Chapter 16 Nutrition in metabolic and Respiratory Stress

1616
Nutrition in
Metabolic and
Respiratory
Stress
Copyright © 2017 Cengage Learning. All Rights Reserved.

© Cengage Learning 2017
Introduction
• Metabolic stress
– Disruption in the body’s chemical environment
due to the effects of disease or injury
• Respiratory stress
– Characterized by inadequate oxygen and
excessive carbon dioxide in the blood and
tissues

The Body’s Responses to Stress and
Injury
• Stress response
– Body’s nonspecific response to a variety of
stressors
• Energy nutrients mobilized from storage
• Heart rate and respiration (breathing rate) increase
• Blood pressure rises
• Energy diverted from processes that are not life
sustaining

Injury (cont’d.)
• Hormonal responses to stress
– Hormones released into the blood soon after
an injury occurs
– Catecholamines
• Fight-or-flight hormones: epinephrine and
norepinephrine
– Glucagon
• Causes release of nutrients from storage

Injury (cont’d.)
• Hormonal responses to stress
– Cortisol
• Enhances muscle protein degradation
• Prolonged exposure impairs wound healing,
promotes insulin resistance
– Aldosterone
• Stimulates kidneys to reabsorb more sodium
– Antidiuretic hormone
• Stimulates kidneys to reabsorb more water

Injury (cont’d.)
• The inflammatory response
– Immune system’s nonspecific response to
infection or tissue injury
– Functions
• Contains and destroys infectious agents (and their
products)
• Prevents further tissue damage
– What are classic signs of inflammation?

The Inflammatory Process

The Inflammatory Process (cont’d.)

Responses to Stress and Injury: The
Inflammatory Response (cont’d.)
• Mediators of inflammation: regulate the
inflammatory process
– Histamine: released from granules within
mast cells, causing vasodilation and capillary
permeability
– Cytokines: produced by white blood cells (and
some other types of cells)
– Eicosanoids: derived from dietary fatty acids

• Systemic effects of inflammation: acute-
phase response
– Liver increases production of acute-phase
proteins (C-reactive protein, complement,
hepcidin, fibrinogen, prothrombin, etc.)
– Plasma concentrations of albumin, iron, and
zinc levels fall

• Systemic effects of inflammation
– Muscle catabolism makes amino acids
available for glucose production, tissue repair,
immune protein synthesis
– Systemic inflammatory response syndrome
(SIRS): raised heart and respiratory rates,
abnormal white blood cell counts, and fever
– What is the condition known as shock?

Nutrition Treatment of Acute Stress
• Initial treatments
– Administer intravenous solutions
– Treat infections, repair wounds, drain
abscesses, and remove dead tissue
(debridement)
• Following stabilization
– Provide nutrition assessment and therapy

(cont’d.)
• Determining nutritional requirements
– Principle goals of nutrition therapy
• Preserve lean (muscle) tissue
• Maintain immune defenses
• Promote healing
– What are complicating factors in assessing
the nutritional needs of an acutely stressed
patient?

Nutrition Treatment of Acute Stress:
Determining Nutritional Requirements
(cont’d.)
• Estimating energy needs in acute stress
– Indirect calorimetry (critically ill patients)
– Multiply estimated resting metabolic rate
(RMR) by a stress factor (Box 16-6)
– Equations with built-in stress factors (Table
16-2)
– Multiply body weight by appropriate factor
• Critical care: 25-30 kcal/kg
• Hypocaloric feedings (obese pt.): 11-14 kcal/kg

(cont’d.)
• Protein requirements in acute stress
– Nonobese critically ill patients: 1.2 to 2.0
grams per kilogram body weight per day
– Obese patients given hypocaloric feedings:
2.0 to 2.5 grams per kilogram ideal body
weight per day
– Glutamine and/or arginine supplementation
may benefit some patient populations

(cont’d.)
• Carbohydrate and fat intakes in acute
stress
– Carbohydrates: generally 50% to 60% of total
energy requirements
– Patients with severe hyperglycemia: fat may
supply up to 50% of kcalories
• Micronutrient needs in acute stress
– Specific requirements remain unknown but
thought to be increased

(cont’d.)
• Approaches to nutrition care in acute
stress
– Initial care: simple intravenous solutions
– Enteral feedings or parenteral feedings may
be required
– Transition to oral feedings
• High-kcal, high-protein diet often prescribed
• Take care to avoid overfeeding
• Oral supplements often provided

Nutrition and Respiratory Stress
• Chronic obstructive pulmonary disease
(COPD)
– Conditions characterized by the persistent
obstruction of airflow through the lungs
– Main categories:
• Chronic bronchitis: persistent inflammation and
excessive mucus secretions in airways
• Emphysema: breakdown of elastic structure and
destruction of walls of bronchioles and alveoli

The Respiratory System

Nutrition and Respiratory Stress: COPD
(cont’d.)
• Associated with abnormal levels of oxygen
and carbon dioxide in the blood
• Shortness of breath (dyspnea)
• May lead to respiratory or heart failure
• Causes of COPD
– Primary risk factor: smoking
– Exposure to pollutants
– Genetic factors

(cont’d.)
• Treatment of COPD
– Primary objectives
• Prevent the disease from progressing
• Relieve major symptoms (dyspnea and coughing)
– Recommendations
• Quit smoking
• Obtain flu and pneumonia vaccinations
– Bronchodilators, corticosteroids; supplemental
oxygen therapy in severe cases

(cont’d.)
• Nutrition therapy for COPD
– Main goals
• Correct malnutrition
• Promote the maintenance of a healthy body weight
• Prevent muscle wasting
– Main focus of the nutrition care plan: usually,
encouraging adequate food intake
• Small, frequent meals; adequate fluids in between
• Excessive energy intakes increase CO2 production

(cont’d.)
• Pulmonary formulas
– More kcalories from fat and fewer from
carbohydrate
• Incorporating an exercise program
– Prevent or reverse muscle loss
– Aerobic training and resistance exercise
– May need to increase activity gradually over 4
to 6 weeks

Nutrition and Respiratory Stress (cont’d.)
• Respiratory failure
– Potentially life-threatening condition
• Impaired gas exchange between the air and
circulating blood
• Abnormal levels of tissue gases
– What are possible causes of respiratory
failure?
– Acute respiratory distress syndrome (ARDS)
• Requires emergency care

Nutrition and Respiratory Stress:
Respiratory Failure (cont’d.)
• Consequences of respiratory failure
– Severe hypoxemia: low O2 in blood
– Hypercapnia: excessive CO2 in blood
– Hypoxia: low O2 in tissues
– Acidosis: acid accumulation in tissues
– Cyanosis: bluish cast in the skin
– Headache, confusion, and drowsiness
– Heart arrhythmias and, ultimately, coma

• Treatment of respiratory failure
– Focuses on supporting lung function and
correcting underlying disorder
– Treatment plans vary considerably
• Oxygen therapy via face mask or nasal tubing
• Mechanical ventilation
• Diuretics
• Other medications

• Nutrition therapy for respiratory failure
– Energy needs
• Indirect calorimetry or predictive equations
• Avoid overfeeding (can increase CO2)
– Protein needs
• Mild or moderate lung injury: 1.0 to 1.5 g/kg/day
• ARDS patients: 1.5 to 2 g/kg/day
– Fluids: monitored to prevent imbalances

• Nutrition support in respiratory failure
– Indication: patient unable to eat meals
– Enteral feedings
• Intestinal feedings may be preferred over gastric
feedings to reduce aspiration risk
– Parenteral nutrition support
• May be considered when aspiration risk is high

Nutrition in Practice: Multiple Organ
Dysfunction Syndrome (MODS)
• MODS: progressive dysfunction of 2 or
more organ systems
– Results when shock causes organ failure
– Typically first lungs, then heart, liver, kidneys,
and GI tract
• Risk factors: age, severe SIRS, infection,
blood transfusions

Nutrition in Practice: Multiple Organ
Dysfunction Syndrome (MODS)
• Treatment
– Lung support
– Fluid resuscitation
– Support of heart and blood vessel function
– Kidney support
– Protection against infection
– Nutrition support
• Prevention: mitigate organ stress

Chapter 16 Nutrition in metabolic and Respiratory Stress

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