clin infect dis. 1997 nichols 609 19

609

Current Practices of Preoperative Bowel Preparation Among North AmericanColorectal Surgeons

Ronald Lee Nichols, Jeffrey W. Smith, Rena Y. Garcia, From the Department of Surgery, Tulane University School of Medicine,

Ruth S. Waterman, and James W. C. Holmes New Orleans, Louisiana

In North America, the rate of infections following colorectal surgery decreased after the introduc-tion of oral antibiotic bowel preparation against colonic microflora. Eight hundred eight board-certified colorectal surgeons were surveyed for their current bowel preparation practices beforeelective procedures. The 471 responders (58%) all use mechanical preparation: oral polyethyleneglycol solution (70.9% of the respondents), oral sodium phosphate solution with or without bisacodyl(28.4%), and "traditional" methods of dietary restriction, cathartics, and enemas (28.4%). Mostsurgeons (86.5%) add oral and parenteral antibiotics to the regimen; 11.5% add only parenteralantibiotics, 1.1% add only oral antibiotics, and 0.9% add no antibiotics. Generally (77.8% of cases),oral neomycin and erythromycin or metronidazole are combined with a perioperative parenteralantibiotic. Most individuals start the preparation as outpatients the day before surgery, and theparenteral drugs are added to the regimen 1— 2 hours before the procedure. The use of outpatientbowel preparation is increasing; however, patient selection is critical, and education is needed toreduce the rate of complications.

The true role of colonic intraluminal bacteria, both faculta-tive and anaerobic, in the etiology of infectious complicationsfollowing colorectal surgery was clarified —25 years ago[1-4]. Both the colonic bacterial burden and the rate of subse-quent infections were significantly decreased when the preoper-ative bowel preparation included orally administered antibioticseffective against both bacterial types [3, 4]. Specifically, itwas shown that mechanical preparation and a three-dose oralantibiotic regimen consisting of 1 g each of erythromycin baseand neomycin resulted in suppression of the facultative andanaerobic constituents of the colonic and fecal microflora.

Currently, it is generally accepted that effective bowel prepa-ration includes various oral or parenteral antibiotics, alone orin combination, that have aerobic and anaerobic activities com-bined with an effective mechanical preparation [5]. Many dif-ferent antibiotic regimens have been proposed and tested clini-cally, with some yielding better results than others. Althoughoriginally only oral antibiotics were used effectively, in currentpractice, they are now most often combined with perioperativeparenteral antibiotics. Various mechanical preparations havealso been used to reduce the gross intraluminal contents duringthe surgical procedures.

A previous survey done in 1988, and reported in 1990 [6],showed that the most preferred bowel preparation at that timewas oral polyethylene glycol (PEG) solution for mechanical

Received 30 July 1996; revised 1 October 1996.This work was presented in part at the 9th Annual Meeting of the Surgical

Infection Society-Europe held on 30 May to 1 June 1996 in Paris.Reprints or correspondence: Dr. Ronald Lee Nichols, Department of Surgery

(SL-22), Tulane University School of Medicine, 1430 Tulane Avenue, NewOrleans, Louisiana 70112-2699.

Clinical Infectious Diseases 1997; 24:609-19© 1997 by The University of Chicago. All rights reserved.1058-4838/97/2404-0011$02.00

cleansing combined with preoperative oral neomycin/ery-thromycin base and a perioperative parenteral second-genera-tion cephalosporin antibiotic. Since the time frame of theprevious survey, several new antibiotics have become avail-able for use, older agents have become generic and theirprices have been reduced, and additional clinical studies ofvarious bowel preparations have been conducted [5]. Therehas also been an increased influence of managed care ap-proaches to treatment in the interests of cost containment.An impetus toward preoperative bowel preparation to be con-ducted on an outpatient basis, commonly at the patient'shome, has likewise gained support [7].

There remains some controversy over which antibiotics pro-vide the optimal prophylaxis; the duration of preparation;whether oral, parenteral, or a combination is preferred; andwhich mechanical method should be used. In an attempt togather current knowledge of North American bowel preparationpractices before elective colorectal procedures, we sent a sur-vey to all currently active board-certified colorectal surgeonsin the United States (including Puerto Rico) and Canada (seeappendix at the end of the text).

Methods

The names and addresses of all currently active board-certi-fied colon and rectal surgeons in the United States and Canadawere obtained from the American Society of Colon and RectalSurgeons (Arlington Heights, IL). These physicians were senta questionnaire inquiring about their preoperative bowel prepa-rations before elective surgical procedures. The 20 questionscovered demographics, patient numbers and types, and bothmechanical and antibiotic preparative techniques. Specificquestions concerned the use of oral vs. parenteral antibiotics,preferred mechanical cleansing procedures, and the total dura-tion of the preparation.

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610 Nichols et al. CID 1997;24 (April)

In many questions, the responses added up to more thanthe number of surgeons responding because the questionnairesasked open-ended questions rather than limiting or forcingchoices to one answer. A Likert scale (a five value rating scaleranging from "not important" to "very important" ) was usedto evaluate the factors influencing the overall choice of bowelpreparations. Eight hundred eight questionnaires were sent intwo mailings in March and May 1995. The respondents wereasked to return the anonymous questionnaires by either prepaidbusiness reply mail or toll-free facsimile. The responses wereanalyzed by use of Statview 4.01 (Abacus Concepts, Berkeley,CA) on a Macintosh PowerBook 5300.

Results

Participating surgeons. Four hundred seventy-one (58%)of the 808 colon and rectal surgeons who were sent question-naires returned their surveys within 4 months, and their re-sponses were analyzed for this report. Responses were receivedfrom 45 states, the District of Columbia, Puerto Rico, and threeCanadian provinces. Response rates for the states or provinceswith more than five board-certified surgeons ranged from 44%to 88%.

Most surgeons (391 [83%]) identified their community sizeas large (population, >100,000); 72 (15.3%), as medium (pop-ulation, 25,000-100,000); and only 8 (1.7%), as small (popula-tion, <25,000). The most commonly reported medical affilia-tions were a community hospital (62.6%), teaching hospital(44.4%), or a large medical center (33.3%) (table 1). The re-sponding surgeons received their colon and rectal surgery boardcertification an average of 11.4 years ago (range, 1-39 years).Only three surgeons had been recertified in colon and rectalsurgery, all since 1991.

Four hundred forty-seven surgeons indicated the number ofprocedures that they perform each month. They reported ap-proximately equal average numbers of colon (6.1) and rectal(8.3) procedures each month and twice as many anal procedures

Table 1. Location of professional practices of respondents to a sur-vey on North American bowel preparation practices before electivecolorectal procedures.

Practice typeNo. of

affiliations*Percent of

respondents

Community hospital 295 62.63Teaching hospital 209 44.37Large medical center 157 33.33Medical school 48 10.19Veterans hospital 14 2.97Military hospital 11 2.34Health maintenance organization 1 0.21

* Respondents reported all affiliations; the total number of affiliations isgreater than the number (471) of surgeons responding.

(15.4) (table 2). Most of their procedures are elective(86%-91% depending upon the type of procedure), with mostof the patients being admitted to the hospital on the day ofsurgery (65%-81%) following completion of the bowel prepa-ration at home.

Mechanical procedures. All 471 surgeons who reportedtheir bowel preparative procedures routinely use some form ofmechanical preparation with their patients (figure 1). The mostcommonly preferred forms of mechanical bowel preparationare oral PEG solution (70.9% of respondents), oral sodiumphosphate-buffered solution with or without bisacodyl(28.4%), or the "traditional" usage of dietary restriction, ca-thartics (including magnesium citrate or sulfate), and enemas(28.4%) (table 3). Only a small number of surgeons reportedthat they routinely use whole-gut irrigation, mannitol, or othermethods.

The preferred time to start the mechanical preparation isusually 18-24 hours before the surgical procedure (figure 2).Although there is some variation in the timing, all respondentsstart the preparation r 24 hours before the procedure. Mostpatients complete this mechanical preparation on an outpatientbasis at home before hospital admission.

The traditional bowel preparation, when used, is started anaverage of 29.8 hours (range, 12-48 hours) before the surgicalprocedure. Those surgeons preferring PEG solution employ anaverage of 3.7 L (range, 1-8 L) over 3-4 hours (range, 1-24hours). Although the participants reported their most commonlyused mechanical methods, they would consider other proce-dures when they thought that it was in the patients' best inter-ests or when it was medically indicated. Factors in the decision-making process include noncooperative or noncompliantpatients; those who are very young, old, or frail; or thosewith disease states that might be compromised (e.g., severediverticulitis; active colitis; inflammatory bowel disease; pul-monary, cardiac, or renal disease; severe nausea, cramping, orconstipation; partial obstruction; or tight strictures).

Antibiotic prophylaxis. Of 468 respondents, almost all (464[99.1%]) reported that they routinely use preoperative prophylac-tic antibiotics (table 4). Most (391 [85.4%]) of the 458 surgeonswho listed the rationale for antibiotic choice reported that theantibiotics should protect against facultative and anaerobic colonicbacteria. Smaller numbers of surgeons were concerned with eitheraerobes alone (42 [9.2%]) or anaerobes alone (25 [5.4%]). Corre-spondingly, 45.9% (194) of 423 surgeons reported that both facul-tative and anaerobic bacteria were responsible for infections fol-lowing colorectal procedures at their hospitals. Problems withfacultative bacteria alone were reported by 43.7% (185) of thesurgeons, while only 8% (34) related concerns solely with anaero-bic infections. Ten surgeons (2.4%) were unsure of the bacterialcause of infections at their institutions.

The choices of oral and parenteral antibiotics are listed intable 5. The 471 surgeons who responded reported a total of711 different antibiotic regimens, 625 of which include oralantibiotics. The many regimens had slight variations in theantibiotic and dosage choices, and for this report, the parenteral



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I Mechanical preparation

28.4%*

"Traditional"cathartics and enemas

70.9%*Polyethylene glycol

solution (po)

28.4%*

Sodium phosphatesolution (po)

0.9%*

None Oralonly

86.5%*

Oral plusparenteral

11.5%*

Parenteralonly

Oral components

Neomycinplus erythromycin 53.4%**plus metronidazole 35.0%*"

Parenteral componentsSecond-generation

cephalosporin 65.4%**Other cephalosporin 6.8%**Penicillin/inhibitor

combination 8.3%**Metronidazole 7.5%**

CID 1997;24 (April) Preoperative Preparation of the Colon 611

Table 2. Operative procedures performed per month by 447 respondents to a survey on North Americanbowel preparation practices before elective colorectal procedures.

Average no. Percent of patientsType of of procedures Percent of Percent of admitted on theprocedure per month (range) emergent procedures elective procedures day of surgery

Colon 8.3 (1-60) 10.0 89.7 65.4Rectal 6.1 (0-60) 8.0 91.1 72.5Anal 15.4 (1-200) 14.5 85.5 80.9

choices were combined into antibiotic families. As can be seen,the most prevalent oral regimens are neomycin with eithererythromycin or metronidazole. In most cases (77.8% of the711 regimens), oral neomycin and either erythromycin or met-ronidazole are combined with the perioperative use of a paren-teral antibiotic.

The oral antibiotics are normally started on the day beforesurgery (97.2%), with only 11 respondents (2.8%) beginning themearlier than 1 day before (figure 2). Of all reported regimens, theparenteral antibiotics most often chosen are second-generationcephalosporins (figure 1). Some surgeons prefer to use a first-or third-generation cephalosporin, penicillin with a /3-lactamaseinhibitor, or intravenous metronidazole. Most surgeons start theparenteral antibiotics 1 hour before surgery (figure 2).

Most (93.7%) of the surgeons limit the routine administrationof the parenteral antibiotics to four or less doses stopping within24 hours after surgery. A few, however, do give the drugs for 2to 4 days. The surgeons stated that the antibiotic regimens wouldbe continued if perforation or spillage was noted during surgery.They also would consider alternate regimens, presumably in-creased duration or different drugs, for immunocompromised pa-tients or those with Crohn's disease, prosthetic devices, antibioticallergies, or cardiac valve replacements.

Influencing factors. Six factors were addressed concerningthe surgeons' choices for bowel preparation. The results showedthat the most important concerns are reduced rates of infectionsin their patients that result from both reduction of bacterial burdenand a grossly clean colon at the time of operation (table 6). Patientacceptability and ease of administration were of lesser importance,while the least important concern was the cost of the preparation.Specific questions concerning the use of a home bowel preparationbefore surgery were also addressed. Although most surgeons (283[59.5%] of 476) thought it was as good as inpatient administration,approximately one-third (146 [30.7%]) did not agree, and 10%(47) thought it was usually all right but did express concerns forsome patients.

The concerns noted by the surgeons who responded "no"and "usually OK" included such problems as dehydration,lack of compliance, the patients' inability to self-administer aneffective enema, and an inadequately prepared colon foundduring surgery. They believed that certain patients should notreceive home bowel preparations unless there was adequatesupervision by a family member or visiting nurse. These pa-tients would be elderly individuals, those with disabilities, non-reliant or nonmotivated patients, or those distracted or overlyanxious over the impending surgery. Only a small number

I Liquid or low-residue diet I

Figure 1. Preoperative bowelpreparation regimens currentlyprescribed in North America. All471 surgeons answering the surveyreported the use of mechanicalpreparation. Most (70.9%) of thesurgeons use oral polyethyleneglycol solution, but equal use oforal sodium phosphate solution(28.4%) or "traditional" prepara-tive techniques (cathartics and ene-mas; 28.4%) was also reported.Antibiotics are added to the regi-men by 99.1% of the surgeons,with most employing both oral andparenteral types. * = percent ofsurvey respondents; ** = percentof 711 antibiotic regimens re-ported.

Antibiotic preparation



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612 Nichols et al. CID 1997; 24 (April)

Table 3. Mechanical preparations used by respondents to a surveyon North American bowel preparation practices before elective colo-rect4l procedures.

Mechanical preparation usedNo.* of

preparationsPercent of

respondents

Polyethylene glycol solution 334 70.9Sodium phosphate solutions 134 28.4"Traditional" 1. 134 28.4Whole-gut irrigation 11 2.3Mannitol 9 1.9Other 4 0.9

* Respondents reported their normally used preparation(s); the total number(626) of preparations is more than the number (471) of surgeons responding.All surgeons used some form of mechanical preparation.

t With or without bisacodyl.I Combination of dietary restriction, enemas, and cathartics.

of surgeons thought that a home preparation should only beperformed for colonoscopy and that an inpatient preparationshould be used for all other procedures.

Discussion

During colon and rectal surgical procedures, it is importantto avoid bacterial contamination of the peritoneal cavity oradjacent tissues by colonic microflora to prevent serious post-operative intraabdominal or surgical site infections. For mostof this century, surgeons have tried to sterilize the lumen ofthe colon to reduce the rates of surgical morbidity and mortalityfollowing colon or rectal surgery [2]. As early as 1951, Fine-gold [8] reported on the effects of various antimicrobials onthe colonic microflora. Although coliform bacteria were sup-pressed, the anaerobes were not significantly affected.

Before the 1970s, the primary method of reducing the bacte-rial burden was through effective mechanical cleansing [2].In 1971, studies of traditional mechanical cleansing (dietaryrestrictions, cathartics, and enemas) showed that although grosslumps of stool were removed, bacterial counts in the remainingliquid colonic contents were still significant [9]. Oral antibioticsused at that time (e.g., sulfonamides, streptomycin, kanamycin,and neomycin) had activities effective in suppressing faculta-tive bacteria alone but often failed to prevent postoperativeinfection [2, 3, 10]. In addition, the oral antibiotics were givenfor up to 5 days, resulting in intracolonic overgrowth of staphy-lococci or yeast. Consequently, many' believed thatantibiotic prophylaxis was of little use and did not routinelyemploy it [2].

In the early 1970s, it was found that the intraluminal anaero-bic microflora of the colon and rectum greatly outnumberedthe facultative organisms (— 1,000 to 1) [10, 11] . In1972-1973, it was shown that the addition of an antibioticeffective against the predominant anaerobic bacteria (oralerythromycin base) to an antibiotic previously shown to beeffective against facultative organisms (oral neomycin) was

successful in suppressing intraluminal bacteria when adminis-tered in 1-g doses at 1 P.M., 2 P.M., and 11 P.M. on the daybefore the surgical procedure [3, 4]. Pharmacokinetic studiesshowed that neomycin is not absorbed and remains bacteriolog-ically active within the lumen of the colon, while high intralu-minal and serum levels of erythromycin are found at the timeof surgery (8 A.M.) [ 12, 13]. Both intraluminal (local) andserum (systemic) antibiotics are thought to contribute towardreducing the occurrence of postoperative infections [5].

Figure 2. Timing of the mechanical and antibiotic components ofthe preoperative bowel preparation in North America. Most surgeonsstart the mechanical procedures within 18-24 hours before the opera-tive procedure. The oral antibiotics are administered 12-18 hoursbefore, with parenteral antibiotics being added to the regimen within1 hour of the procedure.



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CID 1997; 24 (April) Preoperative Preparation of the Colon 613

Table 4. Use of oral and parenteral antibiotic bowel preparativetechniques by respondents to a survey on North American bowelpreparation practices before elective colorectal procedures.

No. (%) using parenteral antibiotics

Use of oral antibiotics Yes No

Yes 405 (86.5) 5 (1.1)No 54 (11.5) 4 (0.9)

NOTE. Four hundred sixty-eight of 471 surgeons responded to this ques-tion; all reported the use of mechanical bowel preparation in their preoperativeregimen.

Although the early reports showed the efficacy of oral pro-phylaxis in suppressing the colonic microflora, later studiestested the idea that parenteral antibiotics added to or substitutedfor the oral agents could also be effective [5]. Many differentregimens comparing a multitude of antibiotics were studiedwith varying and conflicting results [5]. On the basis of thesereports, some surgeons, predominantly those in Europe, prefersystemic parenteral agents alone, whereas North American sur-geons favor a combination of oral and parenteral agents [14].

It is important that one be cautious when evaluating theresults of prophylactic studies. For example, results of a two-center trial that were published independently showed strikingdifferences in the rates of infections between the two arms:oral neomycin/erythromycin and parenteral metronidazole/cef-triaxone (site 1, 41% and 10%, respectively; site 2, 4% and7%, respectively) [15, 16]. A questionable study design waslater noted, since mechanical cleansing was used only at thesecond hospital [17]. Therefore, it is imperative that multicentertrials be published together to enable readers to make informedjudgments based upon all available data.

Previous surveys have shown that the percentage of NorthAmerican colon and rectal surgeons using effective antibioticprophylaxis has increased from —85% in 1979 to 100% in 1988[6, 18, 19]. In 1976, one survey indicated that 6% of surgeonsdid not use antibiotic prophylaxis but relied upon mechanicaltechniques to reduce the rate of postoperative infections [20]. Itwas also seen that systemic antibiotics alone were used by 8%of the respondents, oral antibiotics alone were used by 37%, anda combination of both were used by 49%. A sizable percentage(18%) of the surgeons began to administer the systemic antibioticspostoperatively, a practice now known to be suboptimal. Althougha small percentage (0.9%) of surgeons still fail to use effectiveantibiotic prophylaxis, our survey indicates that it remains thestandard of care in North America.

In 1990, a comparison with British surgeons indicated that92% used antibiotic prophylaxis routinely [21]. However, only17% used topical (oral) antibiotic prophylaxis. Seventy-eightpercent of the British surgeons favored a regimen of parenteralcephalosporin plus metronidazole. A three-dose regimen (oneduring surgery and two postoperatively) was reported by 43%of the surgeons, while an additional 48% continued to adminis-ter the antibiotics beyond the three doses.

Although the antibiotic combination should be effective aspreoperative prophylaxis, both the duration of administrationand the use of mechanical preparations with enemas (3 8%),purgatives (37%), mannitol (19%), or whole-gut irrigation (6%)are in sharp contrast to North American practices and mighthelp explain the traditionally higher rates of wound infectionin the United Kingdom [5]. In the United States, rates of post-operative infection following administration of appropriate oralagents, with or without the addition of a parenteral agent, havebeen constantly reported to be < 10% among patients withoutadditional risk factors for infection [22].

Table 5. Most commonly used oral and parenteral antibiotics for preoperative bowel preparation before elective colon or rectal surgery in aNorth American survey.

No. using parenteral antibiotic(s)

Cephalosporin0-Lactamase inhibitor

combinations Metronidazole Other TotalOral antibiotic(s) First-generation Second-generation Third-generation

Neomycin 1 3 0 1 0 6Plus clindamycin 0 2 0 0 0 0 2Plus erythromycin 22 222 26 30 20 14 334Plus metronidazole 18 153 8 21 16 3 219Plus erythromycin and

metronidazole 6 21 5 0 0 0 32Metronidazole 4 7 2 0 0 0 13

Plus erythromycin 4 11 0 3 0 1 19Total with oral

antibiotics 55 419 41 55 37 18 625Total without oral

antibiotics 7 46 4 16 6 86Total 62 465 48 59 53 24 711

NOTE. Four hundred seventy-one respondents listed all regimens commonly prescribed by them.



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Table 6. Factors influencing choices of bowel preparation in a sur-vey on North American bowel preparation practices before electivecolorectal procedures.

FactorNo. of

respondents Mean score* Mode Median

Reduced rate of infections 464 4.80 4 5Reduction of bacteria at

operative site 454 4.53 4 5Cleanliness of operative

site 457 4.43 4 5Patient acceptability 459 4.07 4 4Ease of administration 461 3.98 4 4Cost 460 3.26 3 3

* Higher scores indicate greater importance. Choices varied from 1 (notimportant) to 5 (very important).

Our survey of clinically active colorectal surgeons foundthat oral antibiotics remain well accepted and that the rate ofuse (91.8%) is similar to that reported in 1990 (87.6%) [6]. Amore limited survey from the same period showed that 87%of 206 surgeons used oral prophylaxis [19], while one con-ducted in 1976 indicated its use by 86% of 582 surgeons [20].From 1988 to the present, the rate of the use of parenteralantibiotics, with or without oral agents, has slightly increasedfrom 96.6% to 98.1% [6], which is in contrast to the ratesreported for 1988 and 1976 (90% and 57%, respectively) [19,20]. Parenteral antibiotics are usually administered within 1hour of surgery, a time frame that will provide adequate serumand tissue levels at the time of the procedure. The practice ofhaving "on call" parenteral agents in the operating roomshould be discouraged, as it often results in inadequate tissuelevels during the procedure.

In 1988, 63% of surgeons continued to administer parenteralantibiotics 1 day postoperatively, and 25% continued their usefor 2-3 days postoperatively [19] . Currently, almost 94% ofsurgeons limit administration to a single day (one to fourdoses). This practice is in accordance with the current thoughtthat longer administration does not decrease the incidence ofinfection but may actually contribute toward an increase in thenumber of resistant organisms. However, certain conditionsrequire extended antibiotic administration: delayed operations,oral antibiotics not administered properly, fecal spillage duringthe procedure, prolonged operations (i.e., >3.5-4 hours), andperformance of a rectal resection (e.g., abdominal-perineal op-erations) [14, 23, 24].

The "ideal" antibiotic prophylaxis would result in few in-fections and would be inexpensive, easy to administer, andwell tolerated by patients. The most popular regimens emulatethis ideal by utilizing oral neomycin plus either erythromycinor metronidazole combined with a perioperative parenteral anti-biotic (table 5). Although the additional benefit of perioperativeantibiotics has not been verified, all recent surveys have showntheir popularity. The agents most often added are second-gener-ation cephalosporins (67.7% of cases), drugs that possess activ-

ities against both aerobes and anaerobes. Certain other lesserused regimens exhibit variable activities against these organ-isms, and thus their use should be reconsidered. Those regimenswith oral metronidazole or metronidazole plus erythromycinalone do not cover the facultative gram-negative bacteria. How-ever, the addition of an effective parenteral antibiotic or anti-biotics tends to cover these organisms and will help protectagainst postoperative infection.

Despite the numerous studies showing the benefit of oralprophylaxis, 54 (11.5%) of our respondents administer onlyparenteral prophylaxis with drugs that fail to protect againstall intestinal microflora. Some of the antibiotic regimens re-ported in our survey are redundant, using multiple antibioticswith like spectra (table 5). While the length of administrationis limited, there remains some concern that this practice mayresult in the evolution of resistant organisms. It was noteworthythat none of the responding surgeons reported prophylaxis withimipenem/cilistatin. This combination was used in one Britishtrial without oral prophylaxis and was associated with an infec-tion rate of 26.4%, a rate much higher than seen in NorthAmerican trials [25]. We believe that the use of this combina-tion should remain limited to a therapeutic setting.

All surgeons responding to our survey use mechanical bowelcleansing; the most popular preparation is PEG solution(-4 L administered over 3-4 hours the morning of the daybefore surgery). This regimen has steadily increased in popular-ity since 1987-1988, while the use of "traditional" procedureshas decreased [6, 19]. Although mannitol bowel preparationremains common outside the United States, the rate of its usehere has now decreased to <2%.

While not previously reported, a large number (28.4%) ofour surgeons now routinely use oral sodium phosphate solutionwith or without bisacodyl in a one- to two-dose regimen beforeadministration of the oral antibiotics. This solution cleansesthe bowel by acting as an osmotic purgative and has beenshown to be effective for colorectal cleansing without causingany significant clinical problems [26]. It is currently used atour hospital, and its efficacy has been shown to be superiorto that of PEG solution in promoting colonic cleansing withrelatively small volumes.

Although PEG solution has been approved for bowel cleansingbefore colonoscopy and roentgenographic examinations with bar-ium enemas, oral sodium phosphate solution is also approved forbowel cleansing before surgery [27]. Its use, however, shouldbe limited to those patients without evidence- of kidney disease,congestive heart failure, or other contraindications.

The routine use of mechanical cleansing has recently beenchallenged in several reports from the United Kingdom andIreland [21, 28-30]. On the basis of observations followingemergent and elective colorectal surgery, the researchers con-cluded that mechanical preparation is not needed to furtherreduce infection rates provided that effective antibiotics areadministered.

Irving and Scrimgeour [28] reported an infection rate of8.3% among 72 patients undergoing elective and emergent



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colorectal procedures without bowel cleansing. They believethat oral antibiotics are unnecessary and that bowel cleansingis exhausting to the patient and simply turns solid feces into anuncontrollable liquid. Brownson et al. [29] reported equivalentwound infection rates but higher intraabdominal infection ratesamong patients mechanically cleansed with PEG solution thanamong those not mechanically cleansed. Burke and colleagues[30] found that the presence of solid stool in the colon did notappear to increase infection rates. Despite these reports, webelieve that further controlled studies are needed before thediscontinuance of mechanical preparation can be recom-mended.

Most surgeons responding to the present survey indicatedthat a grossly clean colon during surgery is an important factorin their choice of bowel preparation. The most commonly usedmethods of bowel cleansing can be performed on an outpatientbasis and can be completed the day before surgery. The increas-ing use of the sodium phosphate solution shows that an effec-tive mechanical preparation can be obtained relatively quicklywithout undue stress in the nonobstructed patient. We believethat a clean colon is technically easier to work with; if thecolon is clean, the chance of solid fecal spillage decreases, andnormal colonic motility returns more quickly in the postopera-tive course.

In 1988, a survey showed that most patients (61%) wereadmitted to the hospital the day before surgery, and 33% wereadmitted 2 days before [19]. Very few (3%) received thebowel preparation as outpatients and were admitted on theday of the surgical procedure. The use of outpatient bowelpreparation is now increasing, with one report showing the rateof its use increasing from zero to 88% in a 4-year period endingin 1992 [7]. The widespread use of this technique has notresulted in increased rates of infections or other complications[7, 31-33]. Moreover, yearly savings in hospitalization costsof more than $150 million were estimated for the United Statesalone [7].

Approximately 60% of our survey respondents believe thatthe home preparation can be as good as the one in the hospital.They indicated, however, that not all patients are candidates forthis procedure. Elderly patients or those with contraindicatingconditions should not have a home preparation unless they aresufficiently supervised and adequate written and oral instruc-tions are provided. At our institution, home bowel preparationis routinely used and is generally believed to be beneficialprovided that the patients are screened and educated about theprocedures.

The present survey of board-certified colon and rectal sur-geons indicates that antibiotic prophylaxis efficacious againstboth facultative and anaerobic colonic microflora is routinelyused and that effective mechanical preparations are used. Al-though the cost of the complete preparation was of less concern,the surgeons prefer one that is acceptable to the patient, is easyto administer, and results in a low incidence of postoperativeinfection. These conditions are accomplished by removinggross feces from the intestines by mechanical cleansing, reduc-ing the burden of intraluminal bacteria with administration oforal antibiotics, and providing adequate serum and tissue levelsof antibiotics (oral agents with or without parenteral agents) atthe time of the operation.

No significant changes in antibiotic choices were found fromprevious surveys. Although the most common mechanicalpreparation remains oral PEG solution, the use of oral sodiumphosphate solution with or without bisacodyl is rapidly increas-ing. It appears that a combination of a home bowel preparationand both preoperative oral antibiotics (neomycin plus erythro-mycin or metronidazole) and perioperative parenteral anti-biotics (second-generation cephalosporin) is currently the pre-ferred method of prophylaxis for elective colon and rectalsurgery.

The use of outpatient mechanical preparation is increasing,apparently without an increase in the rate of complications. Itis imperative that adequate precautions be taken to maintainthe current low level of complications now observed.



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Appendix

Bowel Preparation Survey — 1995

DEMOGRAPHICS

1) In what year did you become board certified in colon and rectal surgery? 19

2) In which state do you practice?

3) In which size community do you practice?

Small

(<25,000)

Medium (25-100,000)

Large

(>100,000)

4) In which type of institution do you practice? Check ALL that apply.

Community hospital

Veterans Administration hospital

— Large medical center Military hospitalTeaching hospital

Medical school

5) Approximately how many procedures do you perform each month?

Colon Rectum Anus

6) What percentage of your cases are elective or emergent?Elective: % Colon % Rectum % AnusEmergent: % Colon % Rectum ,% Anus

7) What percentage of your cases are admitted to the hospital the day of surgery?% Colon % Rectum % Anus

BOWEL PREPARATION PROCEDURES

Please answer the following questions regarding preoperative bowel preparation for elective , colonand rectal surgical procedures.

1) Which form of mechanical, preparation do you normally use?None

"Traditional" using cathartics and enemas over hours / days

PEG (polyethylene glycol solution) liters over hoursMannitol grams

Whole-gut lavage liters over hoursOther

2) The mechanical preparation is usually started hours before the operative procedure isscheduled.

3) Are there instances where you feel an alternate mechanical preparative method (not yournormal method as checked above) should be used? Please list:

Completed questionnaire can be sent by FAX to 1-800-813-6157 4-[Page 1 of 3]



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4) Which form ofslat antibiotic , prophylaxis do you normally use? Check ALL that apply.

NoneAminoglycoside

Neomycin mg q hrs X doses

Kanamycin mg q hrs X doses

Clindamycin mg q hrs X doses

Erythromycin base mg q hrs X doses

Metronidazole mg q hrs X doses

Tetracycline mg q hrs X doses

Other mg q hrs X doses

5) The ad antibiotics are started hours before the operative procedure is scheduled.

6) Which form of parenteral , antibiotic , prophylaxis do you normally use?

NoneFirst generation cephalosporin gram(s) q hrs X doses

CefazolinOther

Second generation cephalosporin gram(s) q hrs X doses

CefotetanCefoxitinOther

Third generation cephalosporin gram(s) q hrs X doses

CeftizoximeCeftriaxoneOther

Other gram(s) q hrs X doses

7) The =Mad antibiotics are started hours before the operative procedure is scheduled.

8) Which microorganisms do you feel are most important to protect against in surgical infectionsfollowing colorectal surgical procedures?

Aerobic bacteria (E. coli, Kiebsiella, Enterococcus, etc.)

Anaerobes (B. fragilis, Clostridia, etc.)

Both are equally importantNeither are important

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9) At xox institution, which microorganisms are most implicated in surgical infections followingcolon and rectal procedures?

Aerobic bacteria:

Anaerobes:

Both aerobes and anaerobes are equally implicated.

— Neither are recovered.

10) In patients which you consider "high risk", are special antibiotic precautions (e.g., longerprophylaxis, additional antibiotics, larger doses) utilized?

No

Yes:

11) Rate the following factors in influencing your choice of bowel preparation (mechanical &antibiotic):

Not Veryimportant Neutral important

Cleanliness of operative site 1 2 3 4 5

Cost 1 2 3 4 5

Ease of administration 1 2 3 4 5

Patient acceptance 1 2 3 4 5

Reduction of bacteria at operative site 1 2 3 4 5

Reduction of post-surgical infections 1 2 3 4 5

12) Do you feel that home bowel preparation with the patient admitted to the hospital on the day ofsurgery is as good as a full hospital based preparation?

YES

NO (why not)

13) What is the average daily cost per patient day at your institution? $

ADDITIONAL COMMENTS if desired:

Thankyou for your valua6k time.We appreciate your input for this important survey!

4 Completed questionnaire can be sent by FAX to 1-800-813-6157 4-[Page 3 of 31



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CID 1997; 24 (April) Preoperative Preparation of the Colon 619

Acknowledgments

The authors thank the American Society of Colon and RectalSurgeons and the Fellows of the American Society of Colon andRectal Surgeons. This report would not have been possible withouttheir diligence in filling out the questionnaires. We also thankWhitney T. Michaels, B.S., M.P.H., for her help in reviewing thesurvey data and analyses.

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Documents

oral antibiotics

preferred bowel preparation

oral neomycin

oral sodium phosphate

colonic microflora

effective bowel preparation

rate of infections

colonic bacterial burden