Welch Allyn Schiller AT-2plus - Calibration Factors Explained

AT-2plus User Guide Spirometry Supplement Page 22
AT-2plus Spirometry Supplement Page 22
Calibration
Last Calibration date of last calibration
BTPS Factor calculated BTPS (=> Body Temperature, Ambient Pressure, Saturated with water vapour)
value. This value compensates for the difference in inhaled and exhaled humidity. The unit is
set for measuring exhaled volume (100% humidity, Temp 36.8
o
), and so when inhaled volume is
measured this factor is applied. The SP-1 uses ambient temperature to calculate the BTPS
factor. This is sufficient for accurate FIVC calculation. The formula used is as follows:
BTPS = 0.033 +
273.15 + 36.8
273.15 + Tu
Where: Tu is the ambient temperature in degrees centigrade
0.033 is the equivalent to 760mmHg at 22
o
C
273.15 is degrees absolute
Calibration Factor calculated value between measured and effective calibration air volume
Temperature ambient temperature in
o
C (or
o
F) dependent on device setting
Measured Volume air volume measured by the system from the calibration pump
Reference Volume entered air volume depending on the size of the calibration pump and times the air was pumped
through the sensor; e.g. pumping 2 litres 3 times amounts to 6 litres (the recommended volume
with a 2 litre pump is 4 litres and with a 3 litre pump 6 litres)
Calibration
Last Calibration date of last calibration
BTPS Factor calculated BTPS (=> Body Temperature, Ambient Pressure, Saturated with water vapour)
value. This value compensates for the difference in inhaled and exhaled humidity. The unit is
set for measuring exhaled volume (100% humidity, Temp 36.8
o
), and so when inhaled volume is
measured this factor is applied. The SP-1 uses ambient temperature to calculate the BTPS
factor. This is sufficient for accurate FIVC calculation. The formula used is as follows:
BTPS = 0.033 +
273.15 + 36.8
273.15 + Tu
Where: Tu is the ambient temperature in degrees centigrade
0.033 is the equivalent to 760mmHg at 22
o
C
273.15 is degrees absolute
Calibration Factor calculated value between measured and effective calibration air volume
Temperature ambient temperature in
o
C (or
o
F) dependent on device setting
Measured Volume air volume measured by the system from the calibration pump
Reference Volume entered air volume depending on the size of the calibration pump and times the air was pumped
through the sensor; e.g. pumping 2 litres 3 times amounts to 6 litres (the recommended volume
with a 2 litre pump is 4 litres and with a 3 litre pump 6 litres)