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The Fundamentals

Practical Gastrointestinal Endoscopy: The Fundamentals, Sixth Edition. Peter B Cotton and Christopher B Williams

© 2008 Peter B Cotton, Christopher B Williams, Robert H Hawes and Brian P Saunders, ISBN: 978-1-405-15902-9

Page 114

CHapter 6106

thresholds and individual attitudes to pain are not always easy
to predict before colonoscopy, because tolerance of the (pecu-
liarly unpleasant) dull quality of visceral pain varies so much.
It is sensible to warn the patient that there will be a few seconds
of the sensation of �wind� distension at some point during the
procedure, but to give feedback at once, rather than suffering
in silence.

During a typical and correctly performed colonoscopy, minor
pain is experienced by the patient for only 20�30 seconds. Using
moderate or no sedation, and employing the skills, changes of
position, and other �tricks of the trade� described below, pain
only occurs during looping in the sigmoid colon and whilst pass-
ing the sigmoid�descending colon junction. During the rest of a
normal procedure a patient with average pain threshold should
experience little more than mild distension or the urge to pass
�atus. It is worth pointing out to the patient that pain is useful
to the endoscopist because it shows that a loop is forming, but is
not dangerous and can usually be stopped in a few seconds (by
straightening out the loop that is causing it).
The use of sedation has advantages and disadvantages. The
unsedated or very lightly sedated patient can cooperate by
changing position, needs no recovery period, and can travel
home unaided immediately. The colonoscopist is also encour-
aged to develop dexterous and gentle insertion technique. On
the other hand, some endoscopists who never employ sedation
also admit to only 70�80% success in performing total colonos-
copy, presumably because some examinations were intolerable.
If light �conscious sedation� is used (typically equivalent in ef-
fect to 2�3 glasses of wine or beer), the patient is likely to �nd
the examination tolerable, even enjoyable, or to have amnesia for
it. The endoscopist is helped to be thorough by the knowledge
that the patient is comfortable, and is also more likely to achieve
total colonoscopy in a shorter time. Using heavy sedation en-
doscopists can get away with ham-handed and forcibly loop-
ing technique�a bad investment in the long term, less likely to
achieve complete examinations, more likely to result in compli-
cations, and more expensive in instrument repair bills.

It is often said that it is dangerous to sedate, because the safety
factor of pain is removed. This is not strictly true, providing that
the endoscopist�s threshold of awareness lowers as the patient�s
pain threshold is raised�taking restlessness or changes of fa-
cial expression as a warning that tissues and attachments are
being overstretched.

Most endoscopists use a balanced approach to sedation that
will be affected by many factors, including personal experience
and the individual patient�s attitude. A relaxed patient with a

Page 115

ColonosCopy and Flexible sigmoidosCopy 107

short colon having a limited examination rarely needs sedation,
but an anxious patient with a tortuous colon, severe diverticular
disease, or a bad previous experience needs protection. Patients
with irritable bowel syndrome or pain as presenting features
are likely to be hypersensitive to stretch and will benefit from

A very few patients have a morbid fear of colonoscopy, a low
pain threshold, or a known “difficult” colon that justifies offer-
ing light general anesthesia. General anesthesia is only likely
to be hazardous if it allows an inexperienced colonoscopist to
use brutal technique while the patient cannot protest. However,
even experienced endoscopists are more likely to “push the lim-
its” and to become more mechanistic if patients are routinely
anesthetized and “out of it.”

Nitrous oxide inhalation

Nitrous oxide/oxygen inhalation can be a useful “half-way
house” between no sedation and conventional IV sedation. The
50 : 50 nitrous oxide/oxygen mixture is self-administered by the
patient, inhaling from a small cylinder fitted with a demand
valve. Breathing the gas through a small single-use mouthpiece
(Fig. 6.1) avoids the difficulties that can be experienced in get-
ting a good fit with a face mask, and also the phobia that some
patients experience with masks.

The patient is shown how to inhale, then “pre-breathes” for
a minute or two as the endoscopist prepares to start the pro-
cedure, with the intention of achieving gas saturation of the
body fatty tissues. Thereafter it takes only 20–30 seconds of gas
breathing, when required, to obtain a “high” that makes short-
lived pain significantly more tolerable. Nitrous oxide/oxygen
inhalation should prove useful for some flexible sigmoidoscop-
ies and, used alone, can be sufficient for motivated patients hav-
ing total colonoscopy by a skilled endoscopist. Scared patients,
prolonged or difficult examinations, and examinations by inex-
pert endoscopists require conventional sedation.

Intravenous sedation

The ideal sedative regime for colonoscopy would last only 5–10
minutes, with a strong analgesic action but no respiratory de-
pression or after-effects, allowing the patient to be comfortable
yet accessible and able to change position during the procedure,
but then to recover rapidly afterwards. The nearest approach to
this ideal is currently given by IV delivery, through an in-dwell-
ing plastic cannula, of a benzodiazepine hypnotic such as mida-
zolam (Versed® 1.25–5 mg maximum) or diazepam (Valium®

Fig. 6.1 Nitrous oxide/oxygen
mixture is breathed through a

Page 228

Index 221

lesions 53–4
retroflexion in (J maneuver)

47–8, 48
see also entries beginning with

stomas 104, 172
stretchers 12
submucosal lesions
colon 169
sampling, upper GI tract 58
suction/aspiration 10
air in hepatic flexure 156, 156,

colonic air and fluid 129
failure 114
polypectomy specimens

185–6, 186, 187
rectal fluid or residue 123
suction/biopsy channel 9–10,

10, 11
blockage 14–15, 114
cleaning 17, 18
suction/instrumentation port

10, 122
suction traps 12, 12
biopsy specimen collection 58,

polyp retrieval 185, 185–6, 187

tattooing 198, 198
teicoplanin 27, 110–11
telangiectasia, bleeding 79–80
teniae coli 119–20, 120
appendix orifice 158, 158
sigmoid colon 130, 130
transverse colon 153, 153
tenting 189, 189
therapeutic colonoscopy 176–206
complications 92
equipment 176–82
therapeutic upper endoscopy

through-the-scope (TTS) balloon

dilation 62, 62, 202
thumb control 38, 126–7, 126–7
tip (endoscope)
angulation see angulation
colonic perforation 91
control 7, 9
deflectable elevator or bridge

9–10, 11
direct forward vision 10, 10
lateral vision 10–11, 11
toluidine blue 55
torque-steering 122, 123, 127–8,


sigmoid colon 130
splenic flexure 147–8, 148
transverse colon 153–4
see also corkscrewing
total colonoscopy 89, 93, 106, 159
trans-anal endoscopic

microsurgery (TEMS) 192–3
trans-illumination 159, 159, 167
transverse colon 152–5
drooping 152, 153
endoscopic anatomy 152–3,

hand-pressure over 155
identifying 166–7
passage through 153–4, 153–5
triangular configuration 146,

152, 152–3
tri-prong grasping device 73, 73
triamcinolone 64
trolleys 12
tuberculosis 15, 95
two-handed one-person

colonoscopy 124–5
two-person colonoscopy 124

ulcerative colitis 94, 171, 197
bleeding 75, 77–9, 78, 79
colorectal 171
stigmata 78
see also duodenal ulcers; gastric

umbilical 7, 8
underwater colonoscopy 144
universal precautions 15
unplanned events 23–6
colonoscopy 90–2
see also complications
upper endoscopy
diagnostic see diagnostic upper

endoscopes 11
indications 22–3
medications/sedation 32–4
monitoring 31
patient education and consent

26–31, 28–30
patient preparation 31
recovery and discharge 34–5
risks and complications 23–6
therapeutic 61–84
upper GI bleeding, acute 74–80
complications of hemostasis 80
identifying source 75
lavage 74–5
timing of endoscopy 74

Page 229


ulcers 77–9
variceal 75–7
vascular lesions 79–80
uvula 40, 40

Valium® see diazepam
vancomycin 27
varices 75–7
banding 76, 76
care after treatment 77
esophageal 52
gastric 76, 77
injection sclerotherapy 76, 76–7
vascular lesions, bleeding 79–80
Versed® see midazolam
video monitors 2, 7, 8
video-proctoscopy 119, 122, 172
videoscopes 12

villous adenomas 170
vocal cords 40, 40
volvulus 204

waiting rooms 3
walking-stick handle effect 134,

134, 147
wash-out techique, multiple

polyps 197
water channel see air/water

water supply, sterile 18
water-wash failure 114
web sites 208
wind pain 135
women, colon anatomy 134, 152

Z-line 43, 43
Zenker’s diverticulum 52
Zollinger–Ellison syndrome 55

upper GI bleeding, acute

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