An interventional study of Rectal Barostat Study and Fecoflowmetry in Constipation, sponsored by Mayo Clinic. Recruiting at 1 site in United States. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-21.
Sponsored by Mayo Clinic · Not applicable, Interventional, and Basic science
Researchers are trying to better understand why constipation occurs and improve the tests for diagnosing these conditions.
Study includes a screening visit and a study day. During the initial screening visit for this study, subjects will complete three (3) questionnaires about their bowel symptoms, overall health, and anxiety and depression. A blood sample (about 4 tablespoons) will be drawn to study the relationship between genes and certain bowel habits. Subjects will be asked to provide a single stool sample to look at the bacteria in the stool.
Before the study, subjects will receive 1 to 2 Fleet's enemas to clean the rectum. After receiving the Fleet's enema (administered through a small plastic tube in the rectum), a swab attached to a small rectal catheter will be used to brush the lining of the rectum and obtain a stool specimen. Then, rectal and anal pressures will be measured by placing a small catheter (plastic tube) in the rectum, and withdrawing it slowly. Rectal sensation will be measured by inflating a small balloon in the rectum.
There are 2 procedures (rectal barostat study and fecomanoflowmetry), each of which lasts approximately 90 minutes. During the rectal barostat study, contractions will be recorded with a balloon inserted into the rectum and inflated. After the barostat study is completed, your rectum will be filled with a small amount of paste. Two thin catheters will be inserted into the anus to measure pressures and electrical activity (electromyography or EMG). Then, you will be asked to sit on a commode, contract (squeeze) your anal muscles, blow into a balloon, and expel the paste into the commode.
1,046 studies on the registry are indexed under Constipation; 161 are open to participants now.
This study's planned enrollment of 160 is above the median of 75 across 884 interventional studies indexed under Constipation.
Browse Constipation studies →Mayo Clinic is the lead sponsor of 3,269 studies on the registry; 672 are open to participants now.
Of its 452 completed or terminated interventional studies of FDA-regulated products, 321 (71%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Sixty healthy individuals (20 men and 40 women) will undergo an anorectal study which comprises of a rectal barostat study followed by fecoflowmetry
Diagnostic Test: Rectal Barostat Study · Diagnostic Test: Fecoflowmetry
60 constipated individuals (20 men and 40 women) will undergo an anorectal study which comprises of a rectal barostat study followed by fecoflowmetry
Diagnostic Test: Rectal Barostat Study · Diagnostic Test: Fecoflowmetry
Contractions will be recorded with a balloon inserted into the rectum and inflated
Rectum will be filled with a small amount of paste.Two thin catheters will be inserted into the anus to measure pressures and electrical activity (electromyography or EMG). Subjects will be asked to sit on a commode, contract (squeeze) your anal muscles, blow into a balloon, and expel the paste into the commode.
Rectal emptying
Measured by fecomanoflowmetry calculating the mean and maximum flow rate in various conditions (mg/sec), defecated volume (mg), flow time (sec) and time to maximum flow (sec). The amount of artificial stool evacuated is expressed in milligrams. The duration is in seconds. These 2 metrics are integrated to measure mg evacuated/second.
Time frame: Baseline
Rectoanal pressures
Measured by anorectal manometry in mmHg
Time frame: Baseline
Anal sphincter electromyography (EMG)
Units - mV
Time frame: Baseline
Rectal compliance measured with a barostat
Pressure (mmHg) corresponding to half-maximum rectal volume during rectal distention
Time frame: Baseline
Rectal Capacity measured with a barostat
Rectal volume (ml) at maximum distending pressure during rectal distention
Time frame: Baseline
Rectal contractile response to distention measured with a sinusoidal oscillator
Rectal balloon is inflated to a preload volume of 125ml. The balloon is then oscillated around baseline volume by 25mL for 20 min at a frequency of 5 counts per minute (cpm). The mean rectal pressure (cm H2O) will be calculated over the multiple oscillation cycles within the 20 minute distention segment.
Time frame: Baseline
Rectal sensory threshold for first sensation to defecate using barostat balloon distention
The sensory threshold for first sensation to defecate is measured by stepwise inflation of the balloon (0-44 mm Hg, at 4 mm Hg increments). During this assessment participants are asked to report when they have the first sensation to defecate.
Time frame: Baseline
Rectal sensory threshold for desire to defecate using barostat balloon distention
The sensory threshold for desire to defecate is measured by stepwise inflation of the balloon (0-44 mm Hg, at 4 mm Hg increments). During this assessment participants are asked to report when they have the desire to defecate.
Time frame: Baseline
Rectal sensory threshold for maximum urgency during barostat balloon distention
The sensory threshold for maximum urgency to defecate is measured by stepwise inflation of the balloon (0-44 mm Hg, at 4 mm Hg increments). During this assessment participants are asked to report when they have the maximum urgency to defecate.
Time frame: Baseline
Rectal balloon expulsion time
During this test, the time (seconds) required to expel a water-filled rectal balloon (50 ml) will be compared between healthy people and patients
Time frame: Baseline
Started Jan 2019 (actual). Primary completion is estimated for Dec 2028, 119 months after the start.
Of 243 non-industry interventional studies with no phase under Constipation, half reached primary completion within 17 months of starting (the median), counting those still running; a quarter within 7 and three quarters within 35. This study's planned 119 months is above that.
Counting every sponsor, half of 314 studies reached it within 14 months; a quarter within 6 and three quarters within 30.
How these figures are worked out, and which studies are left out of them.
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