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Nutritional Assessment and Support Clinical Nutrition Outline • Malnutrition - definition - types • Physiology - fasting - starvation - stress & trauma • Nutritional Assessment • Nutritional Support - timing - enteral vs. parenteral - calculations Clinical Nutrition Nutrition • intake of nutrients to provide energy for… - performance of mechanical work maintenance of organ/tissue function heat production maintenance of metabolic homeostasis • TEE (total energy expenditure) - REE or BEE (fasting resting or basal energy expenditure) ~ 70% (~1 kcal/kg/hr) - activity expenditure ~ 20% avg. but very variable - thermic effect of feeding ~ 10% (intake increases the metabolic rate) Clinical Nutrition Malnutrition • estimated that >50% of hospitalized patients exhibit malnutrition • improving the nutritional status of hospitalized patients… - improves wound healing decreases infectious complications (in the severely malnourished) decreases non-septic complications decreases mortality rate, in some studies • results in the catabolism of energy stores - adipose (oxidation of triglycerides) ~ 13kg in average person - glycogen (glucose) ~ 0.5kg, mostly in muscle - protein (not stored - in use by body) • skeletal muscle ~ 6kg • other protein stores (organs, visceral proteins, nerve tissue) ~ few hundred grams Clinical Nutrition Types of Malnutrition Marasmus - cachexia chronic calorie malnutrition – relatively balanced diet, but too little for too long usually the result of a longstanding problem (months) see wasting of fat, skeletal muscle (weakness) visceral protein stores less affected Kwashiorkor (West African term – “disease of the displaced child”) - “malnourished African child” (after weaning) with edema and protuberant abdomen more rapid development and worse prognosis chronic protein malnutrition (unbalanced diet) or the onset of physiologic stress fat & skeletal muscle reserves are less depleted (carbohydrates drive insulin) visceral protein stores & immunity are affected early Marasmic kwashiorkor - combined features – usually what is seen in ICU / ill patients chronically starved person with stress of illness (hypermetabolic state) worst prognosis – nutritional support tend to increase fat mass unless the underlying stressors are reversed Clinical Nutrition Early Fasting Human fuel supply consumption Nerve Liver Muscle 75 g/d amino acids glycogen glucose RBC WBC gluconeogenesis lactate pyruvate glycerol Adipose fatty acids FFA oxidation in mitochondria * lose 5% body protein stores per week ketones Muscle Heart Kidney Clinical Nutrition Adapted Fasting Human fuel supply Muscle 20 g/d (2 to 6 weeks) consumption Liver Nerve amino acids glucose RBC WBC gluconeogenesis lactate pyruvate glycerol Adipose fatty acids FFA oxidation in mitochondria ketones Muscle Heart Kidney Clinical Nutrition Traumatized Human fuel supply consumption Reparative Process Liver Visceral & Muscle 250 g/d amino acids glycogen Nerve glucose gluconeogenesis lactate pyruvate glycerol Adipose fatty acids RBC WBC FFA oxidation in mitochondria ketones Muscle Heart Kidney Clinical Nutrition Nutritional Assessment Clinical Nutrition Normal Nutrition Calories - US standard diet for 70kg active man contains ~2700 kcal protein ~325 kcal (81 grams) fat ~1125 kcal (125 grams) carbohydrates ~1250 kcal (312 grams) amount needs to be decreased for inactivity Protein - US standard diet ~80 grams/d (12% of caloric intake) - protein-free diets result in negative nitrogen balance • lose .34 grams protein/kg/d (nitrogen in urine, feces, skin,breath, sputum, etc.) - titrate dietary protein to just keep a positive nitrogen balance • need .38 to .52 grams protein/kg/d (higher estimate b/o inefficiency in utilization) - most use .43 as a minimum and 0.5 - 0.8 gm/kg/d as average - amount needs to be increased for stress (hypercatabolic) Clinical Nutrition Nutritional Assessment • Every patient should prompt three questions - Does malnutrition exist? - Is malnutrition likely to occur? - When and how to correct the situation? Clinical Nutrition Does malnutrition exist? • poor intake - weight loss last 6 months (25% false positive, 33% false negative) • <5% considered mild malnutrition • >20% considered severe malnutrition - weight change in last 2 weeks • allows you to decide whether they can correct the situation on a hospital diet - GI symptoms of anorexia, N/V, diarrhea, malabsorption, obstruction • hypercatabolic pre-admission - infection, sepsis - trauma, burns - major surgery or pulmonary disease • anthropometric changes - loss of SQ fat, muscle wasting, BMI < 14 • functional changes - muscle weakness, respiratory effort • lab studies - albumin, transferrin, prealbumin, RBP, cholesterol, immune function Clinical Nutrition Does malnutrition exist? Subjective Global Assessment Scale (SGA Scale) • graded on 6 features weight change intake GI symptoms functional capacity physiologic stress physical alterations • each feature is rated A = no deficit B = mild deficit C = severe deficit • scored overall A = well nourished = 16% septic complications B = mild to moderate malnutrition = 43% septic complications C = severe malnutrition = 69% septic complications Clinical Nutrition Is Malnutrition Likely to Occur? • poor intake - NPO for more than 3-5 days - GI symptoms of anorexia, N/V, diarrhea, malabsorption, obstruction • hypercatabolic - infection, sepsis - trauma, burns - major surgery or pulmonary disease Clinical Nutrition Simplified Assessment • • • • severe burn or trauma NS within 24-36 hours severe physiologic stress and diet will be compromised NS NPO for >7 days NS use history, wt loss, alb < 3.2, TLC < 1500 and decision chart days before tube feeding days before TPN no malnutrition and no stress 7-10 10-14 either 1-5 5-10 both 1-3 3-5 patient status Clinical Nutrition Nutritional Support Clinical Nutrition Route of Administration • Enteral - more physiologic (doesn’t bypass gut mucosa and liver) less complicated (supplements, NG tube, PEG, DHT, naso-jejunal tube) less costly (especially cyclic, intermittent, or bolus feeding) fewer infectious and other complications better at preserving gut mucosal integrity and preventing microbial translocation • Parenteral - use only if you cannot use the gut • • • • • bowel surgery bowel obstruction ileus not enough bowel / severe malabsorption no gut access Clinical Nutrition Estimate Needs calories - basal or resting energy expenditure (BEE or REE) men: 66 + (13.7 x kg wt) + (5 x cm ht) – (6.8 x age) women: 665 + (9.6 x kg wt) + (1.7 x cm ht) – (4.7 x age) - activity factor bed rest: +5-20% light activity: +50% ambulatory: +30% moderate activity: +75% - stress factor minor surgery: +20% major infection: +40-50% skeletal trauma: +30% severe burn: +50-100% - special cases (unstable sepsis, hypotension) protein - basal 0.5 - 0.8 gm/kg/d - increased for stress Clinical Nutrition Estimate Needs (critically ill) BMI (kg/m2) Energy Requirements (kcal/kg/day) <15 35-40 15-19 30-35 20-29 20-25 >29 15-20 Clinical Nutrition Estimate Needs (Practical Method) • calories per kg/day unstable: bed rest: mild stress or activity: moderate s/a: severe s/a: 15-20 25 30 35 40 • protein grams per kg/day - no stress: mild stress: dialysis moderate stress: severe stress: 0.8 1.0 1.3 1.5 2.0 80 kg patient 2400 kcal 120 grams protein Clinical Nutrition TPN Calculations carbo=D70 lipid=F20 protein=AA10 protein=4 kcal/gram AA10=10 grams/dl AA10 =40 kcal/dl AA10 =0.4 kcal/cc 80 kg patient 2400 kcal 120 grams protein protein 120x4=480 kcal 480/0.4=1200 cc 2400-480=1920 kcal fat=9 kcal/gram F20=20 grams/dl F20=180 kcal/dl F20=1.8 kcal/cc dextrose=3.45 kcal/gram D70=70 grams/dl D70=241 kcal/dl D70=2.4 kcal/cc lipid 2400x30%=720 kcal 720/1.8=400 cc 1920-720=1200 kcal carbo 1200/2.4=500 cc *propofol is ~F10 = 1 kcal/cc Clinical Nutrition Monitoring Nutritional Status/Support • • • • • correct fluid and electrolyte abnormalities first watch for refeeding syndrome (fluid retention/CHF, low phos, K, Mg, high glucose) if serum glucose is hard to control, increase lipid ratio (up to 50-66% of calories), but remember that lipid is less nitrogen preserving than dextrose (below 150 g/d dextrose) if triglycerides are hard to control, lower the lipid ratio (can be removed for periods) follow weights daily, prealbumin weekly, and UUN occasionally grams protein intake/6.25 = (grams UUN + 3) grams N deficit x 6.25 = extra grams protein needed albumin rise prealbumin rise transferrin rise sensitivity 61% 88% 67% specificity 41% 70% 55% PPV 86% 93% 87% NPV 17% 56% 27%