RESP Flashcards
What is FEV1?
The force expiratory volume in 1 second (Max inspiration followed by max exparation)
How much of the vital capacity can healthy individuals expire in 1 seconds?
80% of vital capacity
What is vital capacity?
The maximal volume of air that can be expired following maximum inspiration
What is inspiratory reserve volume?
The amount of air that can be inhaled above tidal volume during a forceful breath in.
What is tidal volume?
The amount of air that moves in and out of the lungs with each respiratory cycle
What is functional residual capacity?
The amount of air remianing in the lungs at the end of a normal exhalation
What is residual volume?
The volume of air remaining in the lungs after maximum forceful expiration
What is expiratory reserve volume?
The volume of air, above normal tidal volume that can be exhaled during a forceful breath out
What is vital lung capacity?
The maximum amount of air you can forcibly exhale after fully inhaling.
What is the average tidal volume?
500ml male
400ml female
What is FVC?
Forced vital capacity–> The total amount of air forcibly expired.
What is an FEV1 or FVC result compared with?
The predicted value for that patient: if it’s 80% or greater than the predicted value then the result is normal.
What is the different between the FEV1 and FVC test?
FEV1 is the forced expiratory volume in 1 second, whereas FVC is the full amount of air that can be exhaled in a complete breath
Which test is better (FEV1/ FVC) and why?
FEV1 is more reproducible
What does a low FVC indicate?
Airways restriction
What is the FEV1/ FVC ratio?
The proportion of FVC exhaled in the 1st second
What does it indicate the if the FEV1/ FVC ratio is below 0.7?
Airways obstruction
Why does a low FEV1/FVC ratio indicate airway obstruction?
The FEV1 is reduced due to the obstruction but the overall capacity doesn’t change
What does a normal/ high FEV1/FVC ratio with low FVC (and FEV1) percentages (<80%) indicate?
Airways restriction
Why does a high FEV1/ FVC ratio indicate airway restriction?
Easy for them to breathe out quickly but low FVC as they can’t exhale fully
Which of inspiration and expiration is an active process?
Inspiration
What structures does air move through to get to the lungs and what are the two zones?
Conducting airway:
Trachea–> Main bronchi–> Lobar bronchi–> Segmental bronchi–> Terminal bronchioles
Respiratory airway:
Respiratory bronchioles–> Alveolar duct–> alveolar sac
What happens during inspiration?
The diaphragm contracts and flattens and the external intercostal muscles elevate the ribs and sternum.
The volume increases and pressure decreases, meaning the environmental pressure is now greater so air rushes in down a pressure gradient
What happens during expiration?
Relaxation of the diaphragm and external intercostal muscles, decreasing the volume of the thoracic cavity and increasing the pressure, forcing air to move out.