BTPS Correction for Ceramic Flow Sensor

The Accuracy of a Handheld Portable Spirometer

“…Because of this, spirometers that use static BTPS correction factors are prone to yield results that increasingly overestimate true values. The Pneumocheck does not avoid this erroneous source by taking into consider- 16 for a device that uses a static BTPS correction factor was opposite to the observed underestimation of values for all indexes measured. The buildup of moisture within the flow-sensor is another possible source of error that can be ruled out.…”

Standardisation of spirometry

“…In situations where the ambient air temperature is changing rapidly (.3˚C in ,30 min), continuous temperature corrections may be necessary. Spirometer users should be aware of potential problems with testing performed at lower ambient temperatures: 17˚C is the lower limit [55][56][57][58][59][60][61][62][63] for ambient temperature, unless a manufacturer states that their spirometer will operate accurately at lower ambient temperatures. If barometric pressure is not used in calculating the BTPS correction factor, the range of barometric pressures over which the BTPS correction factor is valid must be published by the manufacturer.…”

“…The rationale for this recommendation is based, in part, on the problems with finite cooling times of gases in volume-type spirometers [55][56][57] and the problems of estimating BTPS correction factors for flow devices [58][59][60]. When a subject performs an FVC manoeuvre, the air leaving the lungs is ,33-35˚C [61,62] and saturated with water vapour.…”

“…It is usually assumed that expired gas does not cool as it passes through the flow sensor. This may not be the case, particularly with unheated flow sensors [58,59]. The error will increase if the flow sensor is located further from the mouth and more cooling occurs, as is the case when a filter is placed in front of the flow sensor.…”

Cost and Quality Issues Related to the Management of COPD

“…Temperature correction has been noted as a source of error in both volume and flowbased instruments. 18,19,20,21,22,23 Temperature measurement and consequent BTPS correction varies between manufacturers and physicians should seek an unambiguous explanation from the manufacturer regarding the temperature correction in the equipment they use. Software sophistication, transducer accuracy, and increased computing power has each contributed to improve the accuracy and quality of spirometry data.…”