Pathophysiology of Trauma: Nutritional Therapy

1. بسم الله الرحمن الرحيم

2. Nutritiona therapy in trauma patients M. Safarian, MD PhD.

3. Pathophysiology of Trauma • Definition: any sudden physical damage to the body • Mostly occurs in young patients • Little or no protein-depletion

5. استرس سپتي سمي تروما سوختگي جراحي واکنش هيپرمتابوليک Flow phase پاسخ هورموني پروتئينهاي فاز حاد پاسخ ايمني افزايش اوت پوت قلبي، افزايش مصرف اکسيژن افزايش دماي بدن افزايش کاتابوليسم پروتئين افزايش متابوليسم پايه Ebb phase شوک هيپوولمي کاهش دماي بدن کاهش مصرف اکسيژن

6. Ebb Phase Flow Phase Energy Expenditure Time Metabolic Response to Trauma Cutherbertson DP, et al. Adv Clin Chem 1969;12:1-55

7. Metabolic Response to Trauma: • Ebb Phase • Characterized by hypovolemic shock • Priority is to maintain life/homeostasis  Cardiac output  Oxygen consumption  Blood pressure  Tissue perfusion  Body temperature  Metabolic rate

8. Metabolic Response to Trauma: • Flow Phase •  Catecholamines •  Glucocorticoids •  Glucagon • Release of cytokines, lipid mediators • Acute phase protein production

9. Metabolic Response to Trauma Fatty Acids Glucose Amino Acids Fatty Deposits Liver & Muscle (glycogen) Muscle (amino acids) Endocrine Response

10. Metabolic Response to Trauma 28 24 20 16 12 8 4 0 Nitrogen Excretion (g/day) 10 20 30 40 Days Long CL, et al. JPEN 1979;3:452-456

11. Major Surgery Cirugía mayor Moderate to Severe Burn Quemadura moderada a grave Nitrogen Loss in Urine Severe Sepsis Sepsis grave Infecci Infection ó n Cirug Elective Surgery í a electiva Basal Metabolic Rate Severity of Trauma: Effects on Nitrogen Losses and Metabolic Rate Adapted from Long CL, et al. JPEN 1979;3:452-456

12. Cardio vascular Response to Trauma • First : increase heart rate and total peripheral vascular resistance. • Blood loss of one third: fall in blood pressure and bradycardia syncope. • Blood loss of > 44% : tachycardia • Compromised blood supply in the gut: bacterial translocation

13. Inpatient management • Electrolyte and volume correction • Hydrodynamic control • Determine the type of nutrition support • Determine nutritional demand

14. Timing and Route of Feeding • Timing of feeding: within 24-48 hrs • Route of feeding: EN is preferred to PN • Stomach is preferred to small bowel • Small bowel is preferred if : • flail chest, spinal cord injury, severe pelvic fracture, major soft tissue injury or closed head injury.

15. Timing and Route of Feeding • Total enteral nutrition (TEN) • Prevent gut mucosa atrophy • Preserve gut flora • Better ultilization of nutrients • Reduce stress response • Maintain immunocompetence

16. Timing and Route of Feeding • Contraindication • Full-blown shock • Sepsis and incomplete resuscitation: reduced splanchnic blood flow → non-occlusive bowel necrosis

17. Determining Calorie Requirements • Indirect calorimetry • Harris-Benedict x stress factor x activity factor • 25-30 kcal/kg body weight/day

18. Determining Calorie Requirements • Using harris benedict to calculate REE: • Males = 66.5 + (13.5 W) + (5H) - (6.8A) • Females =655 + (9.6W) + (1.8H) - (4.7A) • Error :7-24 % more than real needs.

19. Determining Calorie Requirements

20. Metabolic Response to Overfeeding • Hyperglycemia • Hypertriglyceridemia • Hypercapnia • Fatty liver • Hypophosphatemia, hypomagnesemia, hypokalemia Barton RG. Nutr Clin Pract 1994;9:127-139

21. Metabolic Response to Overfeeding • Over feeding : increase in TEN (thermic effect of nutrition) up to 30% & affect cardio vascular & pulmonary system. • TEN is depends on : substrate and the rate • The largest is for protein : 20-30% • Moderate increase by CHO: 6-8% • Minimum by fats: LCT< MCT 2-3%

22. Macronutrient needs during Stress Carbohydrate • At least 100 g/day needed to prevent ketosis • Carbohydrate intake during stress should be between 30%-40% of total calories • Glucose intake should not exceed 5 mg/kg/min

23. Macronutrient needs during Stress Fat • Provide 20%-35% of total calories • Maximum recommendation for intravenous lipid infusion: 1.0 -1.5 g/kg/day • Monitor triglyceride level to ensure adequate lipid clearance

24. Macronutrient needs during Stress Protein: • Requirements range from 1.2-2.0 g/kg/day during stress (all pnt losses should be fully replaced) • Comprise 20%-30% of total calories during stress.

25. With resolving stress, the energy requirements remain the same but the protein needs decrease to 1.2 g/kg

26. Macronutrient needs during Stress Urine urea nitrogen (UUN): to evaluate degree of hyper metabolism (stress level) Urine urea (g/d) Stress level 0- 5 Normometabolism (No stress) Mild hyper cat (SL one) 5-10 10- 15 Moderate hyper cat(SL two) >15 severe hyper cat(SL three)

27. Macronutrient needs during Stress No Stress Moderate Stress Severe Stress Stress Level Calorie:Nitrogen Ratio Percent Potein / Total Calories Protein / kg Body Weight > 150:1 150-100:1 < 100:1 < 15% protein 15-20% protein > 20% protein 0.8 g/kg/day 1.0-1.2 g/kg/day 1.5-2.0 g/kg/day

28. Amino acid supplements

29. Glutamine in Metabolic Stress • Considered “conditionally essential” for critical patients • Depleted after trauma • Provides fuel for the cells of the immune system and GI tract • Helps maintain or restore intestinal mucosal integrity

30. Arginine in Metabolic Stress • Provides substrates to immune system • Increases nitrogen retention after metabolic stress • Improves wound healing in animal models • Stimulates secretion of growth hormone and is a precursor for polyamines and nitric oxide • Not appropriate for septic or inflammatory patients.

31. Key Vitamins and Minerals

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