Mechanical Bowel Preparation

in Elective Colorectal Surgery

Is it evidence based ?

Dennis CK NgPYNEH

21-5-2005

BackgroundMortality of colorectal surgery is mainly due to sepsisVery high mortality (>20%) before the introduction of iv antibiotics and mechanical bowel preparation

Glenn F, et al, Ann Surg 1966

Decrease the bacterial loadImproving bowel handlingEnable palpation of whole bowelAvoid mechanical disruption of anastomosis by well-formed stoolFacilitate the on-table colonoscopy

Precipitate intestinal obstructionSpillage of bowel contentElectrolyte and osmolarity disturbance

Current StatusNow, more than 99% of colorectal surgeons routinely employed mechanical bowel preparation

Zmora O, et al, Am Surg 2003

In my hospitalLow residual diet 3 days beforeFluid diet 1 day beforeNaPO4 the day before OT

Is it really necessary?Primary anastomosis may be safe in an unprepared bowel in obstructed colon (emergency operation)

White CM, et al, Dis Colon Rectum 1985Mealy K, et al, Br J Surg 1988

Dorudi S, et al, Ann R Coll Surg Engl 1990Naraynsingh V, et al, Br J Surg 1999

Is it really necessary?Primary repair of the bowel in penetrating colonic injury is safe in unprepared bowel

George SM, et al, Ann Surg 1989Sasaki LS, et al, J Trauma 1995

Jacobson LE, et al, Am Surg 1997 Curran TJ, et al, Am J Surg 1999

Conrad JK, et al, Dis Colon Rectum 2000

Literature SearchRandomized Controlled Trials and Meta-analysis from literatureKeywords:

Mechanical bowel preparationElective colorectal surgery

Randomized Controlled Trial

9 RCTs available in literatureFrom 1992 to 20036 are full papers, 3 are abstracts

Year Format Size

MBP / no MBP

Bowel Prep

Brownson et al

1992 Abstract 179 86 / 93 PEG

Burke et al 1994 Full paper

186 82 / 87 Sodium picosulfate

Santos et al 1994 Full paper

157 72 / 77 Mannitol, laxative, enema

Fillmann et al 1995 Full paper

60 30 / 30 Mannitol

Miettinen et al 2000 Full paper

279 138 / 129

PEG

Tabusso et al 2002 Full paper

47 24 / 23 PEG, mannitol

Zomera et al 2003 Full paper

415 187 / 193

PEG, enema

Bucher et al 2003 Abstract 93 47 / 46 PEG, phophonate

Fa-Si-Oen et al 2003 Abstract N/A 125 / 125

PEG

Randomized Controlled Trial

AdvantageLevel Ib evidenceHomogeneity of the procedures

DisadvantageInadequate sample size (power of 80% need 950 patients)Impossible in a single center

Year

Anastomostic Leakage

Wound Infection

Prep No Prep

Prep No Prep

Brownson et al 1992

8/67 1/67 5/86 7/93

Burke et al 1994

3/82 4/87 4/82 3/87

Santos et al 1994

7/72 4/77 17/72 9/77

Fillmann et al 1995

2/30 1/30 1/30 2/30

Miettinen et al 2000

5/138 3/129 5/138 3/129

Tabusso et al 2002

5/24 0/23 2/24 0/23

Zomera et al 2003

7/187 4/193 12/187 11/193

Bucher et al 2003

4/47 1/46 4/47 1/46

Fa-Si-Oen et al 2003

7/125 6/125 9/125 7/125

Meta-analysis4 meta-analysis available in literature

Cameron Platell et al1998, Disease of the Colon & Rectum

Pascal Bucher et al2004, Archieves of Surgery

K Slim et al2004, British Journal of Surgery

Cochrane Database of Systematic Review2004

Meta-analysisAdvantage

Level Ia evidenceCan have adequate power because the patient numbers are larger

DisadvantageHeterogeneity between studiesDetails of individual study is not enoughPublication bias

Meta-analysis Cameron Platell et al

Pascal Bucher et al

K Slim et al

Cochrane Database of Systematic Review

Year 1998 2004 2004 2004

Brownson et al, 1992

× × × ×

Burke et al, 1994 × × × ×

Santos et al, 1994 × × × ×

Fillmann et al, 1995

× × ×

Miettinen et al, 2000

× × ×

Tabusso et al, 2002

×

Zomera et al, 2003 × × ×

Bucher et al, 2003 × ×

Fa-Si-Oen et al, 2003

× ×

MethodsSearch into literature (no restriction on year, language, format)Randomized controlled trials onlyQuality of studies are reviewedOriginal data from the author Meta-analysis performed using raw data

K Slim et al, 2004

Pascal Bucher et al, 2004

Pascal Bucher et al, 2004

Cochrane Database of Systematic Review, 2004

Cochrane Database of Systematic Review, 2004

Cochrane Database of Systematic Review, 2004

Anastomostic leakage

Wound infection

Mortality

Cameron Platell et al1998

More in MBP group (p<0.114)

More in MBP group (p<0.002)

N/A

Pascal Bucher et al2004

More in MBP group (p=0.03)

More in MBP group (p=0.15)

More in MBP group (p=0.60)

K Slim et al2004

More in MBP group (p= 0.032)

More in MBP group (p=0.175)

More in MBP group (not significant)

Cochrane Database of Systematic Review2004

More in MBP group (p=0.003)

More in MBP group (p=0.07)

More in MBP group (not significant)

ResultsSignificantly more anastomotic leakage in patients receiving mechanical bowel prep when compared with no prepIncreased septic complications and mortalities in patients receiving mechanical bowel prep, but not statistically significant

ProblemsMainly use PEG, effect of other form of bowel prep?Antibiotics and mechanical bowel prep introduced at the same time, how about bowel prep alone?The results are confined to the open surgery, role in lap surgery?

Year Format Size MBP / no MBP

Bowel Prep

Brownson et al

1992 Abstract 179 86 / 93 PEG

Burke et al 1994 Full paper

186 82 / 87 Sodium picosulfate

Santos et al 1994 Full paper

157 72 / 77 Mannitol, laxative, enema

Fillmann et al 1995 Full paper

60 30 / 30 Mannitol

Miettinen et al

2000 Full paper

279 138 / 129 PEG

Tabusso et al 2002 Full paper

47 24 / 23 PEG, mannitol

Zomera et al 2003 Full paper

415 187 / 193 PEG, enema

Bucher et al 2003 Abstract 93 47 / 46 PEG, phophonate

Fa-Si-Oen et al

2003 Abstract N/A 125 / 125 PEG

ProblemsMainly use PEG, effect of other form of bowel prep?Antibiotics and mechanical bowel prep introduced at the same time, how about bowel prep alone?The results are confined to the open surgery, role in lap surgery?

ProblemsMainly use PEG, effect of other form of bowel prep? Antibiotics and mechanical bowel prep introduced at the same time, how about bowel prep alone?The results are confined to the open surgery, role in lap surgery?

ConclusionNo good evidence (level I or II) so far from literature showed mechanical bowel prep can reduce complicationsActually, it may be more dangerous than no bowel prep in elective open colorectal surgeryThe applications of studies are limited by their power and methods

Current ConsensusBefore further powerful evidence from literatureRoutine use of bowel prep is still the common practice

Any changes we can made?

? NaPO4 instead of PEG

? Selective bowel preparationNot in right hemicolectomyNot in endoscopically obstructed lesionsFavor in lap surgery

Thank You