Tetra-NIRS Clinical Study

The purpose of this evaluation is to validate the previous clinical study results using a Near-Infrared Spectroscopy (NIRS) device, as compared to the conventional urodynamics (UDS) testing. The experiment will use the commercially available Tetra-NIRS and Laborie UDS equipment. The hypothesis is that the Tetra-NIRS device, in the clinical environment, provides data to enhance the analysis using the standard urodynamics equipment (stand-alone Urodynamic procedure).

This is a study of the commercially available Tetra-NIRS device to compare the results collected against conventional urodynamics. The study will evaluate male patients with lower urinary tract symptoms (LUTS) as well as female subjects with over-active bladder (OAB). The Tetra-NIRS unit uses near infrared light at 3 different wavelengths to measure changes in haemoglobin and cytochrome from the detrusor muscle from the human bladder wall. This process is similar to what is used for cerebral and muscle oxygenation monitoring (e.g., pulse oximetry). Previous clinical feasibility studies have identified the correlation between the changes in haemoglobin and cytochrome of the bladder, and bladder pressure values obtained during urodynamics procedures and uroflow procedures. For this study the Tetra-NIRS results will not be used by the urologist/nurse to guide in patient management and treatment decisions, but rather will only be used to collect measurements from the patient for the purposes of this study. The Tetra-NIRS sensor patch will be adhered externally to the skin surface where the bladder is located. For this study, a minimum of 30 male subjects with LUTS and 30 female subjects with OAB scheduled to undergo a urodynamics procedure are to be enrolled. Up to 20 female subjects with OAB will be enrolled. The investigators will attempt to equally enrol male subjects into each of the two categories including obstructed and non-obstructed groups according to prostate hyperplasia (equivocal subjects will be determined by the investigator).

All patients were recruited to the same arm and receive Urodynamics testing as part of the routine diagnostic work-up, plus the Tetra-NIRS intervention.

Urodynamics will be performed as per standard of care for patients enrolled, whereby one catheter is inserted into the bladder and one in the rectum to analyze bladder filling, storage and voiding conditions via pressures measured and urine flow rates detected by a uroflowmeter. Tetra-NIRS will be concurrently performed where Tetra-NIRS unit uses near infrared light at 3 different wavelengths to measure changes in haemoglobin and cytochrome. A patch is applied externally to measure these changes in the detrusor muscle of the human bladder wall. This process is similar to what is used for cerebral and muscle oxygenation monitoring (e.g., pulse oximetry). Previous clinical feasibility studies have identified a correlation between the changes in haemoglobin and cytochrome and the pressure values obtained during urodynamics procedures.

Number of Participants With Urodynamic Detrusor Overactivity Events or Prostatic Obstruction as Detected by Tetra-NIRS Compared to Urodynamics

The Tetra-NIRS device provides a linear pattern similar to the pressures obtained during urodynamics. The NIRS output shows relative change in hemoglobin concentrations (oxygenated and deoxygenated) where the numerical value does not actually indicate the concentration, so there is no unit of measure. The numerical output is used to track change over time, or trendline analysis. A qualified interpreter studied tracings for significant changes (+/-2 Hb units) in the NIRS patterning during detrusor overactivity events. As well, under its' approved intended use, Tetra-NIRS trendline analysis was compared against urodynamics during voiding in males, such that a downward trend during voiding indicates urethral obstruction, and an upward trend indicates an unobstructed urethra.

Inclusion Criteria: The selection of subjects enrolled for testing must meet the following criteria: Subjects must be 18 years of age or older. Subjects are patients of one of the institutions and are currently scheduled for UDS Male subjects must have LUTS Female subjects must have OAB Subjects must give their informed consent prior to enrolment. Exclusion Criteria: The patient has an existing health condition which the investigators feel will not allow for safe or accurate measurements with the Tetra-NIRS device.

Mastoroudes H, Giarenis I, Vella M, Srikrishna S, Robinson D, Cardozo L, Karrouze I, Campbell A, Macnab A. Use of near infrared spectroscopy as an alternative to videourodynamics to detect detrusor overactivity in women with the overactive bladder syndrome. Urology. 2012 Sep;80(3):547-50. doi: 10.1016/j.urology.2012.05.036. Epub 2012 Jul 26.