Increasing diuresis rate in patients with Overactive Bladder symptom complex as a possible treatment

The average natural forced diuresis for patients (mean 6.90, SD 2.8 ml/min) is
significantly lower than the diuresis for volunteers (mean 12.1, SD 3.4 ml/min)
(p<0.001).This could mean that patients had a deficit in water household,
probably because their drinking behaviour was different from the healthy
volunteers. We know people with OABsc drink less than healthy volunteers
because drinking has been associated by the patients with need to go to the
toilet.
However we hypothesize that patients could get a development of bladder
sensations more similar to healthy volunteers when their diuresis velocity
increases. The clinical relevance of this hypothesis can be that we can help
patients with OABsc to make their urgency and intensity of sensations develop
different (e.g. more equal to healthy volunteers) and maybe get rid of a
component of their symptoms. This hypothesis will be the tested in our future
study.

1) Is the difference in diuresis between patients and volunteers caused by a
dept in water household in patients and if so can we increase the diuresis in
patients by correcting this?
2) Can we influence the pattern of bladder sensations by increasing the
diuresis in patients with OABsc?

We have to gain information about the baseline of sensation-development during
bladder filling for al the patients when diuresis is assumed to be *not
optimal*; this means a suspected diuresis rate lower than the diuresis in
healthy people. Afterwards we have to conduct information about the development
of the bladder sensations when diuresis rate has increased and approaches
diuresis rate of healthy volunteers. This will be done by organising 2
(group)sessions for all patients: session 1: normal intake; session 2: higher
intake. The principal investigator will be present during the sessions.
Before every session each subject will be asked to drink 1000 ml of water in
the hour before the session begins to establish a normal but elevated diuresis.
On arrival at the session the subject will be asked to void and continue
drinking a further 1000 ml through out the session (200 ml per 10 minutes).
This water load will facilitate urine production and bladder filling reaching a
capacity over approximately 1-2 hr period (numbers based on our preliminary
work).
During the normal intake session (about 1 hour) the patients are asked to
record their sensation and grade it every 10 minutes (see appendix1). Moreover
they are asked to fill in this sensation on an empty curve (appendix2) which we
developed during the focus-group study and with which we objectivised the
different shapes of curves between patients and healthy subjects. For each
subject the bladder capacity at maximum sensation will be determined by
measuring the urine volume voided at the end of the session. Afterwards we can
calculate the diuresis velocity during this first session.

No risks.
Patients may benefit because we hypothesise that their symptoms may alter en
decrease after drinking more and getting rid of their deficit in
waterhousehold.