Nutrition and Dietetics in the Normal Patient
Study Aims Definition Malnutrition Actual body weight Ideal body weight Predicted body weight Nutritional assessement Calculation of nutritional needs Complications of overfeeding
Introduction Malnutrition common Defined as 10% of USUAL body weight Predisposition to Delayed healing Post-operative Infection Added Morbidity and Mortality Recognition thus important Preventable disease Treatable disease
Introduction (cont...) Usual / actual body weight As measured by scale Ideal body weight Male H 2 * 20 Female H 2 * 25 Predicted body weight Male 50 + 0.91 (Height in cm 152.4) Female 45.5 + 0.91 (Height in cm 152.4)
Nutritional Assessment 1. History and examination 2. Anthropological markers 3. Biochemical markers 4. Calculations of energy and protein requirements
Nutritional Assessment History Pre- morbid conditions Estimates the risk of malnutrition Hepatic and renal failure IBD Cancer and HIV/AIDS Burns and head injuries Conditions that limit intake or increase output History of recent weight loss Dietary Hx Intake concerning calory (energy), protein, vitamin and trace elements
Nutritional Assessment Physical Examination Caloric intake Subcutaneous fat of buttocks and extremities Protein status Extremity muscle bulk and strength Temporal wasting Vitamin intake Changes in skin, mucosa and skin appendages Skin texture change Cheilosis and glossitis Peripheral neuropathy ect
Nutritional Assesement Physical Examination (cont... ) Trace elements Sx similar to vitamin def + menal changes
Nutritional Assessment History and physical examination The above determines the risk for malnutrition Guidelines for identifying patients at risk Weight Overweight (BMI 30) and underweight (BMI < 18) Weight loss more than 10% actual weight Alcoholics NPO more than 5 days Medication with anabolic effect / antinutrient porp
Nutritional Assessment Anthropological Markers Body Mass Index (BMI) Weight (kg) / height 2 < 18 underweight < 10 Severely malnouraged Gross overweight is a risk for malnutrition Skinfold thickness (SFT) Measures subcutaneous fat and thus energy reserve (10-13 mm) Midarm circumference (MAC) Muscle bulk and therefore somatic protein status (22 23 cm)
Nutritional Assessment Anthropological Markers (cont... ) Bio-electrical Impedance Analysis Single frequency models unreliable Dual frequency modes in current clinical assessment Expensive initial outlay Accurate measurement of body composition
Nutritional Assessment Biochemical anlysis Serum proteins Estimates visceral protein reserve Overall poor reliability due to complex factors Overall markers include Total serum protein, albumin, tansferrin and total lymphocyte count Due to long half live reflects chronic malnutrition More sensitive markers due to shorter half live Pre-albumin, retinol binding protein, ceruloplasmin Reflects acute changes in nutritional status
Nutritional Assessment Biochemical anlysis Nitrogen balance Measures protein synthesis and breakdown Protein intake is the sum of all nitrogen intake (Enteral and parenteral) Protein breakdown is measured by nitrogen excretion in urine, faeces, fistula ect Calculations N intake = g protein / 6.25 N output = (urine urea * urine volume/day(l) * 0.028) + losses (3 6g) Balance Positive = anabolism Negative = catabolism Mild 5 10g Moderate 10 15g Severe 15g
Calculation of nutritional needs Energy requirements TE = NPE + PE TE = Total energy requirements, NPE = Non-protein energy,pe = protein energy NPE = Carbohydrate + Lipids PE = 1.2 2 g/kg IBW NPE = 25 30 Kcal/kg IBW Carbohydrates = 5 g/kg Lipids = 1 1.5 g/kg or 20kcal/kg
Complications of overfeeding Carbohydrates Glucose oxidation rate No more than 5 mg/kg/min Delivers 4 cal / g or Complications Hyperglycemia and hyper-osmolar states Hapaic steatosis due to lipogenesis Increased CO 2 and lactate production
Complications of overfeeding Lipids ipids Lipid infusions Maximum rate 1 1.5 g/kg Given as short, medium and long chain Delivers 9cal / g Complications of overfeeding Hiperlipedaemia and pancreatitis Fat overload syndrome Immiunological supression HSR
Complications of overfeeding Proteins Amino-acid and protein infusion 1.2 2 g / kg Delivers 4 cal / g Given as variaty of amino-acids Complication Azothemia