Hydraulic resistance and damping in catheter-transducer systems

Taylor, Bonnie; Donovan, Francis M.

doi:10.1109/51.256965

Cited by 3 publications

(2 citation statements)

References 12 publications

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“…The catheter must therefore have a correct combination of length, diameter and compliance of the material to maximize the accuracy in the signal, as these parameters dictate the amount of damping of the system and its natural frequency. The properties and dimensions of catheters should be chosen to provide the highest possible natural frequency and thus maximize the flat frequency response necessary to produce a high-fidelity measurement [6]–[8]. In general, stiffer catheters increase the accuracy of the measurement; however, more compliant materials are necessary for better navigation in complex anatomies.…”

Section: Introductionmentioning

confidence: 99%

Catheter-Induced Errors in Pressure Measurements in Vessels: An In-Vitro and Numerical Study

Vecchi

Clough

Gaddum

et al. 2014

IEEE Trans. Biomed. Eng.

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Accurate measurement of blood pressure is important because it is a biomarker for cardiovascular disease. Diagnostic catheterization is routinely used for pressure acquisition in vessels despite being subject to significant measurement errors. To investigate these errors, this study compares pressure measurement using two different techniques in vitro and numerical simulations. Pressure was acquired in a pulsatile flow phantom using a 6F fluid-filled catheter and a 0.014” pressure wire, which is considered the current gold standard. Numerical simulations of the experimental set-up with and without a catheter were also performed. Despite the low catheter-to-vessel radius ratio, the catheter traces showed a 24% peak systolic pressure overestimation compared to the wire. The numerical models replicated this difference and indicated the cause for overestimation was the increased flow resistance due to the presence of the catheter. Further, the higher frequency pressure oscillations observed in the wire and numerical data were absent in the catheter, resulting in an overestimation of the pulse wave velocity with the latter modality. These results show that catheter geometry produces significant measurement bias in both the peak pressure and the waveform shape even with radius ratios considered acceptable in clinical practice. The wire allows for more accurate pressure quantification, in agreement with the numerical model without a catheter.

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Section: Introductionmentioning

confidence: 99%

Catheter-Induced Errors in Pressure Measurements in Vessels: An In-Vitro and Numerical Study

Vecchi

Clough

Gaddum

et al. 2014

IEEE Trans. Biomed. Eng.

View full text Add to dashboard Cite

show abstract

“…Dynamic response of such a pressure-measuring system has been investigated in the previous studies (e.g., Geddes et al, 1984), and it was pointed out that the dynamic response was non flat mainly due to elasticity of the pressure sensor while effect of compressibility of the fluid is negligible. The methods to correct these effects have been studied in literatures (Donovan et al, 1991;Taylor and Donovan, 1992;Donovan et al, 1994;Aydin, 1998). In these studies, the behavior of the pressure-measuring system was modeled as that of a harmonic oscillator with one degree of freedom, and parameters in the model equation, the natural frequency and the damping factor, were determined by calibration.…”

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confidence: 99%

An attempt to measure fluctuating local pressure in free turbulent flow in water

Kawata

Maeda

Obi

2014

JFST

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We developed a technique for the measurement of fluctuating hydraulic-pressure at an arbitrary point in turbulent flow. A pressure-measuring system was composed of a miniature static-pressure probe (SP-probe), a strain-gagetype pressure transducer, and a tube connecting them. A model equation of dynamic response of the pressuremeasuring system was introduced, and a calibration technique for determining parameters in the model equation was developed. Effects of the size of the SP-probe, length of the tube, and sensitivity of the pressure sensor were systematically investigated using several SP-probes, tubes, and pressure transducers with different sizes, lengths, and sensitivities, and fluctuating hydraulic-pressure measurement was performed in a wake of a circular cylinder.In the past hydraulic wall-pressure measurement, a strain-gage-type pressure transducer was used as a pressure sensor and connected to the pressure tap on the wall by tubing. Dynamic response of such a pressure-measuring system has been investigated in the previous studies (e.g., Geddes et al., 1984), and it was pointed out that the dynamic response was non flat mainly due to elasticity of the pressure sensor while effect of compressibility of the fluid is negligible. The methods to correct these effects have been studied in literatures (Donovan et al., 1991;Taylor and Donovan, 1992;Donovan et al., 1994;Aydin, 1998). In these studies, the behavior of the pressure-measuring system was modeled as that of a harmonic oscillator with one degree of freedom, and parameters in the model equation, the natural frequency and the damping factor, were determined by calibration.

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Harmonic Analysis of Perfusion Pumps

Dougherty

Donovan

Townsley

2003

Journal of Biomechanical Engineering

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The controversy over the use of nonpulsatile versus pulsatile pumps for maintenance of normal organ function during ex vivo perfusion has continued for many years, but resolution has been limited by lack of a congruent mathematical definition of pulsatility. We hypothesized that the waveform frequency and amplitude, as well as the underlying mean distending pressure are all key parameters controlling vascular function. Using discrete Fourier Analysis, our data demonstrate the complexity of the pulmonary arterial pressure waveform in vivo and the failure of commonly available perfusion pumps to mimic in vivo dynamics. In addition, our data show that the key harmonic signatures are intrinsic to the perfusion pumps, are similar for flow and pressure waveforms, and are unchanged by characteristics of the downstream perfusion circuit or perfusate viscosity.

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Hydraulic resistance and damping in catheter-transducer systems

Cited by 3 publications

References 12 publications

Catheter-Induced Errors in Pressure Measurements in Vessels: An In-Vitro and Numerical Study

Catheter-Induced Errors in Pressure Measurements in Vessels: An In-Vitro and Numerical Study

An attempt to measure fluctuating local pressure in free turbulent flow in water

Harmonic Analysis of Perfusion Pumps

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