7.3 - Measuring the Process Flashcards
What is the function of a peak flow meter?
Measures rate at which air can be expelled from lungs.
What is a vitalograph?
Sophisticated peak flow meter, patient breathes out as fast as they can through a mouthpiece
- Graph is produced showing volume of air produced and its speed.
How does a spirometer work and what is its function?
Measures volume of air inspired and expired by lungs
- Subject should wear a nose clip to ensure air only comes from the mouth and system
- As the subject inhales, oxygen is drawn from the chamber which in turn lowers
- When the subject exhales, the chamber rises
- Air returning to the chamber passes a soda lime cannister to absorb the CO2
- Air movements recorded by a trace on a revolving drum
- Draws a kymograph
Define
Tidal Volume
Vital Capacity
Tidal Volume: Volume of air breathed in and out in one breath. At rest this is 0.5dm3
Vital Capacity: Maximum volume of air that can be expired after the deepest inspiration
Define
Inspiratory reserve volume
Expiratory reserve volume
Inspiratory reserve volume: Maximum volume of air one can inspire over normal inhalation
Expiratory reserve volume: Extra amount of air you can force out of lungs over the normal amount of air you exhale
Define residual volume.
Volume of air that remains in lungs after hardest expiration (cannot be directly measured)
Define total lung capacity.
Vital capacity + residual volume
Define breathing rate and ventilation rate.
Breathing rate: number of breaths taken per minute
Ventilation rate: total volume of air inhaled per min
= tidal volume x breathing rate
Label the different elements of a spirometer trace