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Biomedical subjects

W Robson

Publications and source records attributed to W Robson.

At least 19 recordsLinked to original sources
PubMed2006

Variation in invasive and noninvasive measurements of isovolumetric bladder pressure and categorization of obstruction according to bladder volume.

PURPOSE: We developed a noninvasive test that provides an estimate of isovolumetric bladder pressure by measuring the pressure required to interrupt voiding using controlled inflation of a penile cuff. We noted variation in serial measurements obtained during a single void and, therefore, we determined whether this represents variation in detrusor contraction strength, as predicted in previous studies, or measurement error. MATERIALS AND METHODS: A total of 36 symptomatic men underwent simultaneous invasive and noninvasive pressure flow studies. Corresponding values of isovolumetric bladder pressure and cuff interruption pressure were recorded at each flow interruption and grouped according to bladder volume to calculate measurement error and bias at various points during a void. Individual variation in the 2 measurements across a range of normalized bladder volumes was then examined using ANOVA. RESULTS: Cuff interruption pressure showed a consistent level of accuracy as an estimate of isovolumetric bladder pressure across a range of volumes. There were similar, statistically significant differences in isovolumetric bladder pressure and cuff interruption pressure recorded at specific volume increments with the highest values seen in the mid range and the lowest seen at lower bladder volumes (each p <0.01). When plotting, the maximum recorded value of cuff interruption pressure in each individual on our proposed noninvasive pressure flow nomogram provided the best diagnostic accuracy for obstruction. CONCLUSIONS: This study shows that cuff interruption pressure varies in the expected manner with bladder volume and provides a consistent estimate of isovolumetric bladder pressure throughout a void. These data provide important guidance for interpreting noninvasive pressure flow studies and classifying obstruction on the proposed nomogram.

Adult↗
PubMed2004

An automated penile compression release maneuver as a noninvasive test for diagnosis of bladder outlet obstruction.

PURPOSE: We tested the hypothesis that the previously described penile urethral compression release (PCR) maneuver provides a valid diagnosis of bladder outlet obstruction (BOO) using automated rather than manual penile compression by controlled inflation of a penile cuff. We also investigated urodynamic events underlying generation of the PCR index. MATERIALS AND METHODS: A total of 150 subjects attending for pressure flow studies were studied using conventional and noninvasive cystometry. Patients were classified into urodynamic diagnostic groups using standard invasive studies. The PCR index was calculated for each individual from noninvasive penile cuff data and the results were summarized for each group. ROC analysis of the PCR index was performed to define an optimum threshold for BOO diagnosis. Simultaneous invasive and noninvasive data were used to define the relationship between the PCR index, bladder contractility and the maximum flow rate. RESULTS: The mean PCR index +/- SD was significantly higher in the BOO group compared to the normal cystometry group (215% +/- 84% vs 93% +/- 39, p <0.01). ROC analysis showed that a PCR index of greater than 160% diagnosed BOO with 78% sensitivity, 84% specificity and a positive predictive value of 69%. There was a strong positive correlation between the PCR index and isovolumetric detrusor pressure, which is a measure of bladder contractility (r = 0.44, p <0.01). CONCLUSIONS: The results of this study suggest that the PCR index combines valid estimates of bladder contractility and the maximum flow rate, and it represents a clinically useful, noninvasive urodynamic parameter for the diagnosis of BOO.

Adult↗
PubMed2003

An open-label phase II study of low-dose thalidomide in androgen-independent prostate cancer.

The antiangiogenic effects of thalidomide have been assessed in clinical trials in patients with various solid and haematological malignancies. Thalidomide blocks the activity of angiogenic agents including bFGF, VEGF and IL-6. We undertook an open-label study using thalidomide 100 mg once daily for up to 6 months in 20 men with androgen-independent prostate cancer. The mean time of study was 109 days (median 107, range 4-184 days). Patients underwent regular measurement of prostate-specific antigen (PSA), urea and electrolytes, serum bFGF and VEGF. Three men (15%) showed a decline in serum PSA of at least 50%, sustained throughout treatment. Of 16 men treated for at least 2 months, six (37.5%) showed a fall in absolute PSA by a median of 48%. Increasing levels of serum bFGF and VEGF were associated with progressive disease; five of six men who demonstrated a fall in PSA also showed a decline in bFGF and VEGF levels, and three of four men with a rising PSA showed an increase in both growth factors. Adverse effects included constipation, morning drowsiness, dizziness and rash, and resulted in withdrawal from the study by three men. Evidence of peripheral sensory neuropathy was found in nine of 13 men before treatment. In the seven men who completed six months on thalidomide, subclinical evidence of peripheral neuropathy was found in four before treatment, but in all seven at repeat testing. The findings indicate that thalidomide may be an option for patients who have failed other forms of therapy, provided close follow-up is maintained for development of peripheral neuropathy.

Aged↗
PubMed2001

A crossover randomized trial of transcutaneous electrical nerve stimulation and oxybutynin in patients with detrusor instability.

PURPOSE: Management of idiopathic detrusor instability is difficult in most patients mainly due to the lack of a complete understanding of the pathophysiology. Oxybutynin and transcutaneous electrical nerve stimulation have been used but to our knowledge no direct comparisons have been made. MATERIALS AND METHODS: Patients with frequency, urgency, urge incontinence and proved detrusor instability were studied with urodynamics, quality of life instruments, and frequency and volume charts. Patients were randomized to transcutaneous electrical nerve stimulation or oxybutynin. After 6 weeks of treatment, they were reassessed and after a washout of 2 weeks, they were started on the second arm of treatment and reassessed 6 weeks later. RESULTS: A total of 13 male and 30 female patients were studied. Functional capacity had increased and number of voids daily had decreased significantly compared with before treatment in both arms (p <0.005). There were significant improvements in symptom specific quality of life measures but no changes were found on the global Short Form 36 (SF-36) quality of life questionnaire. The volume to first desire to void and first unstable contraction had increased significantly with oxybutynin but not with transcutaneous electrical nerve stimulation. Of 23 patients 7 were stabilized with treatment, including 2 with oxybutynin only, 2 with either nerve stimulation or oxybutynin and the remaining 3 with only nerve stimulation. Total bladder capacity did not change significantly with either treatment but patients noticed side effects more commonly with oxybutynin. CONCLUSIONS: Both treatments clearly improved subjective parameters. However, only oxybutynin showed significant improvements in objective urodynamic parameters. Transcutaneous electrical nerve stimulation can be used in patients who cannot take oxybutynin. Further studies are needed to show the long-term efficacy and cost analyses of nerve stimulation.

Adult↗
PubMed2001

Transmission of penile cuff pressure to the penile urethra.

PURPOSE: We developed a noninvasive method to measure voiding bladder pressure by inflating a penile cuff to interrupt flow. We tested the underlying assumption that cuff pressure is transmitted to the penile urethra. MATERIALS AND METHODS: In 35 men we simultaneously recorded penile cuff and urethral pressure during 2 experimental protocols for 6 cuffs of various widths and manufactures. Initially a urethral pressure transducer was placed at the mid point of the cuff and urethral pressure was continuously recorded during cuff inflation. In experiment 2 cuff pressure was set at 120 cm. water and the urethral pressure profile was measured by withdrawing the urethral transducer through the cuff width. RESULTS: There was excellent agreement of cuff with urethral pressure over the range of 0 to 200 cm. water for cuffs 37 to 54 mm. wide. Narrower cuffs showed wider variation with less efficient transmission of cuff pressure to the urethral lumen. Similarly maximum pressure in the urethral pressure profile showed best agreement for cuffs 38 and 46 mm. wide. Wider cuffs produced higher and narrower cuffs produced lower transmitted pressure within the urethra. Cuff performance was also related to penile size. Results had good within-subject repeatability. CONCLUSIONS: We demonstrated that pressure transmission from cuff to urethra is optimal at a cuff width of 40 to 50 mm. and recommended this width for other investigations of noninvasive bladder pressure measurement.

Equipment Design↗