Calculations With Spirometer Flashcards
What is a spirometer?
A chamber filled with oxygen taht floats on a tank of water
How is a spirometer used?
• subject breathes from a disposable disinfected mouthpiece attached to a tube connected to the oxygen chamber and wears a nose clip
• breathing in removes oxygen from the chamber - the chamber lid falls
• breathing out pushes air into the chamber and the lid rises
• the movement of the chamber lid are recorded as a Spirograph trace on the kymograph
What is tidal volume?
Volume of air taken in a normal breathe
Usually about 0.5dm^3 and the breathing rate is usually between 12-20 breathes in a healthy adult
How do you calculate tidal volume using a spirometer trace?
• calculate the meal tidal volume of at least three tidal volumes
- measure from tip of peak to bottom of peak
- add the 3 measurements together and divide by 3
What is breathing rate?
Number of breathes taken in or out in one minute ( number of peaks per minute)
How do you calculate breathing rate?
• Measure the amount of peaks in a number of seconds
• divide the number of seconds by 60
• multiply the number of of peaks by divided answer to get breaths per minute
What is residual volume?
Volume of air which remains in lungs after maximum exhalation
(Around 1.5dm^3)
What is functional residual capacity?
Volume of air remaining in the lungs after normal exhalation
What is inspiratory reserve volume?
Extra volume of air that can be inspired
What is expiratory reserve volume?
Extra volume of air that can be expired
What is inspiratory capacity?
Volume of air that can be inspired
(Tidal volume + inspiratory reserve volume)
What is vital capacity?
Greatest volume of air that can be expired after maximum exhalation
What is pulmonary ventilation rate and how do you calculate it?
Total volume of air moved into the lungs in one minute
What is forced vital capacity and how do you measure it?
Maximum volume for f air that can be inhaled or exhaled in one breath
Approx 5.0dm^3
However it varies due to gender, size, age and exercise
What is forced expiratory volume (FEV1)
Maximum volume of air that can be breathed forcefully out of the lung in 1 second
FEV1 decreases with age due to loss of elasticity of the internal intercostal muscles
How do you calculate the rate of oxygen consumption?
Volume of oxygen consumed/ time
How do you find rate of oxygen consumption (investigation)?
