Lung Volumes and Loops

Disease Diagnosis

A chart of patient histories and symptoms that indicate diseases

Expiratory Reserve Volume (ERV)

Amount of air that can be forcefully exhaled after a normal tidal volume exhalation 1200 ml

Inspiratory Reserve Volume (IRV)

Amount of air that can be forcefully inhaled after a normal tidal volume inhalation 3000 ml

types of obstructive disorders

Asthma, Bronchitis, Heavy smokers Decreased airflow by bronchoconstriction

If someone can exhale forcefully for a short moment and then produces a weak stream of air with lots of wheezing the

FEF25-75 will be low

If someone can exhale forcefully 70 to 90 of FVC in 1 second, which of the following is true?

FEV1% is normal.

How would tidal volume change if you inhaled a foreign object which completely obstructed your right mainstem bronchus?

If I inhaled a foreign object that completely obstructed my right mainstream bronchus I believe my tidal volume would be reduced by halve because the left mainstream bronchus would still function and allow for air flow.

Describe the difference between lung volumes for males and females. What might account for this?

In comparison to women, men have a larger thoracic cavity and, therefore, have more room for lung expansion, which leads to a greater lung volume. Since women have smaller thoracic cavities, there is less room for lung expansion, and therefore they have lower lung volumes.

Which of the statements correctly describes the difference between forced vital capacity and vital capacity?

In forced vital capacity assessment it is essential to exhale as quickly and forcefully as possible

Types of restrictive disorders

Neuromuscular disorders, Fibrosis caused by coal dust, Weakening of respiratory muscles, Tuberculosis

It is possible for a patient to have both obstructive and restrictive disorders simultaneously. What would you expect in the lab data of a patient with both obstructive and restrictive disorders

Reduced lung volume with reduced air flow.

Effects of obstructive diseases_____

Such as asthma or emphysema, may be determined by measuring rapid exhalation with a spirometer.

Compare the FEV1/FVC values for obstructive and restrictive disease your values (previous question). How might these values be helpful diagnostically?

The FEV1/FVC values for the restrictive disease were higher than the obstructive disease. This can aid in a diagnosis because if a patient's FEV1/FVC values are higher than normal, it can indicate a restrictive disease and if a patient's FEV1/FVC values are lower than normal, it can indicate an obstructive disease.

Looking at the lab data you collected during the pulmonary function tests, which do you think is a better predictor of a patients' diagnosis: lung volumes or flow volume loops? Explain.

The better predictor of a patients' diagnosis is flow-volume loops. When evaluating the patients, two of the patients had normal lung volumes. However, obstructive flow volume loops indicated that they had an obstructive disorder. Flow volume loops are more effective because if a patient is ill, the patient will have an abnormal flow-volume loop. Whereas if a patient is sick and a lung volume is used to test them; it can still say they have normal lung volume, not providing a proper assessment of the patient's condition.

FEV1/FVC ratio

The fraction of air exhaled in the first second relative to the total volume exhaled; measured as a percentage

Forced Vital Capacity (FVC)

The total amount of air forcefully exhaled from maximum inhalation to maximum exhalation.

Vital Capacity (VC)

The total volume of air that can be exhaled after maximal inhalation. TV+IRV+ERV

Terminal bronchioles

This latter part of the expiration curve represents the emptying of small airways

Total Lung Capacity (TLC)

VC + RV

Tidal Volume (TV)

Volume of air in each breath during regular breathing. 500 ml

Lung Function Diagnosis

a chart of measured lung values and diagnosis parameters

Respiratory Cycle

a single inspiration followed by a single expiration

Your patient has below normal airflow out of the lungs, yet a normal value for vital capacity. Which of the below listed may be the underlying cause?

asthma

Obstructive lung disorder

condition blocking the flow of air moving out of the lungs

Maximal inspiration

contraction of the diaphragm downward and the movement of the ribs upward and outward

Your patient has normal airflow out of the lungs, yet a below normal value for vital capacity. Which of the below listed may be the underlying cause?

degenerative muscle disease

With COPD (chronic obstructive pulmonary disorders), there is a decreased airflow from the lungs. This could be caused by which of the following reasons?

inflammation of major and small airways, destruction of the walls between your lungs' air sacs, excessive mucus production

Residual volume

is the amount of air remaining in the lungs after a maximum forced expiration. 1300 ml

Forced expiration

is the result of the rapid contraction of chest and abdominal muscles, as well as the relaxation of the diaphragm.

How is respiratory rate (breaths/min) calculated, given minute volume and tidal volume?

minute volume (L/min) / tidal volume (L)

Restrictive lung disorders

normal flow of air but a low vital capacity and low inspiratory and expiratory volumes

A patient who has a low FEV1% and a low FEF25-75 in a spirometry test should be diagnosed with

obstruction

The figure shows three spirometry test results. The far left graph is normal. Based on the size, shape, and approximate vital capacity flow-volume loop A, this patient shows

obstruction

The figure shows a spirometry test result. Based on the size, shape, and approximate vital capacity in this diagram, this patient shows

restriction

The figure shows three spirometry test results. The far left graph is A normal. Based on the size, shape, and approximate vital capacity flow-volume loop C, this patient shows

restriction

Peak expiratory volume

the highest point on the exhalation graph

Forced expiratory volume (FEV 1)

the volume of air expelled in the first second of forced exhalation.

How is Minute Volume (L/min) calculated?

tidal volume (L) x respiratory rate (breaths/min)

Pulmonary volume tests

used in conjunction with flow tests (FEV1 and FEF25-75) to differentiate obstructive and restrictive lung diseases.

Spirometer

used to measure lung volumes and capacities

Flow-volume loop analysis

will confirm diagnosis of an obstructive or restrictive lung disease