RSPT 1261 clini final lab (specialties section)

Indications for PFT

·       Shortness of breath (dyspnea)

·       Chronic cough

·       Wheezing

·       Smoking history

·       Suspected lung disease such as COPD or asthma

Contraindications for spirometry

·        Recent myocardial infarction (MI)

·        Recent eye surgery

·        Recent thoracic surgery

·        Recent abdominal surgery

·        Pneumothorax

·        Active hemoptysis

·        Thoracic or cerebral aneurysm

Pack Years formula

Packs Per Day × Years Smoked

Feet and Inches to Total Inches

(Feet × 12) + Inches

Obstructive Lung Disease

·        COPD

·        Emphysema

·        Chronic bronchitis

·        Asthma

Obstructive lung disease spirometry findings

·        ↓ FEV₁

·        ↓ FEV₁/FVC ratio

·        Airflow limitation

Restrictive Lung Disease

·        Pulmonary fibrosis

·        Neuromuscular disorders

·        Chest wall disorders

restrictive lung disease spirometry findings

·        ↓ FVC

·        Normal or ↑ FEV₁/FVC ratio

ATS minimum requirement for FVC

At least 3 acceptable maneuvers must be performed.

How to Coach a Patient Through an FVC

1.      Apply nose clip.

2.      Sit upright.

3.      Seal lips tightly around mouthpiece.

4.      Take the deepest breath possible.

5.      Blast the air out as hard and fast as possible.

6.      Continue exhaling until completely empty.

7.      Keep blowing until instructed to stop.

8.      Take a quick deep breath in if required.

ATS Acceptability Criteria

✅ Good start of test
 ✅ Rapid and forceful initial exhalation
 ✅ No coughing during the first second
 ✅ No leaks around mouthpiece
 ✅ No glottic closure
 ✅ No hesitation at the start
 ✅ Complete exhalation

ATS Reproducibility Standards

·        Best two FVC values are within 150 mL

Best two FEV₁ values are within 150 mL

Common Reasons a Maneuver is Invalid

·        Hesitation at the start

·        Cough

·        Leak around mouthpiece

·        Variable effort

·        Early termination

·        Incomplete exhalation

Spirometry Interpretation Process

Step 1: Look at FEV₁/FVC Ratio
Step 2: Look at FEV₁ % Predicted
Step 3: Determine Pattern

Normal FEV1/FVC ratio

approximately 0.7 - 0.8

Low FEV1/FVC ratio

indicates obstruction

FEV1% predicted >70%

mild

FEV1% predicted 60-69%

moderate

FEV1% predicted 50-59%

moderately severe

FEV1% predicted 35-49%

severe

FEV1% predicted <35%

very severe

Obstructive pattern

Low FEV1/FVC, Low FEV1

Restrictive Pattern

Low FVC
Normal or high FEV1/FVC