Nutrition - Edward Melkun

Nutrition - Edward Melkun - Nutrition Edward Melkun...

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Unformatted text preview: Nutrition Edward Melkun February 5, 2007 Overview Overview Nutrition plays key role in recovery Discussion of changes during critical illness Parenteral and Enteral Nutrition Acute Phase Response Acute Phase Response Changes in AA metabolism Increased acute phase proteins Increased gluconeogenesis Fever Negative nitrogen balance AA metabolism AA metabolism Cytokines and inflammatory mediators circulate to liver Inhibit albumin synthesis and increase acute phase proteins (ex. CRP) Also circulate to brain and act on hypothalamus to increase core temp, and increase ACTH Insulin Resistance Insulin Resistance Decrease in body glucose oxidation and increased liver gluconeogenesis Increased ketogenesis Rise in serum cortisol leads to insulin resistance Increased catecholamines, glucogon, and growth hormone also lead to elevated serum glucose Increased Catabolism Increased Catabolism Critically ill patients may lose 16­20g nitrogen in the urine per day (nl is 10­12g) 1g of urea equal to about 1oz. Of skeletal muscle May result in impaired respiratory muscle strength, heart and gi function Use of Proteins Use of Proteins Leukocytes have decreased half life of 4­6 hours during infection Increased acute phase proteins Average critically ill adult can break down and resynthesize 400g of protein in 24 hours. Nutritional Assessment Nutritional Assessment History – 10% weight loss or more suggests protein malnutrition Exam – Weight/Ideal body weight (<85% predicted), temporal muscle wasting, anthropometrics Nutritional markers ­daily weight – more a measure of fluid status than nutritional status ­24 hour urine urea nitrogen (cannot be used in renal failure) ­albumin 21, prealbumin 2, transferrin 7 ­albumin influenced by fluid status, acute phase response Nutritional Assessment Nutritional Assessment Immune function – skin testing, anergy Predictors of outcome ­ ­ albumin <3.4 related to increased mortality in VA study, linear correlation, APACHE III score factors in albumin ­ caloric intake predicts survival when matched for serum albumin level Nutritional Therapy Nutritional Therapy Resting Energy Expenditure – linked to lean body mass Accurate calculation can be done with metabolic cart, estimated by Harris­ Benedict Adult males: BEE (kcal/day) = 66 + (13.7 x wt in kg) + (5 x ht in cm) ­ (6.8 x age). Adult females: BEE (kcal/kcal) = 655 + (9.6 x wt in kg) + (1.7 x ht in cm) ­ (4.7 x age). Nutritional Therapy Nutritional Therapy Healthy adult – approx 25 kcal/kg/day, 1g protein/kg/day Pretty sick to moderately sick – 30 kcal/kg/day, 1.5g protein/kg/day Very sick – 35 kcal/kg/day, 2g Very Very sick ­ ? 40 kcal/kg/day, ?2.5g EN vs. PN EN vs. PN If the gut works, use it Prevents gut atrophy, translocation, reduced infections, better maintenance of serum albumin, reduced mortality despite equal caloric intake Indications for TPN – short gut, high output fistula, hyperemesis gravidarum Increased rates of infection and complications may be due to failure to maintain tight glucose control Enteral Nutrition Enteral Nutrition FT placement ideally in small bowel Theoretical decrease in incidence of aspiration CDC recommends feeding patients with HOB elevated to reduce risk Theoretical decreased risk in patients with cuffed ET tube Parenteral Nutrition Parenteral Nutrition 3 liters of fluid necessary to give enough calories via PPN due to limitations on dextrose content due to phlebitis risk Dextrose administration should not exceed 3.5mg/kg/min to avoid metabolic complications Fats – Septic patients have decreased ability to utilize dextrose, but use fats well Also prevents essential fatty acid deficiency TPN TPN Complications associated with TPN include increased serious infections including catheter infection, venous thrombosis Metabolic complications include – Volume overload, Essential fatty acid deficiency, Hyperglycemia, Trace mineral deficiency, Refeeding syndrome, Vitamin deficiency, Hypokalemia, Metabolic bone disease, Hypophosphatemia, Hepatic steatosis Hypomagnesemia, Hepatic cholestasis, Hyperchloremic acidosis TPN TPN TPN given at supratheraputic caloric levels of 39kcal/kg/day and 1.8g/kg/day protein did not show any anabolism or increase in lean body mass. Still continued to lose 24g of nitrogen in average day Pts were able to increase fat stores TPN can slow catabolism but not increase anabolism ...
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