FUNDAMENTALS OF SPIROMETRY

Pulmonary Function Test

Uses for Spirometry (4)

Screening

Diagnosing Pulmonary Diseases

Monitoring Progression of Disease

Monitor Improvements post-treatment/lifestyle modification

Process of Spirometry

1. Pre-test Questionnaire (medical hx, smoking status, patient

2. Vitals (Ht, Wt, Temp, BP)

- DO NOT PERFORM IF HEMODYNAMICALLY UNSTABLE

3. Explain Procedure

4. Demonstrate Procedure

5. Enter data into spirometer

6. Perform test, Coach patient!

Who should you NOT perform spirometry on?

if they are hemodynamically unstable

How many efforts are required for spirometry?

3 valid efforts

- coach the patient!

How is Spirometry performed?

patient seated, sitting straight with feet flat on the floor

attach disposable mouth piece, APPLY NOSE CLIP

place teeth on mouthpiece and seal lips around mouthpiece

patient breathes normally for a few breaths then instruct patient to breathe in FULLY

BLOW OUT FAST AND STEADY for as long as possible

- encourage the patient!

rest 15-30 seconds

3 acceptable trials needed

What factors affect lung function?

position

age

ethnic group

weight

height

How does ethnicity/race affect lung volume?

Compare highest vs lowest lung volume by Race and Gender.

caucasians have the highest capacity

african americans have the lowest

males have a larger capacity than females

How to educate and perform spirometry on a transgender patient.

explain to the patient the importance of putting their gender assigned at birth

if transitioned gender is used it can lead to misdiagnosis due to improper lung capacity predictions

How is Spirometry measured in PEDIATRICS?

What is the main measurement needed?

children as young as 5-8 YO can perform spirometry with adjustments such as standing instead of sitting

main goal is getting the FEV1 measurement

dependent on child compliance

Measurements of Pulmonary Function Test

- which volume should we never be able to touch?

Residual Volume (keeps lungs inflated, cannot be measured by spirometry)

Inspiratory Reserve Volume

The amount of air that can be inhaled after a normal inhalation; the amount of air that can be inhaled in addition to the normal tidal volume.

Expiratory Reserve Volume

Amount of air that can be forcefully exhaled after a normal tidal volume exhalation

Residual Volume

Amount of air remaining in the lungs after a forced exhalation

Tidal Volume

Amount of air that moves in and out of the lungs during a normal breath

Inspiratory Capacity

tidal volume + inspiratory reserve volume

Vital Capacity

The total volume of air that can be exhaled after maximal inhalation.

IRV + TV + ERC

Functional Residual Capacity

expiratory reserve volume + residual volume

Total Lung Capacity

vital capacity + residual volume

FVC vs FEV1

FVC: forced vital capacity- max amount total air forced out

FVE1: amount of air forced out within the 1st second of expiration

NORMAL VALUE FOR FVE1, FVC, AND FEV1/FVC RATIO

FEV1 = 80% of predicted value

FVC = 80% of predicted value

FEV1/FVC = 80% of predicted value

FVE1/FVC VALUE THAT IS DEFINITIVELY OBSTRUCTIVE

What is the gray area FVE1/FVC value and a possible diagnosis?

DEFINITIVE OBSTRUCTIVE < 70%

if between 70-80% = possibly asthma

What is Obstructive Lung Disease?

What are (4) examples?

limitation of airflow due to partial or complete obstruction

emphysema, chronic bronchitis, bronchiectasis, asthma

Obstructive Lung Disease:

- Total Lung Capacity

- FVC

- FEV1

- FEV1/FVC ratio

TLC: normal

FVC: normal

FEV1: DECREASED

FEV1/FVC < 80%

What is Restrictive Lung Disease?

What are some examples?

Reduced expansion of lung parenchyma accompanied by a decreased total lung capacity

ILD, Idiopathic Pulmonary Fibrosis, Pneumoconiosis, Sarcoidosis, Chest wall NM disease

Restrictive Lung Disease

- Total Lung Capacity

- FVC

- FEV1

- FEV1/FVC ratio

TLC: DECREASED

FVC: REDUCED

FEV1: Normal/Reduced

FEV1/FVC: Normal

Kyphosis, Scoliosis, Obesity, Rib deformities/fractures, Cardiac enlargement, and Pregnancy are all _________ causes of _______ Lung Disease.

Extrinsic; Restrictive

What is characteristic about the movement of air in OBSTRUCTIVE disease?

air trapping!

How to Diagnose a Patient that is in the Gray Area (FVE1/FVC).

What result would provide a diagnosis?

How should the patient present to perform this test?

if FEV1/FVC is 70-80% -> possible asthma

Bronchodilator Challenge:

- test patient before and after introducing a bronchodilator to see if there is improvement

- if > 12% of improvement = Asthma

Patient must be STABLE

FEV1/FVC VALUE INDICATIVE OF RESTRICTIVE AIRWAY DISEASE

What about FEV1 and FVC? Which is always indicative?

FEV1/FVC > 70%

- consider gray area testing

FEV1: mildly reduced or normal

FVC: < 80% (always reduced!)

- never reduced in obstructive lung dz.

Give FEV1 Values Based on Severity of Obstructive Lung Disease

Mild

Moderate

Severe

Very Severe

mild >/= 80%

moderate: 79-50%

severe: 49-30%

very severe: < 30%

Relative CIs of Pulmonary Function Test

- (5) health conditions

Conditions that may be negatively impacted by increase in pressure:

1. blood pressure conditions/increases in myocardial demand

2. intracranial/intraocular pressures (ex: glaucoma, hydrocephalus shunt)

3. sinus/middle ear pressures (ex: sinus problems, sick, tubes)

4. intra-thoracic and intra-abdominal conditions (ex: surgery)

5. infection control (ex: COVID)