Nutrition in the Critically IllBritney Grayson Bonus conferenceJanuary 2, 2013

In critically ill patients, underfeeding is associated with weakness, infection, an increased duration of mechanical ventilation and death.Low caloric intake is associated with nosocomial bloodstream infections in patients in the medical intensive care unit. Crit Care Med 2004;32: 350-7. Negative impact of hypocaloric feeding and energy balance on clinical outcome in ICU patients. Clin Nutr 2005;24: 502-9. The relationship between nutritional intake and clinical outcomes in critically ill patients: results of an international multicenter observational study. Intensive Care Med 2009;35:1728-37.

Why is enteral feeding so important?

• Gut produces 50% of immunoglobulins. • Without enteral feeding

•Decreased mucosal mass •Shortening of villi •Increased gut permeability •Bacterial overgrowth

• Even an ileus can decrease IgA and promote bacterial adherence • Decontaminating the bacterial tract leads to fewer pneumonias and

bacteremia

Enteral Nutrition (EN) v. Parenteral Nutrition (PN)• Enteral feeding preserves mucosal barrier function and is associated

with ↓ mortality, infection, and hospital stay.

• Early EN v. Early PN= no change in mortality. Increase in infection and other complications in PN alone.

• PN alone associated with hyperglycemia, which, independent of nutrition, can lead to poorer outcomes

• EN is more cost effective, but often does not meet 100% of caloric goals

• EN + PN = mostly good, but risk over feeding which is associated with liver dysfunction

Enteral compared with parenteral nutrition: a meta-analysis. Am J Clin Nutr 2001;74:534-42. Intensive insulin therapy in critically ill patients. N Engl J Med 2001; 345:1359-67. Nutrition support in the critical care setting: current practice in Canadian ICUs — opportunities for improvement? JPEN J

Parenter Enteral Nutr 2003;27:74-83. Liver dysfunction associated with artificial nutrition in critically ill patients. Crit Care 2007;11:R10.

ASPEN Guidelines, 2009• EN preferred over PN. It should be started within 48 hrs and

withheld if the patient is hemodynamically compromised

• If EN is contraindicated, no nutrition for 7 days unless evidence of malnutrition prior to admission.

• If EN cannot meet caloric goals after 7-10 days, consider adding PN.

• All critically ill patients should get antioxidant vitamins and trace minerals.

• Strict glycemic control (110-150 mg/dl)

• ESPEN guidelines recommend initiating PN within 2d for patients who cannot be adequately fed enterally (ESPEN guidelines on parenteral nutrition: intensive care. Clin Nutr 2009; 28:387-400.)

• PN started 48h after ICU admission to starting PN >8d after ICU admission

• Early enteral nutrition in both, normoglycemia (80-110)

Study Design

Randomization

• Amount of PN calculated as the difference between the total energy intake delivered by EN and the calculated caloric goal based on corrected IBW

• PN stopped when EN met 80% of caloric goal or when oral nutrition resumed.

• PN was restarted if EN plus oral nutrition met <50% of caloric goal.

Late initiation of parenteral nutrition was associated with faster recovery and fewer complications, as compared with early initiation

In short, USA > Europe

ASPEN Guidelines, 2009

• EN preferred over PN. It should be started within 48 hrs and withheld if the patient is hemodynamically compromised

• If EN is contraindicated, no nutrition for 7 days unless evidence of malnutrition prior to admission.

• If EN cannot meet caloric goals after 7-10 days, consider adding PN.

• All critically ill patients should get antioxidant vitamins and trace minerals.

• Strict glycemic control (110-150 mg/dl)

Fast facts for the ABSITE

• Remember

Fat 9 kcal/g

Protein 4 kcal/g

Carbohydrate 4 kcal/g

Dextrose 3.4 kcal/g

10% lipids 1.1 kcal/cc

Fast facts for the ABSITE

• Nutritional requirements

• 1g protein/kg/day (20% essential amino acids)

• 30% fat calories

• Rest as carbohydrates

• Basal energy expenditure 25 kcal/kg/day

• Basal metabolic rate increases 10% for each 1 degree above 38.0

Fast facts for the ABSITE

• Central line PN is glucose based, maximum glucose administration is 3g/kg/hr.

• Obligate glucose users: peripheral nerves, adrenal medulla, RBCs, WBCs

• Post operative phases:

Catabolism -> diuresis -> anabolism Days 0-3. 2-5. 3-6.

Fast facts for the ABSITE

• Markers of nutrition

• Albumin (18 days)

• Transferrin (7-10 days)

• Prealbumin (2 days)