BTPS correction for ceramic flow sensor

Details

• Personal Author:
  Ebeling TR ; Hankinson, John L. ; Petsonk, Edward L. ; Viola JO
• Description:
  Several commercially available spirometers use unheated ceramic elements as flow sensors to determine flow and calculate volume of air. The usual method of correcting the resulting flow and volume values to body temperature pressure saturated (BTPS) is to apply a constant factor approximately equal to 30 percent of the full BTPS correction factor. To evaluate the usual BTPS correction factor technique, we tested several sensors with a mechanical pump using both room air and air heated to 37 degrees C and saturated with water vapor. The volume signals used to test the sensors were volume ramps (constant flow) and the first four American Thoracic Society (ATS) standard waveforms. The percent difference in FEV1 obtained using room vs heated-humidified air (proportional to the magnitude of the BTPS correction factor needed) ranged from 0.3 percent to 6.2 percent and varied with the number of maneuvers previously performed, the time interval between maneuvers, the volume of the current and previous maneuvers, and the starting temperature of the sensor. The temperature of the air leaving the sensor (exit temperature) showed a steady rise with each successive maneuver using heated air. When six subjects performed repeated tests over several days (each test consisting of at least three maneuvers), a maneuver order effect was observed similar to the results using the mechanical pump. These results suggest that a dynamic, rather than static, BTPS correction factor is needed for accurate estimations of forced expiratory volumes and to reduce erroneous variability between successive maneuvers. Use of exit air temperature provides a means of estimating a dynamic BTPS correction factor, and this technique may be sufficient to provide an FEV1 accuracy of less than +/- 3 percent for exit air temperatures from 5 degrees to 28 degrees C. [Description provided by NIOSH]
• Subjects:
  Occupational Health Respiratory Function Tests Safety Solvents Temperature
• Keywords:
  Air-temperature Equipment-design Equipment-reliability Measurement-equipment Mechanical-properties-testing Pulmonary-function-tests Signal-devices Spirometry Temperature-effects Testing-equipment Vapors Volumetric-analysis

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• ISSN:
  0012-3692
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DRDS - Division of Respiratory Disease Studies
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  105
• Issue:
  5
• NIOSHTIC Number:
  nn:20049357
• Citation:
  Chest 1994 May; 105(5):1481-1486
• Contact Point Address:
  Dr. Hankinson, DHHS, PHS, CDC, NIOSH, ALOSH, 944 Chestnut Ridge Road, Morgantown, W Va 26505
• Federal Fiscal Year:
  1994
• Peer Reviewed:
  True
• Source Full Name:
  Chest
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:4228e45a6a342487d083f2c6ac71776c93fb6bcf1c03ddf6f91ecd33947e5167aa362ba68df130230c9eefaad59616b88eedc01aef9fabcd72002e6f7a5c4077
• Download URL:
  https://stacks.cdc.gov/view/cdc/203823/cdc_203823_DS1.pdf
• File Type:
  [PDF - 2.96 MB ]