NUTRITON AND METABOLIC STRESS. Metabolic Stress Sepsis (infection) Trauma (including burns) ...
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Transcript of NUTRITON AND METABOLIC STRESS. Metabolic Stress Sepsis (infection) Trauma (including burns) ...
NUTRITON AND METABOLIC STRESS
Metabolic Stress Sepsis (infection) Trauma (including burns) Surgery Once the systemic response is activated, the
physiologic and metabolic changes that follow are similar and may lead to septic shock.
Immediate Physiologic and Metabolic Changes after Injury or Burn
ADH, Antiduretic hormone; NH3, ammonia.
Metabolic Response to StressMetabolic Response to Stress
Involves most metabolic pathways Accelerated metabolism of LBM Negative nitrogen balance Muscle wasting
Involves most metabolic pathways Accelerated metabolism of LBM Negative nitrogen balance Muscle wasting
Ebb PhaseEbb Phase
Immediate—hypovolemia, shock, tissue hypoxia
Decreased cardiac output Decreased oxygen consumption Lowered body temperature Insulin levels drop because glucagon is
elevated.
Immediate—hypovolemia, shock, tissue hypoxia
Decreased cardiac output Decreased oxygen consumption Lowered body temperature Insulin levels drop because glucagon is
elevated.
Flow Phase
Follows fluid resuscitation and O2 transport
Increased cardiac output begins Increased body temperature Increased energy expenditure Total body protein catabolism begins Marked increase in glucose production, FFAs,
circulating insulin/glucagon/cortisol
Hormonal and Cell-Mediated Response
There is a marked increase in glucose production and uptake secondary to gluconeogenesis, and
—Elevated hormonal levels
—Marked increase in hepatic amino acid uptake
—Protein synthesis
—Accelerated muscle breakdown
Skeletal Muscle Proteolysis
From Simmons RL, Steed DL: Basic science review for surgeons, Philadelphia, 1992, WB Saunders.
Metabolic Changes in StarvationMetabolic Changes in Starvation
From Simmons RL, Steed DL: Basic science review for surgeons, Philadelphia, 1992, WB Saunders.
Hormonal Stress ResponseHormonal Stress Response Aldosterone—corticosteroid that causes
renal sodium retention Antidiuretic hormone (ADH)—
stimulates renal tubular water absorption These conserve water and salt to support
circulating blood volume
Aldosterone—corticosteroid that causes renal sodium retention
Antidiuretic hormone (ADH)—stimulates renal tubular water absorption
These conserve water and salt to support circulating blood volume
Hormonal Stress Response—cont’dHormonal Stress Response—cont’d ACTH—acts on adrenal cortex to
release cortisol (mobilizes amino acids from skeletal muscles)
Catecholamines—epinephrine and norepinephrine from renal medulla to stimulate hepatic glycogenolysis, fat mobilization, gluconeogenesis
ACTH—acts on adrenal cortex to release cortisol (mobilizes amino acids from skeletal muscles)
Catecholamines—epinephrine and norepinephrine from renal medulla to stimulate hepatic glycogenolysis, fat mobilization, gluconeogenesis
Systemic Inflammatory Response Syndrome
SIRS describes the inflammatory response that occurs in infection, pancreatitis, ischemia, burns, multiple trauma, shock, and organ injury.
Patients with SIRS are hypermetabolic.
Multiple Organ Dysfunction Syndrome Organ dysfunction that results from direct
injury, trauma, or disease or as a response to inflammation; the response usually is in an organ distant from the original site of infection or injury
Diagnosis of Systemic Inflammatory Response Syndrome (SIRS)
Site of infection established and at least two of the following are present—Body temperature >38° C or <36° C—Heart rate >90 beats/minute—Respiratory rate >20 breaths/min (tachypnea)
—PaCO2 <32 mm Hg (hyperventilation)—WBC count >12,000/mm3 or <4000/mm3
—Bandemia: presence of >10% bands (immature neutrophils) in the absence of chemotherapy-induced neutropenia and leukopenia
May be caused by bacterial translocation
Bacterial Translocation
Changes from acute insult to the gastrointestinal tract that may allow entry of bacteria from the gut lumen into the body; associated with a systemic inflammatory response that may contribute to multiple organ dysfunction syndrome
Well documented in animals, may not occur to the same extent in humans
Early enteral feeding is thought to prevent this
Bacterial Translocation across Microvilli and How It Spreads into the Bloodstream
Hypermetabolic Response to Stress—CauseHypermetabolic Response to Stress—Cause
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
Hypermetabolic Response to Stress—PathophysiologyHypermetabolic Response to Stress—Pathophysiology
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
Hypermetabolic Response to Stress—Medical and Nutritional Management
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000. Updated by Maion F. Winkler and Ainsley Malone, 2002.
NUTRITIONAL ASSESSMENT
Clinical judgment must play a major role in deciding when to begin/offer nutrition support
Determination of Nutrient Requirements Energy Protein Vitamins, Minerals, Trace Elements Nonprotein Substrate
– Carbohydrate– Fat
Energy
Enough but not too much Excess calories:
– Hyperglycemia• Diuresis – complicates fluid/electrolyte balance
– Hepatic steatosis (fatty liver)
– Excess CO2 production• Exacerbate respiratory insufficiency
• Prolong weaning from mechanical ventilation
Indirect Calorimetry
Better estimate in critically ill hypermetabolic patient
The “gold standard” in estimating energy needs in critical care
Can be used in both mechanically ventilated and spontaneously breathing patients (ventilated patients most accurate)
Equipment is expensive and not readily available in many facilities
Indirect Calorimetry
Requires appropriate calibration of equipment, attainment of a steady state for measurement, and appropriate timing of measurement
Requires interpretation by trained clinician Inaccurate in patients requiring inspired
oxygen (FiO2>60%), and with air leaks via the entrotracheal tube cuff, chest tubes or bronchopleural fistula
Indications for Indirect Calorimetry
Patients with altered body composition (underweight, obese, limb amputation, peripheral edema, ascites)
Difficulty weaning from mechanical ventilation Patients s/p organ transplant Patients with sepsis or hypercatabolic states
(pancreatitis, trauma, burns, ARDS) Failure to respond to standard nutrition support
Malone AM. Methods of assessing energy expenditure in the intensive care unit. Nutr Clin Pract 17:21-28, 2002.
Nutrient Guidelines: Carbohydrate
Should provide 60 – 70% calories Maximum rate of glucose oxidation =
~5 – 7 mg/kg/min or 7 g/kg/day* Blood glucose levels should be monitored
and nutrition regimen and insulin adjusted to maintain glucose below 150 mg/dl
*ASPEN BOD. JPEN 26;22SA, 1992
Nutrient Guidelines: Fat Can be used to provide needed energy and
essential fatty acids Should provide 15 – 40% of calories Limit to 2.5g/kg/day or possibly 1 g/kg/day
IV* Caution with use of fats in stressed &
trauma pts – There is evidence that high fat feedings
(especially LCT) cause immunosuppression – New formulas focus on omega-3s
*ASPEN BOD. JPEN 26;22SA, 1992
Nutrient Guidelines: Protein
1.5 – 2.0 g/kg/day to start; monitor response Nonprotein calorie/gram of nitrogen ratio
for critically ill = 100:1 Giving exogenous aa’s decreases negative
N balance by supplying liver aa’s for protein synthesis
ASPEN BOD. JPEN 26;22SA, 1992
Fluid and Electrolytes
Fluid 30-40 mL/kg or 1 to 1.5mL/kcal expended
Electrolytes/Vitamins/Trace Elements Enteral feedings: begin with RDA/AI
values PN: use PN dosing guidelines
ASPEN BOD. JPEN 26;23SA, 1992
Supplemental Glutamine (GLN) in Critical Care Alterations in glutamine metabolism can occur in
critical care, possibly affecting gut function PN solutions traditionally have not contained
glutamine because of instability in solution Animal and human studies suggest that
supplemental GLN in PN may have beneficial effects
Those benefits have not been demonstrated in EN
Glutamine Metabolism
NH2, Amine; NH3, ammonia.
From Simmons RL, Steed DL: Basic science review for surgeons, Philadelphia, 1992, WB Saunders.
MNT in Selected Populations in Critical Care
Acute Spinal Cord Injury
Source: www.spinal-cord-injury-resources.com/ spinal-i...
Acute Spinal Cord Injury (SCI)
Energy requirement for SCI = H/B x 1.1 x 1.2 (Barco et al, NCP 17;309-313, 2002)
Pt with multi-traumas in addition to SCI may have higher needs
Protein needs: 2 g/kg (Rodriguez DJ et al, JPEN 15:319-322, 1991
Nutrition Support in Surgery/Trauma
Graphic source www.nlm.nih.gov/.../ gallery/image/surgery.gif
Postoperative Nutrition Support Introduction of solid foods depends on condition
of GI Oral feeding may be delayed for first 24 – 48
hours post surgery until return of bowel sounds, passage of flatus or soft abdomen
Traditional practice has been to progress from clear liquids, to full liquids, to solid foods
However, there is no physiological reason not to initiate solid foods once small amounts of liquids are tolerated
Energy Requirements in Surgery or Trauma Will vary with type of surgery, degree of trauma Use Ireton-Jones 1992 or Penn State if data is
available* Can use estimate of 25-30 kcals/kg to begin and
monitor response to therapy** Indirect calorimetry yields most accurate
estimates, particularly in pts difficult to assess
*ADA Evidence Analysis Library, accessed 10-06**ASPEN Nutrition Support Practice Manual, 2nd Edition, p. 278
Hypocaloric Feedings
Hypocaloric feedings have been recommended in specific patient populations
Aggressive protein provision (1.5-2.0 gm/kg/day
ASPEN Nutrition Support Practice Manual, 2nd Edition, p. 279
Zaloga GD. Permissive underfeeding. New Horizons 1994
Hypocaloric Feedings Have Been Recommended in: Class III obesity (BMI>40 Refeeding syndrome Severe malnutrition Trauma patients following shock
resuscitation Hemodynamic instability Acute respiratory distress syndrome or
COPD MODS, SIRS or sepsis
Protein or Nitrogen Requirements in SurgeryProtein or Nitrogen Requirements in Surgery 1.2 to 1.5 g protein/kg BW
for anabolism mild or moderate stress Nitrogen requirement estimated from
energy requirements
1.2 to 1.5 g protein/kg BW
for anabolism mild or moderate stress Nitrogen requirement estimated from
energy requirements