Accuracy and limitations of the ultrasonic Doppler blood velocimeter and zero crossing detector

Lunt, M. J.

doi:10.1016/0301-5629(75)90035-6

Cited by 121 publications

(21 citation statements)

References 7 publications

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“…First, our use of 4 MHz (rather than 8 MHz) ultrasound gives better tissue penetration and is likely to result in more satisfactory Doppler signals. Second, spectral analysis of the signals is not subject to the considerable errors and artefacts of the zero crossing technique (26,27) used by Costeloe et al (20) and many other workers to analyze Doppler waveforms. Third, in this study cerebral vasodilation was induced by a linear rise in carbon dioxide concentration from 4.5% up to a maximum of 8.5% which probably resulted in a more marked and consistent fall in cerebral vascular resistance than a single step increase from air to 2 or 3% carbon dioxide as used in the study of Costeloe et al (20).…”

Section: Discussionmentioning

confidence: 99%

Controlled Hypercapnia and Neonatal Cerebral Artery Doppler Ultrasound Waveforms

et al. 1986

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ABSTRACT. Eleven normal term infants undergoing res-The study of cerebral hemodynamics in the newborn infant by Doppler ultrasound is attractive because it is convenient, noninvasive, and apparently safe. There are a number of reports describing this technique in many different pathological situations (1-10) but few which describe findings in normal babies (1 1, 12). There is little information on the hemodynamic processes that underlie changes in Doppler ultrasound readings from the cerebral vessels of newborn babies. It has been claimed that the pulsatility of Doppler waveforms recorded from these vessels correlates with cerebral vascular resistance (1 1, 13, 14). There have been few attempts to validate this supposition. In adult animals a direct correlation between cerebral blood flow calculated from Doppler shift frequencies and that obtained by the microsphere method has been reported (1 5).In animal studies (16, 17) change in blood flow velocity induced by hypercapnia and assessed by Doppler ultrasound correlated with changes in cerebral blood flow using the microsphere technique, but measures of the pulsatility of the Doppler waveform correlated only poorly in newborn dogs and not at all in piglets. Daven et a/. (18) showed hypercapnia to be associated with a fall in pulsatility of the Doppler waveform in sick preterm infants being ventilated for respiratory disease. Griesen et al. (1 9) showed a relationship between Doppler variables and cerebral

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Section: Discussionmentioning

confidence: 99%

Controlled Hypercapnia and Neonatal Cerebral Artery Doppler Ultrasound Waveforms

et al. 1986

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“…QB in the arterial tube was measured by a Doppler ultrasonic device (type DU.01.00.0; Delalande Electronique, Courbevoie, France), as described previously [16,17]. The flowmeter was cali brated using human blood with a Hct of 32%.…”

Section: Hemodynamic Measurementsmentioning

confidence: 99%

Continuous Arteriovenous Hemof iltration: In vivo Functional Characteristics and Its Dependence on Vascular Access and Filter Design

Olbricht

Haubitz

Häbel

et al. 1990

Nephron

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The in vivo functional characteristics of continuous arteriovenous hemofiltration (CAVH) were studied in 21 intensive-care patients with acute renal failure. FH-66 hemofilters were applied. The relationships between prefilter blood pressure (BP), blood flow (QB) and filtration rate (QF) were evaluated by stepwise clamping of the arterial access and simultaneous measurements of these parameters. The correlations between BP and QB, and between QB and QF, were linear (p < 0.001). The total pressure drop across the extracorporeal circuit was 90 ± 12 mmHg with Scribner shunt and 70 ± 13 mmHg with femoral catheters as vascular access. The relative pressure drops across arterial access, hemofilter and venous access for Scribner shunt and for femoral catheter were 30%, 43% and 27% and 12%, 74% and 14%, respectively. At a given BP, QB was lower and transmembrane filtration pressure (TMP) higher in CAVH with Scribner shunt. QB was 102 ± 38 ml/min; QF was 20 ± 7 ml/min. The effects of hemofilter geometry and membrane material on functional parameters of CAVH were evaluated by applying four hemofilters (Amicon D-20 HP, D-30 HP, Gambro FH-66, Fresenius AV-400) consecutively in the same patient. The filters were different with respect to hollow fiber length, its internal diameter, number of fibers and membrane material. BP, hematocrit (Hct) and plasma protein remained constant during measurements. QB increased with decreasing filter resistance. QF did not increase with increasing QB. QF was also not closely related to membrane surface area. The hydraulic permeability (Lp) had a major impact on QF. The Lp of the polysulfone membranes was between 47 and 35% lower than that of polyamide membranes. Hence, at given values of TMP and surface area, polyamide filters may have a higher QF. Filtration pressure dysequilibrium was always present irrespective of filter geometry, membrane material, BP, Hct and plasma protein.

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“…The statistical significance of the difference between simultaneously acquired time-averaged ZC and maximal when ZC is used for the analysis of composite Doppler signals induced by the presence of scatterers of different velocity in the Doppler sample volume [1,2]. The main advantages of the analysis of the full frequency spectrum of the Doppler signal are the detection of the maximal Doppler frequency and the more accurate calculation of the mean Doppler frequency from the weighted intensity of the signal for each frequency.…”

Section: Discussionmentioning

confidence: 99%

Limitations of the zero crossing detector in the analysis of intracoronary doppler: A comparison with fast fourier transform analysis of basal, hyperemic, and transstenotic blood flow velocity measurements in patients with coronary artery disease

Mario

Roelandt

Jaegere

et al. 1993

Cathet. Cardiovasc. Diagn.

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The current clinical standard for the analysis of intracoronary Doppler signals is the application of a zero-crossing (ZC) detector. However, the accuracy of the method is questionable, especially in areas of disturbed flow, as confirmed by in vitro studies, animal experiments, and intraoperative observations. The aim of this study is the comparison of a conventional ZC detector and a custom-designed spectral analyzer (fast Fourier transform, FFT) in the analysis of intracoronary Doppler signals obtained in 19 patients undergoing coronary angioplasty. A 3F catheter with an end-mounted Doppler ceramic crystal was placed over an 0.014" guidewire in a normal or near-normal segment proximal to the lesion to be dilated. The Doppler signal was recorded before and after intracoronary infusion of 12.5 mg of papaverine. In 9 patients high flow velocities could be recorded when the catheter was advanced across the stenosis. The blood flow velocity measurements obtained with ZC were significantly lower than the maximal FFT flow velocity measurements (16 +/- 12 cm/s vs. 29 +/- 18 cm/s, p < .001). In all the conditions of Doppler signal acquisition (baseline, hyperemia, stenosis) a large scattering of the signed differences between corresponding measurements was observed. The standard deviation of the difference ZC-FFT was +/- 11 cm/s and +/- 5 cm/s for the maximal and mean FFT flow velocity, corresponding in both cases to +/- 37% of the mean of the ZC and FFT measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

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Accuracy and limitations of the ultrasonic Doppler blood velocimeter and zero crossing detector

Cited by 121 publications

References 7 publications

Controlled Hypercapnia and Neonatal Cerebral Artery Doppler Ultrasound Waveforms

Controlled Hypercapnia and Neonatal Cerebral Artery Doppler Ultrasound Waveforms

Continuous Arteriovenous Hemof iltration: In vivo Functional Characteristics and Its Dependence on Vascular Access and Filter Design

Limitations of the zero crossing detector in the analysis of intracoronary doppler: A comparison with fast fourier transform analysis of basal, hyperemic, and transstenotic blood flow velocity measurements in patients with coronary artery disease

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