Introduction to Clinical Nutrition

Transcription

1 M-III Introduction to Clinical Nutrition Donald F. Kirby, MD Chief, Section of Nutrition Division of Gastroenterology 1 Things We Take for Granted Air to Breathe Death Taxes Another Admission Our Next Meal! 2 Though Hard to Believe Malnutrition does occur in the United States Malnutrition is more common in hospitalized patients than is generally realized 1/3-1/2 1/2 of patients have significant deficits in one or more of the commonly accepted nutritional indices Physical examination is not specific enough when used as the sole diagnostic tool Millennium Malnutrition A November 2003 report estimates that 842 Million people were malnourished from Their diet supplied 1,400-1,700 Kcal when most diets should supply about 2,300 Kcal. In 26 countries the number of hungry people went up Afghanistan, Congo, Yemen, the Philippines, Liberia, Kenya, and Iraq

2 Potential Energy Sources for Fasting Man Glycogen 2 Days Protein Fat Major Source Malnutrition Affects Every Organ Severe Malnutrition and the Heart Bradycardia Mild Arterial Hypotension Reduced Venous Pressure Decreased Oxygen Consumption Low Stroke Volume Reduced Cardiac Output

3 Lungs Weakness and atrophy of the muscles of respiration Decreased clearance of secretions Impaired host defenses Pneumonia Common cause of death 13 GI Tract Mucosal Atrophy Maldigestion occurs Decreased Gastric Acid Secretion Decreased Gastric Motility 14 Immune System Cell-mediated immunity T Cell important against intracellular parasites Antibody-mediated immunity B Cells specific antibodies Complement Decreased total serum complement Decreased individual components except C 4 Ideal Test for Nutritional Status 1. Specific for deficits of nutritional origin 2. Changes good or bad should be reflected promptly 3. Deviations from normal should have clinical or prognostic significance 4. Readily available 5. Reasonable cost Nutritional Assessment Weight Data 1. History & Physical Weight history 2. Diet History 3. Anthropometric Measurements 4. Plasma Protein a. Albumin/Transferrin Transferrin/ Prealbumin b. Creatinine-Height Index 5. Immunologic Status a. Total Lymphocyte Count b. Skin Tests 17 Usual Body Weight Ideal Body Weight Present Body Weight Weight Equations %UBW = Present Body Weight x 100 Usual Body Weight %IBW = Present Body Weight x 100 Ideal Body Weight 18 3

4 Body Mass Index BMI = Weight (Kg) Height (M) 2 Classification Based on BMI Morbid Obesity > 40 Obese > 30 Overweight > Normal Underweight <18.5 Severe Malnutrition < Anthropometric Measurements Anthropometric Measurements Triceps Skin Fold Fat Stores Midarm Muscle Circumference Protein stores Biochemical Markers Albumin Transferrin Prealbumin Plasma Proteins Albumin 2 Main Functions 1) Binding and transport of small molecules (e.g., drugs, vitamin B6, etc.) 2) Accounts for 70% of the Colloid Osmotic Pressure of Plasma Advantage Readily availability Normal ranges are variable with age and general health of the patient

5 Causes of Hypoalbuminemia 1. Decreased Synthesis - Catabolized at 4%/day - Status of liver synthesis - Amino Acid Deficiency 2. Increased Losses - Nephrotic Syndrome - Burns - Protein-losing Enteropathies 3. Rapid Rehydration 4. Nonspecific 25 Beneficial Effects Attributable to Interleukin 1 & 6 Fever WBC left shift Redistribution of trace metals Albumin Synthesis of acute phase proteins Procoagulant activity Alterations in Intermediary Metabolism 26 Total Lymphocyte Count Determined as follows: WBC x % lymphocytes = TLC e.g., WBC = 6,000mm 3 % lymphocytes = 30% TLC = 6000 x.30 = 1,800mm Screening for Malnutrition Daily dietary intake <1000kcal or 50gm of protein Greater than 10% weight loss Serum albumin <3.0 on admission Anergy 29 Roubenoff R, et al. Malnutrition among hospitalized patients: A problem of physician awareness. Arch Intern Med 1987;147:1462. Points out that we are still failing to teach our housestaff and medical students about nutrition. However, there is hope! They showed that a brief nutrition review coupled with a database could significantly improve physician awareness and change nutrition practices in a large teaching hospital. 30 5

6 Free Beer Tomorrow Consider Patients for Nutrition Support with any of the Following: Impaired ability to maintain adequate oral nutrient intake. e.g., radiation esophagitis Loss of 10% or more of pre-illness weight A pre- or postoperative course requiring more than days without adequate nutrient intake Somatic wasting, e.g. pressure sores or cachexia Reasons for Enteral Therapy Functional GI Tract Neurological Disorders Anoxic Encephalopathy Oropharyngeal-Esophageal Disease Tumor, Trauma, Neoplasms Nasoenteric Tube with a Problem! Multiple Ways to Access the GI Tract

7 Colon Peg Tube In Place Note: No Sutures PEG Button

8 Types of Enteral Diets 1. Blenderized more bulk and fiber 2. Intact Nutrients 3. Chemically Defined 4. Special Formulas Complications of Enteral Nutrition 1. Gastric Distention 2. Gastric Aspiration 3. Diarrhea 4. Constipation 5. Obstruction of Feeding Tube 6. Displacement of the Feeding Tube 7. Hyperglycemia 8. Fluid and Electrolyte Disorders

9 Indications for Parenteral Nutrition Have had no nutrition for 5 days and not expected to eat for more days Exception would be someone who is already at nutritional risk after having been assessed Parenteral Nutrition Overview Can the gut be utilized? What is the estimated time before normal GI function is expected to return? Are there difficulties with venous access? Is Peripheral Vein (PPN) or central vein nutrition (TPN) most appropriate? Are there pre-existing existing electrolyte abnormalities? What are the caloric requirements? Are there any special physiologic considerations? Three-in-one TPN All-in-one TPN Glucose Preparations Glucose Caloric Content Osmolality Concentration (Kcal/liter) (mosm/liter) TPN Standard Solution Amino Acids 4.25% 500ml Dextrose 25% 500ml Sodium 35mEq Potassium 30mEq Chloride 35mEq Acetate 50mEq Magnesium 5mEq Phosphorus 15mM MVI 4ml Trace Elements 1ml NonProtein Calories 850 Kcal/liter Osmolality 1160 mosm/liter 54 9

10 TPN Complications 1. Technical problems with line insertion - Pneumothorax - Air embolism - Arterial puncture - Cardiac perforation & tamponade - Brachial plexus injury - Catheter fragment embolism 2. Post-insertion catheter problems 3. Metabolic complications Metabolic Complications during Parenteral Nutrition 1. General electrolyte disorders hypo/hyper Sodium, Potassium 2. Glucose abnormalities 3. Phosphorus abnormalities 4. Calcium abnormalities 5. Magnesium abnormalities 6. Vitamin & Trace element abnormalities