Perioperative Feeding Considerations

Historically, oral and enteral feeding have been discouraged following GI surgical procedures, with "bowel rest" recommended to promote anastomotic healing and prevent nausea and vomiting [85]. More recently, it has become clear that GI function returns rapidly postop-eratively in most patients, and intraluminal nutrients promote bowel hypertrophy and anastomotic healing [85]. Even in the absence of peristalsis, the small intestine regains the ability to absorb nutrients quickly after surgery. Early enteral nutrition in malnourished surgical patients is associated with improved wound healing, maintenance of gut function and improved gut immune function. It is also associated with decreased length of stay in intensive care [80, 85, 86]. Furthermore, early resumption of oral/enteral feeding is only occasionally associated with unwanted side effects such as nausea, vomiting, colic and anorexia.

Maintenance of nutrition status perioperatively can be facilitated by careful preoperative planning and creation of a postoperative nutrition care plan [82]. Failure to consider nutrition and diet issues periopera-tively can result in lost opportunities to maintain nutrition status and to avoid nutrition related complications. The postoperative nutrition care plan should be determined and discussed with the patient prior to surgery.

It has become commonplace to establish enteral feeding access during major gastrointestinal procedures [87, 88]. Facilitation of early enteral feeding in patients with moderate or severe preoperative malnutrition can improve surgical outcomes [5, 64, 89]. In patients with established preoperative malnutrition, the benefits of enteral access outweigh the risks of enteral access related complications [90]. Intraoperative placement of a gastrostomy or jejunostomy tube for enteral access should be strongly considered in patients who are malnourished preoperatively or in whom a prolonged period of poor oral intake is anticipated (7-14 days).

In addition to planning for access for nutrition support preopera-tively, it is also important to discuss transition back to an oral diet. Upper gastrointestinal surgical resection may be associated with significant postoperative morbidity, including dumping syndrome, delayed gastric emptying, prolonged ileus, obstruction, gastroesophageal reflux and post-gastrectomy syndrome (dumping, fat maldigestion, gastric stasis and lactose intolerance) [91, 92]. Manifestation of these complications can lead to weight loss, malnutrition and increased mortality [93]. Preoperative education to inform patients of normal and abnormal postoperative events can assist them to play an active role in their recovery.

Nutrition education by a registered dietitian has become common place in many settings, including diabetes clinics and even some doctor's offices. For example, the high incidence of malnutrition in bariatric surgery patients [94] has prompted many insurance companies to require nutrition education by a registered dietitian preoperatively [95, 96]. Unfortunately, there are few data on the role of nutrition education in patients undergoing gastrointestinal cancer surgery. Several studies indicate that patients who receive preoper-ative education regarding expectations and pain management [97] experience less anxiety [98, 99] and pain [100, 101], have improved outcomes [102, 103] and increased satisfaction [104, 105].

4.5. Nutrition Support during Chemotherapy

The routine use of PN during chemotherapy in GI cancer patients does not seem to improve patient outcomes [106, 107]. Bone marrow suppression, tumor response and patient survival are not improved in patients receiving adjuvant PN during chemotherapy [108, 109]. PN and EN do have a role in the primary treatment of malnutrition that may be seen as a side effect of chemotherapy, but should be reserved for those patients for whom active treatment options remain and who are clearly malnourished and at risk for worsening malnutrition. It is important to mention that oncology patients appear to prefer PN to EN. The perceived comfort of IV feeding over tube feeding seems to strongly influence patients' choices in this matter [110].

4.6. Immunonutrition

Multiple studies have investigated the impact of "immunonutrition" (EN supplemented with micro- or macronutrients) intended to preserve or improve immune function and thereby improve outcomes in GI cancer patients. Immune enhancing nutrients that have been explored in gastrointestinal cancer patients include omega-3 fatty acids (n3), glutamine (GLN), arginine (ARG), nucleic acids and combinations of these nutrients (Table 7.6). Meta-analyses have demonstrated improved outcomes (reductions in morbidity and mortality) with the use of immunonutrition perioperatively in patients undergoing major GI cancer resections [111, 112].

Glutamine (GLN), the most abundant amino acid in the human body, is an important substrate for rapidly proliferating cells such as lymphocytes, macro-phages, enterocytes, fibroblasts and renal epithelium [113]. There are limited data on the effectiveness of enteral GLN alone because it is commonly supplemented with other immunonutrients. One prospective, randomized study of perioperative parenteral GLN in colorectal cancer patients indicated improved nitrogen balance with glutamine supplementation [114].

The n-3 fatty acids, essential in the diet, favor production of prostaglandins in the 3-series (PGE3) and leukotrienes in the 5-series, which are associated with improved immunocompetence and reduced inflammatory responses. Studies of enteral n-3 fatty acid administration performed in pancreatic cancer patients indicate that n-3 fatty acid supplementation in the range of 2-3 g per day help stabilize weight [115-117]. Parenteral n-3 fatty acid supplementation in colorectal cancer patients increases leukotriene 5 levels and decreases TNF levels [118].

Studies of ARG in combination with other immunonutrients indicate improved immune parameters and a decreased incidence of infection in patients undergoing elective upper and lower gastrointestinal surgery for cancer [119-121]. Patients with colorectal cancer receiving perioperative parenteral ARG experienced enhanced immune responsiveness when compared to controls [122].

Nucleotides, administered in the form of nucleic acids, seem to stimulate nonspecific parameters of immune function; the mechanism

Table 7.6

Studies of the use of Immunonutrients in Gastrointestinal Cancer

First author Year

Study design

Results

Comments

Arginine, RNA and omega-3 fatty acids Daly [66] 1992 EN vs. isEN

Braga [146] Heslin [147]

1995

1995

1996

1997

Braga [148] 1998

EN vs. isEN; upper GI

cancer EN vs. isEN; upper GI

cancer Pre-op, oral EN vs. isEN; colorectal and stomach cancer

Intravenous crystalloid vs. isEN; upper GI cancer surgery

PN vs. EN vs. isEN; gastric and pancreatic cancer

85 Improved nutrition and immune parameters, clinical outcomes in isEN group 42 Improved nutrition and immune parameters in isEN group 60 Improved immune parameters, clinical outcomes in isEN group 40 Improved nutrition and gut function parameters in isEN group

195 Trend toward increased morbidity, mortality in isEN group

166 Increased incidence of cardio-pulmonary complications in PN group. Lower severity of post-op infections and shorter LOS in malnourished isEN group compared to PN group. Earlier return of bowel function in EN groups

Criticized because of post hoc grouping of endpoints

No clinical endpoints

No clinical endpoints isEN outcomes not attributable to jejunostomy-related complications. Mean volume of isEN 300 ml/day 78% of subjects classified as malnourished pre-op

Carlo [77] pancreatic cancer

Senkal [121] 1999

Gianotti [119] 2002

Braga [119] 2002

Farreras [120] 2005

Pre-op and post-op Oral 154 isEN + SOD vs. pre-op and post-op oral EN + SOD; upper gastrointestinal cancer Pre-op isEN + SOD vs. 305 pre- and post-op isEN + SOD vs. SOD alone; cancer of the gastrointestinal tract Pre-op oral isEN = SOD 200 vs. pre-op and post-op isEN + SOD vs. pre-op oral EN + SOD vs. SOD; colorectal cancer Early post-op EN vs. early 66 post-op isEN; gastric cancer

Decreased morbidity, infections, LOS in the isEN group. Earlier return of bowel function in EN groups

Decreased infections; lower cost of complications

EN not tolerated in 16% of patients

No information on pre-operative nutrition status

Decreased post-operative infections and shorter LOS in isEN groups

Malnourished patients excluded

Improved immune response, gut Primarily well-nourished patients oxygenation and microprofusion in both isEN groups

Lower episodes of surgical wound complications; improved parameters of wound healing

(Continued)

Table 7.6 (Continued)

First author Year

Study design

Results

Comments

Arginine, glutamine, and n-3 fatty acids

2001

Omega-3 fatty acids Fearon [116] 2001

Jatoi [115] 2004

Moses [117] 2004

Klek [149] 2005

Post-op EN vs. post-op supplemented EN; gastrointestinal cancers

SOD + standard oral supplement vs. SOD + n-3 FA enriched liquid supplement; pancreatic cancer n-3 FA enriched oral supplement vs. megestrol acetate vs. n-3 FA enriched oral supplement + megestrol acetate; incurable malignancies SOD + standard oral supplement vs. SOD + n-3 FA enriched oral supplement; pancreatic cancer PN vs. PN + GLN vs. PN + n-3 FA; gastric cancer

48 Improved immune parameters, decreased pro-inflammatory cytokines in immune-supplemented EN group

200 Gain of weight and LBM in n-3 fatty acid group

421 Weight stabilization and improved appetite in both groups; no effect on mortality or QOL

24 Increased physical activity and total energy expenditure in n-3 fatty acid group.

105 Improved prealbumin and TLC in GLN and n-3 FA group; shorter hospital stay

Patients with BMI > 30 excluded

SOD, standard oral diet; isEN, immunonutrients supplemented enteral nutrition of action is not understood [70]. There was no effect on survival with nucleotide supplementation in colorectal cancer patients in one study [123].

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