38 Questions
What is the normal clinical range of tidal volume?
300-650 mls
What is the volume that can be inhaled maximally above tidal volume?
Inspiratory reserve volume
What is the normal adult range of expiratory reserve volume?
750-3000 mls
What is the formula to calculate vital capacity?
IRV + ERV + TV
Why do normal values of lung volumes vary widely between individuals?
Due to differences in athletic training and health conditions
What is the purpose of flushing the spirometer with fresh room air between each set of measurements?
To ensure accurate measurements
What is the device used to measure peak flow rate?
Peak flow meter
What is the importance of following safety precautions during lung function tests?
To ensure safety of the operator and patient
What is the maximum time allowed for each set of measurements?
Less than 3 minutes
Why is it essential to refill the spirometer with fresh room air after each use?
To prevent a large drop in oxygen tension
What should be done if the subject shows signs of distress during the experiment?
Disconnect them and allow them to breathe from the atmosphere
What is the role of the subject observer during the experiment?
To monitor the subject for signs of distress
What is the primary purpose of using a nose-clip during the experiment?
To prevent the subject from breathing through their nose
Why must the spirometer be freshly filled before connecting the subject?
To prevent a large drop in oxygen tension
What is the minimum number of people required to conduct the experiment?
4 people, including the subject, observer, computer operator, and spirometer flusher
What is the purpose of having someone to flush the spirometer with fresh room air?
To prevent a large drop in oxygen tension
What factors significantly affect a person's FVC?
Age, sex, and height
What is the normal range of FER in healthy individuals?
70-90%
Which of the following is a characteristic of obstructive airways disease?
Vital capacity takes longer to achieve
What is the purpose of short-acting beta-agonists (SABAs)?
To prevent exercise-induced bronchoconstriction
What is the normal range of FVC in a healthy individual?
3-7 litres
What is the diagnostic criterion for obstructive airways disease?
FEV1/FVC% < 70%
What is the indication for using a peak flow meter?
To monitor lung function in patients with respiratory disease
What is the consequence of using short-acting beta-agonists more than twice a week?
Sign of poorly controlled asthma
What is the primary function of salbutamol in the body?
To relax the muscles surrounding the bronchial tubes
What is the purpose of taking LABAs on a daily basis?
To relax the muscles lining the airways and make breathing easier
What is a characteristic of restrictive airways disease?
Replacement of elastic tissue with fibrous tissue
What is the name of the inhaler that uses a soft mist?
Respimat
What is the name of the combination medication that contains formoterol and budesonide?
Symbicort
What is the purpose of combining LABAs with corticosteroids in the treatment of asthma?
To increase the effectiveness of LABAs
What is the typical range of Forced Vital Capacity (FVC) in liters?
3-7 liters
What percentage of FVC is FEV1 usually between?
70-90%
What is the calculation to find the Forced Expiratory Ratio (FER)?
FER = (FEV1/FVC) * 100
What is the clinical significance of a FER value less than 70%?
It may indicate a lung disease
How is the Forced Expiratory Flow (FEF) 0.2-1.2 measured?
Using a special protractor on the vitalograph trace
What is the purpose of using a peak flow meter?
To replace FEF analysis in many ways
What is the correct procedure to use a peak flow meter?
Zero the pointer, put a clean mouthpiece on the tube, take a big breath, and then blow into the mouthpiece as hard and as fast as you can
What is the significance of obtaining three readings for each subject using a peak flow meter?
To get an average reading
Study Notes
Lung Volume
- A volume is a measurable quantity of gas expired from the lungs, while a capacity is composed of a number of volumes added together.
- Measuring volumes and capacities is part of lung function tests, which can give important clinical and experimental information.
Tidal Volume (TV)
- The amount of gas passing in or out of the lungs with each normal breath.
- Normal clinical range: 300-650 ml.
Inspiratory Reserve Volume (IRV)
- The amount of gas that can be inhaled maximally above tidal volume.
- Normal adult range: 1000-4000 ml.
Expiratory Reserve Volume (ERV)
- The volume that is maximally exhaled from the lungs after a tidal volume.
- Normal adult range: 750-3000 ml.
Vital Capacity (VC)
- The amount of gas that can be moved in/out the lungs between maximal inspiration and maximal expiration.
- Normal adult range: 2000-7000 ml.
- VC = IRV + ERV + TV
Factors Affecting Lung Volume
- Normal values vary widely between individuals and are affected by conditions such as athletic training, pregnancy, and respiratory diseases.
- Actual values depend heavily on body size and sex.
Equipment for Measuring Lung Volume
- Spirometer
- Peak flow meter
- Vitalograph
Safety Precautions
- Ensure the spirometer is flushed with fresh room air between each set of measurements.
- Each set of measurements should be less than 3 minutes.
- A fresh, clean mouthpiece must be used for each subject being tested.
- The spirometer must be refilled with fresh room air after a subject has used it.
- Someone must time measurements and watch the subject for signs of distress.
Vitalograph Analysis
- Forced Vital Capacity (FVC): the volume of air expired from the lungs during a forced expiration.
- Forced Expiratory Volume in 1 second (FEV1): the volume of air expired in the first second of a forced expiration.
- Forced Expiratory Ratio (FER): the percentage of FVC expired in the first second of a forced expiration.
- Forced Expiratory Flow (FEF 0.2-1.2): the average rate at which the first liter of air leaves the lungs during a forced expiration.
Peak Flow Meter Procedure
- Zero the pointer.
- Put a clean mouthpiece on the tube.
- Take a big breath, and then blow into the mouthpiece as hard and as fast as you can.
- Obtain 3 readings for each subject and take the average.
Respiratory Diseases
- Obstructive airways disease: characterized by a forced expiratory ratio (FEV1/FVC%) of less than 70%.
- Restrictive airways disease: characterized by poor distensibility and a decrease in vital capacity.
Treatment for Respiratory Diseases
- Bet a2-agonists (bronchodilators) for quick relief of asthma symptoms.
- Inhaled corticosteroids for chronic asthma management.
- Long-acting beta-agonists (LABAs) for daily use to relax muscles lining the airways.
- Combinations of LABAs and corticosteroids for asthma treatment.
This quiz covers the definitions and measurements of lung volumes and capacities, including tidal volume, inspiratory reserve volume, and more. It's an essential part of lung function tests that provide crucial clinical and experimental information.
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