7.3 Measuring the process Flashcards
what 3 things can be used to measure lung capacity
- peak flow meter
- vitalographs
- spirometer
what does a peak flow meter do
measure the rate at which air can be expelled from the lungs
what does a vitalograph do
- patient breathes out as quickly as possible and the instrument produces a graph of amount breathed out and how quickly
- volume of air = forced expiratory volume in 1 sec
what does a spirometer do
- measures different aspects of lung volume
- used to investigate breathing patterns
define tidal volume
volume of air that moves into and out of the lungs with each resting breath
define vital capacity
volume of air that can be exhaled when the deepest intake is followed by the strongest exhalation
define inspiratory reserve volume
max. air you can breathe in over+above a normal inhalation
define expiatory reserve volume
extra air you can force out over+above normal tidal volume you breathe out
define residual volume
volume of air left in lungs after strongest exhalation
how do you calculate total lung capacity
vital capacity + residual volume
how do you calculate ventilation rate
tidal volume x breathing rate (min)
what happens when oxygen demands increase
- tidal volume can increase from 15% to 50%
- breathing rate increases
explain how a spirometer works
- subject should wear a nose clip so no O2 escapes or enters the system
- subject breathes through mouthpiece
- inhalation = O2 drawn from chamber = chamber descends
- exhalation = O2 enters chamber = chamber rises
- air returning passes through soda lime (absorbs CO2)
- movements are recorded on a revolving drum or by a data logger
how do you measure tidal volume with a spirometer
breathe normally
how do you measure vital capacity with a spirometer
breathe out as deeply as possible
