Is There a Role for Bowel Preparation and Oral or Parenteral Antibiotics In Infection Control in Contemporary Colon Surgery?

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Is There a Role for Bowel Preparation and Oral or Parenteral Antibiotics In Infection Control in Contemporary Colon Surgery?

Susan Galandiuk, MD ^a^,^b^,^c^,^*, Donald E. Fry, MD ^d, Hiram C. Polk, Jr., MD ^e

^a Section of Colon and Rectal Surgery, Department of Surgery, University of Louisville, Louisville, KY 40292, USA

^b Price Institute of Surgical Research, University of Louisville, Louisville, KY, USA

^c Blizard Institute of Cell & Molecular Science, Barts & The London School of Medicine & Dentistry, Queen Mary University of London, London, UK

^d Northwestern University Feinberg School of Medicine, Chicago, IL, USA

^e Department of Surgery, University of Louisville, School of Medicine, Louisville, KY 40292, USA

^* Corresponding author. Section of Colon and Rectal Surgery, Department of Surgery, University of Louisville, Louisville, KY 40292, USA.

E-mail address: s0gala01@louisville.edu

Over the past 90 years, colorectal resection has been associated with a progressive increase in safety for what is still a major and frequently performed operation. It has often been stated that the wide use of antibiotics after World War II was associated with increasing survival after colon surgery [1]; as a matter of fact, the broad application and use of blood banks in the late 1930s [2] and the improved care overall associated with the proliferation of intensive care units in the 1990s correlate better with those improvements. Although there are still outliers in institutional mortality rates in colon surgery, the mortality rate for a large number of voluntarily reporting university teaching and affiliated hospitals is just under 2% for elective operations. Interestingly, even after anastomotic leak, rescue by an early diagnosis and appropriate systemic management, often including diversion, is so much the rule that death rates are still low (Fig. 1) [3].

Fig. 1 Colon resection risk adjusted mortality by hospital for the fourth quarter of 2004 through the first quarter of 2010. These data were provided by the University HealthSystem Consortium and reflects results in 101, 722 patients, of whom 1774 died in hospitals. The risk adjustment was accomplished by proprietary logistic regression modeling techniques, where each patient is assigned a severity of illness level and with it expected length of stay, costs, and mortality. Although the overall mortality is acceptable, it is apparent that some hospitals (to the far right on this figure) have considerable room for improvement (Polk HC Jr, Hohmann S, unpublished data, 2011). Red line is the median.

One major predisposing factor for untoward results in patients who must undergo colon resection is having the operation after a hospitalization of several days. Obviously, that environment sets the stage for a substantial increase in infection rates, often with antibiotic-resistant, hospital-acquired bacteria [4]. Another major trend recently has included omission of bowel preparation to decrease morbidity, especially dehydration in the elderly.

There has been a dramatic shift toward both laparoscopic and robotic colon resection and the use of a variety of stapling devices for anastomoses [5–8]. There has also been an improved standardization of the operation for rectal cancer, including performance of meso-rectal excision with better oncologic outcomes [9]. At this point in time, practice patterns in North America show 90% of segmental colon resections being performed by general surgeons and approximately 75% of all rectal cancer excisions performed by colorectal surgeons. This finding may well represent a worthy professional sharing of procedures of the type discussed herein. Another significant advance over this decade has been the broad, even worldwide implementation of fast-track pathways for elective surgery, to both decrease hospital length of stay and reduce nonoperative complications, as has been studied and described repeatedly by Kehlet [10].

For the purposes of this review, it is presumed that the vast majority of colon resections, especially the elective ones, are performed for colon cancer or diverticulitis. In this setting, oral antibiotics and bowel preparation with laxatives are less widely used now than they were 10 years ago. Emergency surgery of the colon, such as for hemorrhage or obstruction or acute diverticulitis, produces entirely different outcomes with in-hospital death rates ranging from 16% to 25% in many recent reports [11]. Furthermore, interest in 1- and 2-year survival rates has disclosed more late deaths than commonly known, often but not exclusively caused by progression or recurrence of cancer and intercurrent disease, such as cardiovascular disorders.

Parenteral antibiotic administration

Surgical site or operative wound infection rates for elective colon resection were as high as 80% in the 1930s [12], and progressively improved to approximately 40% by the end of the 1960s. Effective preoperative systemic antibiotics as defined by Polk and Lopez-Mayor [13] further reduced surgical site infection (SSI) rates and no further placebo-controlled trials are necessary to prove that generally accepted point [14]. SSI does have variably reported rates. However, literally hundreds of reports on colorectal or other gastrointestinal operations support this view, of which a few deserve further reference [15–17]. During the last 2 decades, there have been at least 3 rigorously evaluated patient studies following elective colorectal resection that have shown SSI rates higher than expected when appropriate systemic antibiotics were given and patients were followed for 30 days following operation [12,17,18]. Many recent quality and safety studies [19] focus on 3 factors: (1) choice of an antibiotic with emphasis on safety, an appropriate spectrum, and one that remains in the incision for the duration of the operation; (2) administration of the first dose, ideally 30 minutes before incision; and (3) prompt discontinuation of the systemic antibiotic is important, even a single dose, to avoid antibiotic-related serious morbidity, such as Clostridium difficile colitis as notably reported with ertapenem [20].

The authors think that additional methods may be needed to supplement systemic antibiotics, especially when errors of omission or commission, as previously noted, occur (Table 1) [21–29]. Accurate timing of the first dose related to time of incision and prompt discontinuation is essential [30].

Table 1 Surgical wound infections comparing oral antibiotic bowel preparation plus systemic antibiotics versus systemic antibiotics alone in elective colon surgery

Mechanical bowel preparation

Preoperative preparation of the colon has been a special method of prevention of SSI. Human stool may have as many as 10¹² bacteria per gram and purging fecal material before colonic surgery has always seemed intuitively correct [31,32]. Actually, mechanical cleansing alone does not reduce the density of bacteria in the mucosal fluid and it has never been shown to reduce SSI by itself. This conclusion was recognized 70 years ago and has been revalidated by a host of clinical trials (Table 2) [31–39] and the obligatory meta-analysis over the last 10 years [40]. The recently identified failures of mechanical preparation have led to some surgeons abandoning preparation altogether. Understanding the failure of mechanical preparation alone led clinicians in the pre-World War II and post-World War II era to pursue antimicrobial methods to reduce the bacterial concentration of colonic contents [1,41–43].