Understanding Mechanisms of Normal and Disordered Defecation

Study Overview
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Brief Summary
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Researchers are trying to better understand why constipation occurs and improve the tests for diagnosing these conditions.

Detailed Description
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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.

Official Title
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Understanding Mechanisms of Normal and Disordered Defecation

Conditions
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Constipation

Intervention / Treatment
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* Diagnostic Test: Rectal Barostat Study
* Diagnostic Test: Fecoflowmetry


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria Male and female volunteers aged 18-80 years. Able to provide written informed consent before participating in the study. Able to communicate adequately with the investigator and to comply with the requirements for the entire study. Individuals with chronic constipation for 1 year, with 2 or more of the following symptoms for 3 months or longer: <3 bowel motions/week, straining ≥ 25% of time, hard or lumpy stools ≥ 25% of time, anal digitation ≥ 25% of time, incomplete evacuation ≥ 25% of time, feeling of anorectal blockage ≥ 25% of time. Able to provide written informed consent before participating in the study. Able to communicate adequately with the investigator and to comply with the requirements for the entire study. Exclusion Criteria Clinical evidence of significant cardiovascular, respiratory, renal, hepatic, gastrointestinal, hematological, neurological, psychiatric or other disease that may interfere with the objectives of the study and/or pose safety concerns. Current symptoms of a functional gastrointestinal disorder assessed by questionnaire. Putative risk factors for pelvic floor trauma: i.e. six or more vaginal deliveries, birthweight >4500gms (macrosomia), or known 3rd or 4th degree perineal tear. Medications that are likely to alter gastrointestinal motility: e.g., opiates and anticholinergic medications; a stable dose of thyroxine and low doses of tricyclic agents (e.g., up to amitriptyline (50 mg daily). Active rectal inflammation, cancer; perianal sepsis; history of pelvic radiation, rectosigmoid surgery or inflammatory bowel disease.* Anxiety or depression as assessed by the Hospital Anxiety and Depression Questionnaire. Pregnant women, prisoners and institutionalized individuals.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Healthy Individuals<br>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<br>* Contractions will be recorded with a balloon inserted into the rectum and inflated<br>Diagnostic Test: Fecoflowmetry<br>* 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.<br>|
| Active Comparator: Constipated Individuals<br>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<br>* Contractions will be recorded with a balloon inserted into the rectum and inflated<br>Diagnostic Test: Fecoflowmetry<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | Baseline | 
| Rectoanal pressures | Measured by anorectal manometry in mmHg | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Anal sphincter electromyography (EMG) | Units - mV | Baseline | 
| Rectal compliance measured with a barostat | Pressure (mmHg) corresponding to half-maximum rectal volume during rectal distention | Baseline | 
| Rectal Capacity measured with a barostat | Rectal volume (ml) at maximum distending pressure during rectal distention | 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. | 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. | 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. | 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. | 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 | Baseline |