What is Endoscopy? Endoscopy is a medical procedure that enables a doctor to view different parts of the body using an endoscope. An endoscope is a long flexible tube that has a light source, camera, and different channels that allow air, water, and instruments to be passed through it. The endoscope is usually passed through a natural opening of the body such as the mouth, anus, nose, vagina and urethra. There are several different types of endoscope which include: Colonoscope: Gastroscope: Duodenoscope: Bronchoscope: Cystoscope: Hysteroscope: Laryngoscope: Inserted at the anus and views the large bowel. Inserted via the mouth and used to view the oesophagus, Stomach, and the first part of the duodenum. This scope is inserted via the mouth and is passed through to the duodenum via the oesophagus and the stomach and used to view and perform procedures on the bile duct and/or the pancreatic duct. This procedure is known as Endoscopic Retrograde Cholangio-Pancreatogram (ERCP). Also inserted via the mouth and passes through the trachea to observe the lungs. This scope is passed into the bladder via the urethra and to view the bladder and ureters. This scope is passed through the cervix via the vagina and is used to examine the uterus. This scope is passed through the nose into the throat and is used to view the larynx. At Chermside Day Hospital we use the colonoscope and the gastroscope for gastrointestinal endoscopy and the cystoscope for flexible cystoscopy.
Upper Gastrointestinal Endoscopy Upper Gastrointestinal Endoscopy is a procedure used to view the oesophagus, stomach and the duodenum. It is also known as an endoscopy (endo), gastroscopy (Gas), oesophagogastroduodenoscopy (OGD), or a panendoscopy (PES). A patient may be referred for an upper gastrointestinal endoscopy when a doctor determines there is a need to investigate the cause of symptoms such as: o Abdominal pain o Heartburn / reflux o Nausea o Bloating o Vomiting o Anaemia o Chest pain o Difficulty swallowing o Unexplained weight loss
The Oesophagus The oesophagus is the muscular tube, approximately 25cm long, which runs in a reasonably straight line through the mediastinum of the thorax. It runs through the diaphragm at the oesophageal hiatus where it enters the abdominal cavity and joins the stomach at the cardiac orifice. The cardiac orifice is surrounded by the gastroesophageal or cardiac sphincter, which acts like a valve, and with the aid of the diaphragm is closed when food is not being swallowed. Gastroesophageal Reflux Reflux occurs when the chyme from stomach is regurgitated through the lower oesophageal sphincter into the oesophagus. The sphincter may spontaneously and temporarily relax one to two hours following a meal allowing the gastric contents to move back into the oesophagus. The acid regurgitated into the oesophagus is usually neutralised and cleared with in one to three minutes by the peristaltic action of the oesophagus and the tone of the lower oesophageal sphincter is reinstated. Reflux Oesophagitis Reflux Oesophagitis can result due to a combination of factors which create an inflammatory response. When at rest the lower oesophageal sphincter generally maintains an area of high pressure that prevents acids regurgitation. Those who develop reflux oesophagitis tend to have a lower pressure than normal and events that increase abdominal pressure, such as vomiting, coughing, lifting or bending can contribute to its development. Other factors such as disorders that delay gastric emptying, therefore increasing the length of time reflux can occur and increasing the acid content of the chyme; weak oesophageal peristalsis, which
allows refluxed chyme to remain in the oesophagus for longer periods than normal; and disorders that weaken the lower oesophageal sphincter such as pyloric strictures and hiatal hernias can contribute to the development of reflux oesophagitis. (http://www.patient.co.uk/doctor/gastro-oesophageal-reflux-disease) Hiatal Hernia An Hiatal Hernia is a structural abnormality whereby the upper part of the stomach protrudes (herniates) through the diaphragm and into the thorax. As the diaphragm is no longer supporting the lower oesophageal sphincter gastric contents may move into the oesophagus causing oesophagitis and/ or oesophageal ulceration. There are two types of Hiatal hernia: Sliding Hiatal Hernia occurs when the stomach slides through the oesophageal hiatus into the thoracic cavity. Paraoesophageal hiatal hernia the greater curvature of the stomach herniates through a second opening in the diaphragm and lies next to the oesophagus. Barretts oesophagus The actual cause of Barretts oesophagus is not known however it is found more in those that have long standing gastro oesophageal reflux disease. Persistent reflux, over time, causes the normally pinkish white squamous cells of the oesophagus to change into red columnar cells which are similar to those that line the stomach. Barretts oesophagus is a risk factor for cancer therefore when it is seen or suspected the gastroenterologist may take lots of biopsies to confirm diagnosis and to check for dysplasia. Barretts dysplasia can be difficult for the gastroenterologist to visualize. Therefore the nurse may be asked to draw up an acetic acid solution that the gastroenterologist will flush down the gastroscope and over the required area. This is known as acetic acid chromoendoscopy and enables the gastroenterologist to visualise dysplastic areas and perform targeted biopsies.
This picture shows a normal Z line. The Z line is where the squamous epithelial cells of the oesophagus change into columnar gastric epithelium. (http://mmspf.msdonline.com.br/ebooks/headnecksurgeryot olaryngology/sid1401404.html) Barretts oesophagus showing the long segments of changed epithelium. (http://www.barrettsadvice.com/?p=5) Other lesions of the oesophagus include: Schatski s ring (constriction resulting from mucosal hyperplasia of the gastroesophageal junction Mallory Weiss tear which is a tear of the mucous membrane in the distal oesophagus or the proximal stomach. It is generally caused by forceful vomiting or coughing and can also be caused by epileptic convulsions. Eosinophillic Oesophagitis is an allergic inflammatory condition of the oesophagus whereby eosinophils, which are not normally present in the oesophagus of healthy individuals, infiltrate the oesophagus and can contribute to chronic inflammation and tissue damage. Oesophageal Ulcers Oesophageal varices are dilated sub mucosal veins that occur due to portal hypertension often as a consequence of cirrhosis of the liver. Oesophageal varices can cause a major medical emergency when bleeding. Oesophageal Dilatation Oesophageal dilatation is a procedure whereby the gastroenterologist uses a dilator to stretch (or dilate) the oesophagus. Dilatation may be carried out to
reduce symptoms caused by strictures (can be caused by reflux), scarring (i.e. after cancer treatments), or for motility disorders. There are several different types of dilators that are available to the doctors; balloon dilators, Maloney dilators or Savary-Gillard dilators. The dilator most commonly used in CDH is the Savary-Gillard dilatory which is a bougie that is passed into the oesophagus over a guidewire. The doctor first takes a look at the at the area to be dilated with the endoscope. There are different sized bougies at CDH available to the doctor. The Doctor will chose the appropriate sized dilator and will place the guide wire through the endoscope. The Endoscope will then be removed with the nurse carefully holding the guidewire in place. The bougie is then lubricated and placed into the oesophagus via the guidewire by the doctor. Dilators need to be sterilised before use so the nursing staff need to ensure cleaning room staff are aware that there are dilatations on the list. Savary-Gillard Dilators (http://www.wjgnet.com/2150-5349/full/v2/i6/46.htm) The Stomach The stomach has four major parts the cardia, fundus, body and the pylorus. It acts as a mixing area and a holding reservoir for food and will vary in size throughout the day as when empty it can have the volume of approximately 50mls but when full and really distended can hold up to 4 L of food. The stomach experiences some of the most unforgiving conditions of the entire digestive tract as gastric juices are corrosively acidic and without an intact mucosal barrier these juices will digest the stomach itself. Helicobactor Pylori Helicobactor Pylor is a spiral shaped bacterium that infects up to 90% of people in developing countries and approximately 40% of Australians over the age of 60. It more common in certain ethnic groups such as Middle Eastern, Asian and eastern European. It affects both men and women equally and may be asymptomatic but can also cause symptoms such as burping, nausea and burning pain in the upper
abdomen. Up to 60% of stomach ulcers and at least 90% of duodenal ulcers are thought to be caused by Helicobactor infection. It is also associated with gastric cancer and lymphoma. The mode of transmission is unclear however it is thought to be transmitted via the fecal-oral route or oral-oral route. Helicobactor pylori causes inflammation in the lining of the stomach which causes the mucous barrier to be disrupted and may also cause an increase in the amount of acid produced. This appears to allow the acid to cause inflammation and ulcers. Many of the doctors routinely biopsy for Helicobactor Pylori either by taking gastric biopsies and sending them to histology or by taking a gastric biopsy and placing the specimen in a Helicobactor urea tube (HUT test). The specimen is placed in the tube which contains an orange medium, presence of the Helicobactor will turn the medium pink. (http://medicaldiagnostics.net.au/products/hut-rapid-urease-test/) Helicobactor Pylori along with autoimmune conditions may cause chronic gastritis (inflammation of the stomach). Chronic gastritis tends to occur most often in elderly people and can cause thinning and degeneration of the stomach wall. There are two classifications of chronic gastritis, type A (fundal) and type B (antral) with Chronic fundal gastritis (atrophic gastritis) being the most severe type. Alcohol, medications (aspirin and NSAIDS, infections and some allergic conditions are associated with acute gastritis. Erosions associated with acute gastritis are generally superficial and resuts as an injury to the protective mucosal barrier. If the stomach appears to be inflamed the gastroenterologist may do gastric biopsies as well as a HUT test. The Small Bowel
The small bowel is where digestion is completed and almost all absorption occurs. It is a convoluted tube that starts at the pyloric sphincter and ends at the ileocecal valve. It is divided into three parts, the duodenum, jejunum and ileum, however only the first and second parts of the duodenum are routinely viewed and biopsied during upper gastrointestinal endoscopy at Chermside Day Hospital. Villi are visible once inside the small bowel. These finger like projections increase the surface area of the small bowel and therefore greatly increase its absorptive capabilities. Coeliac Disease People with Coeliac Disease have an abnormal immune reaction to gluten, a protein found in wheat, barley, rye and oats. This reaction causes the villi lining the small bowel to become inflamed and flattened (known as villous atrophy). Therefore absorption can be greatly decreased and there may be symptoms such as weakness and fatigue, iron deficient anaemia and/or other vitamin and mineral deficiencies, failure to thrive in children or delayed puberty, recurrent mouth ulcers and altered mental alertness and irritability. Gastrointestinal symptoms such as nausea, constipation, diarrhoea, vomiting, flatulence, cramping and bloating, steatorrhea and abdominal pain may also be present. Small bowel histology may be taken to confirm diagnosis of Coeliac Disease. Small bowel mucosa in a patient with Coeliac Disease (http://www.kolumbus.fi/hans/gastrolab/e009.htm) Lactase deficiency Lactase deficiency prevents the breakdown of lactose (milk sugar) into monosaccharides hence preventing lactose digestion and absorption across the intestinal wall. There is a deficiency of disaccharidase in the micro villi caused by a genetic defect in which lactase is generally lacking. This deficiency does not usually develop until adulthood and is most common in certain ethnic groups such as Africans, Latinos, and Native Americans. Gluten-sensitive enteropathy (Coeliac disease), enteritis, and bacterial overgrowth can also cause secondary (acquired) lactase deficiency.
Biopsies are regularly taken at CDH to test for Lactase deficiency. This biopsy must be taken first, before the biopsy forceps have come into contact with formalin. The Specimen is a fresh specimen and is wrapped in foil and placed in an empty specimen container. The specimen is then labelled and stored in the freezer (next to the drug cupboard) until the appropriate pathology company collects it. A laminated card indicated a disaccharidase biopsy has been taken must then be placed in the specimen bag to indicate a specimen is in the freezer awaiting collection. Small bowel biopsies may also be taken to look for causes of malabsorption, inflammation, diarrhoea and other indications. It is beneficial to always look at the patient s referral before the procedure so you get an idea as to why the procedure is taking place and the biopsies that may need to be performed. If you unsure as to why a biopsy is being performed it is fine to ask doctors or other staff to improve your understanding. BIOPSY FORCEPS All the Biopsy forceps used at CDH are cold which means they cannot be used with diathermy. All the biopsy forceps are disposable and are thrown away after the conclusion of each procedure. We currently have three types of biopsy forceps that enable the doctors to take different sized bites of tissue. Please familiarise yourself with the different types of biopsy forceps and where they are located. Colonoscopy Colonoscopy is a procedure where a colonoscope is used to view the large bowel and the last part of the ileum (terminal ileum). Some of the reasons a patient may be referred for colonoscopy include symptoms such as diarrhoea (bloody, mucousy or normal), constipation, blood stained stools and abdominal pain. Previous polyps, a family history of polyps or polyposis or a family history of bowel cancer are also common reasons for referral. The large bowel is divided into sections, rectum, sigmoid, descending, transverse, ascending and the cecum. In the Cecum the ileocecal valve can then be intubated for access to the terminal ileum. Unlike the small bowel the large bowel contains
no villi for increased absorption with the mucosa consisting of simple columnar epithelium, lamina propria and muscularis mucosae. The absorptive cells in the epithelium primarily absorb water although small amounts of electrolytes and vitamins are also absorbed. The wall of the right side of the colon is much thinner than that of the left and this has to be considered when removing polyps from the right side of the colon. (http://www.acm.uiuc.edu/sigbio/project/digestive/late/lg_intestine.html) Diverticular Disease Diverticula are small pouches that occur in the wall of the colon in places where the muscularis has weakened. Diverticula are very common and many people that have diverticula are unaware they have them until they have a colonoscopy however some experience symptoms when the diverticula develop inflammation. This is known as diverticulitis and it can cause fever, abdominal pain, distension, nausea and vomiting.it may also lead to perforation, peritonitis and bleeding. A paediatric colonoscope may be required if the patient is known to have diverticular disease. If diverticulitis becomes a recurring problem the patient may require surgery. Inflammatory Bowel Disease
ULCERATIVE COLITIS Ulcerative Colitis is a chronic inflammatory disease that can occur anywhere in the large bowel. Inflammation generally occurs in the rectum and sigmoid colon however it is possible for the entire large colon to be affected. Initial lesions may occur in those susceptible between 20 and 40 years of age with tiny ulcers appearing on the surface of the mucosa, which may bleed. The intestine produces more mucous than normal, which may contain pus, and Inflammation present in the bowel reduces its ability to reabsorb water from the faeces leading to diarrhoea. Complications can include deep ulceration, perforation and fulminant colitis / toxic megacolon (partial or full shut down of normal colonic contractions). CROHN S DISEASE Crohn s disease can occur anywhere from the mouth to the anus, however it commonly affects the small bowel and the colon; the rectum is seldom involved. Crohn s disease can be patchy with large areas of normal tissue in between diseased areas called skip lesions. All layers of the intestinal wall maybe affected therefore complications such as strictures, abscesses, fistulas and fissures may ensue. Polyps A colonic polyp is extra tissue that grows from the surface of the large bowel. The polyps can vary in size and shape, ranging from flat polyps that are difficult to distinguish on the surface of the bowel to big mushroom shaped polyps on stalks. Polyps are often benign (hyperplastic polyps) but there are certain types of polyps (tubular adenomas and sessile serrated adenomas) that can become cancerous if they are left in the bowel. Polyps may be asymptomatic or there may be symptoms such as blood mixed in with the stool on defecation, constipation and diarrhoea. There are also polyposis syndromes, which are a group of hereditary syndromes such as familial adenomatous polyposis (FAP), hereditary nonpolyposis colorectal cancer (HNPCC) and hyperplastic polyposis. Depending on the type of polyp and its location it may be removed and sent to pathology so the type of polyp can be determined. Sometimes polyps can be of mixed tissue type meaning sometimes hyperplastic polyps will contain adenomas. Removal of a polyp generally involves the use of a snare, possibly diathermy (hot), and a polyp trap in order to capture the polyp and send it away to pathology. SNARES There are many different types of snares on the market. They come in different shapes and sizes and can have different features. At CDH we keep oval and hexagonal snares made by different companies. They come in different sizes ranging from 10mm up to 27mm. Different snares are good for different types of polyps. The doctor may have preferences for different types of snares, which will be recorded on their preference sheet. It is important that you familiarise yourself with the different types of snares kept at Chermside Day Hospital. It is also prudent
to ask the doctor what snare he or she would prefer for that particular polyp before you open the packet. Most of the snares at CDH are disposable and should be discarded after each procedure. Polyps may be snared with or without diathermy that is hot or cold. (http://en.academic.ru/dic.nsf/enwiki/11563896) (http://www.olympus.nl/medical/en/medical_systems/applications/gastroenterology_ 1/treatment_of_lesions/polypectomy hot_biopsy/polypectomy.html) INJECTORS Submucosal injection is often use to aid in the removal of large sessile serrated adenomas. Injecting a fluid into the submucosa from the margins of the polyp help to elevate the polyp and prevent perforation of the bowel. The polyp is
injected using a long sclerotherapy needle, which has been primed by the nurse before handing the needle over to the doctor. There are different types of fluid that may be used to lift the polyp and the main fluids used at CDH are Saline and Gelofusine. The doctor may request that these solutions are first mixed with methyl blue or indigo carmine, and may want adrenaline added if they think bleeding may be of concern. If a bag of Gelofusine is used to remember to label the bag with any additives that have been placed in it as well as the date and time it was prepared. Again, you should familiarise yourself with the doctors preferences at the start of the list and ask the doctor what he or she would like to use before priming the needle. Ensure the needle is retracted before handing it to the doctor and when it is removed from the scope. When the needle is placed in the working area, again ensure the needle is retracted and if there is a clip on the needle to prevent the needle from opening it should be placed back on at this stage. The sclerotherapy needle should be disposed of in the large sharps container. HAEMOSTASIS Bleeding is possible complication of both endoscopy and colonoscopy. Some people have risk factors we need to be aware of such as the use of blood thinning medications (e.g Warfarin, Plavix, etc) and blood clotting disorders such as factor V Leiden. Anaemia, or bleeding from the bowel are symptoms for which patients are referred therefore there are also occasions where we find the cause of bleeding, such as Watermelon stomach (Gastric Antral Vascular Ectasia) and we need to take measures to stop it. There are different mechanisms which can be used to achieve haemostasis. At CDH we primarily use clips, diathermy and occasionally Argon however it is important to understand that there are many products available on the market to prevent bleeding in the GI tract such as poly loops, sprays, gold probe and coag graspers, etc. Clips When a polyp, especially a stalked or large one, is removed there is always a chance of bleeding. This may be minimised with the use of diathermy however sometimes there is a need for other haemostasis mechanisms to be used. At CDH clips are the main mechanism used to prevent further bleeding in the patient. The clip may be applied before the procedure (on a stalked polyp) or after the procedure depending on the doctor s preference. The clip comes in a sheath, however some doctors prefer the sheath to be removed before the clip is handed to them so again ensure that you know the doctors preferences or ask what the doctor would prefer. If the clip is left in its sheath it should be advanced to the end of the sheath before handing it to the doctor. When in the endoscope it may be rotated if required by turning it in an anti clockwise direction. The Boston Scientific clips may be open and closed with out any detriment to the clip, however once the clip has been deployed it cannot be retrieved and reopened.
(http://www.bostonscientific.com /global-endoscopy/resolution-clip.html) (http://www.gastrohep.com/images/image.asp?id=1262 Argon Argon Plasma Coagulation is a non-contact thermal approach to haemostasis. Argon gas is used to deliver an evenly distributed field of energy by a probe held adjacent to the tissue. The patient has a diathermy plate applied and a high voltage spark is delivered to the tip of the probe, which ionizes the argon gas and delivers the energy with a tissue penetration of 2-3mm. The leads for Argon are kept in different places within the procedure room. Familiarise yourself with the Argon machine. There are directions for its use in the procedure room. Diathermy (ERBE) The diathermy machine has settings for both cutting and coagulation. These settings are set depending on the doctor s preferences. Before using the diathermy check with the doctor that the ERBE is on the required settings and the doctor has access to the foot pedal as well as having all the necessary equipment ready to go. At CDH most procedures performed using ERBE are monopolar therefore the procedure will require the placement of a grounding pad on the patient. Placement of the grounding pad is important as if it is improperly placed a burn to the patient may result. The pad should be placed over a well vascularised area and the nurse should ensure the entire plate has good contact with the skin. Placement where there is scar tissue, excessive hair, tattoos, plates, pins and artificial devices should be avoided. The energy will take the route of least resistance therefore the front of the grounding pad should face the area where the procedure will take place (e.g. the bowel) so the pad will pick up all signals from the device being and minimise the energy passing though any prosthetic devices and minimise the risk of burn. Any grounded object can complete the circuit. Ensure the area under the patient is dry and the patient has no metal jewellery in contact with metal on the bed, ideally jewellery should be removed. Once the device used (e.g. snare) is no longer required, disconnect the active cord from the device until it is required again. Endoscopes Chermside Day Hospital currently uses the Pentax i10 series of gastroscopes and Colonoscopes. It is important that you understand the workings of these scopes. Diagrams and manuals can be found in the cleaning room. There are also stringent
guidelines that govern how the scopes are cleaned, how long they can hang in the cupboard for and what equipment needs to be changed between lists. This information can again be found in the cleaning room in the infection Control in Endoscopy, 3 rd Edition. Useful resources The Dave Project Boston Scientific Endoscopy Channel You Tube GENCA Gastroentorology Nurses College of Australia GESA Gastroenterological Society of Australia American Gastroenterology Assp References Carr, S., & Watson, W. (2011) 'Eosinophilic esophagitis'. Allergy, Asthma & Clinical Immunology 7, (1) 1492-1497. Available at http://http://www.aacijournal.com/content/7/s1/s8 [Accessed 18 September 2014] Coeliac Australia (2012) Coeliac Disease Symptoms [Online] Available at http://http://www.coeliac.org.au/symptoms/ [Accessed 19 March 2011] Cohen, J. (2014) Argon plasma coagulation in the management of gastrointestinal hemorrhage [Online] Available at http://http://www.uptodate.com/contents/argon-plasma-coagulation-in-themanagement-of-gastrointestinal-hemorrhage [Accessed 19 March 2014] Crohn's & Colitis Australia (2009) What is Crohn's Disease [Online] Available at http://http://www.crohnsandcolitis.com.au/what-is-crohns.php [Accessed 19 March 2014] Crohn's & Colitis Australia (2009) What is Ulcerative Colitis [Online] Available at http://http://www.crohnsandcolitis.com.au/what-is-ulcerative-colitis.php [Accessed 19 March 2011] Better Health Channel (2012) Gastritis [Online] Available at http://http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/gastritis [Accessed 19 March 2014]
Gastro.net (2012) Colorectal Polyps [Online] Available at http://http://www.gastro.net.au/diseases/colorectalpolyps.html [Accessed 19 March 2014] Medical Diagnostics Australia (2014) Hut Diagnostics Test [Online] Available at http://http://medicaldiagnostics.net.au/products/hut-rapid-urease-test/ [Accessed 18 March 2014] Digestive Health Foundation (2010) Helicbactor Pylori (H Pylori)[Online] Available at http://http://www.gesa.org.au/files/editor_upload/file/gesa%20helicobacter%20 Pylori.pdf [Accessed 17 March 2011] Helicobactor Pylori (2009) Centre for Digestive Diseases [Online] Available at http://http://www.cdd.com.au/pages/disease_info/heliobacter_pylori.html [Accessed 18 March 2014] Helicobactor Pylori (2011) Knott, L., Kenny, T., [Online] Available at http://http://www.patient.co.uk/health/helicobacter-pylori-and-stomach-pain [Accessed 18 March 2014] Kabbaj, N., Salihoun, M., Chaoui, Z., & Acharki, M. (2011) 'Safety and outcome using endoscopic dilation for benign oesophageal stricture without fluoroscopy'. World Journal of Gastrointestinal Pharmacology and Therapeutics 2, (6) 46-49. Available at http://http://www.wjgnet.com/2150-5349/full/v2/i6/46.htm [Accessed 18 March 2011] Patient.co.uk (2014) Barretts Oesophagus [Online] Available at http://http://www.patient.co.uk/health/barretts-oesophagus-leaflet [Accessed 17 March 2014] Roy Pounder, Peter Cotton, Pete Peterson, Guido Tytgat (2014) GastroHelp.com [Online] Available at http://http://www.gastrohep.com/ebooks /ebook.asp?book=1405120800&id=4 [Accessed 17 March 2014] St James Healthcare Endoscopy Department (2012) Electrocautery & Basic Endoscopy Procedures [Online] Available at http://http://sjheducation. weebly.com/uploads/8/0/5/5/8055457/electrocautery basic.sjh.pdf [Accessed 19 March 2014] American Society for Gastrointestinal Diseases (2012) Understanding Esophageal Dilation [Online] Available at http://http://www.asge.org/patients /patients.aspx?id=392 [Accessed 18 March 2011] Wheaton, G., Kandaswamy, P., & Bhandari, P. (2011) 'Acetic acid enhanced
chromoendoscopy is more cost effective than protocol guided biopsies in a high risk Barrett's population; results from a large prospective series'. Gut 60, (1) A32- A33. Available at http://http://gut.bmj.com/content/60/suppl_1/a32.2. abstract[accessed 18 March 2014]