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987 Ultrasound residual urine volume: Is it valid and reliable?
987
Ultrasound residual urine volume: Is it valid and reliable? Eur Urol Suppl 2014;13;e987
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Ordaz Guzmán J., Arlandis Guzmán S., Bonillo García M.A., López Acón J.D., Conca Baenas M.A., Jiménez Cruz J.F. H.U. La Nueva Fe, Dept. of Urology, Valencia, Spain INTRODUCTION & OBJECTIVES: Clean Intermitent Catheterization (CIC) is a gold standard treatment in many voiding dysfunction patients. Postvoid residual volume (PVR) measurement is necessary to establish the appropriate number of CIC. Discordance between ultrasound measurement of PVR and real PVR volume (measured by bladder drainage) is often found. To assess whether ultrasound postvoid residual volumes (PVR) are reproducible (reliability) by different observers and close to those obtained by bladder catheterization as gold standard (validity). MATERIAL & METHODS: Prospective, double-blind study involving 441 patients attending our neurourology department to undergo an urodynamic study because of LUTS. We included patients of both sexes, with and without neurological disease, meeting the following conditions: (1) urine infection free, (2) urethral catheterisation possible and not contraindicated, (3) no previous bladder enlargement surgery nor (4) bladder pathological anatomical conditions. Postvoid residual volume (PRV) was blind-measured with ultrasound by two experienced examiners, if any detected PRV >100 mL, the patient was then voided by catheterisation: 173 (39,2%) altogether. Outcomes were established by three groups (PVR 0-100 mL, 101-200 mL, >200 mL). Reliability was proved using intraclass correlation coefficient (ICC) with 95% confidence interval (CI) and Kappa index for each group whilst global agreement was performed with a Bland-Altman plot. Sensibility and specificity for each group with 95% CI and COR curves (with 100 and 200 mL as cut-off points) demonstrated validity analysis, taking catheterisation volume as gold standard. Finally, a linear regression (LR) formula could predict real PVR out of an ultrasound measure. RESULTS: Our sample includes 155 (35,2%) men and 286 (64,8%) women, neurogenic patients 146 (33,1%). Reliability; ICC: 0-100 mL =0,96 CI 95% (0,95-0,96), 101-200 mL =0,77 (0,63-0,86), >200 mL =0,79 (0,57-0,90). Kappa index (p<0,000): 0100 mL = 0,88, 101-200 mL =0,75, >200 mL =0,80. Echomeasures mean difference (Bland-Altman plot) =0,85 mL CI 95% (-1,77–3,49). Validity; sensibility and specificity group data are respectively 0-100 mL =96,1% CI 95% (91,1-100%) and 77,6% (68,7-87,6%), 101-200 mL =62,2% (46,9-77,5%) and 83,3% (76,4-90,2%), >200 mL =55,1% (40,1-70%) and 100% (99,5-100%). COR curve areas >100 mL 0,97 (0,95-0,99), >200 mL 0,95 (0,92-0,98). LR: Real PVR (mL) = 20,86 CI 95% (10,38-31,34) + 1,20 (1,13-1,27) * Ultrasound PVR (mL). R =0,93; R2 adjusted =0,88 (Anova p<0,000). CONCLUSIONS: Ultrasound is a reliable diagnostic test to quantify PVR given it's high reproducibility rate and interobserver agreement, it can ensure diagnosis given a positive PRV due to it's high specificity whereas may have considerable false negative results (low sensibility). Moreover ultrasound measurement of PVR may underestimate real PVR, high ones most, so the initial number of CIC needed in patients with substantial PVR shouldn’t be decided by ultrasound but by catheterisation.
Ultrasound residual urine volume: Is it valid and reliable? Eur Urol Suppl 2014;13;e987
Print! Print!
Ordaz Guzmán J., Arlandis Guzmán S., Bonillo García M.A., López Acón J.D., Conca Baenas M.A., Jiménez Cruz J.F. H.U. La Nueva Fe, Dept. of Urology, Valencia, Spain INTRODUCTION & OBJECTIVES: Clean Intermitent Catheterization (CIC) is a gold standard treatment in many voiding dysfunction patients. Postvoid residual volume (PVR) measurement is necessary to establish the appropriate number of CIC. Discordance between ultrasound measurement of PVR and real PVR volume (measured by bladder drainage) is often found. To assess whether ultrasound postvoid residual volumes (PVR) are reproducible (reliability) by different observers and close to those obtained by bladder catheterization as gold standard (validity). MATERIAL & METHODS: Prospective, double-blind study involving 441 patients attending our neurourology department to undergo an urodynamic study because of LUTS. We included patients of both sexes, with and without neurological disease, meeting the following conditions: (1) urine infection free, (2) urethral catheterisation possible and not contraindicated, (3) no previous bladder enlargement surgery nor (4) bladder pathological anatomical conditions. Postvoid residual volume (PRV) was blind-measured with ultrasound by two experienced examiners, if any detected PRV >100 mL, the patient was then voided by catheterisation: 173 (39,2%) altogether. Outcomes were established by three groups (PVR 0-100 mL, 101-200 mL, >200 mL). Reliability was proved using intraclass correlation coefficient (ICC) with 95% confidence interval (CI) and Kappa index for each group whilst global agreement was performed with a Bland-Altman plot. Sensibility and specificity for each group with 95% CI and COR curves (with 100 and 200 mL as cut-off points) demonstrated validity analysis, taking catheterisation volume as gold standard. Finally, a linear regression (LR) formula could predict real PVR out of an ultrasound measure. RESULTS: Our sample includes 155 (35,2%) men and 286 (64,8%) women, neurogenic patients 146 (33,1%). Reliability; ICC: 0-100 mL =0,96 CI 95% (0,95-0,96), 101-200 mL =0,77 (0,63-0,86), >200 mL =0,79 (0,57-0,90). Kappa index (p<0,000): 0100 mL = 0,88, 101-200 mL =0,75, >200 mL =0,80. Echomeasures mean difference (Bland-Altman plot) =0,85 mL CI 95% (-1,77–3,49). Validity; sensibility and specificity group data are respectively 0-100 mL =96,1% CI 95% (91,1-100%) and 77,6% (68,7-87,6%), 101-200 mL =62,2% (46,9-77,5%) and 83,3% (76,4-90,2%), >200 mL =55,1% (40,1-70%) and 100% (99,5-100%). COR curve areas >100 mL 0,97 (0,95-0,99), >200 mL 0,95 (0,92-0,98). LR: Real PVR (mL) = 20,86 CI 95% (10,38-31,34) + 1,20 (1,13-1,27) * Ultrasound PVR (mL). R =0,93; R2 adjusted =0,88 (Anova p<0,000). CONCLUSIONS: Ultrasound is a reliable diagnostic test to quantify PVR given it's high reproducibility rate and interobserver agreement, it can ensure diagnosis given a positive PRV due to it's high specificity whereas may have considerable false negative results (low sensibility). Moreover ultrasound measurement of PVR may underestimate real PVR, high ones most, so the initial number of CIC needed in patients with substantial PVR shouldn’t be decided by ultrasound but by catheterisation.