Metabolism And Nutrition In Trauma[1]

SURGERY 081606 METABOLISM IN= ingested nitrogen I. REVIEW Nutrients - Proteins o 4 kcal/ g - Carbohydrates o 4 kcal/g (oral) o 3.4kcal/g (parenteral) - Lipids o 9 kcal/g - water - vitamins - minerals Glucose Metabolism Glucose in circulation ↓ Glucose goes into the cytoplasm ↓ Glucose is converted into Pyruvate ↓ Pyruvate can be converted to AcetylCoa in the mitochondria and enter Kreb’s Cycle Or Pyruvate can be converted to Lactate to enter Cori’s Cycle Fatty Acid Metabolism Triglycerides in circulation ↓ Fatty Acid + glycerol ↓ Can enter cell for metabolism OR Remain in circulation (hypertriglyceredemia)

UN= 24-hr urine nitrogen RNL= remaining nitrogen loss = 3.1 (constant) 0 NB= normal + NB= pregnant women - NB = stressed individuals Respiratory Quotient (RQ) RQ = VC02 / V02 VC02= C02 produced V02= 02 produced Glucose Oxidation 1 glucose + 6O2 = 6CO2 + 6H2  RQ = 6/6 = 1 Fat Oxidation 1 palmitate + 23O2 = 16CO2 +16H20  RQ= 16/23 = 0.7 Protein Oxidation 1 AA + 5.1 O2 = 4.1 CO2 + 2.8 H20  RQ= 4.1/5.1 = 0.8 Lipogenesis - RQ > 1.0 – 8.0 - Should be avoided in nutrition Nutrient Utilization Regulation - nutrient availability - stress

Amino Acids

Excess Glucose Supply

Essential - body cannot synthesize - have to provide in the diet

↑ glucose  pyruvate  AcetylCoa  ↑ ATP (Kreb’s Cycle)  negative feedback  AcetylCoa  ↑ Triglycerides and CO2

Conditionally Essential - glutamine - arginine Non-essential - NH3 – R- COOH - used for protein synthesis

An increased glucose level in circulation triggers cellular take-up of glucose. Glucose is converted to pruvate and pyruvate is converted to AcetylCoa to complete the Kreb’s cycle resulting in the generation of ATP. However, increased ATP levels provides negative feedback, inhibiting AcetylCoa from completeing the Kreb’s cycle. AcetylCoa consequently moves out of the cell where it undergoes lipogenesis producing CO2 and triglycerides.

Nitrogen Balance NB = IN – (UN + RNL)

SURGERY METABOLISM 1

Excess Fatty Acids

 will yield approximately same value

↑ Free Fatty Acid  Beta oxidation  Acetyl Coa  ↑Ketones (if low insulin) or ↑Triglycerides (if high insulin)

Protein Requirement

Fatty acids in the circulation go inside the mitochondria where it undergoes beta oxidation. AcetylCoa is produced which moves into the cytoplasm. It is converted to Ketones during low insulin states or Triglycerides during high insulin states. Inflammatory Response (Glucose) Glucose  Pyruvate  Lactate  Cori Cycle TNF- alpha, IL- 6 and IL- 1 prevent the conversion of pyruvate into AcetylCoa in the mitochindria, thus pyruvate is converted to lactate instead. ↑TNF-alpha, ↑IL-6, ↑IL1 = ↑lactate production

For Healthy individuals = 0.8- 1.0 For Stressed = 1.0- 2.0 Carbohydrate Requirements -

Must provide 50% to 60% of total calories Necessary for CHON metabolism

Fat Recommendations -

source of energy + essential FA o linoleic acid: 2-7 g/day 20% - 30% of total calories

Calorie Distribution Inflammatory Response (Fatty Acids) Triglyceride  FA + glycerol  FA  triglyceride  circulation TNF and IL-1 inhibit carnitine, which metabolizes fatty acids in the mitochondria. Thus FA are converted back to triglycerides and are brought back into the circulation. ↑TNF, ↑IL-1 = ↓carnitine = hypertriglyceridemia Malnutrition - energy expenditure must be calculated based on ABW, not - using IBW will over-feed the patient resulting in ↑triglycerides, ↑FA Obesity - energy expenditure must be calculated based on IBW - using ABW will over-feed the patient resulting in ↑triglycerides, ↑FA

Normal CHO = 60% Fat = 25% CHON= 15% Catabolic State CHO= 45% Fat = 30% CHON= 25% Vitamins and Minerals Fat Soluble Vitamins - A, D, E, K Water Soluble Vitamins II. METABOLIC RESPONSE TO TRAUMA AND STARVATION Early Fasting - energy comes from muscles - ↑ gluconeogenesis Late Fasting - energy from ketones

Calculating Basal Energy Expenditure Metabolic Reaction to Starvation Harris Benedict Equation  variables: age, weight, height, gender, activity levels, etc “Rule of Thumb” Method  calorie requirement: 25-30 kcal/ kg/ day

Hormone Norepi Norepi Epi T4

Source Sympathetic NS Adrenals Adrenals Thyroid

↓ ↑ ↑ ↓

SURGERY METABOLISM 2

*There is less energy expenditure in starvation! Metabolic Response to Trauma Ebb Phase - hypovolemic shock - ↓ Cardiac output - ↓ O2 consumption - ↓ Blood pressure - ↓ Tissue perfusion - ↓ Body temperature - ↓ Metabolic rate

↑ hyperglycemia ↑ gypertriglyceridemia ↑ hypercapnia ↑ fatty liver ↑ hyperphosphatemia ↑ hypermagnesemia Macronutrients During Stress

Flow Phase - ↑ catecholamines - ↑ glucocorticoids - ↑ glucagon - ↑ cytokines, lipid mediators - ↑ acute CHON production from muscle = loss of body mass Endocrine Response - FA from FA deposits - Glucose from liver/ muscle glycogen - AA from muscle *There is increased energy expenditure in trauma!

Carbohydrates - at least 100g/day to prevent k-sis? (sorry can’t understand my handwriting) - CHO intake 30%- 90% of total Calories Fat - provide 20%- 35% of total calories - intravenous: 1.0- 1.5 Protein - 20%- 30% of total calories

Cal: Nitogen %CHON/ total calories CHON/ kg body weight

No Stress >150:1 45% CHON 0.8g/kg/day

Cal: Nitogen %CHON/ total calories CHON/ kg body weight

Moderately Stressed 150-100:1 15- 20% CHON 1.0-1.2/g/kg/day

Cal: Nitogen %CHON/ total calories CHON/ kg body weight

Severely Stressed <100: 1 >20% 1.5-2.0g/kg/day

( - ) Nitrogen Balance in Patients Burns – Most severe N loss Severe sepsis Infection Elective Surgery – Least severe

Metabolic Rate Body Fuel Body CHON Urinary Nitrogen Weight Loss

Starvation ↓

Trauma ↑↑

Conserved conserved ↓

wasted wasted ↑↑

Slow

rapid

*Body adapts to starvation but not during disease or trauma! Injury Stress Factor Minor Surgery 1 – 1.10 Long Bone 1.15 – 1.3 Fracture Burns 1.2 – 2.00  based on Harris Benedict equation Metabolic Response to Over- feeding

Conditionally Essential Amino Acids (in metabolic stress) Glutamine - body cannot synthesize glutamine in stress - depleted after trauma - fuel for immune system and GIT Arginine - provides substrates for immune system - ↑ Nitrogen retention - ↑ wound healing - ↑ growth hormone - Do not use for septic patients! Arginine ↑ activity of immune system, giving it to patient might exhaust him/her Vitamins A – wound healing, tissue repair B – metabolism, CHO utilization

SURGERY METABOLISM 3

C – collagen synthesis E – antioxidant Pyridoxine – CHON synthesis Iron and B12 – oxygen delivery Nutritional Assesment Nutrient Requirements -

Medical History Physical Examination Anthropometric Measures

Short Method Nutrient Intervention

Nutritional Evaluation SGA: Subjective Global Assessment History - weight change in the past 3-6 months or 2 weeks - dietary intake compared to usual - GI symptoms - functional capacity - Metabolic needs of diseases Physical Examination - loss of subcutaneous fat - muscle wasting - ankle edema - sacral edema - ascites

-

Nutrient counseling Oral supplements Enteral tube feeding Parenteral

*Rule: if the patient’s GIT is functional, use oral supplements and enteral tube feeding. Only of the GIT is non-functional will parenteral methods be used! * refer to Clinical Decision Making Algorithm for Nutritional Support Summary -

nutrient utilization depends on availability (fasting) and inflammatory response (stress) Nutritional requirements ↑ during trauma

SGA Grading System A- well nourished (0) B- moderately nourished with suspicion of malnourishment (1) C- severely malnourished (2) Biochemical Markers for Nutrient Evaluation -

serum albumin (not <3.5) serum transferring prealbumin

Anthropometrics Measures TSF MAC

BMI Nomogram Underweight <18.5 Normal 18.5-25 Overweight 25- 30 Obese >30 *based on American statistics, Asian classification much less

SURGERY METABOLISM 4