GI Physiology

Please do not come to the hospital wearing or carrying valuables. You may be asked to change your clothing and given a cap to tuck all your hairs into. You may leave your belongings, your dentures, hearing aids, glasses and contact lens in a secure locker provided by us, the key of which will remain with you or your relation till you leave.

At first our nursing staff will review all your previous medical records. They will ask you the last time you had anything to eat or drink and if you have any allergies. They will ask about special needs or concerns. You will lie on a stretcher in the procedure room. Safety devices will be kept to keep you safe, comfortable and secure throughout your procedure. After the procedure you will have privacy to change and tidy up. Your esophageal manometry report will be made available as soon as possible, and you can discuss your findings with your doctor.

Food in the stomach may get inhaled into the lungs, thus we prefer to call patient fasting in the morning. If you are taking any medication daily on regular basis (like diabetes, blood pressure, heart ailments) please discuss the timing of the doses with your doctor.

Please remove your dentures before the procedure. If dislodged during the procedure they may accidentally come into your airway and obstruct your breathing. There is a very small risk of dental crowns or bridge work may be damaged.

All major hospitals have stringent protocols for sterilization, and we assure that all aseptic precautions are in place to prevent transmission of infection during the procedure.

INDICATIONS:

Evaluation of patients with hiatus hernia, for customizing decisions about continuing medical treatment and decisions about surgery.
Evaluation of non cardiac chest pain or oesophageal symptoms not diagnosed on
Evaluation of achalasia or another type of non obstructive dysphag
Evaluation of esophageal motility problems associated with systemic diseases.

The procedure could be challenging in the following situations::

Patient with altered mental status.
Known pharyngeal or upper esophageal obstruction (eg tumor).
Impaired hearing.

Please do not come to the hospital wearing or carrying valuables. You may be asked to change your clothing and given a cap to tuck all your hair into. You may leave your belongings, your dentures, hearing aids, glasses and contact lens in a secure locker provided by us, the key of which will remain with you or your relation till you leave.

At first our nursing staff will review all your previous medical records. They will ask you the last time you had anything to eat or drink and if you have any allergies. They will ask about special needs or concerns. You will lie on a stretcher in the procedure room. Safety devices will be kept to keep you safe, comfortable and secure throughout your procedure. After the procedure, you will have the privacy to change and tidy up. Your oesophagal manometry report will be made available as soon as possible, and you can discuss your findings with your doctor.

When you eat a meal, the digestion and passage of food from the stomach through 12 to 15 feet of small intestine is done rapidly in just 6-8 hours; after which, the residue reaches the large intestine (also called colon). The transit in the colon slows drastically, and may normally take up to 16 hours to cross the 3-4 feet to the anus. In severe constipation, the Transit time through the small intestine remains 6-8 hours. But if the Transit time in the colon is prolonged, and stools may stay in the colon sometimes even for 5-7 days. This is called “Slow Transit Constipation”. But sometimes, the colon may bring the stools to the bottom “on time”; but you may not pass them out if the anal sphincters do not obey your command to relax. This is called “Dyssynergic defecation”. The Colon Transit Time test helps differentiate between the types of constipation, as well as the severity; thus will help choose a treatment for you.

you really have Constipation at all;
if the entire colon is slow, or;
if the pelvic floor is not relaxing to your commands.

Typically the test could take 5 days, 1-2 days to empty the colon, 1 ½  days to take the markers, and 2 days for the X-rays. Here I am describing a Time Table that is conveniently over a weekend; (minus 48 hours (Friday) to plus 60 hours – (Tuesday).

You have been given 12 capsules for the test. Each capsule contains 5 markers, thus we are using 60 markers for your test. The markers are made with a special Medical Grade resin, which is inert; that is, will not react with any body fluid. The chemical composition is such that it will not harm you. The marker will pass down the colon with the same speed of digested food. Its shape is such that it will not be missed or confused with anything on an x-ray examination.

We look to see how many markers are seen left behind on both these X-rays, to decide what type of constipation you have. We need to actually count all markers seen on each x-ray plate, and look for the distribution in the colon. There are many interpretations to this exercise, but to put it in a few words; if the markers are seen “all over” it could mean the whole colon is slow. If the markers are clustered in the pelvis, you may not be able to relax your anal muscles in a coordinated fashion to allow normal defecation.

Two days before the procedure:  cleaning the colon

Many severely constipated patients have become comfortable (as well as used to) a strong laxative by the time they come for the test. Some of these laxatives are habit forming (especially the ayurvedic / traditional medicine type; like choornas, etc). We do not recommend the use of these on a regular basis. However, this is the best way to get your colon clean. Thus, two nights before the procedure, I am recommending you to take the laxative that you are used to ONLY THIS ONE TIME, just to help us!

Take Peglec in 2 liters water in the morning, the day before the procedure. Look carefully at the color of the last stools you pass. If the color of the last stool after the Colon Wash has the same color as the water you drank; this means you have passed all stools through the wash and the colon is now empty. But in case you are still passing fecal masses following Peglec solution, you may need to repeat the bowel cleansing on the morning of the procedure. Please call me if you still see yellow feces in the fluid you pass out in the last stools on Friday.

You are allowed to eat your normal diet throughout the 5 days of the procedure.

Day of starting the procedure, take the Transit Time Capsules:

You will take 4 capsules washed down with 1-2 full glasses of water each time, on

Day of the procedure night (Hour zero,                         4 capsules)
Next day morning 9 am (Hour zero +12,                 4 capsules)
Next day evening 9 pm (Hour zero+ 24,                                 4 capsules.

You will NOT take ANY laxative after you have taken the first capsule till ALL X-ray examinations are over!!!! (for 5 days at least).

The X-ray examination:

You will be doing the X-rays on a Digital X-ray machine at any X-ray Clinic of your convenience. Which Clinic you choose for the X-ray can be decided earlier with me. The test you will ask for at the X-ray Clinic is “Plain X-ray Abdomen with Pelvis Lying Down”.

Third day morning 9 am (Hour zero +36)
Fourth day morning 9 am (Hour zero + 60)

We will see both these X-rays on fourth day evening, if necessary, another X-ray may be needed on a later day if the Transit Time is too slow.

PRE PREPARATION FOR TEST  You need to fast for at least 4 hrs before the test; If u have test in morning do not eat or drink after midnight.

POST TEST:As you will not need sedation for this examination, you are free to eat whatever you wish immediately after the test, you may also leave for work immediately. You should receive the report in 10-20 minutes following the end of the test.

We have involuntary control through the day due to a competent anal sphincter. We do not need to pay attention to doing this. Even if we lift a bag, a full bucket, or cough, strain – we do not leak stools as the sphincter reflexly contracts.

We can hold back stools till it is socially acceptable to pass them. As stools arrive in the rectum, we may not even be aware. At a particular volume, we just become aware they have started filling, but our mind briefly registers this without getting distracted from the task at hand. With more stools, the sense of rectal distension is more constant, and we realize the need to look for a socially acceptable place to do the needful. If more time passes, your involuntary control is ‘letting go’ but you can efficiently hold back “voluntarily” ‘till you get there’.

Once your higher intellect decides it is ‘good to go’, the sphincter relaxes, with simultaneous contraction of the rectum, to quickly & reflexly evacuate the stools and be done. Inability to clear stools could be due to a poor effort to push, else an inability to relax the sphincter.

To analyse if we are pooping right, the steps will be

• How is my unconscious control?
• How much stool needs to arrive for me to just get to know?
• What is the volume to get a constant sensation?
• What volume will I just “have to go”?

When I do go, is the reflex quick to clear?

We eat two or three meals a day, the food travels down the gut, and digestion may be complete in 6 to 12 hours after each of those meals. Only the undigested residue reaches the colon, which absorbs the water to make formed stools. All formed stool is ultimately accommodated in the rectum, and we acquire a trained habit of passing stools; ritually on waking in the morning.

So, the “Team” of the rectum and anus are responsible to “receive & store” stools without distracting you; and “efficiently discharge” them at your habitual time. Anorectal manometry assesses whether this is happening correctly in your case.

To understand how this “Rectum-Anus Team” works, let’s split their work into parts:

Through the day the anus remains closed, without needing to pay attention to doing so. Even if we lift a bag or filled bucket, or cough or strain; we should not leak stools or gas.

In manometry, a catheter is passed into the rectum and this resting function is assessed.

The balloon at the tip of the catheter is serially inflated with increments of water. Smaller volumes may not be sensed at all. At a threshold volume, you will just feel “some stools have arrived”. This is the first sensation.

Rectal compliance: Henceforth, while receiving every increment of water in the distending balloon, the rectum senses a stretch; then distends to accommodate the volume. You will sense each distension, but given time; this will fade away and you will not feel an ‘urge to go’. At one volume of water, the sensation of rectal distension will not fade away. This volume is called ‘volume for constant sensation’.

Urge to evacuate: further distension may lead to the step where you may feel, that if the balloon is not deflated, it may pass out on its own. This stage is the complete capacity of the rectum. The balloon is then deflated completely.

Passing stools: the rectal balloon will contain 50 ml of warm water, and you will be asked to evacuate the balloon, ‘like passing stools’. Normally, you will be able to expel the balloon within 60 seconds. We understand you are doing this in a lying down position, you are not in the privacy of your own toilet, and have medical personnel around you. All of us will be supportive and would help you focus on the test.

In case you find it difficult to pass the balloon out of the rectum, we will identify the reason and will help you complete the test.

It seems you have been suffering from “Acid Peptic” symptoms for some time. Typically, these are described as“heartburn” – a burning pain behind the breastbone that comes after meals (or some trigger food in the meals), or if you lie down after a meal. This happens because the acid in the stomach actually does come into the food pipe (oesophagus). Over the last 2 to 3 decades, Medicine has progressed to a point where most persons can get permanent relief with a short course of tablets.

However, this may unfortunately not happen all the time.

You may be having typical “acid peptic” symptoms, and; in spite of optimum medication as well as lifestyle modifications, your symptoms may continue to hamper your living to an extent that you cannot go off medication, or you may be considered better off with surgery. Before this life-changing decision, your doctor may consider proving that acid is actually getting into your oesophagus and staying there long enough to cause damage; in spite of all the treatment.
On the other hand, the acid in the oesophagus may be felt like an atypical symptom like sour fluid coming into the throat, diffuse chest pain not always after meals, choking/wheezing and hoarseness, etc. These atypical symptoms often respond to standard treatment as reflux too. You possibly have been using a medication, either “on-demand” or after doctor’s orders; and you have not been completely relieved of your symptoms. Now, your doctor is not sure if all the symptoms are due to acid reflux.
You may be reporting acid-peptic symptoms, respond to standard therapy, but your endoscopy may not reveal acid-related injury to the oesophagus. Doctors often label this as NERD (non-erosive reflux disease). If you fail to go off therapy, the presence of acid in the oesophagus will need to be proved.

Thus, you have been advised a test called “24 hour pH metre”; a test that is meant to detect, and quantifies a reflux event and correlates it to a “symptom event” during a study period.

Fine catheters have been made that are passed through the nose and the lowermost tip is placed 5 cm above the GE junction (the junction between the food pipe and the stomach). This has a sensor that detects a change in the pH to acid. Some catheters have 2 sensors; the lowermost is placed as usual above the GE junction, and a higher sensor is placed close to the throat to detect how high the acid rose. A “Bravo” capsule is a ‘wireless’ method of achieving the same purpose. This capsule is clipped inside the oesophagus 5 cm above the GE junction, and it remotely sends information to a detector outside the body. A recent innovation is MII-pH metry (Multichannel intraluminal impedance) which can detect acid as well as non-acid reflux into the oesophagus.

24 hour pH metry is done for 2 purposes.

Off treatment, it is done to find out if you have reflux of acid at all.
On treatment, it is done to find out whether the treatment has really suppressed the acid, and what the reasons are, that you still complain of acid reflux.

In case your test is being done to diagnose acid reflux, I may choose to stop mediation, and allow your natural acid to form normally.

PPIs such as Omeprazole / Pantoprazole will be discontinued 2 weeks before the test.
H2 blockers (Ranitidine / Famotidine) as well as promotility drugs (like Metoclopramide –Reglan, Perinorm; Itopride – Ganaton, Domperidone – Domstal, Motilium M will be stopped the day before the test. You may use 2 tablespoons of Liq Gelucil as frequently as every 4 hourly. Another option is Sy Gaviscon 2 tablespoons just after every meal.
Even these antacids should not be taken on the morning of the test (thus, no medication since midnight prior to the test).

In case your 24 hour pH metry is being done to know why treatment is failing, or; what is the cause of symptoms while on treatment, I may ask you not to stop any of the treatment that is acid suppression related before, on the day of the test, as well as after the test.

You may use the guidance of the doctor for any other medication you are concurrently using.

Before coming for the test, try giving your symptoms a name that will best describe them. When you come for the test, the doctor will ask you which symptom bothers you the most is, and key this in as “Number 1”. Usually, patients have up to 3 symptoms that commonly describe their reflux; these will be ranked 2 and 3. More symptoms can also be accommodated. The following is a list of symptoms patients use to describe reflux, but they have minor differences in cause or management:

• Heartburn burning sensation in the midline behind the breast bone.
• Regurgitation is a feeling of a sour-tasting fluid flowing up to the throat
• Chest pain is diffuse pain over the chest
• Laryngospasm is a sense of choking of breath
• Wheeze a spasm restricting breathing, audible breathing
• Globus is a sense of something stuck in the throat
• In case there is any other way to describe the symptom, feel free to do so.

On the day of the test, you will be called fasting (at least 6 hours). Have a bath before you come in, as you will not be able to bathe till the test is over. You will need to stay in the hospital for 24 hours, thus you will go home the next morning.

A Manometry is first done to locate the position of the GE junction. The pH catheter probe will be then passed through the nose; following which you will go back to your room.

A fine catheter called the “sensor” is passed through the nose; this detects the pH in your food pipe. It will be taped to your cheek on one side, so it does not interfere with eating. It is connected to a “Recorder” that contains a “Memory Card” where all data is being stored. The Recorder is given to you in a “Carrying Case”, which helps you safely carry with you over your shoulder or on your belt all the time. After the procedure is done, the ‘Memory card’ is removed from the recorder, and inserted into a Computer where software generates the information as well as the report.

The pH sensing catheter is a single-use catheter; any damage to it will mean we will need to buy another catheter for you. The junction of the catheter into its socket is secure. Any displacement will not set off an alarm, but the device will have stopped receiving signals from the probe. So, do be careful with it.

Obviously, you are not allowed to open the Recorder, or the battery. The Recorder is not water proof (no showers / tub baths), and will get damaged if it falls. You may wear it under your clothes if it will keep it safe; but it should be accessible to key-in events. We advise the Recorder to be in a Back-pack when used in children; so they do not use it like an X-Box game; but will be accessible to a parent / guardian for keying in events.

While in bed, do not keep the carrying case around your neck. It is not to be kept in temperatures outside the 0 – 40oC (32 – 104 oF) range.

If you are wandering about in the hospital, do not go near the X-ray or MRI departments, or through a metal detector. Persons with implanted devices (pacemakers, etc) should inform us in advance as we would need to assess the safety.

Patients with ‘special needs’, like children, visually handicapped, or those with cognitive impairment (find it difficult to follow instructions) should be assisted through their stay by an adult or a guardian.

As you are leaving the Procedure room, make sure you have understood the use of the buttons on the Recorder device. You will see that the screen is empty, thus is conserving the battery in standby mode.

Display: To light up the screen, push on the ‘display light’. Pushing any buttons firmly gives an audible ‘beep’ as feedback, and its function will be displayed on the screen. You need not keep pressing the button repeatedly.

Position: Your position (erect/supine) affects your tendency to reflux. Thus push the ‘Upright key’ when erect, and the ‘recumbent key’ when lying down. The software will be able to tell us how much & how long you reflux lying down. If you are awake through the day, remain erect. Unless you would wish to sleep – don’t stay on a recliner that is neither flat nor sitting. You are expected to spend the day as you normally do; do not assume you are a sick patient and lie down all the time.

Meals: Meals may contain acidic food; we don’t want that to confound the readings. You should key in ‘Begin meal’ when you start a meal; and ‘End meal’ when you finish. eat at least 2 meals at your normal times; prefer the food you know will cause symptoms (provoke symptoms, but don’t overdo it; needing to treat you during the test is a lost cause!). Avoid snacking, sucking on sweets, and chewing gum during the test; it will mess with the results.

Acid related symptoms: There are 3 other keys numbered 1, 2, 3. These keys are to be used to tell the recorder when you are having symptoms. The keys will be programmed by the doctor; he will tell you which number key is to be used for which symptom. It may happen that only 2 keys have been programmed for use. Pressing key number 3 will still produce a beep, but no event will be recorded. On the other hand, you may wish to track more than 3 symptoms. The doctor will then program the most important 3 to designated keys; for other symptoms, you will push the ‘Diary key’, note the time as shown on the Recorder device at that time; and note the symptom you wished to report.

Alarms: The battery in the device usually will last through the procedure. But if it gives an alarm for “Low Battery”, inform the nurse. A designated person/nurse with put the device on standby (press ‘light’ + ‘Event1 / Enter’; and press ‘V to stop recording). After a fresh battery has been inserted, the device will automatically initiate startup but will need to be turned on.

The morning after:

Please have your breakfast as usual in the morning. You may brush your teeth and use mouthwash. The taped catheter to your cheek may make it difficult if you wish to shave. You may have your bath only after the assembly has been removed. This will be done after at least 22 hours after insertion.

What does the report of 24 hour pH metry tell me?

Acid injury to the food pipe can occur when the pH drops below 4. The continuous recording will measure 6 parameters;

How many minutes was the pH in your esophagus below 4?
How many fractions of this was in the upright position, how much lying down?
How many episodes of reflux did you have in 24 hours?
How many of these were longer than 5 minutes?
How many minutes was the longest episode of reflux?

From these 6 parameters, a Composite Reflux score (or, DeMeester score) is calculated which is a global measure for comparison and standardization. A score over 14.72 indicates significant reflux. A high DeMeester score may change your treatment plan in favour of surgery; it may also be used to show your reflux has reduced after surgery.