The influence of intubation on urinary flow parameters in pressure-flow study and its significance for urodynamic diagnosis

Cheng, Y. S.; Xu, Shengfei; Jiang, Chen; Wu, Xiao‐Yu; Chen, Zhong; Du, Guangsheng

doi:10.1007/s00192-022-05082-z

Cited by 4 publications

(4 citation statements)

References 25 publications

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“…This interference of the indwelling urethral catheter with pressure and flow readings may result in misdiagnosis. 38 This highlights the importance of having a catheter-free alternative method to carry out voiding phase of a CMG.…”

Section: Discussionmentioning

confidence: 99%

“…One of the main challenges of this procedure is the non-physiological condition caused by the presence of the urethral catheter and partial or complete occlusion of the urethra. This interference of the indwelling urethral catheter with pressure and flow readings may result in misdiagnosis 38 . This highlights the importance of having a catheter-free alternative method to carry out voiding phase of a CMG.…”

Section: Discussionmentioning

confidence: 99%

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Pressure Measurement in a Bladder Phantom Using Contrast-Enhanced Ultrasonography—A Path to a Catheter-Free Voiding Cystometrogram

Kalayeh¹,

Fowlkes²,

Chen³

et al. 2022

Invest Radiol

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ObjectivesThe long-term goal of this study is to investigate the efficacy of a novel, ultrasound-based technique called subharmonic-aided pressure estimation (SHAPE) to measure bladder pressure as a part of a cystometrogram (CMG) in a urodynamic test (ie, pressure-flow study). SHAPE is based on the principle that subharmonic emissions from ultrasound contrast microbubbles (MBs) decrease linearly with an increase in ambient pressure. We hypothesize that, using the SHAPE technique, we can measure voiding bladder pressure catheter-free. This is of importance because the CMG catheter, due to its space-occupying property and non-physiological effects, can undermine the reliability of the test during voiding and cause misdiagnosis. In this study, we tested this hypothesis and optimized the protocol in a controlled benchtop environment.Materials and MethodsA bladder phantom was designed and built, capable of simulating clinically relevant bladder pressures. Laboratory-made lipid-shelled MBs (similar in composition to the commercial agent, DEFINITY) was diluted in 0.9% normal saline and infused into the bladder phantom using the CMG infusion system. A typical simulated CMG consists of 1 filling and 4 post-filling events. During CMG events, the bladder phantom is pressurized multiple times at different clinically relevant levels (small, medium, and large) to simulate bladder pressures. Simultaneous with pressurization, MB subharmonic signal was acquired. For each event, the change in MB subharmonic amplitude was correlated linearly with the change in bladder phantom pressure, and the SHAPE conversion factor (slope of the linear fit) was determined. In doing so, a specific signal processing technique (based on a small temporal window) was used to account for time-decay of MB subharmonic signal during a simulated CMG.ResultsA strong inverse linear relationship was found to exist between SHAPE and bladder phantom pressures for each of the CMG filling and post-filling events (r2 > 0.9, root mean square error <0.3 dB, standard error <0.01 dB, and P < 0.001). SHAPE showed a transient behavior in measuring bladder phantom pressure. The SHAPE conversion factor (in dB/cm H2O) varied between filling and post-filling events, as well as by post-filling time. The magnitude of the SHAPE conversion factor tended to increase immediately after filling and then decreases with time.ConclusionsMicrobubble subharmonic emission is an excellent indicator of bladder phantom pressure variation. The strong correlation between SHAPE signal and bladder phantom pressure is indicative of the applicability of this method in measuring bladder pressure during a CMG. Our results suggest that different SHAPE conversion factors may be needed for different events during a CMG (ie, at different time points of a CMG). These findings will help us better protocolize this method for introduction into human subjects and allow us to take the next step toward developing a catheter-free voiding CMG using SHAPE.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Pressure Measurement in a Bladder Phantom Using Contrast-Enhanced Ultrasonography—A Path to a Catheter-Free Voiding Cystometrogram

Kalayeh¹,

Fowlkes²,

Chen³

et al. 2022

Invest Radiol

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“…The size of the catheter seems to be one of the factors explaining this phenomenon but not the only one 8,9 . Furthermore, the alterations induced by the catheters have been proposed to be capable of leading to a misdiagnosis of BOO or DU 10 …”

Section: Introductionmentioning

confidence: 99%

“…8,9 Furthermore, the alterations induced by the catheters have been proposed to be capable of leading to a misdiagnosis of BOO or DU. 10 Considering free uroflowmetry (UFM) to be a closer surrogate of a patient's daily life micturition, it seems interesting to assess the parameters of free and invasive UFM in patients with overactive bladder. Specifically, we aim to compare both measurements in patients with concomitant DU or BOO and ultimately evaluate how free UFMs vary among different definitions of DU/BOO.…”

Section: Introductionmentioning

confidence: 99%

Defining bladder outlet obstruction and detrusor underactivity in females with overactive bladder: Are we forgetting about the free uroflowmetry?

Arévalo-Vega

Ponce

Valdevenito

et al. 2023

Neurourology and Urodynamics

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Introduction: Both detrusor underactivity (DU) and bladder outlet obstruction (BOO) can coexist in patients with overactive bladder. Definitions of both DU and BOO are based on pressure-flow study (PFS) data. However, invasive urodynamics study can differ from a natural micturition, in fact, discrepancies between free uroflowmetry (UFM) and PFS have been largely described. Our goal is to assess the correlation of free-flowmetry and PFS among patients with OAB and to evaluate how different definitions of DU/BOO are able to discriminate patients with different free UFMs. Methods: A retrospective review of urodynamics performed at a single institution was conducted. Females with OAB who voided more than 150 mL in both UFM and PFS were included. Parameters from both voiding episodes were compared with nonparametric test. Two definitions of DU were applied; PIP1: Pdet@Qmax+Qmax < 30 and Gammie: Pdet@Qmax < 20 cmH 2 O, Qmax < 15 mL/s, and BVE < 90% (Bladder voiding efficiency). Also, two definitions of obstruction were chosen; Defretias: Pdet@Qmax ≥25 cmH 2 O and Qmax ≤ 12 mL/s and Solomon-Greenwell female BOO index ≥ 18.Patients who matched with each definition were compared to those who did not, to assess if any definitions were able to discriminate different noninvasive uroflowmetries.Results: A total of 195 patients were included. Overall, mean age was 55 ± 12 years, 90.8% had mixed urinary incontinence, and 39% complained of at least one voiding symptom. Globally, Qmax and BVE correlated poorly between UFM and PFS, showing that most of the variation corresponded to a systematic error. Twenty-two individuals were found to have DU, they had a difference of 13 mL/s on both maximum flows. Fifty-four patients showed BOO, with a difference between their Qmax of 19 mL/s. Among the four definitions analyzed, only PIP1 and Defreitas were able to discriminate patients with actually a lower Qmax on the free UFM.

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Influence of transurethral catheters on urine pressure-flow relationships in males: A computational fluid-dynamics study

Mascolini

Fontanella

Berardo

et al. 2023

Computer Methods and Programs in Biomedicine

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The influence of intubation on urinary flow parameters in pressure-flow study and its significance for urodynamic diagnosis

Cited by 4 publications

References 25 publications

Pressure Measurement in a Bladder Phantom Using Contrast-Enhanced Ultrasonography—A Path to a Catheter-Free Voiding Cystometrogram

Pressure Measurement in a Bladder Phantom Using Contrast-Enhanced Ultrasonography—A Path to a Catheter-Free Voiding Cystometrogram

Defining bladder outlet obstruction and detrusor underactivity in females with overactive bladder: Are we forgetting about the free uroflowmetry?

Influence of transurethral catheters on urine pressure-flow relationships in males: A computational fluid-dynamics study

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