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Energy- & Protein-Modified Diets for Metabolic & Respiratory Stress Chapter 24 Nutrition & Diet Therapy, 7th Edition Stress in the Body • Body’s response to severe stress can threaten survival • Stress increases nutritional needs considerably—increasing risk of malnutrition • Metabolic stress: disruption of body’s internal chemical environment • Respiratory stress: characterized by inadequate oxygen supply & excessive carbon dioxide in blood & tissues • Both types of stress can lead to hypermetabolism, wasting & life-threatening complications Nutrition & Diet Therapy, 7th Edition I. Body’s Response to Stress & Injury • Stress response: non-specific response of the body to variety of stressors (ex. infection, fractures, surgery, etc.) • Metabolic processes focus on immediate survival – Energy nutrients mobilized from storage & made available in the blood – Energy is diverted from non-essential processes (like growth…) – Heart & respiratory rates increase to deliver oxygen & nutrients to cells – Long-term stress results in damage to body processes due to diversion of energy, nutrients to organs needed for survival Nutrition & Diet Therapy, 7th Edition Nutrition & Diet Therapy, 7th Edition Body’s Response to Stress & Injury • Inflammatory response – Quick, non-specific immune system response to infection or tissue injury – Contains & destroys infectious agents & their agents; prevents further tissue damage Classic Signs of Localized Inflammation Swelling Redness Heat Pain Nutrition & Diet Therapy, 7th Edition Inflammatory Response Nutrition & Diet Therapy, 7th Edition Body’s Response to Stress & Injury • Systemic effects of inflammation – Acute-phase response: changes in body chemistry resulting from inflammation, infection or severe injury • Release of acute-phase proteins & blood clotting proteins • Decreased plasma concentrations of albumin, iron & zinc • Muscle catabolism & negative nitrogen balance • Elevated metabolic rate, increased numbers of neutrophils • Lethargy, anorexia • Fever Nutrition & Diet Therapy, 7th Edition • Systemic inflammatory response syndrome and sepsis-long term – Whole-body response to unresolved inflammation or infection • Increased heart rate & respiratory rate • Elevated WBC levels • Critical elevation of body temperature – Complications • Excessive fluid retention & tissue edema • Low blood pressure • Impaired blood flow • Can lead to shock—affecting functioning of multiple organs II. Nutrition Treatment in Acute Stress • Determining nutritional requirements – Major metabolic changes in metabolic stress • • • • Hypermetabolism Negative nitrogen balance Hyperglycemia Insulin resistance – Feeding patient during acute stress presents challenges • Overfeeding increases risks of refeeding syndrome • Underfeeding worsens negative nitrogen balance & increases lean tissue losses Nutrition & Diet Therapy, 7th Edition Refeeding syndrome—develops when malnourished individual is aggressively fed; associated with fluid & electrolyte imbalances; hyperglycemia Nutrition Treatment in Acute Stress • Determining nutritional requirements (con’t) – Nutritional assessment • Complicated by fluid imbalances & lab data • Amounts of pro & E to provide are controversial (p.660, T. 24-2 provide guidelines) • Assortment of medical conditions that cause metabolic stress makes each situation unique • Clinicians must observe patient’s responses & readjust nutrient intakes as necessary – Estimation of protein needs • Intakes recommended during acute stress are higher than DRI values • Variable needs, but range between 1.0-2.0 grams per kg body weight daily (burn patients require more, 2-2.5 g/Kg, due to significant protein losses) • Glutamine & arginine supplementation may be indicated, studies still being done. Nutrition & Diet Therapy, 7th Edition Nutrition Treatment in Acute Stress • Determining nutritional requirements (con’t) – Carbohydrate & fat • Bulk of energy needs are supplied by carbohydrate & fat – 50-60% total kcalorie intake from carbohydrate sources – Fat intake (if patient does not have hypertriglyceridemia) may be 1-1.5 grams per kg daily – Frequent assessment of nutritional needs necessary – Micronutrients: h need for B,C, & A vits, Zn • Approaches to nutrition care – Initial care—maintain fluid & electrolyte balances w/IV – Once feeding begins—combination of methods to meet nutritional needs – Nutritional support as warranted • Enteral nutrition preferred • Parenteral nutrition if adequate nutrient intakes cannot be provided from enteral feedings alone Nutrition & Diet Therapy, 7th Edition III. Nutrition & Respiratory Stress • Chronic obstructive pulmonary disease (COPD) – Group of conditions characterized by persistent obstruction of airflow through the lungs • Chronic bronchitis • Emphysema – Both conditions reduce capacity of lungs to maintain normal oxygen & carbon dioxide levels in the blood – Shortness of breath (dyspnea) occurs – May lead to respiratory or heart failure – 4th leading cause of death in U.S. Nutrition & Diet Therapy, 7th Edition Nutrition & Diet Therapy, 7th Edition Nutrition & Respiratory Stress • COPD (con’t) – Debilitating condition • Dyspnea generally worsens as condition progresses • Results in dramatic reductions in physical activity & quality of life • Associated with other chronic illnesses, anxiety, depression & psychological distress – Causes • Smoking tobacco is primary risk • Genetic susceptibility contributes to development, especially in patients with early-onset COPD Nutrition & Diet Therapy, 7th Edition Nutrition & Respiratory Stress • COPD (con’t) – Treatment • Primary objectives of treatment: prevent disease from progressing & relieve major symptoms • Smoking cessation • Influenza & pneumonia vaccinations • Medications – Bronchodilators – Corticosteroids Nutrition & Diet Therapy, 7th Edition • Nutrition – Promote maintenance of healthy body weight & prevent muscle loss – Improve food intake – Small, frequent meals – Adequate fluid intake – High-kcalorie, high-protein diet if undernourished – Liquid supplements to improve weight gain or exercise endurance – E-restricted diet for gradual weight loss if overweight or obese – Specialized formulas – Incorporating exercise program Nutrition & Respiratory Stress • Respiratory failure – Gas exchange between air & circulating blood becomes greatly impaired – May develop from chronic disease (ex., COPD) or acute respiratory failure – Various factors affecting lung function may contribute to cause – Acute respiratory distress syndrome (ARDS) • Acute form of respiratory failure, life threatening • Commonly triggered by severe trauma or infection Nutrition & Diet Therapy, 7th Edition Nutrition & Respiratory Stress • Respiratory failure (con’t) – Consequences • Low blood levels of oxygen (hypoxemia) & excessive carbon dioxide in blood (hypercapnia) – Acidosis – Increased respiratory rate – Cyanosis (blue skin), other symptoms • Inadequate oxygen supply to tissues (hypoxia) Nutrition & Diet Therapy, 7th Edition – Treatment • Focuses on supporting lung function & correction of underlying disorder • Treatment plan depends on specific disorder – Oxygen therapy – Mechanical ventilation – Monitoring & supporting fluid balance – Diuretics – Medications to treat infection, keep airways open, relieve inflammation • Mechanical ventilation controls the rate & amount of O2 supplied to a person’s airways Nutrition & Diet Therapy, 7th Edition Nutrition & Respiratory Stress • Respiratory failure (con’t) – Nutrition therapy • Individualized, based on patient’s condition – Provide enough E & protein to support lung function; increased cal, but not excessive as this generates extra CO2 and may increase respiratory problems. – Fluid restrictions to help reduce pulmonary edema • Enteral feeding preferred over parenteral nutrition – Nutrition support • Tube feedings are used if intestinal tract is functional – Intestinal feeding preferred over gastric – Nutrient-dense formula (2 kcalories per mL, less fld. needed) • Parenteral nutritional support may be necessary if risk of aspiration is too high to continue enteral feedings Nutrition & Diet Therapy, 7th Edition Nutrition in Practice—Multiple Organ Failure • Also referred to as multiple organ dysfunction syndrome – Late stage of severe illness or injury that results from severe inflammatory response – Failure of 2 or more of body’s organ systems – Involves lungs, liver, kidneys, GI tract – Involvement of 3 or more organs is associated with fatality rate of almost 100% • Cause – Systemic inflammatory response syndrome (SIRS) • Normal adaptive response to severe insult • Can progress to shock, resulting in impairment of numerous organ systems • Risk Factors: Age, Severity of SIRS, Infection, Blood transfusion Nutrition & Diet Therapy, 7th Edition Nutrition & Diet Therapy, 7th Edition Nutrition & Diet Therapy, 7th Edition Nutrition in Practice—Multiple Organ Failure • Treatment – Lung support – Fluid resuscitation – Support of heart & blood vessel function – Kidney support – Reversal or prevention of infection – Nutrition support Nutrition & Diet Therapy, 7th Edition