[Endoscopy Sedation][Gastroscopy]
[Colonoscopy][Liver Biopsy]
[Endoscopic Retrograde
Cholangio-Pancreatography (ERCP)]
Dr G M Andrew, BA (Hons), MBBS
Rapid strides have been made in gastro-intestinal endoscopy (gastroscopy, colonoscopy, ERCP, and related techniques) in the last thirty years. Gastro-intestinal endoscopy, once largely diagnostic, has evolved such that therapeutic procedures are often performed at the same time. This may prevent the need for major surgery. Safe and effective sedation has been a major factor in the development of therapeutic endoscopy. However, not all patients require sedation for endoscopic procedures. Some patients are quite comfortable with no sedation, or only minimal sedation, depending on the type and duration of the procedure.
Patients usually have three major concerns prior to endoscopy - the outcome of the procedure (could it be cancer?), complications of the procedure, and most importantly the question "Doctor, how much will I feel the procedure?" or "Will it hurt?" With modern sedation and careful monitoring the great majority of patients will feel comfortable during the procedure.
It is most likely that you will have your endoscopy in a day surgery unit in a public or private hospital. During the procedure an anaesthetist or sedationist (doctor or nurse trained in sedation and resuscitation) will be present throughout the procedure to provide monitoring of your level of consciousness, your cardiorespiratory state and provide the right amount of anaesthetic sedation to keep you comfortable throughout.
Prior to the procedure, you will meet the doctor giving the sedation. You will be asked (by the doctor or nursing staff) to provide your medical history, including the reason you are having the test, whether you have heart or lung disease (including asthma, angina or heart failure), liver or kidney disease, gastro-intestinal bleeding or other bleeding problems, or anaemia. The anaesthetist will wish to ensure you have fasted (i.e. not had food or drink) for the required number of hours before the procedure. A brief physical examination may be performed. If you are dehydrated, intravenous fluids may be administered. The doctor will wish to know your allergies and a list of your medications.
This is the time to ask any questions you may have regarding the sedation. An intravenous cannula or needle will be placed in the back of the hand or forearm. This is for the administration of intravenous sedative drugs.
When you are wheeled into the procedure room, you will be connected to monitoring equipment which is essential when sedative agents are to be used. Monitoring detects early signs of impaired lung or heart function resulting from the sedatives, permitting early correction, thus maximising patient safety. Years ago, the anaesthetist would monitor the patient by checking skin colour, pulse rate, and rate of breathing. Modern equipment, in combination with careful clinical observation, can do much better than this.
You will also be given a mask or some type of oxygen delivery system to increase the level of oxygen in the air that you are breathing - this is now standard for endoscopic procedures. Oxygen will continue throughout the procedure. When you are asleep you may be aware of suction in the mouth or throat, which is used to remove any unwanted secretions.
Pulse OximetryPulse oximeters are the most important monitors to have been developed in the last fifteen years. They should be used in every endoscopy procedure room, and be available in recovery areas.
The pulse oximeter measures the differential absorption of red and infra-red light by oxygenated and deoxygenated haemoglobin. A light emitting diode, located in a fingertip probe, sends a light wave through the tissues and monitors the reflected wavelengths coming back as the blood passes through the capillaries. The pulse rate and oxygen level (saturation) of haemoglobin in the blood can be measured. All healthy patients will have an oxygen saturation greater than 96% when breathing room air. If the oxygen saturation in the blood drops, the machine will alarm, and the anaesthetist will undertake measures to correct the situation to avoid an emergency.
These measures are also frequently used when sedative agents are given, particularly in elderly patients or patients who have a cardiac history. The ECG is useful for detecting cardiac rhythm abnormalities (arrhythmias) and insufficiency of blood supply to the heart muscle (cardiac ischaemia).
A typical print-out from a patient monitor is shown below. The top tracing is an ECG, the bottom tracing the pulse rate. The monitor also shows continuously the pulse rate, the last blood pressure recording, and the oxygen saturation.
In the ideal situation, the patient should be lightly sedated (i.e. drowsy but still able to be woken), pain free and cooperative, unable to remember the procedure, and free of anxiety and fear.
The features of an ideal drug for sedation for endoscopy include:
· Anxiolytic (reduces anxiety)
· Amnestic (reduces memory of the procedure)
· Analgesic (takes away pain)
· Rapid onset of action
· Predictable sedative effects, in proportion to the dose
· Safe over a wide range of doses
· Water soluble and free of pain or irritation on injection
· Rapid recovery with no hangover
No single agent has all these properties, and therefore 2 or even 3 drugs are commonly used. Sedation is often achieved using a benzodiazepine, in combination with an opioid for pain relief and a barbiturate-like hypnotic agent if deeper sedation is required.
All the agents used cause a mild temporary depression of lung function, and some mild temporary effects on the heart, particularly when used in combination. This reinforces the need for adequate monitoring by direct observation and monitoring equipment.
These cause sedation but have no effect on pain. The original benzodiazepine used in day surgery and endoscopy was diazepam. However, the plasma elimination half-life for diazepam has been estimated at between 24 and 57 hours, and its breakdown metabolites also have sedative properties. This means that it takes a long time to recover from the effects, which often last until the next day. It is therefore an unsuitable agent for day procedures.
A newer sedative agent, called MIDAZOLAM, is now very commonly used. This is a short-acting benzodiazepine with useful amnesia for events during the procedure (it does not cause amnesia for events before or after the procedure). The plasma elimination half-life is one tenth that of diazepam, and therefore it is cleared from the blood very quickly. Furthermore the breakdown products (metabolites) are short lived, and have no sedative properties. The dosages range from 1mg to about 10mg.
Midazolam has few side effects and if they occur they are very rarely serious. Depression of breathing is the most important. Others include an itchy nose, rash, dizziness, anxiety, irritability, vivid dreams, twitching movements. Midazolam should not be used in patients with myasthenia gravis, acute glaucoma, and patients known to be allergic to this class of drug. It should be used with caution in patients with serious lung diseases particularly chronic obstructive airways disease.
Pregnancy: while midazolam is not thought to cause fetal malformations in humans, it should be avoided in the first 3 months of pregnancy unless the potential benefits outweigh the risks.
Lactation: midazolam is excreted in breast milk and should be avoided in breastfeeding mothers. Alternatively a breast pump can be used and the milk discarded for the first few hours after the procedure.
These are for pain relief. The short acting opioid fentanyl (or its relative alfentanil) is often used in combination with midazolam. The effect of fentanyl lasts for about thirty minutes and provides good relief from pain. The major side effect is depression of breathing. The rate and depth of breathing decreases within a minute or so of the drug being injected. A drop in pulse rate (bradycardia) may also occur. Dosage is in the range 1 - 1.5 ug/kg, with lower doses in the elderly or in impaired renal function or hepatic function. Lower doses may be required in patients with lung and heart diseases and in patients on the newer type 2 MAOI drugs (a type of antidepressant medications). Fentanyl is contraindicated in patients taking the older type 1 MAOI drugs.
Pregnancy: the safe use of fentanyl has not been established in the first 3 months of pregnancy, and therefore it should be used only where the potential benefits outweigh possible risks.
Lactation: it is not known if fentanyl is excreted in breast milk and fentanyl should be avoided in breastfeeding mothers, or precautions taken to prevent the baby receiving any fentanyl (see above).
Barbiturates have been used for many years to put people to sleep at the start of an operation (often called 'induction'). Propofol is a newer non-barbiturate short acting anaesthetic induction drug which, due to its rapid onset of action and short recovery period, is ideally suited for endoscopy sedation. It amplifies the sedative effects of the other analgesic and hypnotic agents, and causes profound sedation, depending on the dose.
In summary, propofol is a 'stronger' drug than midazolam in producing sedation, which makes it very useful, but a greater level of monitoring is required. Propofol causes pain in the arm on injection in about 30% of patients but this passes off in a minute or so.
Pregnancy: propofol should not be used in pregnancy.
Lactation: propofol should not be used in breastfeeding mothers.
Normally the recovery from the effects of the above agents is gradual and pleasant. However, specific antagonists for the benzodiazepines and for opioid narcotics are available for use in emergencies and (rarely) electively - these reverse the effects of the above drugs very quickly.
Flumazenil is a specific benzodiazepine receptor antagonist which acts within seconds. Naloxone is an opioid antagonist which reverses the respiratory and analgesic effects of opioids.
Usually you will be regaining conscious awareness just as you are being wheeled to the recovery area. You may be attached to the same monitors as were used in the procedure area. You will be closely monitored at this time by experienced nursing staff, who will check your blood pressure and vital signs frequently. This is a time to relax and gradually awaken. A long awaited cup of tea and a light meal may be provided about an hour after your procedure. Often it is wise to eat only lightly for the rest of the day following an endoscopic procedure.
You will be fit for discharge when you are wide awake, have had some food, and are able to get up, get dressed, and walk around without any unsteadiness. Another person should accompany you home. You must not drive or use machinery for the remainder of the day.
For the remainder of that day (and sometimes the next, if you still feel tired and unsteady),
do not -
Upper gastrointestinal endoscopy (gastroscopy) is a commonly performed procedure allowing direct visual examination of the inside of the upper gastrointestinal tract (oesophagus, stomach and duodenum) using a flexible instrument through which a live image passes. Current endoscopes transmit the image electronically whereas earlier instruments transmitted the image along fibreoptic bundles.
Gastroscopy has many purposes. It allows an examination of the upper gastrointestinal tract for abnormalities, which may be recorded on photograph. This procedure also allows the removal of polyps (small benign growths), injection of bleeding blood vessels, the taking of samples of tissue (biopsies) for examination by a pathologist, and dilatation of strictures in the oesophagus (gullet). Gastroscopy also allows insertion of a feeding tube into the stomach through the abdominal wall (PEG tube) for patients who are unable to eat. If any of these additional procedures are planned as part of your gastroscopy they should be discussed with you in advance.
Prior to the procedure you will asked not to eat or drink. This is to allow a satisfactory examination and to minimise the risk of vomiting during the test.
A soft, thin flexible tube
is passed into the stomach via the mouth. This takes about 5 minutes and is done
under intravenous sedation (medication which may be used include midazolam, fentanyl,
and propofol). Reactions to these medications are rare. After the procedure you
must not drive or use machinery until the next day, or longer if you feel unsteady
or tired the next day. If you object to the use of sedation you should discuss
this with your doctor. Some patients tolerate gastroscopy without sedation.
Gastroscopies are usually done in a hospital, usually on a day case basis. You would be required to attend the hospital for about 3 hours if you have sedation for your gastroscopy. You will need to arrange transport to and from the hospital.
A barium meal x-ray of the stomach will give similar information but it is not as accurate in detecting ulcers and other abnormalities, and it does not allow biopsies to be taken. It does not require sedation or hospital admission.
Gastroscopy is extremely safe, however complications very occasionally occur. Complications are more common where a therapeutic procedure is performed such as dilatation of a stricture in the gullet, removal of polyps (polypectomy) from the stomach, or insertion of a PEG feeding tube.
Some complications of gastroscopy and related procedures include:
Everything will be done to minimise the risk of these complications. There are ways of detecting these complications early and specific treatments are available if they do arise. Very rarely there may be a need for hospitalisation, major surgery, intravenous feeding, or blood transfusion. Although death can result from complications of gastroscopy & oesophageal dilatation this is extremely rare.
Special Precautions will need to be taken if you:
To examine the lower gastrointestinal tract (colon or large bowel), to remove polyps (small benign growths), inject bleeding blood vessels, and to take samples of tissue (biopsies) for examination by a pathologist. Colonoscopy is the most reliable method of bowel examination but small abnormalities including cancers can very occasionally be missed.
Prior to the procedure you will be given a bowel preparation kit with instructions. The bowel preparation cleans the colon. Without this it is not possible to perform a full examination of the colon. Although the bowel preparation is unpleasant, it is very rare for it to be harmful. If you have had difficulties with the preparation in the past, or if you have severe heart, lung, or kidney disease you should discuss this with the doctor.
A long, thin flexible tube
is passed around the bowel from the anus. This takes about 15 minutes and is done
under intravenous sedation (Midazolam, Fentanyl, and sometimes Propofol). Reactions
to these medications are rare. After the procedure you must not drive or use machinery
until the next day, or longer if you feel unsteady or tired the next day. If you
object to the use of sedation please discuss.
Colonoscopies are done in a hospital, usually on a day case basis. You would be required to attend the hospital for about 3 hours if you have sedation for your colonoscopy. You will need to arrange transport to and from the hospital.
A barium enema x-ray of the bowel will give similar information but it is not as accurate for certain problems, it does not allow biopsies or removal of polyps. It does not require sedation or hospital admission.
Colonoscopy and polypectomy are very safe. Serious complications are rare. These include:
Everything will be done to minimise the risk of these complications. There are ways of detecting these complications early and specific treatments are available if they do arise. Very rarely there may be a need for hospitalisation, major surgery, intravenous feeding, or blood transfusion. Although death can result from complications of colonoscopy this is very rare.
Special Precautions will need to be taken:
A liver biopsy involves your doctor taking a small piece of tissue from your liver so that they can examine it to see if there is any damage or disease to the liver.
The reasons why your doctor may want to do a liver biopsy could be that your liver function tests (LFTs) may be abnormal, possibly suggesting that your liver is not working properly or you may have an enlarged liver. For the doctor to accurately determine what is wrong with your liver, a liver biopsy may be the best approach.
Before you have your liver biopsy, the doctor will do some tests to ensure that the risks of the biopsy are kept to a minimum. First, your doctor will take some blood to see if it clots properly (since the liver produces some of the factors that help blood to clot). Your doctor will also ask you what medications you take . make sure you mention .blood thinning. medications, including aspirin. One week before surgery, it is recommended that you stop taking aspirin, ibuprofen and anticoagulants (such as warfarin).
You have to go to the hospital for a liver biopsy. For the biopsy, you will be lying on a hospital bed and the nurse will put in an intravenous (IV) line so that you can be given medication for the procedure.
When you have the biopsy, you will be lying on your back or turned slightly on your left side, with your right arm above your head. You will be given some local anaesthetic with a needle to numb the area and then the doctor will make a small incision (.cut.) in your right side, near your ribcage. The doctor will then put a biopsy needle in and take out a small piece of your liver within the needle. Sometime the doctor may use an ultrasound image of your liver to help guide the needle to the right spot.
The doctor will ask you to hold your breath for 5-10 seconds while they put the needle into your liver. You might feel a dull pain when this happens. The actual procedure should take only a few minutes. After the biopsy, you will get a bandage put over the incision and you will have to lie on your right side, pressed up against a towel, for at least 2 hours. Sometime patients may need to stay in hospital for up to 24 hours after the biopsy to recover from the sedative and to allow the medical staff to check for complications before you can go home.
Since you may be having a sedative, you will need to arrange for someone to drive you home, as you can.t driver after having a sedative. You have to go directly home and remain in bed for 8-12 hours, depending on what your doctor tells you. And to make sure that the incision and you liver can heal, you shouldn.t exert yourself too much for the next week. You might get a little bit of soreness at the incision site and you might get some pain in your right shoulder.
There are some risks involved in having a liver biopsy, such as puncture of the lung or gallbladder, infection, bleeding and pain, but these complications are rare. You should ask the doctor about these complications, how to recognise them, and what action to take.
The nature of the test, including possible side-effects and complications, will
be discussed with you before the test. If you wish to have more information please
advise your doctor before the test.
To examine the bile ducts and pancreatic ducts, to remove gallstones from the bile ducts, to dilate strictures in the bile ducts, to dilate or cut strictures due to a tumour of the duodenum, pancreas or bile ducts, and to keep open a stricture by the use of a plastic or metal tube called a stent. The procedure also allows samples of tissue (biopsies) to be taken for examination by a pathologist.
Sphincterntomy involves making a small cut in the lower part of the bile duct where the duct opens into the duodenum. This is done using an instrument passed through the endoscope. You do not feel the cut. This procedure allows better access into the bile duct, removal of gallstones, and other procedures to be performed.
Prior to the procedure you will asked not to eat or drink, usually for 8 hours. This is to allow a satisfactory examination and to minimise the risk of vomiting during the test. You will be asked to come to the hospital before the test to complete admission procedures, be admitted and checked for any medical problems, have an intravenous line inserted, and have any premedication and antibiotics if required.
The test is done in the X-Ray Department (you will be taken there from the Ward). After the sedation is given, a long, thin flexible tube is passed into the stomach via the mouth and a thin plastic tube inserted into the bile and pancreatic ducts. In about 5% of patients this is not successful. The procedure takes up to 45 minutes and your are under intravenous sedation throughout (Midazolam, Fentanyl, and sometimes Propofol). Reactions to these medications are rare. After the procedure you must not drive or use machinery until the next day, or longer if you feel unsteady or tired the next day. If you object to the use of sedation please discuss with your doctor.
Similar information can be obtained by Percutaneous Cholangiography which is done by a Radiologist. This is generally a more difficult procedure with a slightly higher risk of complications. Removal of gallstones and treatment of strictures and tumours also can be done by open surgery, which involves an operation under general anaesthetic, a much longer stay in hospital, and higher risk of complications. If gallstones are left in the bile ducts, or if blockage of the bile ducts is not relieved, life-threatening problems may occur.
Sometimes ultrasound, CT cholangiography, and MRI cholangiography can give very similar information to that provided by ERCP, however these investigations do not allow therapeutic procedures to be performed. Your doctor will discuss these investigations with you if you wish.
ERCP, sphincterotomy, and stent insertion are normally safe procedures and are only done when other methods of diagnosis or treatment have failed. Complications (mostly minor) occur in about 5% of patients, including:
Everything will be done to minimise the risk of these complications. There are ways of detecting these complications early and specific treatments are available if they do arise. Very rarely there may be a need for hospitalisation, major surgery, intravenous feeding, or blood transfusion. Although death can result from complications of ERCP this is rare.
ERCP is a technically difficult procedure and in about 5% of patients there is a need to repeat the procedure at a later date for a variety of reasons e.g. to check that gallstone extraction has been successful, or to remove residual gallstones.
Special Precautions will need to be taken:
Some useful links providing further information:
ASGE policy and procedure
manual on GI endoscopy
http://www.asge.org/gui/patient/index.asp
General information about colonoscopy
http://www.gastro.com/html/colonoscopy.html