Download MNT for Metabolic Stress: Sepsis, Trauma, Burns, Surgery

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 Stress
 Involves most metabolic pathways
 Accelerated metabolism of LBM
 Negative nitrogen balance
 Muscle wasting
Ebb Phase
 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
Starvation
From Simmons RL, Steed DL: Basic science review for surgeons, Philadelphia, 1992, WB Saunders.
Hormonal 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
Hormonal 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
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 chemotherapyinduced 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—Cause
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
Hypermetabolic 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 Surgery
 1.2 to 1.5 g protein/kg BW
for anabolism mild or moderate stress
 Nitrogen requirement estimated from
energy requirements