Nutritional Support in Colorectal Surgery

Acknowledgment

We gratefully acknowledge Maureen E. Rombeau, MA, for editorial assistance.

Introduction

Surgeons are justifiably proud of their seminal contributions to nutritional care of the hospitalized patient. These contributions include quantifying the prevalence of malnutrition, confirming the association of malnutrition with adverse clinical outcomes, discovering parenteral nutrition (PN), and demonstrating, in selected groups of patients, that providing nutritional support (NS) may either prevent or correct malnutrition-associated morbidity. Despite the lack of confirmatory data in many surgical populations, surgeons must still decide when, what, and how to feed their patients while recognizing that the alternative is starvation.

In this chapter we review the assessment of nutritional status, indications for NS, dietary components and their delivery, and new directions in NS, with particular emphasis on colon and rectal surgery (CRS). For purposes of discussion, NS is defined arbitrarily as the provision of oral supplements, enteral feeding, or parenteral nutrients. Every attempt has been made to provide evidence-based recommendations. A complete discussion of this topic is beyond the scope of this short review. For more extensive information, the reader is referred to the Web site of the American Society for Parenteral and Enteral Nutrition (ASPEN) at http://www.nutritioncare.org/ .

Nutritional Assessment

The decision to provide NS is based, in part, on measurement of criteria predictive of a malnutrition-induced adverse outcome. It should be emphasized that these measures are not totally determined by the patient’s nutritional status; they are also influenced by the primary diagnosis, degree of metabolic stress, and presence of infection. Extensive information is available on nutritional assessment for perioperative NS, ranging from sophisticated multivariate indices (which are more feasible with dedicated teams performing these functions) to more readily performed clinical history and measurement of serum proteins. Important assessment criteria to initiate NS are shown in Box 83-1 .

BOX 83-1

Strong and Moderate Indications for Perioperative Nutritional Support

Strong Indications

ONE of the following:

Nonvolitional loss of ≥10% usual body weight within 2-3 mo prior to hospitalization
Serum albumin <3.0 g/dL in euvolemic state

Moderate Indications

TWO of the following:

Current oral intake meeting <50% of total energy needs
Starvation >7 days
Anticipation of nutritional support >7 days
Serum prealbumin <150 mg/dL in euvolemic state

It should be noted that these criteria are guidelines and not absolute recommendations for NS. Clinical judgment remains the most important determinant in deciding when, what, and how to feed patients.

Indications for Nutritional Support

General Indications

General indications for perioperative NS for the patient undergoing CRS include severe malnutrition as determined clinically by weight loss and reduced serum proteins. Significant loss of body weight is perhaps the most important single indication for NS. Nonvolitional loss of more than 10% of usual weight within 3 months prior to surgery and/or a serum albumin level less than 3 g/dL in the euvolemic state are important criteria to initiate some type of perioperative NS ( Box 83-1 ).

Severe Malnutrition

The indications for NS, particularly for parenteral feeding, have become more limited during the past 40 years because of the lack of confirmatory data in the most common groups of minimally and moderately malnourished patients.

Severe malnutrition in perioperative patients is associated with adverse postoperative outcomes, including increased infection, poor wound healing, anastomotic breakdown, coagulopathy, and heart failure. Delaying an elective colorectal operation to improve the patient’s nutritional status may therefore be beneficial, but only if the patient is severely malnourished. The decision to use NS preoperatively must be made with an appreciation of the rising costs of health care, issues with third-party payor reimbursement, and administrative pressures to decrease hospital stay. In a recent Cochrane Review of preoperative nutrition in patients undergoing digestive tract surgery, it was concluded that immune-enhancing nutrition and PN had significant outcome benefits; however, trials evaluating standard enteral or oral supplemental nutrition were inconclusive.

One of the goals of preoperative nutrition in this patient population is to minimize loss of nitrogen from skeletal muscle by decreasing the duration of fasting and supporting muscle mass and immune function. Despite these metabolic goals, data only support aggressive NS for the most severely malnourished surgical patients because neither preoperative PN nor enteral nutrition (EN) provides a clear benefit in either the borderline or mildly malnourished patient. Moreover, multiple studies that failed to show a clear benefit, and that occasionally showed a detriment in these patients, led ASPEN to conclude that perioperative NS in patients with cancer should be limited to persons with severe malnutrition who are likely to be unable to eat for more than 7 to 10 days after surgery, as shown in Box 83-1 . PN should be given to patients who will not be able to meet their nutritional requirements by oral or enteral tube feeds within the same period.

Postoperative Nutrition

With the exception of the severely malnourished preoperative patient, most NS is provided postoperatively. The traditional postoperative management of keeping patients “nil by mouth” (NPO) until clinical signs of return of bowel function are present is no longer justified. To our knowledge, there is no significant outcome benefit with starting a clear liquid diet versus a regular or low-residue diet. However, initiating a regular diet offers numerous nutritional advantages, including increased caloric intake, decreased protein catabolism and weight loss, improved patient satisfaction, and decreased length of hospital stay. Moreover, level 1 evidence supports early postoperative feeding in patients undergoing elective colon and rectal surgery. Initiation of enteral feeds within 2 days of surgery shortens postoperative ileus and enhances return to oral intake. Thus, it behooves the colorectal surgeon to anticipate these issues and plan appropriately; for example, intraoperative placement of feeding tubes may be warranted to allow for early EN in the malnourished patient with colorectal cancer. PN should be reserved for patients who cannot meet their nutrient needs by 7 days after surgery. Fast-track or enhanced recovery programs begin oral intake within 24 hours of surgery (see the Early Postoperative Feeding: “Fast Track” section). Early administration of an oral diet diminishes the duration of a postoperative ileus, decreases postoperative complication rates, and lowers mortality. No significant increase in anastomotic leaks or dehiscence occurs, and early feeding results in a trend toward lower infection rates and decreased length of hospital stays. The major complication related to the early initiation of a diet is an increased risk of vomiting and bloating.

Specific CRS Indications

Inflammatory Bowel Disease

Almost all patients with Crohn disease and approximately one third of those with ulcerative colitis will require surgery. Some degree of malnutrition is common among most perioperative patients with inflammatory bowel disease (IBD) because of insufficient dietary intake, malabsorption, chronic inflammation, and adverse effects of medications. The extent of malnutrition depends on the chronicity of the disease, its severity, and the degree of involvement of the small intestine.

Preoperative malnutrition, as defined by unintended weight loss, or decreased serum proteins such as albumin and prealbumin, is associated with increased postoperative morbidity in persons with IBD. In fact, a preoperative serum albumin level less than 3.5 g/dL was associated with an increased risk of anastomotic leak after colon resection. Thus aggressive preoperative and postoperative NS has been recommended for selected surgical patients with IBD.

Insufficient data exist to support either a specific perioperative feeding regimen or generalized goals of nutritional care for patients with IBD.

Some patients with Crohn disease have undergone multiple resections of both the small and large intestine, leading to short bowel syndrome. Nutritional management of these patients is particularly challenging. This topic is described elsewhere in this book ( Chapter 72 ).

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