Journal of Applied Physiology, Vol 77, Issue 6 2659-2665, Copyright © 1994 by American Physiological Society

ARTICLES

Evaluation of a symmetrically disposed Pitot tube flowmeter for measuring gas flow during exercise

J. Porszasz, T. J. Barstow and K. Wasserman
Department of Medicine, University of California, Los Angeles Harbor Medical Center, Torrance 90509.

We evaluated the effect of airflow and gas composition on the linearity of measurement of airflow by a new disposable flowmeter. The flowmeter is based on the principle of differential pressure measurement across two symmetrically disposed Pitot tubes. Nonlinearities arising from the pressure-to-airflow relationship and sensitivity to changes in gas density were linearized with appropriate software and monitoring of the gas composition. With room air used as the respired gas, the measured tidal volume from a piston pump assembly was consistently within 1-2% of the target tidal volume for each of five flowmeters tested across physiological ranges of flow. Changing gas densities by varying concentrations of O2, CO2, and N2 led to errors in tidal volume measurement that ranged up to 6-8%. However, because the errors were predictable, they were corrected by software to within 0.6% of the target volume. Measurement of minute ventilation during exercise was within 1-2% of that determined from bag collections. We conclude that this type of flowmeter can accurately measure exercise minute ventilation and has advantages over some other flowmeters because of its ruggedness, reproducibility, and ease of sterilization or replacement compared with other flowmeters.

This article has been cited by other articles:

				F. M. Iaia, M. Thomassen, H. Kolding, T. Gunnarsson, J. Wendell, T. Rostgaard, N. Nordsborg, P. Krustrup, L. Nybo, Y. Hellsten, et al. Reduced volume but increased training intensity elevates muscle Na+-K+ pump {alpha}1-subunit and NHE1 expression as well as short-term work capacity in humans Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R966 - R974. [Abstract] [Full Text] [PDF]

				M. Mohr, P. Krustrup, J. J. Nielsen, L. Nybo, M. K. Rasmussen, C. Juel, and J. Bangsbo Effect of two different intense training regimens on skeletal muscle ion transport proteins and fatigue development Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2007; 292(4): R1594 - R1602. [Abstract] [Full Text] [PDF]

				A. G. Williams, S. S. Dhamrait, P. T. E. Wootton, S. H. Day, E. Hawe, J. R. Payne, S. G. Myerson, M. World, R. Budgett, S. E. Humphries, et al. Bradykinin receptor gene variant and human physical performance J Appl Physiol, March 1, 2004; 96(3): 938 - 942. [Abstract] [Full Text] [PDF]

				ATS/ACCP Statement on Cardiopulmonary Exercise Testing Am. J. Respir. Crit. Care Med., January 15, 2003; 167(2): 211 - 277. [Full Text] [PDF]

				D. R. Bassett Jr., E. T. Howley, D. L. Thompson, G. A. King, S. J. Strath, J. E. McLaughlin, and B. B. Parr Validity of inspiratory and expiratory methods of measuring gas exchange with a computerized system J Appl Physiol, July 1, 2001; 91(1): 218 - 224. [Abstract] [Full Text] [PDF]

				M. E. F. Pedersen, P. Robach, J.-P. Richalet, and P. A. Robbins Peripheral chemoreflex function in hyperoxia following ventilatory acclimatization to altitude J Appl Physiol, July 1, 2000; 89(1): 291 - 296. [Abstract] [Full Text] [PDF]

				S Jones, P M Elliott, S Sharma, W J McKenna, and B J Whipp Cardiopulmonary responses to exercise in patients with hypertrophic cardiomyopathy Heart, July 1, 1998; 80(1): 60 - 67. [Abstract] [Full Text]

				P. Robach, D. Biou, J.-P. Herry, D. Deberne, M. Letournel, J. Vaysse, and J.-P. Richalet Recovery processes after repeated supramaximal exercise at the altitude of 4,350 m J Appl Physiol, June 1, 1997; 82(6): 1897 - 1904. [Abstract] [Full Text] [PDF]