Short Protocol Barostat for Assessment of Anorectal Function Versus Standard Protocol Barostat in Healthy Volunteers

• Assessment of anorectal perception thresholds with short protocol barostat in healthy volunteers [ Time Frame: during hospital stay, estmated 0.5 days ] [ Designated as safety issue: No ]
  

• anorectal perception thresholds in % in relation to rectal capacity assessed in ml [ Time Frame: at time of hospital stay approx 0.5 days ] [ Designated as safety issue: No ]

  Comparison of anorectal perception thresholds and rectal capacity with the simplified barostat protocol with:

  1. the anorectal perception thresholds and rectal capacity in accordance with the standard protocol
  2. the pressure of the anal sphincter and the length at rest and during voluntary contraction,
  3. the length and the morphological integrity of the anal sphincter detected by ultrasound
  
  

Device: anorectal manometry
High-resolution anorectal manometry is done under standard clinical conditions with a 10 cm catheter inserted into the rectum loaded with pressure transducers at a distance of 6 mm in the sphincter area and an attached latex balloon at the catheter tip. It will measure the length of the anal sphincter, the static pressure and the clamping pressure during at least 3 over 40 seconds sustained maneuvers according to a standardized protocol. Mean and maximum pressure increase over the resting pressure during the first 30 seconds of the squeeze and the maximum possible squeeze time will be documented. Moreover, the initial anorectal perception threshold, the perception of urge to defecate and maximum tolerable volume balloon will be documented.
Other Name: AHRM
Device: barostat
For the barostat study a balloon will be attached to the catheter. Instead of a barostat machine a 60ml syringe and a sphygmomanometer will be connected to the catheter and the catheter will be positioned in the rectum. The balloon is then dilated gradually to assess perception, urge and discomfort threshold in relation to rectal volume.
Other Name: barostat

For a coordinated anorectal function in addition to the anal sphincter the perception of rectal distension (visceral perception) and elasticity / compliance of the anorectum and stool consistency is important. A disturbed anorectal function may lead to functional defecation disorders or incontinence.

The currently available methods for measuring physiological assessment of anorectal function mostly focus on measurement of sphincter pressures, but generally provide no complete explanation for the underlying pathophysiology of defecation disorders. By voluntary contraction of the striated muscles of the external anal sphincter and puborectalis muscle defecation can be further delayed. In addition, however, other continence mechanisms play an important role.

The Group for the Study of functional gastrointestinal disorders at the Clinic for Gastroenterology at the University Hospital of Zurich has a great expertise in the establishment of new research methods such as the already in routine clinical practice used high-resolution anorectal manometry and has conducted numerous studies with anorectal Barostat. To use the results of Barostat also in everyday clinical practice in patients with defecation disorders this technique means significant simplification of the instrumental methodology and shortening of the work described in the literature. Before the simplified barostat can be used with the shortened protocol in different patient groups and clinical practice, it generally requires the validation of the technique in healthy subjects to define the range of normal values.