Chapter 16 Nutrition in metabolic and Respiratory Stress

1616Nutrition in

Metabolic andRespiratory

Stress

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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



The Body’s Responses to Stress and 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




• 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





• 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.)



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



Nutrition Treatment of Acute Stress (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



Nutrition Treatment of Acute Stress: Determining Nutritional Requirements (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



Nutrition Treatment of Acute Stress: Determining Nutritional Requirements (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



Nutrition Treatment of Acute Stress (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




• 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




• 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




• 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

Education