URIKA, continuous ultrasound monitoring of urinary bladder filling in patients with urinary retention

Urinary incontinence (UI) and urinary retention are relatively common. Urinary
retention after anaesthesia and surgery ranges between 5% and 70%.
In the previous study "URIKA, continuous ultrasound monitoring of urinary
bladder filling in children with dysfunctional voiding: a pilot study" (METC
nr: 15/050, NL51346.041.14) the URIKA bladder monitor is used for measuring the
bladder diameter in children with dysfunctional voiding. The study with
children is still ongoing.
Because we think that this bladder monitor could be an addition to the
monitoring of adult patients, this study was designed. In this study, the focus
lies on adults who suffer from postoperative urinary retention (POUR). Urinary
retention occurs when the patient is unable to empty or sufficiently empty the
bladder.
To increase the effectiveness of current clinical treatments, the URIKA device
is developed. The URIKA device is an ultrasound sensor which is capable of
measuring the distance between the anterior * and posterior wall of the
bladder. It can measure the filling status of the bladder and can inform the
patient when the bladder reaches its maximum capacity.

Primary Objective: Is the detection chance of the bladder influenced by the
angle in which the ultrasound sensor is fixated?
Secondary Objective Can the URIKA Bladder Monitor (UBM) be used to predict the
point where the BladderScan reaches the threshold of 600 ml?

In this observational study (time: 10 months), 30 adult patients that underwent
surgery with spinal anesthesia with the age of 18 years and up, will be
measured real-time with the URIKA bladder monitoring device every 30 seconds
(two times per minute) during their time on the recovery. The UBM will measure
under a specific angle (pointing downwards into the pelvis). Three angles are
used, therefore the group of 30 patients are divided into three groups:

* Patients 1-10 will be measured under an angulation of 10 degrees
* Patients 11-20 will be measured under an angulation of 20 degrees
* Patients 21-30 will be measured under an angulation of 30 degrees

The expected time frame of this study for the patients lies between 2-3 hours.
At the start of the study, a BladderScan will be made, to determine the bladder
volume. This scan is standard clinical care during observation at the recovery.
Every following half hour an extra BladderScan will be made, until the endpoint
of the study. The endpoint of the study is defined as the moment when the
patient is ready to leave the recovery.

The patient is subjected to an ultrasound monitoring session of 2-3 hours.
During this session the URIKA device will determine the urinary bladder
diameter. As a reference volume measurements with the BladderScan will be made.
There are no known risks associated with ultrasound monitoring or imaging when
the ultrasound intensity is limited according to the current Food an Drug
Administration regulations. The burden is relatively low for the patient.