Bowel prep - yes or no? Ian Botterill Dept Colorectal Surgery St James’ University Hospital Leeds

Goligher (1970’s) “…there are great advantages to operating on an empty colon …if the growth is stenotic, days should be set aside … excellent preparation may be obtained with 30l via the irrigation machine …my preference is 5-6 days, initial softening then vigorous expulsion with castor oil … finally, massive colonic irrigation in the terminal phase ….this process can be exhausting for frail, elderly patients ….some suggest that it may lead to hypovolaemia and circulatory imbalance” Surgery of the Anus, Rectum & Colon 3 rd edition 1975

Heresy…. Irving et al 1987 (BJS) - retrospective, uncontrolled study - no bowel prep y anastomoses - no leaks - 8% wound sepsis

The BJS response “this paper which challenges accepted surgical practice, is a veritable little bomb of a paper, brief, iconoclastic and disrespectful of hallowed tradition in surgery” Professor David Johnston, BJS 1987;74:553-4

Justification for using bowel prep Poor mechanical bowel prep associated with anastomotic dehiscence 1 “Notwithstanding recent publications….intuitively it is unfathomable to believe that stool does not have deleterious effect on a healing anastomosis” 2 1Irvin, Goligher BJS 1973;60: Surgery for the Colon, Rectum & Anus 2 nd ed. Gordon & Nivatvongs. 1999

Downside of bowel prep Hypovolaemia - ↓ cardiac output / shock - ↓ coronary artery filling - colonic mucosal ischaemia Electrolyte disturbance - fits - dysrhythmias - myopathy - nausea Diarrhoea - lack of sleep &vitality Colonic explosion

Bowel prep - creation of a need for ‘pre-optimisation’? Pts undergoing major elective surgery (large DGH) Randomised to: - standard care - HDU pre-optimisation (fluids +/- 2 inotropes) guided by PAFC / CVP Active treatment group -required 1.5l IV fluid -↓ M&M & ↓ LoS Wilson et al. BMJ 1999;318:

Cochrane review 2004 Inclusion criteria - randomised clinical trials, elective surgery - leak rate (1 y outcome) clearly stated Stratified (where possible) - low anterior resection - colo-colic / intra-peritoneal anastomosis

Cochrane review -2 y outcome measures Mortality Peritonitis Re-operation Wound sepsis Extra-abdominal (infectious / non-infectious) Total infection rate

Recruitment to Cochrane review Oral bowel prep (+/- enema) versus nil Standard meta-analysis methodology

Studies included / excluded 14 studies identified - 5 excluded: no control (3) elemental diet in controls (1) ill-defined outcomes (1) 9 included - 7 english / 1 spanish / 1 portugese - 3/9 abstracts - 9 trials: 789 oral prep / 803 no oral prep

Cochrane review: problems…. Power calculation 0/9 Intention to treat analysis 0/9

Cochrane review -casemix of included studies No anastomosis - 2/9 included pts without an anastomosis - 2/9 included pts ultimately not anastomosed Preoperative radio / chemoradiotherapy - 0/9 studies reported use Antibiotic prophylaxis - 2/9 did not describe use Demographics - 3/9 did not describe demographics / operation - 1/9 described significant diff’s

Cochrane review: -exclusion criteria in the papers No description of exclusion criteria (4/9) Recent antibiotics / bowel prep (3/9) Failure to tolerate prep (2/9) No anastomosis performed (2/9)

Potential bias in included papers (1) None used ITT analysis -3/9 withdrew pts after randomisation (5%,31%,10%) Selection bias: 5/9 randomisation not described Blinding: 8/9 not blinded Performance bias: nil detected

Potential bias (2) Attrition bias: -4/9 did not describe withdrawls Detection bias -4/9 did not describe diagnostic processes Reporting bias - 5/9 no stratification of leaks into anastomotic subgroups

Results: 1 y outcome measure (anastomotic leak) Low rectal colontotal Bowel prep 9.8%2.9%6.2% No bowel prep 7.5%1.6%3.2%* *p=0.003

2 y outcome measures Focal peritoneal sepsis -5.7% (bowel prep) -2.5% (no prep) p=0.05 Other 2 y endpoints - no significant differences

Sensitivity analysis Exclusion studies with inadequate randomisation - OR unchanged, significance lost (T2 error) Exclusion of studies in abstract form - no effect Exclusion of study including children - no effect Exclusion of studies including no anastomosis - ↓ OR of leak 2.1 (2.3) p=0.03

Length of stay? Multimodal peri-operative recovery package Managed care pathways Henrik Kehlet24hrs & 48hrs post sigmoid colectomy L.o.S. only quoted in 1/9 articles reviewed!

NumberAge (yrs) ASA 3&4Op’nStay (d) BO (d) Morbidity Mortality Readmission R&L colectomy 2 (2-60) 28% 4% 15% 16711Sigmoid colectomy 2 (2-9) 26% nil rectopexy32nil 3% nil 2955reversal Hartmann’s 327% nil 7% ASA 2+ R & L colectomy % nil 7% 14 / 1164 / 68Possum matched R & L colectomy 3 v. 73 Summary of published data (to 2004)

Cochrane conclusions for practice Oral bowel prep “… not been shown to be valuable … may lead to ↑ anastomotic leakage … oral bowel prep should be omitted”

Cochrane conclusions -implications for research “results of this show the necessity of completing more, properly designed trails” …blinding & stratification …consider pre-op radiotherapy …inclusion & exclusion criteria …define discharge criteria, dropout & outcome measures

Proposed avoidance of oral prep… Colon surgery - R hemi / extended R hemi / subtotal -L hemi* Permanent stoma - Hartmann’s - APER* - PPC & ileostomy Proctology -Abdominal rectopexy* -Anal sphincter repair* -Rectal flap advancement* PPC & IPAA* * Use enema

Proposed cases for oral prep? Generally need defunctioning - TME Undergone RT / CRT Possible need for on-table colonoscopy - the ‘unknown’ colonoscopist - severe sigmoid diverticular disease - small tumour - consider tattooing for laparoscopic resection

Dogma (n.) : - a doctrine or code of beliefs accepted as authorative -a doctrinal notion asserted without regard to evidence or truth Recognise morbidity of bowel prep Recognise limitations of current evidence base - effect of radiotherapy - type of procedures & pts suitable for accelerated care Summary