Nutrition for Patients with
Metabolic or Respiratory Stress
Chapter 16
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The Stress Response
• The body’s attempt to promote healing and resolve
inflammation when homeostasis is disrupted
• Intensity of the stress response depends to some extent
on the cause and/or severity of the initial injury
• Metabolic stress
– Changes in metabolic rate
– Heart rate
– Blood pressure
– Nutrient metabolism
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The Stress Response (cont’d)
• Hormonal response to stress
– Ebb phase
o Immediate post-injury phase
o Typically lasts 12 to 24 hours
o Characterized by:
 Shock with hypovolemia and diminished tissue
oxygenation
 Cardiac output, oxygen consumption, urinary
output, and body temperature fall
 Glucagon and catecholamine levels rise
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The Stress Response (cont’d)
• Hormonal response to stress (cont’d)
– Treatment goals
o Restore blood flow to organs
o Maintain adequate oxygenation to all
tissues
o Stop bleeding
– Ebb phase ends when the patient is
hemodynamically stable
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The Stress Response (cont’d)
• Hormonal response to stress (cont’d)
– Flow phase
o Metabolic response to stress
o Counterregulatory hormones
 Makes energy available to carry on
essential bodily functions
o State of hypercatabolism and
hypermetabolism created
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The Stress Response (cont’d)
• Hormonal response to stress (cont’d)
– Flow phase (cont’d)
o Oxygen consumption, cardiac output, carbon
dioxide production, and body temperature
increase
o Length of phase depends on:
 Severity of injury or infection
 Development of complications
– Glycogen is depleted within the first 24 hours
after the injury
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The Stress Response (cont’d)
• Inflammatory response
– Acute-phase response
o Body’s attempt to destroy infectious agents and
prevent further tissue damage
o Characterized by a change of at least 25% in the
plasma concentration of certain proteins known as
acute phase proteins
 C-reactive protein is positive protein
 Negative acute phase proteins decrease in
response to inflammation; albumin is one
example
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The Stress Response (cont’d)
• Inflammatory response
– Acute-phase response (cont’d)
o Cytokines and other immune system molecules
 Regulate acute phase proteins
 Produce changes in other cells that cause systemic
symptoms of inflammation
 Anorexia
 Fever
 Lethargy
 Weight loss
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Question
• The treatment goals of the ebb phase of the
stress response are what?
a. Maintain protein catabolism
b. Maintain oxygenation to all tissues
c. Decrease blood flow to nonvital organs
d. Decrease bleeding
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Answer
b. Maintain oxygenation to all tissues
Rationale: Treatment goals are to restore blood
flow to organs, maintain adequate oxygenation to
all tissues, and stop bleeding. This initial phase
ends when the patient is hemodynamically
stable.
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The Stress Response (cont’d)
• Inflammatory response (cont’d)
– Systemic inflammatory response syndrome
(SIRS)
o Life-threatening condition
o May occur when severe inflammation lasts
longer than a few days
o Heart rate, respiratory rate, white blood cell
count, and/or body temperature become
critically elevated
o If caused by infection, sepsis may occur
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The Stress Response (cont’d)
• Inflammatory response (cont’d)
– Systemic inflammatory response syndrome (SIRS)
(cont’d)
o SIRS and sepsis cause:
 Excessive fluid accumulation
 Low blood pressure
 Impaired blood flow
o Inadequate oxygenation of tissues can lead to
shock and multiple organ failure
– Patient’s prior nutritional status is an important
predictor or morbidity and mortality
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The Stress Response (cont’d)
• Nutritional needs
– Considered after the patient is hemodynamically
stable
– Overwhelming nutritional concern during metabolic
stress is protein catabolism
o Can lead to impaired immune system functioning,
increased risk of infection, impaired or delayed
wound healing, and increased mortality
– Primary goal of nutrition therapy is to protect lean
body mass and prevent or alleviate malnutrition
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The Stress Response (cont’d)
• Nutritional needs (cont’d)
– Calories
o Indirect calorimetry is rarely used
o Harris–Benedict equation is not for the
critically ill
o Basal energy expenditure (BEE)
o Multiply the patient’s weight in kilograms by
a specified calorie level
 Adjusted upward or downward based on
the patient’s response
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The Stress Response (cont’d)
• Calories (cont’d)
– Underfeeding
o Excessive calorie intake increases
metabolism, oxygen consumption, and
carbon dioxide production
 Increases the burden already placed
on the heart and lungs to regulate
blood gases
 Refeeding syndrome
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The Stress Response (cont’d)
• Underfeeding (cont’d)
– Feeding critically ill patients at 100% of
calculated need is associated with worse, not
better, clinical outcomes
– Underfeeding during critical illness (80% calories)
is associated with shorter ICU and hospital stays
– Modest calorie intake is also associated with a
higher chance of achieving ventilator
independence before leaving the ICU
– Hypocaloric intake is maintained for 3 to 5 days
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The Stress Response (cont’d)
• Nutritional needs (cont’d)
– Protein
o Recommendations for protein are not universally
agreed upon
 Range from 1.0 g/kg to 2.0 g/kg
 Patients with severe burns may need 2 to 2.5 g/
kg
o Specific types of amino acids given may influence
the stress response and recovery
 Arginine and glutamine, two nonessential amino
acids, may become conditionally essential
during periods of stress
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The Stress Response (cont’d)
• Nutritional needs (cont’d)
– Carbohydrates and fat
o Should provide 50% to 60% of total calorie needs
o Fat may provide up to 40% of total calories
– Fluid
o Highly individualized requirements according to
losses that occur through exudates, hemorrhage,
emesis, diuresis, diarrhea, and fever
o Avoid overhydration
o Decreased renal output is a frequent complication
of metabolic stress
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The Stress Response (cont’d)
• Nutritional needs (cont’d)
– Micronutrients
o Vitamin and mineral requirements during stress are
unclear
o Trauma and burn patients have been documented
to have high urinary and tissue losses of the trace
elements selenium, zinc, and copper
 When replaced:
 Patients experienced significantly fewer
infections
 Wound healing also improved
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The Stress Response (cont’d)
• Method of feeding
– Enteral nutrition (EN) is recommended over
parenteral nutrition (PN) in critically ill patients
who are hemodynamically stable and have a
functional GI tract
o Common complication in critically ill patients is
gastroparesis
– Parenteral nutrition is required when the GI tract
is nonfunctional
o Associated with increased rate of
hyperglycemia
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The Stress Response (cont’d)
• Method of feeding (cont’d)
– Oral diets are provided as soon as possible
– Nutrition support—either complete or
supplemental tube feedings—is necessary
when calorie needs are not met through an
oral intake
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Question
• Is the following statement true or false?
Systemic inflammatory response syndrome
(SIRS) is a life-threatening condition that may
occur when severe inflammation lasts longer
than 24 hours.
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Answer
False.
Rationale: Systemic inflammatory response
syndrome (SIRS) is a life-threatening condition
that may occur when severe inflammation lasts
longer than a few days.
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Burns
• Extensive burns are the most severe form of
metabolic stress
• Fluid and electrolyte replacement to maintain
adequate blood volume and blood pressure are
the priorities of the initial post-burn period
• Degree of hypermetabolism and
hypercatabolism in the metabolic response
phase correlates to the extent of burn
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Burns (cont’d)
• Nutrition therapy
– Priority is to meet calorie and protein needs
o Protein needs are typically 2.0 to 2.5 g/kg
 Especially if burns cover more than
10% of total body surface area
o Calorie and protein needs increase if
complications develop
o Vitamin C, vitamin A, and zinc, plus a
multivitamin, are recommended by the
Shriners Burn Institute
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Burns (cont’d)
• Nutrition therapy (cont’d)
– Develop less gastroparesis when they are
given nasogastric or nasoduodenal tube
feedings within 8 to 12 hours after admission
– When oral intake is less than 75% of
estimated need for over 3 days, EN should be
used for total or supplemental nutrition
– Total parenteral nutrition is used with
extreme caution
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Respiratory Stress
• Occurs when gas exchange between the air and
blood is impaired
• May cause hypermetabolism
• When nutritional needs are not met, fewer nutrients
are available to maintain respiratory muscle function
• Chronic or acute respiratory stress can lead to:
– Respiratory failure
– Multiple organ failure
– Death
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Respiratory Stress (cont’d)
• Chronic obstructive pulmonary disease
– As many as 60% of patients with chronic
obstructive pulmonary disease (COPD) have
malnutrition, which is associated with poor
outcomes
– Many patients with COPD are hypermetabolic
– Chronic inflammation
– Anorexia may occur
– Early satiety
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Respiratory Stress (cont’d)
• Chronic obstructive pulmonary disease
(cont’d)
– Nutrition therapy
o Correcting or preventing malnutrition is the
priority
o High-calorie, high-protein diet is used
o Some patients may be overweight from
steroid use
o For patients hospitalized with exacerbation of
COPD, calorie needs may be 140% above BEE
o Protein need may be 1.2 g/kg body weight
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Question
• You are admitting a burn patient to your unit. He is
a healthy 18-year-old, 6' 2" tall with a weight of 180
pounds. His burns cover over 15% of his body.
What would you expect his approximate protein
needs to be?
a. 150 g to 191 g
b. 159 g to 200 g
c. 164 g to 205 g
d. 175 g to 216 g
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Answer
c. 164 g to 205 g
Rationale: Protein needs are typically 2.0 to 2.5 g/kg
especially if burns cover over 10% of total body
surface area.
180/2.2 = 81.8 kg
81.8x2 = 163.6
81.8x2.5 = 204.5
Range of protein requirement = 163.6 g to 204.5 g
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Ventilator Dependency and
Carbohydrate Restriction
• Patients on ventilator support may benefit from
a restricted carbohydrate intake
– Carbohydrates produce more carbon dioxide
when they are metabolized than do either
proteins or fats
– This creates a greater burden on the lungs
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Promoting Maximum Intake in Patients
Whose Needs Are High and Appetite Is Low
• Work with client and family to solicit food
preferences
• Young children may regress in their eating
behaviors
• Adults may prefer foods they associate with
recovery as children (e.g., chicken soup)
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Promoting Maximum Intake in Patients
Whose Needs Are High and Appetite Is
Low (cont’d)
• Encourage the family to bring food from home
• Discourage intake of empty-calorie food and
beverages
• Provide nutrient-dense liquid supplements
between meals
• Provide emotional support and allow the patient
to verbalize feelings
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Promoting Maximum Intake in Patients
Whose Needs Are High and Appetite Is
Low (cont’d)
• If possible, schedule debridement and other
medical and surgical procedures at times when
they are least likely to interfere with meals
• Provide pain medication as needed before meals
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When TPN May Be Necessary
• For patients with:
– Adynamic ileus
– Intractable diarrhea
– Bleeding related to Curling’s ulcer
– Pancreatitis
– Pseudoobstruction of the colon
– Patients who cannot receive tube feedings for
longer than 2 to 3 days
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