Spirometer

A spirometer is an apparatus for measuring the volume of air inspired and expired by the lungs. It is a precision differential pressure transducer for the measurements of respiration flow rates. The spirometer records the amount of air and the rate of air that is breathed in and out over a specified time. The Spirometer and attached flow head function together as a pneumotachometer, with an output signal proportional to airflow. It was invented by John Hutchinson in 1846.The output produced by a spirometer is called a kymograph trace. From this, vital capacity, tidal volume, breathing rate and ventilation rate (=tidal volume x breathing rate) can be calculated. From the overall decline on the graph, the oxygen uptake can also be measured.

A spirometer is one of the basic pulmonary function tests.

History

In 1852 John Hutchinson published a paper describing his water spirometer and the measurements he had taken of over 4,000 subjects, describing the relationship between lung capacity and height. He had begun his work on spirometry in 1844 and discontinued it later in the year.

It is possible to make a simplified spirometer of your own. Simply take two soda straws, and an aluminum can filled with water, allowing some airspace at the top. Place one straw deeply in the water, place the other one just above the water. Ensure that the straws are sealed in some way. Exhaling through one straw will displace water which can be measured as it exits the second straw. Multiply the displaced water volume by 10 for tidal volume and 100 for lung capacity.

ee also

*Spirometry
*Incentive spirometer
*Respiratory system
*Lung volumes
*Cardiopulmonary physiotherapy

ources

[http://medizin.li/spirometer/spirometer-history.html A short history of spirometry and lung function tests]