Pulmonary Function Testing Equipment
The primary instrument used in pulmonary function testing is the Spiro meter. It is designed to measure changes in volume and can only measure lung volume compartments that exchange gas with the atmosphere. Spiro meters with electronic signal outputs (pneumotachs) also measure flow (volume per unit of time). A device is usually always attached to the Spiro meter which measures the movement of gas in and out of the chest and is referred to as a Spiro graph. Sometimes the Spiro graph is replaced by a printer like the unit used in this laboratory. The resulting tracing is called a Spiro gram. Many computerized systems have complex Spiro graphs or printouts that show the predicted values next to the observed values (the values actually measured). The unit will have in memory all of the prediction tables for males and females across all age groups. In sophisticated Spiro meters, there maybe special tables of normal values programmed into the machine for selection when Blacks, children or other groups are being tested who may vary from the normal PFT tables established for Caucasian adults.
Next