Lung Function Tests

Question 1

Restrictive Disorders - Characteristics and Values

Answer 1

Reduction in lung volume (TLC, RV, FVC).
Difficulty inhaling due to stiffness in lung tissue or chest wall.
↑ Elastic recoilment, ↓ Lung compliance.
Total lung capacity reduced.
TLC <80%, FVC (forced vital capacity)<80%.

Question 2

Restrictive Disorders (7)

Answer 2

Interstitial lung disease
Pulmonary fibrosis
Scoliosis and obesity
Pneumothorax
Neuromuscular disease
Pneumonia
Tuberculosis

Question 3

Obstructive Disorders - Characteristics and Values

Answer 3

Reduction in airflow (FEV1, FEV1/FVC)
Difficulty exhaling, air remains in the lungs.
Shortness of breath. ↑ airspace, ↑ accumulation of gas.
↓ elastic recoilment, ↑ lung compliance.
FEV1/FVC <70%.

Question 4

Obstructive Disorders (4)

Answer 4

COPD
Asthma
Bronchiectasis
Cystic Fibrosis

Question 5

COPD - Signs and Symptoms (4)

Answer 5

Dyspnea.
Chronic cough or sputum and/or history of exposure to risk factors.
Hyperinflated chest.
Resting tachypnea.

Question 6

COPD - Outcomes related to different Types and Hyperinflations

Answer 6

Chronic Bronchitis (airways): FVC, FEV1, FEV1/FVC, SVC(slow vital capacity), RAW (airway resistance).
Emphysema (alveoli destruction): Same plus TLC, TGV (total gas volume), RV (residual volume), DLco.
Static Hyperinflation: ↑ end exp. lung volume. TLC↑, TGV, RV↑.
Dynamic Hyperinflation: ↑EELV above the static value. IC↓ (insp. capacity).

Question 7

GOLD Classification

Answer 7

Severity of airway obstruction in COPD.
Mild: FEV1 ≥ 80% predicted
Moderate: 50% ≤ FEV1 < 80% pred.
Severe: 30% ≤ FEV1 < 50% pred.
Very Severe: <30% pred.

Question 8

Spirometry - Characteristics and Values

Answer 8

Diagnosing obstructive diseases and help diagnose restrictive diseases.
FEV1/FVC > 70: normal
FEV1/FVC < 70: obstruction (predicted FEV1 determines severity of obstruction)
FEV1 & FVC <80% predicted: obstruction and possible restriction (need plethysmography (TLC&RV).

Question 9

Spirometry - Procedure and Equipment

Answer 9

Nose clip, chair, spirometer, bronchodilator.
Breathe quietly, after quite expiration → full inspiration → Expire as fast and forceful as possible until you can’t → take a deep breath.
At least 3 reproduceable values out of 5-8.

Question 10

Spirometry - Bronchoreversibility

Answer 10

Confirms obstruction.
200mL or 12% difference in FEV1.

Question 11

Body Plethysmography - Procedure

Answer 11

TLC, TV, FRC.
Patient seated in a small booth, end of normal expiration → Mouthpiece closed → make insp. effort → lungs expand → lung pressure↓ → Pressure in cabin ↑.
Calculate change in cabin pressure = change in chest volume.

Question 12

Body Plethysmography - Obstructive Lung Disease Values

Answer 12

Air trapping: RV > 120%
Lung hyperinflation: FRC > 120%
Thoracic hyperinflation: TLC > 120%
Hyperinflation: TLC, TGV, RV (%pred)
Mild: <130, <140, <140
Moderate: 130-150, 140-170, 140-170
Severe: >150, >170, >170

Question 13

Body Plethysmography - Restrictive Lung Disease

Answer 13

TLC <80%, ↓ VC, RV, FRC, Vt.
Combine w/ spirometry: FEV1/FVC relatively normal, FVC and (FEV1) ↓.
Restriction: TLC %predicted.
Mild: 65-80%
Moderate: 50-65%
Severe: <50%

Question 14

Diffusion Capacity Measurement DLco

Answer 14

Can assess severity of obstructive and restrictive diseases, pulmonary vascular disease and pre-operative risk.
Assesses lungs ability to transfer gas from inspired air to the blood stream. Diffusing capacity of lungs for carbon monoxide.

Question 15

Diffusion Capacity Measurement DLco - Values

Answer 15

<80% : reduced
Mild reduction: 60-80%
Moderate reduction: 40-59%
Severe reduction: <40%

Question 16

Asthma - Outcomes (8)

Answer 16

Muscles surrounding bronchial wall contract, airways become inflamed.
FVC
FEV1
FEV1/FVC
FEV 25%-75%
SVC
RAW
Bronchial challenge test
Broncho reversibility test

Question 17

Maximal Inspiratory Pressure

Answer 17

Measure maximal effort of respiratory (insp.) muscles.
Maximal inspiration effort against a closed manometer after a full expiration.
<-30 :muscle failure
Neuromuscular disease, severe COPD, weaning from mechanical ventilation.

Question 18

Maximal Expiratory Pressure

Answer 18

Measure maximal effort of respiratory (exp.) muscles.
Maximal expiratory effort after a full inspiration against a closed manometer.
<60: muscle failure.

Question 19

MIP/MEP - Procedure

Answer 19

Measure 5 times, use highest 3 within 10cmH2O.
1 minute rest allowed between.
Use nose clip, demonstrate maneuver, check for leaks.

Question 20

Peak Flow

Answer 20

Measures maximum expiratory flow, for asthma.
To assess bronchoconstriction without clinical presentation (symptoms).

Question 21

Peak Flow - Method

Answer 21

Every morning do 3 maximum expiratory maneuvers, take highest value. If it has decreased by 10% from the previous day: bronchoconstriction.