FEMALE UROLOGY

Does post-voiding residual volume get less as mobility improves in a rehabilitation ward for older adults?
Weatherall M
Neurourol Urodyn. 2002; 21:132-5

• Impaired bladder emptying is common in frail older adults. This study tests the hypothesis that more complete bladder emptying is associated with better mobility in a rehabilitation ward for older adults. Consecutive admission to a rehabilitation ward for older adults were considered for inclusion in the study in the week after admission to the ward. Exclusion criteria were cognitive impairment such that consent could not be obtained, non-English speaking, or presence of an indwelling urinary catheter. A post-voiding residual (PVR) bladder volume and Rivermead Mobility Index (RMI) were completed for subjects who gave consent, on a weekly basis until discharge. The BladderScan BVI 3000 Diagnostic Ultrasound, instrument was used. Statistical analysis was by a general linear mixed model. In the study period, 114 people were admitted and 57 approached for consent. Twenty-four people gave consent. Fifty percent of participants had a least one PVR greater than 100mL. One person was found to be in urinary retention, with a PVR of greater than 700mL, and was excluded from further analysis. The PVR increased by 1.2mL (95% CI – 4.6 to 7) for each unit improvement in the RMI. This study suggests that PVR does not decline with improvement in mobility in older adults receiving inpatient rehabilitation.
  Editorial Comment
  The author reviews the effect of mobility on post-void residual bladder volume measurement. This study is completed by assessing serial post-void residual measurements as the same time as the Rivermead Mobility Index (RMI) determination. The patients investigated had a weekly bladder scan – with the first scan being within one week of admission –, and this was performed until the patient was discharged from the rehabilitation ward. All scans were performed within half an hour after voiding, and all scans were performed in the supine position. The RMI was completed by patient interview and observation of the ability to stand unsupported for 10 seconds.
  This study is valuable, for it found that there was no substantial relationship between mobility and residual. The report is well written, and the discussion section does an excellent job of self-analysis and critique. An insightful commentary is made about the natural tendency to associate poor mobility with poor bladder emptying and incontinence in frail, older adults. It was surprising to find that there was no correlation between increasing mobility and diminishing post void residual. The study author does point out that due to exclusionary factors in patients agreeing to participate in this study, only 20% of the admissions to the rehabilitation ward were included. In addition, as pointed out by the author, the exclusion criteria of poor mentation and presence of a urethral catheter on admission may have led to a significant selection bias. Of note, the author did point out that a substantial portion of participants had a least one post void residual >100cc.
  During this current era, when it appears that the average patient age is increasing, it is an important fact that perhaps increasing mobility does not diminish post void residual and voiding efficiency. This observation may help guide us to perhaps not be as dismissive of an elevated residual in an elderly female as be secondary to immobility, and spur us to look for other addressable problems of this elevated residual, such as detrusor failure or anatomic causation. It is hopeful that the author in the future will look at the association of mobility and catheter dependent urinary retention in the elderly female population residing in the rehabilitation ward.

Dr. Steven P. Petrou
Associate Professor of Urology
Mayo Medical School
Jacksonville, Florida, USA