RET 2414 Indications for PFT Spring 2026

Indications for DLCO

Evaluate or follow the progress of parenchymal lung disease.

DLCO and systemic disease

Evaluates pulmonary involvement in systemic disease.

DLCO and obstructive disease

Evaluates obstructive lung disease.

DLCO and cardiovascular disease

Evaluates cardiovascular diseases affecting gas exchange.

DLCO and disability

Quantifies disability associated with interstitial lung disease.

DLCO and blood abnormalities

Evaluates pulmonary hemorrhage, polycythemia, or left-to-right shunts.

Purpose of blood gas analysis

Evaluates adequacy of lung function.

Need for supplemental oxygen

Blood gas analysis determines the need for supplemental O2.

Monitoring ventilatory support

Blood gases monitor the adequacy of ventilatory support.

Blood gases and disease progression

Documents severity or progression of pulmonary disease.

Blood gases and PFT correlation

Helps correct or corroborate other pulmonary function measurements.

6-Minute Walk Test

Simple field test to assess functional exercise capacity.

Purpose of exercise testing

Evaluates exercise intolerance and overall fitness.

Exercise-related symptoms

Diagnoses dyspnea, fatigue, or pain during exertion.

Exercise testing for surgery

Assesses preoperative risk for lung resection or reduction.

Exercise testing & transplantation

Evaluates therapeutic interventions such as heart or lung transplant.

Bronchodilators withheld 6 hrs

Do NOT take rescue bronchodilators 6 hrs before testing.

Maintenance meds withheld 12 hrs

Do NOT take long-acting bronchodilators 12 hrs before test.

Tiotropium withheld

Do NOT take 24 hrs before testing.

Smoking and PFT

Do NOT smoke 24 hrs before test; minimum 1 hr. Smoking reduces DLCO.

Caffeine before challenge tests

Avoid caffeine, cola, and chocolate before bronchial challenge tests.

Exercise before PFT

Avoid exercise 1 hr before testing.

Dentures during PFT

Keep dentures in unless loose.

Measuring height and weight

Height and weight must be measured, not self-reported.

Alternative height measurements

Use arm span or ulnar length if patient cannot stand.

Physical assessment

Breathing pattern, RR, breath sounds, SpO2 evaluation before test.

Required history

Includes family/personal lung disease history, smoking, occupation, symptoms.

Importance of coaching

Many PFTs are effort-dependent and require coaching.

Poor effort consequences

Leads to poor reproducibility and inaccurate results.

Spirometry measures

Measures air volume and flow during inhalation and exhalation.

Spirometry and diagnosis

Required or recommended for diagnosis of obstructive lung disease (GOLD/GINA).

Vital Capacity

Air exhaled slowly after maximal inhalation; does not measure RV.

Forced Vital Capacity

Maximal air exhaled forcefully and rapidly after full inspiration.

Flow-volume loop

Assesses dynamic airflow during forced inspiration and expiration.

Indications for spirometry symptoms

Used to evaluate dyspnea, cough, phlegm, abnormal CXR, abnormal ABG.

Spirometry screening

Screens individuals at risk (smokers, hazardous workplaces).

Spirometry preoperative use

Assesses preoperative risk for lung or abdominal surgery.

Spirometry monitoring

Monitors disease progression, therapy response, and exacerbations.

Total Lung Capacity

TLC includes VC + FRC + subdivisions.

Tests for FRC

Nitrogen washout, helium dilution, thoracic gas volumes.

Lung volume indications

Used to diagnose and assess severity of restrictive lung disease.

DLCO purpose

Measures gas uptake across the lungs using carbon monoxide.

DLCO technique

The single-breath breath-hold method is the most common DLCO technique.