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Mechanical Bowel Preparation in Elective Colorectal Surgery Is it evidence based ?. Dennis CK Ng PYNEH 21-5-2005. Background. Mortality of colorectal surgery is mainly due to sepsis Very high mortality (>20%) before the introduction of iv antibiotics and mechanical bowel preparation
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Mechanical Bowel Preparation in Elective Colorectal SurgeryIs it evidence based ? Dennis CK Ng PYNEH 21-5-2005
Background • Mortality of colorectal surgery is mainly due to sepsis • Very high mortality (>20%) before the introduction of iv antibiotics and mechanical bowel preparation Glenn F, et al, Ann Surg 1966
Decrease the bacterial load Improving bowel handling Enable palpation of whole bowel Avoid mechanical disruption of anastomosis by well-formed stool Facilitate the on-table colonoscopy Precipitate intestinal obstruction Spillage of bowel content Electrolyte and osmolarity disturbance
Current Status • Now, more than 99% of colorectal surgeons routinely employed mechanical bowel preparation Zmora O, et al, Am Surg 2003 • In my hospital • Low residual diet 3 days before • Fluid diet 1 day before • NaPO4 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 1985 Mealy K, et al, Br J Surg 1988 Dorudi S, et al, Ann R Coll Surg Engl 1990 Naraynsingh 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 1989 Sasaki 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 Search • Randomized Controlled Trials and Meta-analysis from literature • Keywords: • Mechanical bowel preparation • Elective colorectal surgery
Randomized Controlled Trial • 9 RCTs available in literature • From 1992 to 2003 • 6 are full papers, 3 are abstracts
Randomized Controlled Trial • Advantage • Level Ib evidence • Homogeneity of the procedures • Disadvantage • Inadequate sample size (power of 80% need 950 patients) • Impossible in a single center
Meta-analysis • 4 meta-analysis available in literature • Cameron Platell et al • 1998, Disease of the Colon & Rectum • Pascal Bucher et al • 2004, Archieves of Surgery • K Slim et al • 2004, British Journal of Surgery • Cochrane Database of Systematic Review • 2004
Meta-analysis • Advantage • Level Ia evidence • Can have adequate power because the patient numbers are larger • Disadvantage • Heterogeneity between studies • Details of individual study is not enough • Publication bias
Methods • Search into literature (no restriction on year, language, format) • Randomized controlled trials only • Quality of studies are reviewed • Original data from the author • Meta-analysis performed using raw data
Results • Significantly more anastomotic leakage in patients receiving mechanical bowel prep when compared with no prep • Increased septic complications and mortalities in patients receiving mechanical bowel prep, but not statistically significant
Problems • Mainly 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?
Problems • Mainly 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?
Problems • Mainly 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?
Conclusion • No good evidence (level I or II) so far from literature showed mechanical bowel prep can reduce complications • Actually, it may be more dangerous than no bowel prep in elective open colorectal surgery • The applications of studies are limited by their power and methods
Current Consensus • Before further powerful evidence from literature • Routine use of bowel prep is still the common practice
Any changes we can made? • ? NaPO4 instead of PEG • ? Selective bowel preparation • Not in right hemicolectomy • Not in endoscopically obstructed lesions • Favor in lap surgery