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A computerized timing algorithm for determination of pulmonary tissue volume.

M F Petrini·T M Dwyer·M S Phillips
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Abstract

We developed a computerized method to measure pulmonary tissue volume (Vt) and capillary blood flow (Qc) that requires only a single interface for measurement of a soluble and an insoluble gas. The method uses a timing algorithm that replaces either a marker gas (C18O) or a volume signal. Gas concentrations are stored in digitized form. The data analysis consists of three parts: 1) initial and end-tidal samples found by using minima and maxima; 2) a timing algorithm derived from the end-tidal dead space method (ETDS, J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 44: 782-795, 1978); and 3) calculations of Vt and Qc, also by the ETDS method. Both the timing and Vt and Qc agree well with the hand-calculated values, but the coefficient of variation of Vt is slightly improved (6 vs. 7% manually). We conclude that our computerized method is equivalent to the manual ETDS method, but it is faster and more accurate; in addition, it has the advantage of requiring only one interface without the use of expensive gases.

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CapillariesComputersFemaleHumansLung Volume MeasurementsMalePulmonary CirculationTime FactorsJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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M F Petrini, T M Dwyer, M S Phillips. 1983. A computerized timing algorithm for determination of pulmonary tissue volume.. https://doi.org/10.1152/jappl.1983.55.1.258

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