Nutritional Assessment in Respiratory Disease

1. Chapter 18 Nutritional Assessment of Patients with Respiratory Disease

2. Learning Objectives After reading this chapter you will be able to: Recognize how nutrition and respiration are interrelated Recognize the functional importance of oxygen in nutrition Identify the nutritional significance of measuring oxygen uptake Identify the value of determining the basal metabolic rate and basal energy expenditure

3. Learning Objectives (cont’d) Recognize how starvation affects: Body weight Muscle mass (diaphragm and other respiratory musculature) Forced vital capacity, forced expiratory volume in 1 second, and diffusing capacity of the lung for carbon dioxide Surfactant production Know how some respiratory treatment modalities inhibit patient nutritional status

4. Learning Objectives (cont’d) Identify the by-products of anaerobic (without oxygen) metabolism Identify oxygen’s importance in terms of adenosine triphosphate production Identify how fat, carbohydrate, and protein metabolism affect the respiratory quotient

5. Recognize the daily nutritional requirements for carbohydrate, protein, and fat Identify the protein requirements for normal and severely catabolic patients Recognize the significance of measuring nitrogen balance Learning Objectives (cont’d)

6. Learning Objectives (cont’d) Recognize the problems associated with a low-protein diet Recognize the advantages and disadvantages of a high-carbohydrate diet in regard to the pulmonary system Identify the importance of vitamins and minerals in respiratory function

7. State the methods available for meeting nutritional requirements and their advantages and disadvantages Recognize the methods for assessing nutritional status Identify the role of the RT in nutritional assessment in relation to inspection, auscultation, and laboratory findings Learning Objectives (cont’d)

8. Introduction Nutritional status has major influence on patient outcomes Provides energy for breathing and movement Food quality and quantity affect oxygen needs and CO2 production Nutrients influence lung immune function

9. Interdependence of Respiration and Nutrition O2 and nutrients travel in the blood to tissues Nutrient conversion to energy at cellular level requires O2 to support the process Aerobic metabolism required for life Breathing fuels the metabolic process Thus breathing is part of nutrition

10. Interdependence of Respiration and Nutrition (cont’d) Metabolic rate determines oxygen uptake (VO2) By measuring VO2 at rest, the basal metabolic rate (BMR) or resting energy expenditure (REE) can be calculated

11. Interdependence of Respiration and Nutrition (cont’d) Harris-Benedict equation: basal energy expenditure (BEE) of healthy person at rest Men: 66 + (13.7 × W) + (5 × H) – (6.8 × age) Women: 655 + (9.6 × W) + (1.7 × H) – (4.7 × age) (W = weight in Kg, H = height in cm) True energy measurements are better Direct calorimetry Indirect calorimetry

12. Interdependence of Respiration and Nutrition (cont’d) Direct calorimetry Special room measures heat produced by metabolism Metabolism generates heat, measured in calories This is not practical clinically

13. Interdependence of Respiration and Nutrition (cont’d) Indirect calorimetry VO2 and VCO2 to determine energy consumptionVO2 correlates directly with ATP production The higher the metabolic rate, the higher the VO2 This is now measured with a metabolic cart Now portable Easiest to perform on ventilated patients Nose clips and mouthpiece required for spontaneously breathing patients

14. Nutritional Depletion and Respiration 12 to 16 hours of insufficient carbohydrate intake will result in gluconeogenesis Process of converting muscle and enzyme proteins into sugar This leads to functional tissue loss In starvation: Muscles lose endurance and strength (including those of respiration) Noted by decreased FVC, FEV1, and DLCO Diminished immune function because antibodies are proteins

15. Nutritional Depletion and Respiration (cont’d) Emphysema produces a catabolic state typically with weight loss even with normal caloric intake REE high in malnourished emphysemic patient Exacerbates symptoms of COPD Diminished respiratory muscle strength and exercise tolerance Compromised immune function, thus increased pulmonary infections Increased intake of food can normalize weight Emphysemic patients are not comfortable eating large quantities of food

16. Therapeutic Interactions of Respiration and Nutrition Respiratory therapy may hinder nutrition Bronchodilators cause nausea Nasal oxygen interferes with smell and taste Medications can interact to render nutrients less useful or inhibit some metabolic enzymes Intubation complicates eating process Large meals interfere with diaphragm movement Anxiety, depression often reduce appetite

17. Therapeutic Interactions of Respiration and Nutrition (cont’d) Semistarved states can decrease hypoxic drive Critically ill patients require constant aid Breathing: intubation, mechanical ventilation Feeding: NG tube or even total parenteral nutrition (TPN) Matching energy and nutritional needs with ventilatory needs can be challenging

18. Respiratory System and Nutritional Needs

19. Metabolism Body energy is produced by metabolism Transfers food to ATP—body’s energy source Can occur by aerobic or anaerobic metabolism Oxygen is consumed in the aerobic pathway Very efficient yield of ATP Waste product is CO2, which is exhaled Anaerobic pathway occurs without oxygen Very inefficient Waste product is lactic acid; may result in lactic acidosis

20. Metabolism (cont’d) Amount of CO2 produced by aerobic metabolism is determined by the fuel burned Described by the RQ: CO2 production divided by oxygen consumption Fat has RQ of 0.7 Protein has RQ of 0.85 Carbohydrate has RQ of 1 Burning a combination of the above produces a normal RQ (VCO2/VO2) of 0.8 That is 200 ml CO2/250 ml O2

21. Nutritional Requirements Basic: carbohydrate, protein, fat, vitamins, minerals, water, and O2 Carbs, proteins, fats provide energy and building blocks Vitamins facilitate metabolic pathway reactions Minerals provide elements for molecules Water provides fluidity for blood flow and medium for various chemical reactions Oxygen: without it everything stops

22. Nutritional Requirements (cont’d) Carbohydrate (sugar) Should be largest amount of dietary intake Complex carbs in grains, vegetables, fruits Simple sugars present in the above foods but primarily found in refined processed foods Patients with severe COPD may do better with a lower-carbohydrate, higher-fat diet due to reduced CO2 production

23. Protein Should comprise 12% to 15% of intake Recommended daily amount (RDA) varies 0.8 g/kg for healthy individual 1.2 to 1.5 g/kg for average hospital patient 2 to 2.5 g/kg for severe catabolic patients Nitrogen found only in protein amino acids Quick estimate of protein catabolism is made by multiplying blood urea nitrogen (BUN) by 6.25 Nutritional Requirements (cont’d)

24. Fat Carries fat soluble vitamins: A, D, E, K Important for immunity, clotting, antioxidants, etc. Fats twice as calorie dense as other nutrients Thus efficient for increasing caloric intake for patients on fluid restrictions Higher fat content may decrease dyspnea for COPD patients Nutritional Requirements (cont’d)

25. Vitamins Fat soluble (A, D, E, K) Water soluble (B group and C) Co-factors in enzyme systems for various metabolic functions Nutritional Requirements (cont’d)

26. Minerals Used in chemical reactions and enzyme systems Iron key for role in O2 transport on hemoglobin Omega-3 useful anti-inflammatory for asthmatics Fluid balance important for mucociliary clearance Nutritional Requirements (cont’d)

27. Methods of Meeting Nutritional Requirements Nutritional administration route: enteral or parenteral Enteral is preferred as most natural By mouth if possible (emphysema patient more frequent small meals) If intubated maybe by NG tube, PEG tube Parenteral (last resort) If GI tract not functioning, patient may require TPN, which is IV infusion of all nutrients

28. Nutritional Assessment

29. Role of RTs in Nutritional Assessment Inspection findings Cachectic patients are bony with depressed intercostal spaces Accessory muscles are often readily visible Poor cough secondary to muscle weakness Viscous secretions may suggest dehydration

30. Role of RTs in Nutritional Assessment (cont’d) Auscultation findings Basilar coarse or fine crackles may indicate fluid overload or loss of blood protein Wheezing secondary to food intolerance/allergy Fine late inspiratory crackles may indicate diminished surfactant secondary to malnutrition S3 may indicate fluid overload and CHF S4 may indicate severe anemia

31. Role of RTs in Nutritional Assessment (cont’d) Laboratory findings PFT changes: decreased FVC, FEV1, PEP, PIP ABG changes: Hypercarbia with acidosis due to excessive nutrition or ventilatory failure Anemias decrease oxygen carrying capacity of hemoglobin and thus CaO2 High-fat intake may cause a low PaO2 pH alterations Secondary to foods that are alkalotic or acidotic Lactic acidosis due to low PaO2

32. Summary O2 is crucial for the production of ATP ATP fuels all body functions BMR can be determined if VO2 is known RT can interfere with nutrition Patients with severe COPD may do better with higher-fat, lower-carbohydrate diets Intubated patients typically fed by NG tube TPN is used only as a last resort