A well-organized endoscopy unit with trained staff is essential for good endoscopic practice and training. The unit should have processes for ongoing competency assessment, skills training, and data management. Endoscopes must be thoroughly decontaminated between uses to prevent infection transmission using either sterilization or high-level disinfection depending on the device. Both diagnostic and therapeutic endoscopy can have risks such as perforation, bleeding, infection, and sedation complications, so appropriate patient selection and safety protocols are important.

1. Gastrointestinal endoscopy

2. THE MODERN ENDOSCOPY UNIT
Organisation
A well-designed endoscopy unit staffed by trained endoscopy nurses
and dedicated administrative staff is essential to support good
endoscopic practice and training. Clinical governance with regular
appraisal and assessment of performance should be a routine process
embedded within the unit philosophy. Endoscopist training demands
particular attention, with a transparent process of skills- and theory-
based education centred on practical experience and dedicated training
courses. Experienced supervision of all trainee endoscopists is essential
until competency has been obtained and assessed by an appropriately
validated technique, such as direct observation of practical skills (DOPS)
and review of procedure logbooks.

3. However, all endoscopists should keep an on-going log to record
diagnostic and therapeutic procedure numbers and markers of
competency such as colonoscopy completion rates, polyp detection
rates, mean sedation use and complication rates. Central to this is an
efficient data management system that provides outcome analysis for
all aspects of endoscopy including adherence to guidelines, near
misses, patient satisfaction, decontamination processes and scope
tracking, as well as the more obvious completion and complication
rates.

4. Instrument decontamination
Endoscopes will not withstand steam-based autoclaving and
therefore require high-level disinfection between cases t prevent
transmission of infection. Although accessories may be autoclaved,
best practice requires the use of disposable single-use items
whenever possible. All equipment should be decontaminated to an
identical standard whether for use on immunocompromised/infected
patients or not.

5. This process involves two equally
important stages: first, removal of
physical debris from the internal and
external surfaces of the instrument
and, second, chemical neutralisation of
all microbiological agents. A variety of
agents are available and endoscopists
should familiarise themselves with the
agent in use in their department.

6. The risks of endoscopy
●● Sedation-related cardiorespiratory complications
●● Damage to dentition
●● Aspiration
●● Perforation or hemorrhage after endoscopic dilatation/ therapeutic
endoscopic ultrasound
●● Perforation, infection and aspiration after percutaneous endoscopic
gastrostomy insertion
●● Perforation or hemorrhage after flexible sigmoidoscopy/
colonoscopy with polypectomy
●● Pancreatitis, cholangitis, perforation or bleeding after endoscopic
retrograde cholangiopancreatography

7. SAFE SEDATION
If performed competently the majority of diagnostic endoscopy and
colonoscopy can be performed without sedation or with pharyngeal
anesthesia alone. However, therapeutic procedures may cause pain and
patients are often anxious; thus, in most countries sedation and
analgesia are offered to achieve a state of conscious sedation (not
anesthesia). Medication-induced respiratory depression in elderly
patients or those with comorbidities is the greatest cause of endoscopy-
related mortality and, therefore, safe sedation practices are essential.
The involvement of anesthetists to advise on appropriate protocols is
recommended. Endoscopy in certain situations (particularly pediatric
endoscopy) requires a general anesthetic – this should only be
undertaken by appropriately trained staff with adequate equipment
available.

8. UPPER GASTROINTESTINAL
ENDOSCOPY
EGD is the most commonly
performed endoscopic procedure.
Excellent visualisation of the
esophagus, gastroesophageal
junction, stomach, duodenal bulb
and second part of the duodenum
can be obtained. Retroversion of the
gastroscope in the stomach is
essential to obtain complete views of
the gastric cardia and fundus.

9. Traditional forward-viewing endoscopes do not adequately visualise
the ampulla, and a side-viewing scope should be used if this is essential.
Likewise, although it is possible to reach the third part of the duodenum
with a standard 120 cm instrument, a longer enteroscope is required if
views beyond the ligament of Treitz are required. In addition to clear
mucosal views, diagnostic endoscopy allows mucosal biopsies to be
taken, which may either undergo processing for histological examination
or be used for near-patient detection of Helicobacter pylori infection
using a commercial urease-based kit. In addition, brushings may be taken
for cytology and aspirates for microbiological culture.

10. Indications for esophagogastroduodenoscopy
EGD is usually appropriate when a patient’s symptoms are persistent
despite appropriate empirical therapy or are associated with warning
signs such as intractable vomiting, anemia, weight loss, dysphagia or
bleeding. It is also part of the diagnostic work-up for patients with
anemia, symptoms of malabsorption and chronic diarrhea. However,
increasing ease of access to OGD with the availability of ‘open access’
endoscopy has resulted in a significant number of unnecessary
procedures being performed in young patients with dyspepsia or
gastro-esophageal reflux disease (GORD).

11. In addition to the role of EGD in
diagnosis, it is also commonly used in
the surveillance of neoplasia
development in high-risk patient
groups. Whereas there is consensus
about its role in genetic conditions such
as familial adenomatous polyposis and
Peutz–Jeghers syndrome, controversy
remains about the role and frequency
of endoscopic surveillance in
premalignant conditions such as
Barrett’s esophagus and gastric
intestinal metaplasia

12. Therapeutic
esophagogastroduodenoscopy
Increasing technological advances have revolutionised the
therapeutic applications of upper gastrointestinal endoscopy. However,
appropriate patient selection and monitoring is essential to minimise
complications. The most common therapeutic endoscopic procedure
performed as an emergency is the control of upper gastrointestinal
hemorrhage of any etiology. Band ligation has replaced sclerotherapy in
the management of esophageal varices whereas sclerotherapy using
thrombin-based glues can be used to control blood loss from gastric
and duodenal varices

13. Injection sclerotherapy with adrenaline coupled with a second
hemostatic technique such as heater probe vessel obliteration or
hemoclip application, remains the technique of choice for a peptic ulcer
with an active arterial spurt or high-risk stigmata of hemorrhage Such
high-risk bleeds should be followed by 72 hours of intravenous proton
pump inhibition in all cases.

14. Benign esophageal and pyloric strictures may be dilated under direct
vision with ‘through-the-scope’ (TTS) balloon dilators or the more
traditional guidewire-based systems such as Savary–Guillard bougie
dilators On occasion, more difficult benign strictures can be treated by
the insertion of a fully-covered removable stent, or with a
biodegradeable stent. Likewise, the non-relaxing lower esophageal
sphincter associated with achalasia can be treated by pneumatic
balloon dilatation with a 30–40 mm balloon.

15. Endoscopic dissection techniques
are now being employed to treat
achalasia by natural orifice myotomy
(peroral endoscopic myotomy,
POEM) with good early follow-up
results. An alternative in patients
unfit to suffer endoscopic
complication is the injection of
botulinum toxin into the lower
esophageal sphincter, although this
has a limited (3–6 month) duration
of benefit.

16. There are a limited number of
endoscopic techniques available
to reduce gastro-esophageal
reflux, which rely on tightening
the loose gastro-esophageal
junction by plication or by the
application of radial thermal
energy. These techniques may
have a role in some patients, but
are yet to demonstrate benefit
over surgical fundoplication.

17. endoscopic techniques to tackle
obesity, such as gastric balloon
insertion, have not been associated
with evidence of long-lasting benefit.
In contrast, there is clear evidence
that the insertion of a percutaneous
endoscopic gastrostomy (PEG) tube
enhances nutritional and functional
outcome in patients unable to
maintain oral nutritional intake

18. PEG insertion is often a prelude to treatment of complex orofacial
malignancy, and may be used to support nutrition in patients with
alternative malignant, degenerative or inflammatory diseases.

19. The deployment of self-expanding
metal stents with or without a
covering sheath inserted over a stiff
guidewire leads to a significant
improvement in symptomatic
dysphagia and quality of life in
patients with malignant esophageal
and gastric outlet obstruction.
Covered stents are the mainstay of
treatment for benign or malignant
trachea esophageal fistulae.

20. Perhaps the area of greatest
progress over recent years has
been in the endoscopic
management of early esophageal
and gastric neoplasia with
endoscopic mucosal resection
(EMR) or endoscopic submucosal
dissection (ESD). These techniques
require specialist training, but
have allowed endoscopic
management of mucosal lesions
that were previously subject to
surgical intervention

21. Complications of diagnostic and therapeutic
esophagogastroduodenoscopy
Diagnostic upper gastrointestinal endoscopy is a safe procedure with
minimal morbidity as long as appropriate patient selection and safe
sedation practices are embedded in the unit policy. The mortality rate
is estimated to be less than 1:10 000, with a complication rate of
approximately 1:1000. As mentioned above, the majority of adverse
events relate to sedation and patient comorbidity. Particular caution
should be exercised in patients with recent unstable cardiac ischemia
and respiratory compromise.

22. Perforation can occur at any point in the upper gastrointestinal tract,
including the oropharynx. It is rare during diagnostic procedures and is
often associated with inexperience. Perforation is more common in
therapeutic endoscopy, particularly esophageal dilatation and EMR/ESD
for early malignancy. Early diagnosis significantly improves outcome
and thus all staff must be alert to the symptoms.
Prompt management includes radiological assessment using
CT/water-soluble contrast studies, strict nil by mouth, intravenous
fluids and antibiotics and early review by an experienced upper
gastrointestinal surgeon.

23. ENDOSCOPIC ASSESSMENT OF THE SMALL
BOWEL
The requirement to visualise, biopsy and treat the small bowel is far less
than in the stomach, biliary tree or colon, resulting in a time lag in
technological advances. The most frequent indication is the investigation
of gastrointestinal blood loss, which may present with either recurrent iron
deficiency anaemia (occult hemorrhage) or recurrent overt blood loss per
rectum (cryptic hemorrhage) in a patient with normal OGD (with duodenal
biopsies) and colonoscopy. Other indications include the investigation of
malabsorption; the exclusion of cryptic small bowel inflammation such as
Crohn’s disease in patients with diarrhea/abdominal pain and evidence of
an inflammatory response;

24. Capsule endoscopy
The technique requires three main components: an
ingestible capsule, a portable data recorder and a
workstation equipped with image-processing
software. The capsule consists of an optical dome
and lens, two light-emitting diodes, a processor, a
battery, a transmitter and an antenna encased in a
resistant coat the size of a large vitamin pill. It
acquires video images during natural propulsion
through the digestive system that it transmits via a
digital radiofrequency communication channel to
the recorder unit worn outside the body; this also
contains sensors that allow basic localisation of the
site of image capture within the abdomen.

25. Single/double-balloon enteroscopy
This technique allows the direct
visualisation of and therapeutic
intervention for the entire small bowel
and may be attempted via either the oral
or rectal route. Double-balloon
enteroscopy was developed in 2001 in
Japan; it involves the use of a thin
enteroscope and an overtube, which are
both fitted with a balloon. The procedure
is usually carried out under general
anesthesia, but may be undertaken with
the use of conscious sedation.

26. The enteroscope and overtube are inserted through either the
mouth or anus and steered to the proximal duodenum/terminal ileum
in the conventional manner. Following this the endoscope is advanced
a small distance in front of the overtube and the balloon at the end is
inflated. Using the assistance of friction at the interface between the
enteroscope and intestinal wall, the small bowel is accordioned back to
the overtube. The overtube balloon is then deployed and the
enteroscope balloon is deflated.

27. The process is then continued until the entire small bowel is
visualized. In single-balloon enteroscopy, developed more recently, an
enteroscope and overtube are used, but only the overtube has a
balloon attached. A full range of therapeutics including diagnostic
biopsy, polypectomy, APC and stent insertion are available for balloon
enteroscopy. Some experts advocate routine capsule endoscopy before
balloon enteroscopy in an attempt to localize any lesions and plan
whether oral or rectal access is more appropriate.

28. Current established indications for
single/doubleballoon endoscopy
●● Bleeding from the gastrointestinal tract of obscure cause
●● Iron deficiency anemia with normal colonoscopy and gastroscopy
●● Visualisation of and therapeutic intervention for abnormalities seen
on traditional small bowel imaging/capsule endoscopy

29. ENDOSCOPIC RETROGRADE
CHOLANGIOPANCREATOGRAPHY
This procedure involves the use of a side-
viewing duodenoscope, which is passed
through the pylorus and into the second
part of the duodenum to visualise the
papilla. This is then cannulated, either
directly with a catheter or with the help of a
guidewire Occasionally a small precut is
required to gain access. By altering the angle
of approach one can selectively cannulate
the pancreatic duct or biliary tree, which is
then visualised under fluoroscopy after
contrast injection.

30. The significant range of
complications associated with this
procedure and improvements in
radiological imaging using
magnetic resonance
cholangiopancreatography
(MRCP) have rendered much
diagnostic ERCP obsolete, and
thus most procedures are
currently performed for
therapeutic purposes. There is still
a role for accessing
cytology/biopsy specimens.

31. Therapeutic endoscopic retrograde
cholangiopancreatography
It is essential to ensure that patients have appropriate assessment
prior to therapeutic ERCP, which is associated with a significant
morbidity and occasional mortality. All patients require routine blood
screening including a clotting screen. Assessment of respiratory and
cardiovascular comorbidity is essential. The use of supplementary
oxygen and both cardiac and oxygen saturation monitoring during the
procedure are essential because of the high level of sedation that is
often required.

32. The most common indication for
therapeutic ERCP is the relief of
biliary obstruction due to gallstone
disease and benign or malignant
biliary strictures. The preprocedural
diagnosis can be confirmed by
contrast injection, which will clearly
differentiate the filling defects
associated with gallstones and the
luminal narrowing of a stricture. If
there is likely to be a delay in
relieving an obstructed system,
percutaneous drainage may be
required.

33. The cornerstone of gallstone retrieval is an adequate biliary
sphincterotomy, which is normally performed over a well-positioned
guidewire using a sphincterotome connected to an electrosurgical unit.
Most gallstones less than 1 cm in diameter will pass spontaneously in
the days and weeks following a sphincterotomy, but most endoscopists
prefer to ensure duct clearance at the initial procedure to reduce the
risk of impaction, cholangitis or pancreatitis. This can be achieved by
trawling the duct using a balloon catheter or by extraction using a wire
basket.

34. If standard techniques fail, large or
awkwardly placed stones can be crushed
using mechanical lithotripsy. If adequate
stone extraction cannot be achieved at the
initial ERCP it is imperative to ensure biliary
drainage with the placement of a removable
plastic stent while alternative options are
considered. These include surgery,
endoscopically directed shockwaves under
direct choledochoscopic vision and
extracorporeal shockwave lithotripsy with
subsequent ERCP to remove stone
fragments.

35. Dilation of benign biliary strictures uses
balloon catheters similar to those used in
angioplasty inserted over a guidewire under
fluoroscopic control. It is traditional to insert
a temporary plastic stent to maintain
drainage as several attempts at dilatation
may be required. Self-expanding metal stents
are most commonly used for the palliation of
malignant biliary obstruction and are also
normally inserted after a modest
sphincterotomy. Correct stent placement can
normally be confirmed by a flow of bile after
release and by the presence of air in the
biliary tree on follow-up plain abdominal
radiographs.

36. In addition to the standard techniques discussed above, ERCP is also
used for pancreatic disease and the assessment of biliary dysmotility
(sphincter of Oddi dysfunction) using manometry in specialist centres.
Indications include pancreatic stone extraction, the dilatation of
pancreatic duct strictures and the transgastric drainage of pancreatic
pseudocysts. To minimise the risks of subsequent pancreatitis,
pancreatic sphincterotomy is most safely performed after the
placement of a temporary pancreatic stent to prevent stasis within the
pancreatic duct.

37. Visualisation and sampling
of biliary lesions is becoming
easier and more effective
with the development of
newer through-the-
duodenoscope
cholangioscopes that allow
direct visualisation and
instrumentation of the biliary
and pancreatic ducts.

38. Complications associated with endoscopic
retrograde cholangiopancreatography
The same risks associated with other endoscopic procedures also
apply to patients undergoing ERCP, but risks may be increased because
of the increased patient frailty and high sedation levels required.
Complications specific to ERCP include duodenal perforation
(1.3%)/hemorrhage (1.4%) after scope insertion or sphincterotomy,
pancreatitis (4.3%) and sepsis (3–30%); the mortality rate approaches
1%. It is important to remember that postsphincterotomy
complications may be retroperitoneal and, therefore, CT scanning is
essential in patients with pain, tachycardia or hypotension
postprocedure. Although normally mild, post-ERCP pancreatitis can be
severe with extensive pancreatic necrosis and a significant mortality
rate

39. Risk factors for post-ERCP pancreatitis.
Definite: Suspected SOD; Young age; Normal bilirubin; Prior ERCP-
related pancreatitis; Difficult cannulation; Pancreatic duct contrast
injection; Pancreatic sphincterotomy; Balloon dilatation of biliary
sphincter;
Possible: Female sex; Low volume of ERCPs performed; Absent CBD
stone;

40. COLONOSCOPY
Two key revelations about the practical
performance of colonoscopy have allowed
skilled operatives to achieve a greater than 95%
cecal intubation rate and frequent ileal
intubation with minimal discomfort using light
sedation. The first is that continued inward
pressure of the endoscope results in the
formation of loops within the mobile sigmoid
and transverse colon, decreasing angulation
control at the tip and removing the beneficial
effect of shaft torque to aid steering around
acute bends.

41. The second is that pulling back the
scope regularly with appropriate
torque to ensure a straight passage
through the sigmoid colon and
around the splenic flexure greatly
aids the completion of right-sided
examination. Targeted abdominal
hand pressure to prevent loops in a
mobile colon and regular patient
position change to enhance mucosal
views and remove residual bowel
content are also important aids to
successful colonoscopy.

42. Indications for colonoscopy
●● Rectal bleeding with looser or more frequent stools +/− abdominal pain related to bowel
actions
●● Iron deficiency anemia (after biochemical confirmation +/− negative coeliac serology):
esophagogastroduodenoscopy and colonoscopy together
●● Right iliac fossa mass if ultrasound is suggestive of colonic origin
●● Change in bowel habit associated with fever/elevated inflammatory response
●● Chronic diarrhea (>6 weeks) after sigmoidoscopy/rectal biopsy and negative coeliac
serology
●● Follow-up of colorectal cancer and polyps
●● Screening of patients with a family history of colorectal cancer
●● Assessment/removal of a lesion seen on radiological examination
●● Assessment of ulcerative colitis/Crohn’s extent and activity
●● Surveillance of inflammatory bowel disease
●● Surveillance of acromegaly/ureterosigmoidostomy

43. Therapeutic colonoscopy
The most common therapeutic procedure performed at colonoscopy is
the resection of colonic polyps. Retrieved specimens can be assessed for
risk factors for neoplastic progression and an appropriate surveillance
strategy determined. Small polyps up to 5 mm should be removed by
cheese-wiring with a ‘cold’ snare. Hot biopsy is a technique in which the
tip of a small pedunculated polyp is grasped between diathermy biopsy
forceps and tented away from the bowel wall. A brief burst of monopolar
current is used to coagulate the stalk, allowing the polyp to be removed.
This is rarely performed in current practice due to an increased risk of
immediate and delayed thermal damage to the bowel wall, particularly in
the right colon. Larger polyps with a defined stalk can be resected using
snare polypectomy with coagulating current either en bloc or piecemeal
depending on their size

44. Sessile polyps extending over several centimetres can be removed
by endoscopic mucosal resection, which involves lifting the polyp away
from the muscularis propria with a submucosal injection of saline to
prevent iatrogenic perforation Care should be taken with all
polypectomies in the right colon where the wall may only be 2–3 mm
thick. Removal of large or extensive flat polyps should only be
attempted by appropriately trained endoscopists. Endoscopic
submucosal dissection (ESD) can be used to remove large flat lesions
which are not amenable to EMR.

45. Complications of colonoscopy
Complications during routine diagnostic colonoscopy by an
experienced colonocopist are rare, although perforations have been
reported as a result of excessive shaft tip pressure and with excessive
air insufflation in severe diverticular disease. Total colonoscopy is
contraindicated in the presence of severe colitis; a limited unprepped
examination and careful mucosal biopsy only should be performed.
Polypectomy is associated with a well-documented rate of perforation
(approximately 1%) and hemorrhage (1–2%).

46. Immediate hemorrhage should be managed by re-snaring the polyp
stalk where possible and applying tamponade for several minutes
followed by careful coagulation if this is unsuccessful. Submucosal
adrenaline injection and the deployment of hemoclips are alternatives
if this is not possible. Delayed hemorrhage may occur 1–14 days
postpolypectomy and can normally be managed by conservative
observation. Transfusion may occasionally be required, but repeat
colonoscopy is rarely necessary.

47. If recognized at the time of polypectomy, small perforations should
be closed using clips and the patient admitted for observation.
Symptoms of abdominal pain and cardiovascular compromise after a
polypectomy should alert one to the risk of delayed perforation.
Patients should be kept nil by mouth and receive intravenous
resuscitation and antibiotics. Prompt assessment with plain radiography
and a CT scan will often distinguish between a frank perforation and a
transmural burn with associated localised peritonitis (the
postpolypectomy syndrome). Assessment by an experienced colorectal
surgeon is essential, as surgery is often the most appropriate course of
action.

48. ENDOSCOPIC ULTRASOUND
combines the traditional
mucosal image with a separate
ultrasound view that clearly
depicts the intestinal layers and
proximate extraintestinal
structures. Its use has
revolutionised the staging and
management of upper
gastrointestinal and
hepatobiliary malignancy.

49. There are two main types of echoendoscope: the radial
echoendoscope has a radially arranged ultrasound probe and a
forward-viewing lens. This is used for diagnostic work such as local
tumour staging in the oesophagus and stomach. The linear
echoendoscope is a side-viewing scope with a working channel much
like an ERCP scope, and a linearly arranged ultrasound probe. This
conformation allows ultrasound assessment and ultrasound-guided
sampling of tissues to be performed

50. Indications for endoscopic ultrasound:
Diagnostic:
Staging of oesophageal/gastric malignancy;
Staging of hepatobiliary malignancy;
Diagnosis of choledoccal microlithiasis;
Therapeutic:
Biopsy of paraoesophageal lymph nodes;
Biopsy of submucosal upper GI lesions;
Biopsy of pancreaticobiliary mass;
Biopsy of portal lymphadenopathy;
Biopsy of left adrenal and left liver masses;
Transgastric drainage of pancreatic pseudocyst;
Coeliac plexus block;