?

Devices that measure volume and devices that measure flow

What is a volume-measuring device called?

A spirometer

What is a flow-measuring device called?

A pneumotachometer

What performance characteristics does every measuring device have?

Capacity, accuracy, error, resolution, precision, linearity, and output

What are the three main components of most complete PFTs?

Airway flow rates, lung volumes/capacities, and gas diffusion

When are all three PFT components needed?

When determining the presence and degree of pulmonary impairment

What does spirometry assess?

Pulmonary mechanics

What spirometry measurements are listed in your notes?

SVC, FVC, FEV1, other forced flows, and MVV

What general ability do these spirometry measurements assess?

The ability to move large volumes of air quickly through the airways

What is the most common test of pulmonary mechanics?

Forced vital capacity, or FVC

Why is good patient instruction especially important during FVC testing?

FVC is effort-dependent and requires cooperation

How many acceptable FVC efforts are required to help ensure validity?

At least 3

What does FEV1 measure?

The volume exhaled during the first second of the FVC maneuver.

How is the FEV1/FVC calculated in your notes

Largest FEV1 / largest FVC

What is the FEV1/FVC ratio used to indicate?

Obstruction

What does FEF200-1200 represent?

Average flow early in the FVC maneuver

What does FEF25-75 represent?

Flow during the middle 50% of the FVC

Can spirometry alone provide enough information for lung volumes and a restrictive diagnosis?

No

What three methods are listed for measuring FRC?

N2 washout, He dilution, and thoracic gas volume by plethysmography

Why is diffusing capacity useful?

It helps evaluate lung damage and the alveolar-capillary membrane

How can diffusing capacity help when looking at COPD conditions?

It can help differentiate chronic bronchitis from emphysema

What does DLCO measure?

Transfer of the diffusion-limited gas CO across the alveolar-capillary membrane

What gas is used for DLCO?

Carbon monoxide

What other tests may be used alongside PFTs?

ABGs, oximetry, cardiopulmonary exercise testing, metabolic testing, chest x-ray, CT, and nuclear medicine scans

What four lung volumes are listed?

Tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume

What four lung capacities are listed?

Total lung capacity, inspiratory capacity, functional residual capacity, and vital capacity

What can a PFT measure objectively?

Volumes, flows, diffusion, and related measurements

How can serial PFTs help evaluate disease over time?

They can measure decline or stabilization of lung function