Esophagogastroduodenoscopy (OGD)

Description

Esophagogastroduodenoscopy (OGD) is an endoscopic procedure allowing visualisation of the upper part of the gastro-intestinal tract including the oesophagus, stomach, and first portion of the small intestine (duodenum). It is typically performed with diagnostic intent, however can be combined with other techniques/equipment as a therapeutic intervention.

The procedure is performed either under sedation, or a local throat anaesthetic spray. Recovery is quick, with the patient being discharged after one hour from the procedure end and post-operative care usually involves restricting any heavy lifting/driving within the first 24 hours after discharge.

Complications of the procedure are rare and range from damage to the teeth, to the more serious complications such as a tear/perforation in the lining of either the oesophagus, stomach, or duodenum resulting from penetration damage from the endoscope.

What is it?

An OGD is a procedure allowing the medical team to look at the upper part of the gastro-intestinal tract including the oesophagus, stomach, and the first portion of the small intestine. This is done using a thin, flexible tube called either a gastroscope/endoscope with a light and camera attached to the end. The tube is passed through the mouth, down the oesophagus, and into the stomach. The camera sends live video of the upper gastro-intestinal tract to a TV Screen, allowing the endoscopist to visualise any pathology (1).

Benefits of the Procedure

The Barium Swallow is a less invasive method for visualising the upper gastro-intestinal tract than endoscopy. However, not all conditions can be detected via barium swallow; and it follows that endoscopy has the added benefits of therapeutic uses as well as being a diagnostic procedure (see section “Why is it done?” for a list of different uses). Hence endoscopy is often preferred over barium swallow for patients who are able to tolerate the procedure (5).

Furthermore, If you have a long-term condition such as Gastro-Oesophageal Reflux Disorder or Barrett's Oesophagus, the doctor may want to perform an OGD as part of a regular screening/surveillance programme to check that these conditions have not worsened. You may previously have had an X-Ray or other scans, and hence an OGD may be necessary as a follow-up to check for any diagnosis that may have been missed on

these or to investigate a finding in more detail (6).

The Procedure

On arrival at the hospital, you will be given a change of clothes to wear; and you will be seen by one of the nurses who will discuss the procedure with you and ask you to sign a consent form. The procedure usually only takes about 10 minutes, however it can be longer depending on the reason for the EGD being conducted or if sedation is used. Although the tube enters through your mouth, it should not interfere with any breathing due to it being very thin.

The steps of the procedure are as follows:

• The first stage of the procedure involves applying either the sedative intravenously, or the local throat anaesthetic.

• You will be placed on your left side on the bed with your head bent forward, allowing proper orientation and for the endoscope to pass down more easily through the oesophagus.

• A mouthpiece will be placed between your teeth to prevent damage and to keep your mouth slightly open for the OGD tube to enter.

• The endoscopist will lubricate the tube to make it easier and more comfortable to slide down your throat. The OGD tube will be inserted through the mouthpiece over your tongue and passed down through the oesophagus and into the stomach. The endoscopist will pay careful attention to the structures in the mouth and may inspect the area for some time before inserting the endoscope. This is often the most uncomfortable stage for the patient.

• Any excess saliva in the mouth will be removed using a specialised sucking tool.
• If the endoscopist needs to get a better view of your stomach, they may pass some air down the OGD tube, which may make you feel slightly bloated. Photographs may be taken using the camera which will be added to your medical record.
• At this stage, the endoscopist may perform a number of maneuvers with the endoscope to fully assess the area. These may include rotating the endoscope, and bending the tip of the endoscope to visualise certain areas of the stomach better.
• If a biopsy needs to be taken, the endoscopist can use tiny forceps on the end of the OGD tube to remove some tissue for analysis. This usually cannot be felt.
• Once the procedure is complete, the OGD tube will be removed quickly and without any pain (1).

Some people may not be able to tolerate the procedure, or there may be undigested food in the stomach. These factors may inhibit the procedure and hence it may be necessary to stop the OGD and reschedule. An alternative, less invasive test such as a Barium Meal can be arranged; however this is usually not preferred as OGD gives better results.

Post Procedure

After the procedure you will be transferred to a recovery ward, allowing you to rest until the major effects of the sedative wear off. Here, you will also have your vital signs checked. If you have been administered sedation, you will have to get someone else to pick you up from the hospital and stay with you for the next 24 hours. You will usually be discharged an hour after the procedure has finished and will be given a copy of the endoscopy report.

Risks of Procedure

OGD’s are usually safe procedures and complications are rare. The main complications are to do with the gastroscope damaging the lining of the oesophagus, stomach, or intestine. This may result in bleeding or infection (8). The main risks include:

• A tear/perforation in the lining of the oesophagus caused by damage from the endoscope. While this is rare, if it does happen you will be admitted to the hospital for further treatment and potentially corrective surgery. This complication occurs in between 0.05 - 2.6% of all cases, with the risk being higher if other instruments are used for therapeutic purposes (9).
• If a biopsy is required to be taken, bleeding may occur when tissue is removed. This is usually quite minor and the bleeding stops by itself, but occasionally can require intervention, especially if you are taking any blood-thinning medications. Bleeding occurs in around 0.3% of patients following an EGD (1).
• Damage to the teeth may occur, however this complication risk is mitigated through use of the mouthpiece.

Why is it done?

OGD’s are usually conducted in order to establish a cause for a given problem/symptom in the upper gastro-intestinal tract. It is indicated for a wide variety of different gastro-intestinal disorders and symptoms. The following is a list of the different diagnostic and therapeutic uses of OGD:

Diagnostic

• Investigating long-term dyspepsia (indigestion) that does not respond to standard medical treatment and lifestyle changes.

• Investigating bleeding from either vomiting/coughing up blood. These symptoms can often present acutely to the Accident and Emergency Department, and hence if this occurs, the doctors will ensure you are first stabilised before conducting an OGD procedure.

• To look for the cause of any unexplained iron deficiency anaemia which may occur through internal bleeding. Here, an OGD may be conducted alongside a colonoscopy to check for any lower gastro-intestinal bleeding. This anaemia may manifest itself over time in tiredness and lethargy.

• To look for a cause of any dysphagia (difficulty swallowing). These causes typically occur at the lower end of the oesophagus and include conditions such as achalasia where the lower esophageal sphincter is not able to fully relax.

• Pain in your upper abdomen that does not get better with standard therapy. This pain may be associated with other symptoms such as weight loss and dyspepsia and may indicate more serious disease in the oesophagus or stomach (2).

Therapeutic

• Banding of bleeding oesophageal varices, which are abnormally dilated veins present in the lower third of the oesophagus, most commonly present as a result of liver cirrhosis leading to portal hypertension (high blood pressure in the blood vessels that join the liver). These can often be fatal if left untreated.

• Delivering injections into the upper gastro-intestinal tract. These injections can often be delivered to relax an overly contracted esophageal sphincter which may be affecting the ability to swallow.

• Removal of any foreign bodies. This is done using the small forceps on the end of the endoscope.

• Dilating any stenosis or achalasia present in the lower esophageal sphincter.

• Drainage of any cysts (3).

OGD procedures are also becoming increasingly used in bariatric surgery for the placement of gastric balloons, and hence its uses are expanding into other areas of Medicine (4).

Will I need to do any preparation?

Before the operation, your doctor will talk to you about the need to conduct the OGD procedure. Here, they will discuss any medication that you are currently taking and whether or not these need to be stopped temporarily before your procedure. Most medications can be continued to be taken as normal, however if you are taking any anticoagulants or blood thinning medication the doctor will discuss whether it is necessary to stop these temporarily.

You will need to stop eating or drinking at least 6 hours before your procedure. You can have small sips of water up to 2 hours before the operation.

Anesthesia

These procedures are usually not painful, however to avoid any discomfort in the procedure you may be given a sedative which will make you feel sleepy and drowsy. General Anaesthetics are not given, however you may be offered a local throat anaesthetic spray to numb your throat if necessary. The benefit of the anaesthetic throat spray is that you will be able to go home alone after the procedure has finished as you will be fully awake and alert. A combination of both can be used however the exact method will be agreed when you speak to the nurse on the day of the procedure (7).

Post Procedure

After the procedure you will be transferred to a recovery ward, allowing you to rest until the major effects of the sedative wear off. Here, you will also have your vital signs checked. If you have been administered sedation, you will have to get someone else to pick you up from the hospital and stay with you for the next 24 hours. You will usually be discharged an hour after the procedure has finished and will be given a copy of the endoscopy report.

Caring for yourself at home

If you have been administered sedation you will be advised not to operate any heavy machinery or drive within the first 24 hours. If you develop any severe abdominal pain, fever, or vomiting/passing out large amounts of blood please seek urgent medical attention.

Where can I find more information?

NHS information on endoscopy - https://www.nhs.uk/conditions/endoscopy/