Enteral and Parenteral Nutrition in the Critical Care SettingManagement of patient nutrition has long been a topic of controversy. Questing of timing, route of administration and composition of feeding solution constituents are several variables that share a lack of consensus. There is a 50% rate of malnutrition cited in hospitalized patients. Many states associated with critical care admissions have altered metabolic rates.
Some examples of increased catabolism are multiple injury trauma, sepsis, organ failure (CHF, ARF, RF), and ventilator dependent status. It is important to assess for a history of such hyper- or altered metabolic states like Diabetes Melitus, Alcoholism, Renal Failure, and COPD. Over feeding is associated with: immunosuppression, hyperglycemia, liver dysfunction and refeeding syndrome. EnteralNo associated immune suppression, no associated infection complications, easier to maintain electrolyte balance.
ParenteralImmune suppression (the converse is also true- malnutrition also causes immune suppression), fatty liver, potential for pneumothorax, line infections, loss of gut barrier, hyperosmolality, refeeding syndrome Feeding tubes – great option, if the gut works, use it. Prealbumin (2-3 day t1/2)Transferrin (8-10 day t1/2)Albumin (14-20 day t1/2)Nitrogen balance studies can aid in the clinical picture of nutrition status although there is not any clinical evidence of their effect on morbidity and mortalityBMI = (weight in kg) / (height in meters)MEE (measured energy expenditure) 104. 67 – 146. 54 kj/kg can be used to estimate the avg. daily caloric requirementMifflin-St Jeor formula REE = 9. 99 x weight + 6.
25 x height – 4. 92 x age + 166 x sex (males, 1; females, 0) – 161. Simplification of this formula REE (males) = 10 x weight (kg) + 6. 25 x height (cm) – 5 x age (y) + 5; REE (females) = 10 x weight (kg) + 6.
25 x height (cm) – 5 x age (y) – 161. Harris-Benedict equation – Males BEE (kcal) = 66. 5 + 13. 8 x weight (kg) + 5 x height (cm) – 6. 8 x age (yrs)Females Males BEE (kcal) = 655. 1 + 9.
6 x weight (kg) + 1. 8 x height (cm) – 4. 7 x age (yrs)Indirect calorimetry (metabolic cart) – measures the CO2 produced and the O2 consumed. Also gives the RQ (respiratory quotient)a value 1 suggests carbohydrate oxidation and overfeeding. Specific Requirements in TPNProtein – In the ICU a stressed patient can tolerate 1-1. 5 g/kg of protein per day at 4 kcal/gCarbohydrates – Allocate 40-55% of total calories as Dextrose in TPN solution 3.
4 kcal/gLipids – 0. 5-1 g/kg per day or 20-30% of total calories per day at 9 kcal/gFluids – An estimate of fluid needs in TPN solution is 30 ml/kg to beginRenal Failure – Vitamin DAlcoholism – Thiamine, Folate, Niacin, B12Liver Failure – A, E, KAlthough research has not shown evidence for the use of BCAA (Branched chain amino acids their use in liver failure, and other protein intolerant states can be justified. References:Mifflin MD, St. Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals.
Am J Clin Nutr. 1990; 51:241 -247Ireton-Jones Carol, Robbyn Kindle, Effects of Home Parenteral Nutrition on Resting Metabolic Rate: A Case Study. Nutrition in Clinical Practice , Vol. 19, No.
6, 637-639Stone Sue MD, Nutritional Support of the Critically Ill and Injured Patient, Crit Care Clin – 01-JAN-2004; 20(1): 135-57ASPEN Board of Directors. Guidelines for use of parenteral and enteral nutrition in adult and pediatric patients. J Parenter Enteral Nutr 2002;26(1 Suppl):1SA- 138SA .
