MS , FACRSI , FAIS.
Surgeon , Coloproctologist and GI Endoscopist.
Jabalpur Hospital and Research Centre.
Email : firstname.lastname@example.org
For a colorectal surgeon there is nothing like working in a bowel which
is devoid of faecal matter and which is clean and empty. Thus there
is a great conveinence to the surgeon to operate on an empty bowel than
on one loaded with faecal matter . It is reasonable to suppose that
operation on the bowel, especially those involving a suture line or
an anastomosis is safer and less likely to be associated with gross
faecal contamination and sepsis if the intestine is in a relatively
or completely empty condition. This assumption forms the basis for the
practice of mechanical bowel preparation prior to major colorectal surgery.
The practice has been so widely accepted that it has never been subjected
to any stringent scrutiny. Different workers in this field have
different opinion about the bowel preparation prior to major colorectal
surgery. Huges stated that preoperative bowel preparation does not affect
the outcome of major colorectal surgery. Tyson and spauiding clamed
that mechanical cleansing alone could be effective in reducing the bacterial
content of the bowel.
Why Do We Need Bowel Preparation -
¢ Simplifies the procedure.
¢ Procedure takes lesser time (Disreases risk of anaestesia)
¢ Minimizes the complications like fecal contamination during surgery.
¢ Increases the accuracy of endoscopic procedures.
When to do it -
¢ Prior to Colonoscopy.
¢ Prior to barium enema.
¢ Prior to elective colorectal surgeries.
¢ Prior to laparoscopic surgeries.
¢ Prior to certain elective gynaecological surgeries.
Regimen : Background & Chronology -
Prior to early 80's.
¢ Purgatives with enemas.
Senna, Castor oil, Bisacodyl .
¢ Magnesium sulphate / Citrate.
¢ PEG-ELS - Std Method.
Late 90's- PEG cotinues to enjoy the status of the method of choice.
Renewed interest in sodium phosphate.
Bowel preparation taught to me in early 1980s was -
¢ Cap. Neomycin 1Gm QID 3 days.
¢ Tab Metrogyl 400 mg TDS 3 days.
¢ Bowel wash BD 3 days.
¢ Castor oil 30 ml OD 2 day.
¢ Liquid diet only 2 day.
¢ Parental antibiotics
(single dose) 2 hours
Ideal Bowel Preparation Regimen.
¢ Acceptable to patients.
¢ Easy to adminiter.
¢ Well tolerated.
¢ Reliable in emptying the colon of all formed fecal matter and
most liquid material.
¢ Not affect the colon's appearance,either for gross visual examination
or later histological examinations.
Bowel preparation is divided into -
¢ Mechanical Cleaning.
¢ Antibiotics what and when ?
¢ Role of pre and probiotics.
¢ Any role of emergency settings ?
a. Obstructive lesions.
(1) Mechanical Cleaning. -
Four main methods are being regularly employed for the purpose to secure
a relatively empty large bowel for colorectal operations.
(a) Administration of conventional purgative drugs - Castor oil
given in the dose of 60 ml two days prior to the operation early in
the morning so that its action which normally takes 6 to 8 hours will
have been completed well before night time . During the last preoperative
day the patient is given massive washout per anum. If the patient is
admitted in the hospital two or three days prior to administration of
castor oil mielder aperient such as magnesium sulphate or liquid paraffin
15 ml thrice a day is given to soften the faeces accumulated above the
lesion. This soften faeces can negotiate easily through the narrow portion
of the bowel . Then the main aperient is given on the second preoperative
day. It is usually possible with this regimen to obtain an empty or
at least not grossly loaded bowel at the time of operation. The exception
is when there is complete annular neoplasm in which case despite vigerous
preoperative purgation and enema, considerable faecal residue is found
in the colon above the growth at operation.
(b) Use of elemental diet - Minimal residue diet is given to
the patients due for bowel operation. On such a diet there was a striking
reduction in the bulk and bacterial content of the stools. But another
study with five days regimen of elemental diet plus mechanical preparation
with milk of magnesia and bisacodyl suppositories. No bowel antiseptics
were given. The result shown that mechanical preparation of the bowel
was good but effect on the bacterial content of both aerobic and anaroebic
bacteria was disappointing so in addition to mechanical bowel preparation
an antibacterial preparation should be given as well.
(c) Whole gut irrigation - A nasogastric tube of 3 mm diameter
is passed into the stomach via the nose. Patient in a semi sitting position
on an examination table with a 20 cms diameter hole under the buttock.
The irrigant consisting of
Sodium Chloride - 6.14 gms
Potassium Chloride - 0.75gms.
Sodium bicarbonate - 2.94 gms.
And distill water 1000 ml is delivered to the stomach via the nasogastric
tube by a peristaltic pump at a rate of 75 ml per minute. The bowel
action starts after 40 to 60 minutes from the start of irrigation. Clear
fluid starts from 90 minutes on wards and the irrigation is continued
for one hour . During the irrigation there is an absorption of 1.5 liters
per hour of fluid which is excreated by the kidneys. This form of bowel
preparation is not advised for elderly patients or those with impared
heart or kidney functions.
Mannitol - Mannitol is not absorbed in the GI tract and reaches
the colon undigested.
Oral administration of mannitol alone with a rapid intake of large amount
of fluids produces a vigorous osmotic catharsis, for preparation of
bowel for colonoscopy or colorectal surgery. Its effect is to produce
much the same short of massive washout from above, that is a much similar
method as whole gut irrigation, without the patient having being submitted
to nasogastric intubation and to sit continuously on a commode. The
mannitol is made in a 10% solution in water one litre of such fluid
mixed with fruit juice and ice to make more palatable, is drunk in half
an hour . Then drinking a plenty of water in the next hour . Ending
with passage of clear fluid from the anus . Two problems in connection
have been uncovered - (a) Increased predisposition to generation of
explosive gases in the bowel prepared by mannitol , which could be a
hazard in connection with the use of colonoscopic diathermy. (b) Incidence
of septic complication after colorectal operations when mannitol preparation
had been employed. So a systemic antibiotic cover with gentamicin and
metronidazole is given . Now a days Mannitol has been discontinued as
a method of bowel preparation because -
¢ In the colon,the bacterial colony ferments Mannitol into methane,
which is an expolsive gas.
¢ The usage of electrocuatery during surgery can result in an explosion
due to the presence of this methane.
PEG (Poly Ethylene Glycol) -
¢ Introduced in 1980 by Dr Banner.
¢ Non digestible / non absorbable.
¢ Osmotically balanced.
PEG : Machanism of Action - Clenses the bowel by washout of ingested
vertually no net absorption or excreation of water or ions.
¢ Virtually no net shift of fluid and electrolytes.
¢ Good bowel preparation.
¢ Contraindicated patients with ileus,gastric retension,gastrointestinal
obstruction,bowel perforation , toxic colitis and toxic megacolon.
Supplied as powders to be reconstituted by the patient
2 liters of reconstiuted fluid to be taken . The product is given the
night before the morning examination. If given on the same day, a minimum
of one hour should elapse between the appearance of clear stools and
Oral Sodium Phosphate (NaP) - It is a buffered oral saline osmotic
laxative.Renewed interest due to recent studies and good acceptance.
It is marketed as "Fleet Soda" in USA
and "EXELYTE" in India.
Sodium Phosphate - Is a Saline laxative which acts by osmotically
retaining water in the bowel, and by drawing water into the bowel, from
the body ,causing a watery diarrhea. Given at least 5 to 6 hours before
the procedure.It is available in liquid form. To be added to 300 ml
of fluid before consuming it. But it is to be used with caution in children
and adult with renal problems. Its chronic use may lead to electrolyte
Mode of Action of Sodium Phosphate Solution - It has a cathartic action
is due to osmotic properties. The volume created is not the volume consumed
but the volume created is by our own body fluid . Low volume intake
however does not lead to depletion of intravascular volume. Presence
of Glycerin lubricates the colon and facilitates the bowel movement.
Moreover it should be taken with 300 ml of liquid.
Contraindications of sodium phosphate solution -
¢ Renal Failure
¢ Congestive Heart Failure.
¢ Gastrointestinal Obstruction.
¢ Bowel Perforation.
¢ Congenital Megacolon.
¢ No to be used in pregnant or nursing women since the placenta
actively transports. phosphates and are secreted in the milk in large
Sodium phosphate solution shoul be used with caution in -
¢ Patients taking diuretics,digitalis or other concomitant medications
for cardiac arrhythmias due to excessive Na.
¢ In children (however dehydration was reported in children with
kidney failure, excessive dosage or Hirschprung disease).
¢ Phosphate absorption may be increased in patients with ischaemic
colitis & can cause clinical manifestations.
Assessment of the level of preparation by surgeon -
¢ Excellent : Colon empty and collapsed.
¢ Good : Fluid and gas filled.
¢ Satisfactory : Particulate formed stools.
¢ Poor : Large solid stool.
(2) Antibiotics what and when ?
¢ Colorectal operations are classified as
clean and contaminated procedures.
¢ Antibiotics: without which the wound infection rate : 30 - 60
¢ The rationale of pre-operative antibiotics is
(a) To reduce the colonic bacterial concentration
(b) To obtain sufficient tissue levels of antibiotics during & shortly
¢ What antibiotics - As bacterial contamination of surgical
field by colonic contents causes septic complications so a proper antibiotics
which should be effective against aerobic bacteria - Escherichia coli
and Anaerobic bacteria - Bacteroides fragilis.
(1) Intestinal Antiseptics - Neomycin - 1Gm four hourly for two
days. Matronidazole - Given by mouth before operation acts not only
locally on the contents of the gut but also acts systemically after
absorption. Dose - 400Mgs - two doses at an interval of four hours then
200 Mgs four hourly for 2 days.
(2) Prophylactic antimicrobial Therapy - According to Surgery
of Anus , Rectum and Colon - By John Gloiger . Three dose of Gentamisin
or Tobramicin. The first dose of
80 Mgs of Gentamicin or Tobramicin given one hour before operation.
Second and third dose at 6 and 12 hours later respectively. Similarly
Metronidazole - 500 Mgs of metronidazole is given IV before operation
. Second and third dose is given at six and twelve hours.
According to Baily and Love Text Book of Surgery - Inj. Cefuroxime 750
Mgs and Metronidazole - 500 Mgs is given in the similar way..
Pre & Probiotics - No randomized trails has been done but
Eubioz, Darolac plus, Becelac, Actigut etc has shown excellent postoperative
results in clinical use.
Theoretically pre & probiotics will prevent post operative infection
and proliferation of unwanted bacteria.
According to Surgery of Anus , Rectum and Colon - By John Gloiger .
The regimen of bowel preparation is as follows -
4 Days before surgery - Light diet - Liquid Paraffin 15 ml 8 hourly.
3 Days before surgery - Light diet - Liquid Paraffin 15 ml 8 huorly.
2 Days before surgery - Liquid diet - Morning 1 litre of 10% Mannitol
OR 90 ml of
Intestinal Antibiotics Exelyte in 300 ml of fruit juice + 1 litre water
Neomycin 1 Gm 4 hourly in half an hour.
Metrinidazole 200 Mgs 4 hourly.
1 Day before Surgery - Liquid diet - Morning and Evening enema with
50 Mgs of Intestinal Antibiotics Oxyphenisatin in one litre of water.
Neomycin 1 Gm 4 hourly
Metrinidazole 200 Mgs 4 hourly
On the day of surgery -Nil by Mouth - No enemas, patient is allowed
to go to toilet to
evacuate any fluid that may remain in the rectum.
Summary - Majority prefer Parenteral antibiotics only or with
oral antimicrobials +
oral Poly ethylene glycol or Sodium phosphate solution . With optional
prebiotics and Probiotics.
Conclusion - Oral sodium phosphate solution is an ideal regimen
for bowel lavage.
As it is a patient friendly regimen.