(Adapted from Canadian clinical practice guidelines for nutrition support in mechanically ventilated, critically ill adult patients : DK Heyland, R Dhaliwal, JW Drover, et al. JPEN 2003 27; 5: 355-373).(Updated in June 2005, critical care nutrition website: www.criticalcarenutrition.com)

Clinically relevant questions pertaining to nutrition in the critically ill are listed, the recommendations follow the questions.

1. Does enteral nutrition compared to parenteral nutrition result in better outcomes in the critically ill adult patient?
Recommendation : When considering nutrition support for critically ill patients, use of Enteral Nutrition over Parenteral Nutrition is strongly recommended.

2. Does early enteral nutrition compared to delayed nutrient intake result in better outcomes in the critically ill adult patient?
Recommendation : Early enteral nutrition (within 24-48 hours following admission to ICU) is recommended in critically ill patients.

3. Strategies to optimize delivery and minimize risks of EN : Feeding Protocols Does the use of a feeding protocol result in better outcomes in the critically ill adult patient?
Recommendation : Use of feeding protocol in critically ill patients cannot be recommended at present. If a feeding protocol is to be used, a protocol that incorporates prokinetics (metaclopromide) at initiation with a higher gastric residual volume (250 mls) should be considered as a strategy to optimize delivery of enteral nutrition in critically ill adult patients

4. EN composition : Immune Enhancing: Diets Supplemented With Arginine And Other Select Nutrients. Compared to standard enteral feeds, do diets supplemented with arginine and other nutrients result in improved clinical outcomes in critically ill patients?
Recommendation : Diets supplemented with arginine and other select nutrients should not be used in critically ill patients.

5. Composition of EN: Immune enhancing diets: Fish oils Does the use of an enteral formula with fish oils result in improved clinical outcomes in the critically ill adult patient?
Recommendation : Use of an enteral formula with fish oils should be considered in patients with acute respiratory distress syndrome (ARDS).

6. Composition of EN : Immune enhancing diets: Glutamine Compared to standard care, does glutamine-supplemented enteral nutrition result in improved clinical outcomes in critically ill patients?
Recommendation : Enteral glutamine should be considered in burn and trauma patients. There are insufficient data to support the routine use of enteral glutamine in other critically ill patients.

7. Strategies to optimize benefits and minimize risks of EN : Small Bowel feeding vs. Gastric feeding. Does enteral feeding via the small bowel compared to gastric feeding result in better outcomes in the critically ill adult patient?
Recommendation : Small bowel feeding compared to gastric feeding maybe associated with a reduction in pneumonia in critically ill patients. In units where small bowel access is feasible, routine use of small bowel feedings is recommended. In units where obtaining access involves more logistical difficulties, small bowel feedings should be considered for patients at high risk for intolerance to EN (on inotropes, continuous infusion of sedatives, or paralytic agents, or patients with high nasogastric drainage) or at high risk for regurgitation and aspiration (nursed in supine position). Finally, where obtaining small bowel access is not feasible (no access to fluroscopy or endoscopy and blind techniques not reliable), small bowel feedings should be considered for those select patients that repeatedly demonstrate high gastric residuals and are not tolerating adequate amounts of EN intragastrically.

8. Strategies to optimize benefits and minimize risks of EN: Body position Do alterations in body position result in better outcomes in the critically ill adult patient?
Recommendation : In critically ill patients receiving enteral nutrition the head end of the bed should be elevated to 45 degrees. Where this is not possible, attempts to raise the head of the bed as much as possible should be considered.

9. EN : Continuous vs. other methods of administration? Does continuous administration of enteral nutrition compared to other methods of administration result in better outcomes in critically ill patients?
Recommendation : There are insufficient data to make a recommendation on enteral feeds given continuously vs. other methods of administration in critically ill patients.

10. Combination parenteral nutrition and enteral nutrition. Does the use of parenteral nutrition in combination with enteral nutrition result in better outcomes in the critically ill adult patient?
Recommendation : Parenteral nutrition should not be started at the same time as enteral nutrition. In the patient who is not tolerating adequate enteral nutrition, there are insufficient data to put forward a recommendation about when parenteral nutrition should be initiated. Practitioners will have to weigh the safety and benefits of initiating PN in patients not tolerating EN on an individual case-by-case basis. We recommend that PN not be started in critically ill patients until all strategies to maximize EN delivery (such as small bowel feeding tubes, motility agents) have been attempted.

11. Composition of PN: Glutamine supplementation Compared to standard PN, does glutamine-supplemented PN result in improved clinical outcomes in critically ill patients?
Recommendation : When parenteral nutrition is prescribed to critically ill patients, parenteral supplementation with glutamine, where available, is recommended. There are insufficient data to generate recommendations for intravenous glutamine in critically ill patients receiving enteral nutrition.

12. Strategies to optimize delivery and minimize risks of EN : Motility Agents Compared to standard practice (placebo), does the routine use of motility agents improve clinical outcomes in critically ill patients?
Recommendation : In critically ill patients who experience feed intolerance (high gastric residuals, emesis), the use of metoclopromide as a motility agent should be considered.

13. Role of immune enhancing diet in cancer surgical patients
Recommendation : Immunonutrition has been found to improve the outcome in post surgical cancer patients.

ABSTRACTS

8. Glutamine supplementation in serious illness: a systematic review of the evidence. Novak F, Heyland DK, Avenell A, Drover JW, Su X. Crit Care Med. 2002 Sep;30(9):2022-9.

OBJECTIVE : To examine the relationship between glutamine supplementation and hospital length of stay, complication rates, and mortality in patients undergoing surgery and experiencing critical illness. DATA SOURCES: Computerized search of electronic databases and search of personal files, abstract proceedings, relevant journals, and review of reference lists. STUDY SELECTION : We reviewed 550 titles, abstracts, and articles. Primary studies were included if they were randomized trials of critically ill or surgical patients that evaluated the effect of glutamine vs. standard care on clinical outcomes. DATA EXTRACTION : We abstracted relevant data on the methodology and outcomes of primary studies in duplicate, independently. DATA SYNTHESIS : There were 14 randomized trials comparing the use of glutamine supplementation in surgical and critically ill patients. When the results of these trials were aggregated, with respect to mortality, glutamine supplementation was associated with a risk ratio (RR) of 0.78 (95% confidence interval [CI], 0.58-1.04). Glutamine supplementation was also associated with a lower rate of infectious complications (RR, 0.81; 95% CI, 0.64-1.00) and a shorter hospital stay (-2.6 days; 95% CI, -4.5 to -0.7). We examined several -specified subgroups. Although there were no statistically significant subgroup differences detected, there were some important trends. With respect to mortality, the treatment benefit was observed in studies of parenteral glutamine (RR, 0.71; 95% CI, 0.51-0.99) and high-dose glutamine (RR, 0.73; 95% CI, 0.53-1.00) compared with studies of enteral glutamine (RR, 1.08; 95% CI, 0.57-2.01) and low-dose glutamine (RR, 1.02; 95% CI, 0.52-2.00). With respect to hospital length of stay, all of the treatment benefit was observed in surgical patients (-3.5 days; 95% CI, -5.3 to -1.7) compared with critically ill patients (0.9 days; 95% CI, -4.9 to 6.8).

CONCLUSION : In surgical patients, glutamine supplementation may be associated with a reduction in infectious complication rates and shorter hospital stay without any adverse effect on mortality. In critically ill patients, glutamine supplementation may be associated with a reduction in complication and mortality rates. The greatest benefit was observed in patients receiving high-dose, parenteral glutamine.

9. Should immunonutrition become routine in critically ill patients? A systematic review of the evidence. Heyland DK, Novak F, Drover JW, Jain M, Su X, Suchner U. JAMA. 2001 Aug 22-29;286(8):944-53

CONTEXT : Several nutrients have been shown to influence immunologic and inflammatory responses in humans. Whether these effects translate into an improvement in clinical outcomes in critically ill patients remains unclear.

OBJECTIVE : To examine the relationship between enteral nutrition supplemented with immune-enhancing nutrients and infectious complications and mortality rates in critically ill patients. DATA SOURCES: The databases of MEDLINE, EMBASE, Biosis, and CINAHL were searched for articles published from 1990 to 2000. Additional data sources included the Cochrane Controlled Trials Register from 1990 to 2000, personal files, abstract proceedings, and relevant reference lists of articles identified by database review. STUDY SELECTION : A total of 326 titles, abstracts, and articles were reviewed. Primary studies were included if they were randomized trials of critically ill or surgical patients that evaluated the effect of enteral nutrition supplemented with some combination of arginine, glutamine, nucleotides, and omega-3 fatty acids on infectious complication and mortality rates compared with standard enteral nutrition, and included clinically important outcomes, such as mortality. DATA EXTRACTION : Methodological quality of individual studies was scored and necessary data were abstracted in duplicate and independently. DATA SYNTHESIS : Twenty-two randomized trials with a total of 2419 patients compared the use of immunonutrition with standard enteral nutrition in surgical and critically ill patients. With respect to mortality, immunonutrition was associated with a pooled risk ratio (RR) of 1.10 (95% confidence interval [CI], 0.93-1.31). Immunonutrition was associated with lower infectious complications (RR, 0.66; 95% CI, 0.54-0.80). Since there was significant heterogeneity across studies, we examined several a priori subgroup analyses. We found that studies using commercial formulas with high arginine content were associated with a significant reduction in infectious complications and a trend toward a lower mortality rate compared with other immune-enhancing diets. Studies of surgical patients were associated with a significant reduction in infectious complication rates compared with studies of critically ill patients. In studies of critically ill patients, studies with a high-quality score were associated with increased mortality and a significant reduction in infectious complication rates compared with studies with a low-quality score. CONCLUSION : Immunonutrition may decrease infectious complication rates but it is not associated with an overall mortality advantage. However, the treatment effect varies depending on the intervention, the patient population, and the methodological quality of the study.

10. Supine body position as a risk factor for nosocomial pneumonia in mechanically ventilated patients: a randomised trial. Drakulovic MB, Torres A, Bauer TT, Nicolas JM, Nogue S, Ferrer M. Lancet. 1999 Nov 27;354(9193):1851-8

BACKGROUND : Risk factors for nosocomial pneumonia, such as gastro-oesophageal reflux and subsequent aspiration, can be reduced by semirecumbent body position in intensive-care patients. The objective of this study was to assess whether the incidence of nosocomial pneumonia can also be reduced by this measure. METHODS : This trial was stopped after the planned interim analysis. 86 intubated and mechanically ventilated patients of one medical and one respiratory intensive-care unit at a tertiary-care university hospital were randomly assigned to semirecumbent (n=39) or supine (n=47) body position. The frequency of clinically suspected and microbiologically confirmed nosocomial pneumonia (clinical plus quantitative bacteriological criteria) was assessed in both groups. Body position was analysed together with known risk factors for nosocomial pneumonia. FINDINGS: The frequency of clinically suspected nosocomial pneumonia was lower in the semirecumbent group than in the supine group (three of 39 [8%] vs 16 of 47 [34%]; 95% CI for difference 10.0-42.0, p=0.003). This was also true for microbiologically confirmed pneumonia (semirecumbent 2/39 [5%] vs supine 11/47 [23%]; 4.2-31.8, p=0.018). Supine body position (odds ratio 6.8 [1.7-26.7], p=0.006) and enteral nutrition (5.7 [1.5-22.8], p=0.013) were independent risk factors for nosocomial pneumonia and the frequency was highest for patients receiving enteral nutrition in the supine body position (14/28, 50%). Mechanical ventilation for 7 days or more (10.9 [3.0-40.4], p=0.001) and a Glasgow coma scale score of less than 9 were additional risk factors. INTERPRETATION : The semirecumbent body position reduces frequency and risk of nosocomial pneumonia, especially in patients who receive enteral nutrition. The risk of nosocomial pneumonia is increased by long-duration mechanical ventilation and decreased consciousness.

11. Complications of Pancreatic Surgery and the Role of Perioperative Nutrition. Valerio Di Carlo, Luca Gianotti, et al. Dig Surg 1999;16:320–326

In this prospective randomized trial 100 patients who underwent PD for cancer of the pancreatic head were randomized to receive a standard enteral formula or immuno nutrition with an enteral formula enriched with arginine, omega-3 fatty acids, and RNA or total parenteral nutrition. Postoperative feeding was started within 12 h after surgery. The three regimens were isoenergetic and isonitrogenous. Tolerance of enteral feeding, rate and severity of postoperative complications, and length of hospital stay (LOS) were evaluated. Results showed low rate of postoperative complications in the immuno nutrition group (33%). Also the severity of infectious complications (sepsis score) was lower and LOS was shorter in the immuno nutrition group.

12. Artificial nutrition after major abdominal surgery: Impact of route of administration and composition of the diet. Braga, Marco, Gianotti, Luca et al. Crit Care Med 1998; 26:24-30

Objective : To evaluate the impact of the route of administration of artificial nutrition and the composition of the diet on outcome. Design : Prospective, randomized, clinical trial. Setting : Department of surgery, university hospital. Patients : One hundred sixty-six consecutive patients undergoing curative surgery for gastric or pancreatic cancer. Interventions : At operation, the patients were randomized into three groups to receive: a) a standard enteral formula (control group; n = 55); b) the same enteral formula enriched with arginine, RNA, and omega-3 fatty acids (enriched group; n = 55); and c) total parenteral nutrition (TPN group; n = 56). The three regimens were isocaloric and isonitrogenous. Enteral nutrition was started within 12 hrs following surgery. The infusion rate was progressively increased to reach the nutritional goal (25 kcal/kg/day) on postoperative day 4. Measurements and Main Results : Tolerance of enteral feeding, rate and severity of postoperative complications, and length of hospital stay were recorded. Early enteral infusion was well tolerated.Side effects were recorded in 22.7% of the patients, but only 6.3% did not reach the nutritional goal. The enriched group had a lower severity of infection than the parenteral group (4.0 vs. 8.6). Conclusions: Early enteral feeding is a suitable alternative to TPN after major abdominal surgery. The use of the enriched diet appears to be more beneficial in malnourished and transfused patients.

The enteral route is the preferred route for nutrition. Immune-enhancing diets are beneficial in surgical patients, but may be detrimental in patients with sepsis. Use of parenteral glutamine is associated with reduced complications and hospital stay after major surgery. Use of a 45 degrees semirecumbent position during enteral feeding is a simple, cheap and effective method of preventing nosocomial pneumonia.