The Basics of Nutritional Support Terry L. Forrette, M.H.S., RRT

Transcription

1 Presentation Overview The basics of metabolism Methods to measure metabolic rate Using indirect calorimetry Case studies Importance of Nutritional Support Malnutrition occurs in approx.40% of hospitalized patients Can lead to increased morbidity and mortality Impairment of skeletal, cardiac, respiratory muscle function Impairment of immune function Atrophy of GIT Impaired healing Indications for Nutritional Support Severely malnourished Short bowel syndrome Patient not expected to feed in 7 days Prolonged ileus or intestinal obstruction Entero-cutaneous fistulas Pancreatitis Major bowel surgery Esophageal replacement Gastric or colon surgery Whipple s s procedure Classifications of Malnutrition Nutritionally Depleted Patient Total Calorie Depletion: Marasmus TL Forrette & Associates 1 Wisdom is knowledge applied

2 Kwashiorkor The sickness the older child gets when the next baby is born Reduced protein synthesis leads to higher water potential in blood Tissues swell (oedema) Indications for Nutritional Support Short gut syndrome <0.5 m jejunum/ileum if with colon <1.0 m of small bowel if without colon Patient not expected to feed in 7 days Entero-cutaneous fistulas ESOPHAGECTOMY COLON REPLACEMENT CAUSTIC INGESTION, ESOPHAGEAL STRICTURE Trauma/Disease Issues Duodenal Leak Gastro-duodeno-pancreatectomy TL Forrette & Associates 2 Wisdom is knowledge applied

3 CHO Fuel Sources Lipids Metabolic Rate Metabolism: The Basics Steady-State Condition Substrate Utilization Predictive vs. Measured Proteins Energy Balance Relationship Dietary Intake Stored Calories Anabolism Intake Expenditure Expenditure = Metabolic Rate Activity Energy Expenditure Catabolism Energy Balance Relationship Energy Balance Relationship Dietary Intake Stored Calories Intake > Expenditure Activity Energy Expenditure Dietary Intake Stored Calories Intake < Expenditure Stress Factors Activity Energy Expenditure Increased Anabolism Expenditure = Metabolic Rate Catabolism Anabolism Expenditure = Metabolic Rate Increased Catabolism Energy Requirement in Critical Illness: Different Conditions Methods to Express Metabolic Rate Greenfield 1997 BEE - Basal Energy Expenditure Rarely seen in a hospital setting REE Resting Energy Expenditure Desired conditions for measurements AEE Active Energy Expenditure Measurement during a specific activity TEE Total Energy Expenditure The metabolic rate tells us how much fuel is needed TL Forrette & Associates 3 Wisdom is knowledge applied

4 Fuel (Substrate) Stores Output (24 hr) 70 kg normal individual Intake (24hr) How Much Fuel is There? 70 kg normal individual 120 grams 300 grams 72 grams Fat - 15kg CHO g Protein - 13 kg 120 grams 300 grams 72 grams Output (24hr) 1100 Lipids 140,000 Intake (24Hr) 1100 Total Body Water 34 kg 1 = 1000 calories (c) 1200 CHO Minerals 300 Protein 52, Calculation of Caloric Needs Condition Normal to moderate malnutrition /kg/day Protein/kg/day NPC : N ratio : 1 Moderate stress : 1 Hypermetabolic, stressed : 1 Burns : 1 Calculation of Caloric Needs Protein gm/kg/day 70 kg patient per day Well-nourished gm Stress, sepsis CRF, ARF 1.2 Liver failure Glucose Well-nourished gm Fat Well-nourished gm Critically ill 1.0 Brittle diabetes 2.5 Routes of Administration Nutritional Assessment Maintenance Repletion GI Tract Functional YES NO Enteral Nutrition Parenteral Nutrition TL Forrette & Associates 4 Wisdom is knowledge applied

5 Advantages: ENTERAL 1. more physiological (liver not bypassed) 2. lesser cardiac work 3. safer and more efficient 4. better tolerated by the patient 5. more economical ENTERAL NUTRITION ENTERAL NUTRITION?? Nutritional Support Needed? Contraindications for EN Parenteral Nutrition Severe acute pancreatitis High output proximal fistula Inability to gain access Intractable vomiting or diarrhea Aggressive therapy not warranted ASPEN. The science and practice of nutrition support. A case-based core curriculum. 2001; 143 Peripheral Central TL Forrette & Associates 5 Wisdom is knowledge applied

6 Parenteral Nutrition As Supportive Therapy: Nutritional support can be achieved but alteration in the disease process have not been established. New born GIT anomalies ( gastrochisis, gastrochisis, omphalocele) omphalocele) Alimentary tract obstruction (achalasia (achalasia,, stricture, carcinoma, pyloric obstruction) Prolonged ileus Prolonged respiratory support Large wound losses Venous Access Subclavian Access PARENTERAL NUTRITION Basic Composition of Formulations Carbohydrate = % dextrose Amino Acids Lipid Emulsions Vitamins, trace elements, electrolytes Complications Parenteral Nutrition Related to catheter insertion: 1. Pneumothorax 2. Arterial laceration 3. Hemothorax 4. Air embolism 5. Catheter embolism Septic thrombosis: 1.Antibiotic 1.Antibiotic therapy 2.Fogarty 2.Fogarty catheter embolectomy 3.Excision 3.Excision of the subclavian vein and superior venacava 6

7 Decision Making Financial Impact: GIT functional? YES ENTERAL ROUTE Cost Impact of Malnutrition: NO PARENTERAL ROUTE Short term Long term Short term NGT Gastrostomy, Jejunostomy Peripheral PN Long term Central PN Triad of Nutritional Assessment Robinson, G., M. Goldstein, G. Levine. Impact of Nutritional Status on DRG Length of Stay. JPEN 11:49-51, Condition (100 patients) Average Hospital Charges(Per Patient) Malnourished $16,691 Borderline Malnourished $14,118 Normally Nourished $ 7,692 Hospitals were reimbursed from $4,352 to $5,124 for each patient Anthropometrics Ideal 1919 Harris-Bennedict Body Weight Triceps Skin Fold Arm Circumference Biochemical Indices Anthropometrics Calorimetry Anthropometrics Calorimetry Biochemical Indices Body Mass Index Harris-Benedict Equation Body mass index = body mass (in kg) height (in m) 2 Estimates Basal Metabolic Rate (BMR): BMI: <20 = underweight = acceptable = overweight >30 = obese Male BMR kcal/day = (kg) + 5 (cm) (yrs) Female BMR kcal/day = (kg) (cm) (yrs) Harris-Benedict Equation 7

8 Predicted Values for REE Energy Requirement in Critical Illness: Different Conditions Energy Expenditure needs are determined by combining: Basal Metabolism based on height, weight, gender, and age Dietary Induced Thermogenesis Physical Activity Stress Factors associated with disease, injury and pharmacological intervention Greenfield 1997 Calorimetry Methods Direct Calorimeter Direct & Indirect Systems Energy is measured as the increase in temperature resulting from metabolism within a closed chamber Anthropometrics Calorimetry Biochemical Indices The Basics of IC Measurements Understanding Metabolism CO2 expired CO2 inspired Patient CO2 elimination/min = VCO2 = FICO2 (VE) FICO2 (VI) Cellular Respiration Measured via Indirect Calorimetry O2 inspired O2 expired Patient O2 uptake/min = VO2 = FIO2 (VI) FEO2 (VE) 8

9 Indirect Calorimetry involves measuring Respiration and applying Weir s Equation REE = Resting Energy Expenditure = KCAL/day [[( 3.94 VO2) + (1.11 VCO2)] x 1.44] 2.17 UN RQ expresses the mixture of fuel being burned Exhaled values (RQ) are assumed to be equal to cellular values (RER) When RQ equals RER, steady state conditions exists Metabolic Cost Hyperventilation Lipogenesis Mixed Hypoventilation.65 CHO Respiratory Quotient (RQ) RQ = VCO 2 VO2 Substrate Utilization: Energy versus The RQ Spectrum Lipids What Fuel is Being Burned? 1.5 Respiratory Quotient Just the facts mame... 1 gram kcal/min VO2 VCO2 RQ Lipids CHO Pro What blend of substrates is best for your patient? Measurements with Mask and Mouthpiece Metabolic Rate (REE) How much fuel is needed Substrate Fuel sources available for metabolism Respiratory Quotient (RQ) What s being burned Oxygen Consumption (VO2) the cost to burn a given substrate Carbon Dioxide Production (VCO2) the byproduct of burning a substrate 9

10 Canopy Measurements Measurements during Mechanical Ventilation Measurement Made Through The Ventilator How Accurate is Indirect Calorimetry? Plug and Play Module The Interdependence Between Circulation & Ventilation GE Carestation Collecting the Data Critical Care Steady State Continuous Studies Smooth out periods of non-steady state More reflective of TEE Equipment issues and cost Intermittent Snap shot of REE More influence from activity Cost effective? 10

11 So, which one is best? Dedicated personal to run studies Variability in steady state conditions Consider ICU room space and foot print of the equipment Applications For Indirect Calorimetry Critical Care Ventilator Management Cardiopulmonary Rehabilitation Increasing exercise tolerance Others Oncology patients Hemodynamics Eating disorders Non-Nutritional Applications Cardiovascular Measuring C.O. by indirect Fick C.O. = (a-vo2) x VO2 Measuring flow dependent VO2 in septic ARDS to avoid mathematical coupling Pulmonary mechanics and WOB VO2 of respiratory muscles Measuring influence of PEEP on VD Titrating ventilator settings Interpreting the Data Is there sufficient fuel in the tank? Compare caloric intake and measured REE Is the primary fuel appropriate? Evaluate RQ and match to clinical presentation Is patient anabolic or catabolic? Case Study Ms RP, hx COPD, admitted to MICU with AVF requiring ventilatory support. IC on day 3: REE 1931 kcal, RQ 1.04, TCI 2000 kcal (60/40 mixture of CHO/Lipids). Attempts to wean the patient had failed secondary to CO2 retention. Her diet was changed to a 45/55 mixture. Study after 24 hrs: REE 1895, RQ.84, Over the next 24 hours the patient was gradually weaned from ventilatory support. Comments: This patient s CHO load was excessive leading to lipogensis and CO2 retention. Case Study Mr. KS requiring high VE to maintain eucapnia. Gas exchange studies were performed to determine increased VD or VCO2.Current diet consisted of kcal. REE: 2250, RQ.86. VD.69. C.I = 1.9 L/M2 on a PEEP of 12. Over the next 2 hours the PEEP level was decreased to 8 with a resulting C.I. of 2.3 L/M2. Measured VD was 0.53 and the patient s minute ventilation requirements decreased by 30%. Comments: In this patient, IC studies were useful in R/O excessive CHO feedings and measuring VD, which was increased secondary to excessive PEEP levels. 11

12 Applications For Indirect Calorimetry Questions and Discussion Critical Care Ventilator Management Cardiopulmonary Rehabilitation Increasing exercise tolerance Others Oncology patients Hemodynamics Managing ALI/ARDS 12