spirometers Flashcards
what does a spirometer consist of
-a chamber of air or medical grade oxygen
-floating on a tank of water
what happens in the spirometer when a patient breathes in
-air is removed from chamber
-lid moves down
what happens in spirometer when patient breathes out
-air returns to the chamber
-lid moves back up
what does the movement of the spirometer produce
a trace
what is the function of the soda lime in a spirometer
-absorb co2 from breathing out before the air can re-enter the chamber
-allow a measure of oxygen consumption to be taken (equal to co2 breathed out)
precautions when using a spirometer
-subject = be free from asthma and healthy
-soda lime = refreshed and functioning
-no air leaks in apparatus as this would give invalid results
-mouthpiece sterilised
-water chamber not overfilled as water may enter air tubes
alternative to spirometer
modern spirometer
-small and handheld
-doesn’t measure oxygen consumption
what system is a spirometer
-a closed system
what is used to ensure the spirometer is a closed system
-nose clip
whats the trace called
a kymograph
what is the vital capacity
-the greatest volume of air that can be expelled from the lungs after taking deepest possible breath in
what is the vital capacity dependant on
-the size of the person
-their age
-their gender
-the level of regular excersise
what is the vital capacity on average
-usually between 2.5-5.0dm^3
what is residual volume
-the volume of air that remains in the lungs even after forced expiration
why does the trace decline after each breath over time
-body absorbs oxygen from air breathed in for respiration
-soda lime absorbs co2 so total volume of air in the chamber decreases over time
how to measure the rate of oxygen uptake
-difference in volume of oxygen (volume of oxygen taken in) in the time taken
what is the rate of oxygen uptake measured in
-dm3^-1
to calculate the rate of oxygen uptake, what must u assume
-the volume of carbon dioxide released in exhalation is the same as the volume of oxygen absorbed during inhalation
what is the tidal volume
-volume of air in each breath (usually about 0.4dm^3)
what is the breathing rate
how many breaths are taken usually in a minute
whats the oxygen consumption
-the rate at which an organism uses up oxygen
