Comparison of water and air charged transducer catheter pressures in the evaluation of cystometrogram and voiding pressure studies

Correlation between obesity-related measurements and initial and initial resting intravesical and abdominal pressures in urodynamic study using air-filled catheter system

OBJECTIVES

To establish the initial (before pressure equilibrium) and initial resting intravesical and abdominal pressure in the sitting position using air-filled catheters, to assess the correlation between these pressures and obesity-related measurements, and to estimate if obesity-related measurements can be a guide to interpret initial and initial resting pressures in urodynamic testing.

METHODS

Patients with non-neurogenic lower urinary tract symptoms referred for urodynamic testing in our center were consecutively enrolled in a prospective study from August 2022 to October 2022. The correlation between the initial and initial resting pressures (before and after pressure equilibrium) and obesity-related measurements were analyzed using Pearson's correlation coefficient and multiple linear regression analysis.

RESULTS

Ninety-eight patients aged 56 ± 16 were studied. The 95% range of the initial intravesical and abdominal pressure were 18-42 cmH2 O and 21-60 cmH2 O, respectively. The initial resting intravesical, abdominal, and detrusor pressure in the 95% range were 17-41, 16-42, and -5 to 4 cmH2 O, respectively. Over the multiple analysis, abdominal fat thickness, and body mass index (BMI) correlated independently with initial intravesical pressure, and only visceral fat grade correlated with initial abdominal pressure. BMI correlated independently with initial resting intravesical pressure.

CONCLUSIONS

Our results determined the ranges of values of both initial and initial resting pressures in the air-charged system. Meanwhile, the present study indicated the obesity-related measurements may be used as a guide to interpret the initial and initial resting pressures in urodynamic testing, and may provide a reference for the quality control of these pressures.

In Vitro Validation of a Novel Continuous Intra-Abdominal Pressure Measurement System (TraumaGuard)

Introduction: Intra-abdominal pressure (IAP) has been recognized as an important vital sign in critically ill patients. Due to the high prevalence and incidence of intra-abdominal hypertension in surgical (trauma, burns, cardiac) and medical (sepsis, liver cirrhosis, acute kidney injury) patients, continuous IAP (CIAP) monitoring has been proposed. This research was aimed at validating a new CIAP monitoring device, the TraumaGuard from Sentinel Medical Technologies, against the gold standard (height of a water column) in an in vitro setting and performing a comparative analysis among different CIAP measurement technologies (including two intra-gastric and two intra-bladder measurement devices). A technical and clinical guideline addressing the strengths and weaknesses of each device is provided as well. Methods: Five different CIAP measurement devices (two intra-gastric and three intra-vesical), including the former CiMON, Spiegelberg, Serenno, TraumaGuard, and Accuryn, were validated against the gold standard water column pressure in a bench-top abdominal phantom. The impacts of body temperature and bladder fill volume (for the intra-vesical methods) were evaluated for each system. Subsequently, 48 h of continuous monitoring (n = 2880) on top of intermittent IAP (n = 300) readings were captured for each device. Using Pearson's and Lin's correlations, concordance, and Bland and Altman analyses, the accuracy, precision, percentage error, correlation and concordance coefficients, bias, and limits of agreement were calculated for all the different devices. We also performed error grid analysis on the CIAP measurements to provide an overview of the involved risk level due to wrong IAP measurements and calculated the area under the curve and time above a certain IAP threshold. Lastly, the robustness of each system in tracking the dynamic variations of the raw IAP signal due to respirations and heartbeats was evaluated as well. Results: The TraumaGuard was the only technology able to measure the IAP with an empty artificial bladder. No important temperature dependency was observed for the investigated devices except for the Spiegelberg, which displayed higher IAP values when the temperature was increased, but this could be adjusted through recalibration. All the studied devices showed excellent ability for IAP monitoring, although the intra-vesical IAP measurements seem more reliable. In general, the TraumaGuard, Accuryn, and Serenno showed better accuracy compared to intra-gastric measurement devices. On average, biases of +0.71, +0.93, +0.29, +0.25, and -0.06 mm Hg were observed for the CiMON, Spiegelberg, Serenno, TraumaGuard, and Accuryn, respectively. All of the equipment showed percentage errors smaller than 25%. Regarding the correlation and concordance coefficients, the Serenno and TraumaGuard showed the best results (R2 = 0.98, p = 0.001, concordance coefficient of 99.5%). Error grid analysis based on the Abdominal Compartment Society guidelines showed a very low associated risk level of inappropriate treatment strategies due to erroneous IAP measurements. Regarding the dynamic tracings of the raw IAP signal, all the systems can track respiratory variations and derived parameters; however, the CiMON was slightly superior compared to the other technologies. Conclusions: According to the research guidelines of the Abdominal Compartment Society (WSACS), this in vitro study shows that the TraumaGuard can be used interchangeably with the gold standard for measuring continuous IAP, even in an empty artificial bladder. Confirmation studies with the TraumaGuard in animals and humans are warranted to further validate these findings.

Head-to-head comparison of pressures during full cystometry, with clinical as well as in-depth signal-analysis, of air-filled catheters versus the ICS-standard water-filled catheters

Aims

To compare in vivo differences of two catheter systems for urodynamics to further discover their measurement properties.

Methods

Side‐by‐side catheterization with two catheters for intravesical and abdominal pressure during full cystometry in 36 prospectively recruited patients with analysis of mean and absolute differences at urodynamic events and post hoc in‐depth signal analysis comparing the full pressure traces of both systems.

Results

The mean pressure differences at urodynamic events between air‐filled and water‐filled systems are small, however, with a large variation, without a systematic difference. The majority of the intersystem differences are significantly larger than 5 cmH₂O. Further analysis showed that urodynamic event pressure differences of both systems at the start of the test were carried forward throughout the remainder of the test without subsequent or additional tendency to differ. Post hoc whole test signal analysis with pressures equalized from the first sample shows high cross‐correlation (>0.981) between the pressure signals per location (rectum and bladder) per test and almost zero‐time shift (<0.05 s) of all cystometry pressure samples.

Conclusions

We confirm earlier studies that showed random differences at events between air‐filled and water‐filled pressures during clinical urodynamic testing and confirm that these are intrinsic but not systematic—and still incompletely explained—offset‐baseline differences. We determined on closer full measurement analysis after equalizing, that both systems are similar in displaying urodynamic pressure variations and amplitudes. We also confirm that both systems require awareness of intrinsic measurement properties during urodynamic testing and especially may necessitate adjustment of pressure offsets into a quantitative diagnosis of a urodynamic test.

Usability and safety of the new 5 French air-charged catheter for performing urodynamic studies on pediatric patients

AIMS

To assess the performance and safety of the T-DOC® 5 French air-charged urodynamic catheters in pediatric patients and obtain feedback from providers related to usability performance.

METHODS

Patients ages 12 years and younger undergoing urodynamics were prospectively recruited from two institutions. The T-DOC® 5 French air-charged catheters were used. Issues with catheter placement, adverse events (AEs), and pain scores were assessed. A follow-up telephone call was made to assess for post-urodynamic AEs. Providers completed a clinical user questionnaire. Likert scale was used (1 = most negative and 5 = most positive response) and reported in mean (range).

RESULTS

A total of 28 patients completed the study. The mean age was 55 months (5-130) (10 females, 18 males). One problem was noted with the insertion of an abdominal catheter, secondary to stool impaction. Catheters stayed in place on all subjects, except for one related to patient hyperactivity. There were no AEs during the studies. In total four reported post-urodynamics AEs (one hematochezia, three dysuria). Among nine patients, pain level on the bladder and abdominal insertion was 3.6/10 (0-10) and 3.1/10 (0-10). Five providers completed the questionnaire. The overall ease of use was rated 4.3/5 (3-5). The ease of insertion was 4.1/5 (2-5) and set-up/clean-up time was 4.4/5 (3-5). Tracing stability, subtraction accuracy, and artifact sensitivity were all perceived favorably (respectively 4.8/5 [4-5], 4.6/5 [4-5], and 4.4/5 [4-5]).

CONCLUSIONS

The T-DOC® 5 French air-charged catheter was considered safe and effective in pediatric patients. No AEs occurred during the studies. Providers, using the catheters, reported favorably on catheter usage.

Is the value of urodynamics undermined by poor technique?: ICI-RS 2018

INTRODUCTION

The quality of urodynamic measurements in clinical practice has been debated as a matter of concern. It is considered plausible that this has a direct bearing on patient care and the perceived value of urodynamic testing.

METHODS

This is a report of the proceedings of the Think Tank: "Is the value of urodynamics undermined by poor technique?" from the Annual International Consultation on Incontinence-Research Society, which took place in June 2018 in Bristol, UK. The Think Tank discussed the evidence for deficiencies in urodynamic test quality and considered the implications of improvements for clinical diagnosis and practice.

RESULTS

There is evidence that technique affects urodynamic quality, and that urodynamic practice is variable. Factors such as team skill set, technologies used, and training received will also affect the quality of urodynamic service. Questions exist regarding the influence of technique on the utility and perceived value of urodynamics.

CONCLUSIONS

We suggest research questions that will provide the necessary evidence on the link between technique, reporting, and outcome, and clarify the role of good practice in the utility of urodynamic testing.

Urethral pressure profilometry in artificial urinary sphincter implantation: A case report

BACKGROUND

Artificial urethral sphincter (AUS) implantation is currently the gold standard for treating moderate and severe urinary incontinence. Currently, cuffs are chosen based on the surgeon’s experience, and adjusting cuff tightness is crucial. The T-DOC air-charged catheter has not been proven to be inferior to traditional catheters. We report how intraoperative urethral pressure profilometry is performed using a T-DOC air-charged catheter with ambulatory urodynamic equipment, to guide cuff selection and adjustment.

CASE SUMMARY

A 67-year-old man presented to our hospital with complete urinary incontinence following transurethral prostatectomy, using five pads/d to maintain local dryness. Preoperatively, the maximum urethral pressure (MUP) and maximum urethral closure pressure (MUCP) were 52 cmH2O and 17 cmH2O, respectively. An AUS was implanted. Intraoperatively, in the inactivated state, the MUP and MUCP were 53 cmH2O and 50 cmH2O, respectively; in the activated state, they were 112 cmH2O and 109 cmH2O, respectively. The pump was activated 6 wk postoperatively. Re-measurement of the urethral pressure on the same day showed that in the inactivated state, MUP and MUCP were 89 cmH2O and 51 cmH2O, respectively, and in the activated state, 120 cmH2O and 92 cmH2O, respectively. One month after device activation, telephonic follow-up revealed that pad use had decreased from five pads/d to one pad/d, which met the standard for social continence (0-1 pad per day). There were no complications.

CONCLUSION

The relationship between intraoperative urethral pressure and urinary continence post-surgery can provide data for standardizing AUS implantation and evaluating efficacy.

Comparison of air-filled and water-filled catheters for use in cystometric assessment

INTRODUCTION AND HYPOTHESIS

To determine whether pressure readings measured with air-filled catheter (AFC) and water-filled catheter (WFC) systems are equivalent during cystometric assessment, especially in case of pressure measurements at Valsalva manoeuvres and coughs.

METHODS

Twenty-five subjects were recruited. The commercially available 7-Fr TDOC AFC, which simultaneously reads water and air pressures in the bladder and rectum, was used to compare filling and voiding data recordings. Data were compared using paired t-tests, Bland-Altman plots and linear correlation methods, respectively.

RESULTS

Pressure readings measured by the two systems showed a good correlation at Valsalva manoeuvres [R² = 0.988, 0.968 for vesical pressure (Pves) and abdominal pressure (Pabd), respectively] and at coughs (R² = 0.972, 0.943 for Pves and Pabd, respectively). There was a statistically significant difference between the two different measurement modalities at coughs (p < 0.01), initial resting pressure (p < 0.01) and the maximum pressure at detrusor overactivity (p < 0.01). This indicated that the difference between the two measurement modalities during Valsalva manoeuvres could reach up to 5.2 cmH₂O and 8.1 cmH₂O in Pves and Pabd measurements, respectively. During coughs, the difference could reach up to 20 cmH₂O and 19.5 cmH₂O in Pves and Pabd measurements, respectively.

CONCLUSIONS

Pressure recordings from AFC and WFC systems appear to be interchangeable for some urodynamics parameters such as Pves at Valsalva manoeuvres if the baseline pressure is compensated, but not for fast-changing pressure signals such as coughs. This has to be considered when pressures are being taken with the AFC.