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Proceedings ArticleDOI

Ultrasonic Respiration Analysis

31 Oct 1991-pp 1597-1598
TL;DR: In this article, an ultrasonic respiration analysis system is proposed to determine the velocity of the respiratory gas flow by measuring absolute transit-times of ultrasonic pulse trains, which is calculated by combining the results of the ultrasonic transit-time measurements with temperature measurements along the sound transmission path.
Abstract: We present the design of an ultrasonic respiration analysis system. The system determines the velocity of the respiratory gas flow by measuring absolute transit-times of ultrasonic pulse trains. Besides this standard flow meter function the system computes the 'equivalent molecular weight' M* of the gas flow: M* is calculated by combining the results of the ultrasonic transit-time measurements with temperature measurements along the sound transmission path. The gas composition dependent parameter M* can be used to determine additional respiratory parameters, e.g. functional dead space or total lung volume.
Citations
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Patent
TL;DR: In this article, a method for the measurement of the molar mass of a gas or gas mixture and an apparatus for the performance of the method is described, on which at least one sonic or ultrasonic transmit-receive cell is arranged defining a baseline and preferably arranged obliquely to the axis of the tube.
Abstract: The invention relates to a method for the measurement of the molar mass of a gas or gas mixture and an apparatus for the performance of the method. The gas or gas mixture to be investigated is passed through at least one holder, on which at least one sonic or ultrasonic transmit-receive cell is arranged defining a baseline and preferably arranged obliquely to the axis of the tube. The sonic or ultrasonic transmit-receive elements radiate a pulsed sonic signal, which measures the transit times of the sonic pulses along the baseline. Using a temperature probe for instance the variations in gas temperature along the at least one sonic transmission path is determined. From the transit time of the sonic pulses and the measured or assumed temperature the molar mass is found. The apparatus in accordance with the invention may be employed with advantage in pulmonary function diagnostics.

50 citations

Journal ArticleDOI
TL;DR: The measurement of the tracer gas concentration with the molar mass signal of the ultrasonic flow meter provides a good and simple alternative to respiratory mass spectrometer for FRC measurements in ventilated subjects.
Abstract: Measurement of functional residual capacity (FRC) during mechanical ventilation is important to standardise respiratory system compliance and adjust the ventilator settings to optimise lung recruitment. In the present study we compared three methods to measure FRC. The bias flow nitrogen washout technique (FRCN2MC), the multiple breath nitrogen washout (FRCMBNW) and the multiple breath sulphur-hexafluoride washout using the molar mass signal of an ultrasonic flow meter (FRCMBSF6) were compared in six adult monkeys after endotracheal intubation and during spontaneous breathing and mechanical ventilation at three different positive end-expiratory pressure (PEEP) levels of 0, 5 and 10 cmH2O. Animal research laboratory. We found good agreement between all three methods and they all accurately measured changes in FRC when PEEP was increased. The coefficients of variance of the three measurement techniques were in the same range (1.3–9.2%). The measurement of the tracer gas concentration with the molar mass signal of the ultrasonic flow meter provides a good and simple alternative to respiratory mass spectrometer for FRC measurements in ventilated subjects.

30 citations

Patent
02 Sep 2005
TL;DR: In this article, a method and device are provided for measuring state of lung function of a patient using ultrasonic flow and molar mass measurement without requiring patient cooperation, and statistical analysis of the recorded data in combination with anthropometirc data and/or data form a questionnaire can be used to diagnose various pulmonary ailments or diseases.
Abstract: A method and device are provided for measuring state of lung function of a patient using ultrasonic flow and molar mass measurement. Flow and molar mass signals are recorded during tidal breathing without requiring patient cooperation. Statistical analysis of the recorded data in combination with anthropometirc data and/or data form a questionnaire can be used to diagnose various pulmonary ailments or diseases.

13 citations

Patent
19 May 1994
TL;DR: In this paper, the authors proposed a method in which the gas or gas mixture under analysis is passed through at least one support (5) in which an acoustic or ultrasonic transmitter or receiver cell (S1, S2) is located, preferably at an angle to the axis of the tube, to form a measurement path.
Abstract: In the method proposed, the gas or gas mixture under analysis is passed through at least one support (5) in which at least one acoustic or ultrasonic transmitter or receiver cell (S1, S2) is located, preferably at an angle to the axis of the tube, to form a measurement path. The acoustic or ultrasonic transmitter or receiver elements (S1, S2) emit a pulsed acoustic signal, and the travel times of the pulses over the measurement path are determined. The variation in gas temperature along the at least one acoustic-transmission path is determined by, for instance, a temperature probe. The molecular weight is determined from the travel time of the acoustic pulses and the measured or assumed temperature. The device proposed is suitable for use in diagnosing deficiencies in the functioning of the lungs.

9 citations

Dissertation
01 Jan 2019

3 citations


Cites background from "Ultrasonic Respiration Analysis"

  • ...While some of these are well known and documented, such as correcting flow to account for differences in humidity and pressure (known as the body temperature pressure saturated correction or BTPS), others are not immediately clear from either the official documentation [62], relevant patents [63], or other sources [53, 64, 65]....

    [...]

  • ...Chapter 2: Data context 9 ultrasound emitted by two opposing transducers (comprising an ultrasonic ‘flowmeter’) mounted on either side of an air flow tube [21, 53, 54]....

    [...]

References
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Journal ArticleDOI
TL;DR: A computerized method has been developed to determine the conductance characteristics of pneumotachometers, which improves the accuracy of the on-line measurements of ventilation, and CO2 production during exercise.
Abstract: A computerized method has been developed to determine the conductance characteristics of pneumotachometers. Conductance values of the flowmeter, which correspond to all pressure values, can be determined by a weighted averaging technique, when multiple strokes of a precision 3-liter calibrated syringe are used. The conductance values then allow the measured differential pressures to be converted, point by point, into flows. The accuracy of measured volumes is within +/- 0.5% for a 100-stroke calibration process, and calibration with 50 strokes provides +/- 1% accuracy. The method improves the accuracy of the on-line measurements of ventilation. O2 consumption, and CO2 production during exercise.

111 citations

Journal ArticleDOI
TL;DR: This respiratory air flowmeter is extremely fast and accurate, with low noise (below 9ml/s), with a wide flow range (bidirectional from 0 to 9 l/s and with a linear frequency response up to 70 Hz).
Abstract: The construction and specific function of a new ultrasonic flowmeter are described. The mean velocity of the respiratory air flow is calculated by measuring the transit times of short ultrasonic pulse-trains simultaneously transmitted upstream and downstream at a 650 Hz rate. The flowmeter system consists of a control unit and a separate flowhead. The former includes the power supplies, a controlling microprocessor, most of the signal processing circuitry, and three analog outputs for flow, volume, and temperature, respectively. The flowhead contains the respiratory tube with a constant circular cross section (length 90 mm, diameter 20 mm, dead space 35 cm3), a fast temperature sensor, two electronic circuits for processing of flow and temperature data, and a sound transmission channel with two capacitive ultrasonic wide-band transducers. This respiratory air flowmeter is extremely fast (response time 1-2 ms) and accurate, with low noise (below 9ml/s), with a wide flow range (bidirectional from 0 to 9 l/s) and with a linear frequency response up to 70 Hz.

32 citations

Journal ArticleDOI
TL;DR: This work reviews ultrasonic measurement of fluid flow with emphasis on ultrasonic pneumotachometers (UPTM's) and UPTM's, and presents four principle types: time of flight, sing around, phase shift, and phase-locked frequency shift.
Abstract: We review ultrasonic measurement of fluid flow with emphasis on ultrasonic pneumotachometers (UPTM's). For PTM's we discuss specifications such as dynamic range, resistance, and frequency response. We review fluid flow principles and point out the problems of nonultrasonic PTM's For UPTM's we describe transducer construction, attenuation versus frequency, reflection at interfaces, and acoustic field patterns. We present four principle types: 1) time of flight, 2) sing around, 3) phase shift, and 4) phase-locked frequency shift. For each, we detail principles, advantages, disadvantages, and potential for future development.

19 citations