RPFT flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

PFT pre-test medication hold

Short-acting bronchodilators are typically withheld 4–6 hours, long-acting beta-agonists 12–24 hours, and short-acting anticholinergics 6–8 hours before testing, per laboratory protocol.

Height and weight measurement

Measure standing height without shoes and record weight before testing; these variables, with age, sex, and race/ethnicity, are used to calculate predicted pulmonary function values.

Contraindication to spirometry

Recent myocardial infarction, unstable angina, pneumothorax, active hemoptysis, or recent thoracic or abdominal surgery are contraindications because forced maneuvers increase intrathoracic pressure and cardiovascular demand.

Nose clip during spirometry

A nose clip prevents air leakage through the nose during forced expiratory and inspiratory maneuvers, improving measurement accuracy and reproducibility of flows and volumes.

Rest before PFT

Avoid vigorous exercise for at least 30 minutes and smoking for at least 1 hour before testing, because these can alter airway caliber and test results.

Documenting bronchodilator use

Record the name, dose, and time of any bronchodilator taken before testing so results can be interpreted in light of recent medication exposure.

Predicted values inputs

Age, height, sex, and race/ethnicity are entered into reference equations to generate predicted values and lower limits of normal for pulmonary function tests.

Daily spirometer calibration check

Before each testing day, check spirometer volume with a calibrated 3-L syringe; measured volume should be within ±3.5% of the syringe volume, and log the result.

BTPS correction

Spirometry volumes are reported at body temperature, ambient pressure, saturated with water vapor; converting from ATPS to BTPS corrects for temperature, pressure, and humidity differences.

DLCO gas analyzer calibration

Calibrate carbon monoxide and tracer gas analyzers daily using zero and span gases; verify linearity and record results before patient testing.

Plethysmograph calibration

Calibrate the plethysmograph pressure transducers and box volume daily, verifying known volume and pressure signals before measuring lung volumes.

Leak test

Perform a daily leak test on spirometers and plethysmographs; a leak can falsely reduce measured volumes and flows and invalidate test results.

Biological control subject

A healthy staff member may be tested periodically as a biological control; results should remain within established limits, helping detect system drift not found by syringe checks.

Calibration log requirements

Record date, device, calibrator identity, expected and measured values, and corrective action; retain logs according to laboratory policy and regulatory requirements.

Acceptable spirometry trial

An acceptable FVC trial has a rapid start, no cough in the first second, no glottic closure or leak, and a complete exhalation without early termination.

Reproducibility criterion

The two largest FVC values and the two largest FEV1 values should agree within 150 mL; perform up to three acceptable trials, and more if needed.

Back-extrapolated volume

Back-extrapolated volume should be less than 5% of FVC or 150 mL, whichever is greater, indicating a satisfactory rapid start to the forced expiration.

End-of-test plateau

A plateau is present when the volume change is less than 25 mL during the final second; otherwise continue until at least 6 seconds and up to 15 seconds.

Bronchodilator response testing

Repeat spirometry 10–15 minutes after a short-acting beta-agonist; a significant response is an increase in FEV1 or FVC of at least 12% and 200 mL.

Single-breath DLCO maneuver

From residual volume, inhale the test gas rapidly to total lung capacity, hold the breath about 10 seconds, then exhale smoothly; discard the dead-space washout.

Plethysmography panting

With the shutter closed, the subject pants at about 1 Hz against the occluded mouthpiece while box pressure changes are recorded to calculate thoracic gas volume.

Obstructive pattern

Obstruction is identified by a reduced FEV1/FVC ratio below the lower limit of normal, or below 0.70 when the fixed criterion is used.

Restrictive pattern

Restriction is suggested by reduced FVC with a normal or high FEV1/FVC ratio and is confirmed by total lung capacity below the lower limit of normal.

Mixed pattern

A mixed defect shows both a reduced FEV1/FVC ratio and a reduced total lung capacity, indicating obstructive and restrictive physiology together.

DLCO interpretation

A low DLCO suggests emphysema, interstitial lung disease, pulmonary vascular disease, or anemia; an elevated DLCO may occur with polycythemia or pulmonary hemorrhage.

Lower limit of normal

The lower limit of normal is typically the fifth percentile of the reference population; values below it are considered abnormal rather than using a fixed percent predicted cutoff.

GOLD severity

In COPD, FEV1 percent predicted defines mild (>70%), moderate (60–69%), moderately severe (50–59%), severe (35–49%), and very severe (<35%) airflow limitation.

Hand hygiene before PFT

Perform hand hygiene before and after patient contact and after handling mouthpieces or filters; gloves are worn when contact with respiratory secretions is anticipated.

Single-use mouthpieces

Use disposable mouthpieces and bacterial/viral filters for each patient; never reuse them, and discard into appropriate waste containers after testing.

Disinfection of reusable equipment

Clean and disinfect reusable spirometry and plethysmography components according to manufacturer instructions, ensuring adequate contact time and thorough drying before reuse.

Tuberculosis precautions

For patients with suspected tuberculosis, use a bacterial/viral filter, schedule testing in a separate room, and follow airborne infection isolation and local public health guidance.

Oxygen safety during testing

Keep oxygen cylinders secured and away from heat or open flames; avoid smoking in testing areas because oxygen-enriched environments increase fire risk.