FD in PULMONOLOGY Flashcards
Boyles law ?
air( gas) pressure is inversely proportional to air volume
P1P2= V2V2
Primary principle of ventilation
Air moves down a pressure gradient (from an area of high pressure to low pressure)
What is the atmospheric pressure and intra pulmonary pressure
760mmHg
Muscles used for breathing
Intercostal muscles(main) Diaphragm(main ) Accessory muscles - sternocloidomastoid muscle , Scalene muscle
What happens in inspiration
The volume of the lungs increase due to the constriction of the 2 muscles ( diaphragm and intercostal muscles )
During inspiration , the diaphragm contracts and moves down and it will allow the intrapulmonary volume to increase which will cause the intra pulmonary pressure to decrease (759mmHg, difference is -1mmHg) below the atmospheric pressure so because of the rule of gases , the air will flow into the lungs down its pressure gradient
What happens in expiration ?
The diaphragm and the intercostal muscles relaxes and the diaphragm will move back up to its original place which will cause the intra pulmonary volume to decrease and intra pulmonary pressure to increase (761mmHg) difference is (+1)
Following the rule of gases So gases ( air) will move outside the lungs into the air outside down the pressure gradient
4 Lara nasal sinuses are
Frontal
Sphenoid
Ethmoid
Maxillary
methods of functional diagnostics of pulmonary diseases
Spirometry Bronchial provocation test Pneumotachography Peak flow metry Flow volume curve of forced expiration Body plethysmography
- In spirometry FVC - is
The total amount of air that can forcibly be blown out after full inspiration
Purpose of PFT
1) Diagnosis of symptomatic disease
2) used to screen for early asymptomatic disease in high risk people e.g people with prolonged exposure to amiodarone
3) Used in people with occupational exposure or environmental exposure
4) To prognose known disease
5) Used to estimate surgical risk
6) Used to monitor response to treatment
Obstructive lung diseases are
Chronic bronchitis Bronchial asthma Cystic fibrosis Bronchiectasis Emphysema
Types of PFT
Spirometry Lung volumes DLCo Peak flow metry Arterial blood gas Exercise oximetry Maximum inspiratory and expiration pressures
Tidal volume is ?
the amount of air that moves in or out of the lungs with each respiratory cycle.
Volume of air inspired and expired during quiet normal breathing
Expiratory reserve volume
Inspiratory reserve volume
Inspiratory reserve volume – volume which can be inhaled additionally
after normal inspiration
3. Expiratory reserve volume – volume which can be exhaled additionally
after normal expiration
Residual volume –
volume remaining in the lungs after maximal expiration
Lung volumes are ?
Tidal volume
Inspiratory reserve volume
Expiratory reserve volume
Residual volume
Lung capacities
Inspiratory Capacity - sum of tidal volume + inspiratory reserve volume
Functional reserve ( residual ) capacity - sum of expiratory reserve volume + residual volume
Vital capacity - Tidal volume + inspiratory and expiratory reserve volumes
Total capacity- sum of tidal volume + inspiratory and expiratory reserve volume + residual volume
volume filling the lung after maximal inspiration
What is spirometry ?
A technique used to measure air flow , spread of airflow and some lung (air) volumes
Vital capacity is known as forced vital capacity if it is performed as quickly as possible
True
FEV1 is
Volume of air forcefully exhaled in 1 seconds after maximal inspiration
PEAK expiratory flow rate ( PEFr) is
Maximum slope of curve
What is a flow volume loop ?
A graph of airflow as a function of volume
Spirometry display 2 graphs which are
a volume-time curve, showing volume (liters) along the Y-axis and time (seconds) along the X-axis
a flow-volume loop, which graphically depicts the rate of airflow on the Y-axis and the total volume inspired or expired on the X-axis
What is pneumotachometry ?
It measures the flow rate of gases during breathing.
Peak Expiratory Flow Meter?
It is a portable, hand-held device that does Peak flow measurement which is a procedure in which air flowing out of the lungs is measured. The measurement obtained is called the peak expiratory flow rate (PEFR), or peak expiratory flow (PEF).
A peak flow meter is small and light enough to be used almost anywhere.
Purpose of a peak flow meter ?
It can help to determine when you seek emergency care
It can help to know if your asthma management and treatment is working
When to stop or add medication as directed by a doctor what triggers the asthma attack (such as exercise-induced asthma)
Factors or conditions that interfere with the accuracy of peak flow measurement using peak flow meter are ?
Coughing during procedure Poor seal around the mouthpiece Using bronchodilators Using different brands of peak flow meters Blocking the mouthpiece with the tongue
How do you do the peak flow meter procedure ?
- Before each use, make sure the sliding pointer on the PFM is reset to the zero mark.
- Hold the PFM by the handle.
- Stand up straight.
- Remove chewing gum or any food from your mouth.
- Take a deep breath and put the mouthpiece in your mouth. Seal your lips and teeth tightly around the mouthpiece.
- Blow out as hard and as fast as you can. Remember, a “fast blast” is better than a “slow blow.”
- Note the number where the sliding pointer has stopped on the scale.
- Reset the pointer to zero.
- Repeat this routine three times. You will know you have done the
technique correctly when the three readings are close together.
10.If you cough during a measurement, you should repeat it.
Record the highest of the three readings on a graph or in a notebook. Do not average these numbers together. This is called “peak flow.”
What are peak flow zones ?
Peak flow zones are based on the traffic light concept:
red means danger,
yellow means caution, and
green means safe. These zones are different for each person.
Green in the peak flow zone means
This is the GO zone.
It is from 80 to 100 percent of your highest peak flow reading, or personal best.
This is the zone you should be in every day.
Measurements in this zone signal that air moves well through the large airways and that you can do the usual activities and go to sleep without trouble.
You should continue to follow your asthma plan as directed by your doctor.
What is the yellow Zone in the peak flow meter ?
It is the CAUTION or SLOW DOWN zone
It is 50-80% of personal best
Measurements in this zone are a clue that the large airways are starting to narrow.
mild symptoms- coughing, feeling tired, feeling short of breath, or feeling like your chest is tightening.
These symptoms may keep you from your usual activities or from sleeping well.
You should notify your doctor at this time. He or she may instruct you to increase or change your medications and give you additional instructions to help prevent your symptoms from worsening.
RED zone peak flow meter readings means
This is the STOP zone.
The red zone is less than 50 percent of your personal best. Readings in this zone mean severe narrowing of the large airways has occurred.
This is a medical emergency and you should get help right away. You may now be coughing, very short of breath,
wheezing both when breathing in and out, or having retractions. You may also have problems walking and talking. You should take your reliever medication now and call your doctor.
How to measure lung volumes ?
Spirometry
Gas dilution test ( helium dilution and nitrogen washout )
Imaging studies
Contraindications of spirometry
Pulmonary embolism Pregnancy Children less than 6 years Mental patients recent thoracic or abdominal surgeries Recent brain surgeries Recent eye or ear surgeries Pneumothorax Hemoptysis Stroke Recent MI or acute coronary syndrome
3 things you check in spirometry ?
FVC , VC , MVV
What bronchodilator is used in spirometry and dose and how long should you wait ?
Salbutamol 400mg , wait for 20 mins
Another alternative drug to salbutamol in spirometry is ?
Ipratropium , you wait for 40 mins
During spirometry when checking for MVV , how many seconds should you take a deep and fast breath in and out ?
12 secs
During spirometry when you want to check for FVC and VC, how many secs is required to blow out air hard
6 secs
Why is the interpleural pressure -4mmHg
Due to elasticity of lungs
Surface tension
Elasticity of chest wall
