Pulmonary Disease

1. Pulmonary Disease NFSC 470 McCafferty

2. Components of the Respiratory System • Drive Mechanism • Pumping Mechanism • Gas Exchange Organs

3. Drive Mechanism • Controls breathing patterns • Sensitive to hypoxia and hypercarbia • Modulated by the CNS • Brainstem governs automatic respiration • Cerebral cortex controls voluntary breathing

4. Pumping Mechanism • Air flows in/out as volume of thoracic cavity changes • Regulated by 3 groups of muscles: • Diaphragm: major muscle for inspiratory respiration. Moves up or down to lengthen or shorten cavity. (Inspiration: diaphragm contracts to increase volume of thoracic cage). • Intercostal muscles: internal & external muscles connecting ribs. Contract to pull ribs up and out to increase thoracic diameter • Major role in transition from inspiration to expiration • Provide major muscular work when demands for ventilation increase

5. Accessory muscles: elevate and stabilize chest wall at its largest diameter (once already “open”). Increases efficiency of diaphragm. Active during heavy breathing. Also… • Chest wall assist with inspiration • Abdominals: used in active exhalation, ie. Exercise. Also role in inspiration Inspiration is usually active – major role in pumping mechanism. Expiration is usually passive.

7. Gas Exchange Organs • Upper airway (nose, mouth, pharynx) conducts air and keeps out large particles • Lower airway (larynx, trachea, bronchi, bronchioles, alveolar ducts, and alveoli) • O2 thru alveolar membrane  capillary membrane  Hgb  tissues • CO2 thru capillary membrane  alveolar membrane  through bronchial membrane exhaled • Alveolar membrane produces surfactant (PL): decreases surface tension and tendancy of collapse.

9. Functions of the Respiratory System • Gas exchange • Speech • Cardiovascular • Metabolic Functions

10. Gas Exchange • Normal: 15x/min, 500 ml air, therefore ventilate ~ 11000L air/day • ~6000 L blood moves through per day • ~600 L O2 in and 460 L CO2 removed • Speech Thoracic cage supplies exhaled air to voice apparatus (larynx) • Cardiovascular Nature of lung inflation affects pressure in thoracic cage; can affect heart i.e. pulmonary edema

11. Metabolic Functions • Surfactant production • Formation of angiotensin-converting enzyme (ACE) • Endothelial cells: produce SOD enzymes

12. Definitions I. Partial Pressure: used to indicate the amount of any gas in the atmosphere, alveoli, or plasma • PCO2 Partial Pressure of carbon dioxide • Normal arterial blood values = 35-45 mm Hg • Normal venous blood values = 41-51 mm Hg • PO2 Partial Pressure of oxygen • Normal arterial blood values = 80-100 mm Hg • Normal venous blood values = 35-40 mm Hg • Arterial blood preferred: oxygenated, coming from the heart • Gives idea of how things are throughout the body • Gives idea of how well lungs have oxygenated the blood

13. Note: PCO2 measures respiratory status ↑ PCO2 means poor respiratory function ↓ PCO2 means hyperventilation

14. II. Respiratory Failure A. Obstructive B. Restrictive

15. Symptoms:

16. Effects of Respiratory Ds. On Nutritional Status • intake (see previous slide) • Medications Steroids (anti-inflammatory) cause protein catabolism, gluconeogenesis, muscle wasting and neg. N balance. • Constipation/diarrhea Choice of low fiber foods (2’ dyspnea); poor peristalsis 2’  O2 to GI tract.

17. Respiratory Complications: Malnutrition • Established: •  respiratory muscle structure and fx. •  ventilatory drive •  pulmonary host immune defenses ( susceptibility to infections) • Proposed: A.  surfactant production

18. COPD: Chronic Obstructive Pulmonary Disease • Chronic Obstructive Pulmonary Disease • Slow, progressive obstruction of airways • Maj. Causes: tobacco smoke, environmental pollution, genetic susceptibility

19. Emphysema: lung ds. characterized by • Pts present older, thin, mild hypoxemia but NL HCT values. Cor pulmonale develops later

20. Cron. Bronchitis: • pts NL wt to ovrwt, hypoxemia and  HCT • Cor pulmonale develops early. • Cor Pulmonale:

21. MNT • Assessment: %IBW alone not sufficient; ongoing assessment of LBM

22. Kcals: replete but don’t overfeed! • Indirect calorimetry if possible: Kcal needs have been observed to range from 94% to 146% of predicted

23. Respiratory Quotient • Amount of CO2 produced/amount of O2 consumed… • For glucose: • For fat: • For protein: • RQ for conversion of glucose to fat

24. Prot • Preserve lung, muscle, and immune fx • To preserve appropriate RQ: • Prot: • Fat: • CHO:

25. Micronutrients • Smokers : • Mg and Ca imp in muscle contraction/relax, Mg and Phos monitored • Poss vit D&K

26. Respiratory rehab: exercise, fluids, easily chewed diet w/adequate fiber  GI motility • If experiencing bloating, decrease gaseous foods.

27. To  intake • Prevent aspiration: • TF to  kcals in some pts (aspiration issues) • Issues of O2 use at nighttime (overnight feedings). O2 consumption decreases by 15%-25% during sleep.

28. Respiratory Failure • Causes: • MODS • ARDS

29. Respiratory Failure, cont. • Pts. require O2 by nasal cannula or by mechanical ventilator. • Weaning from vent: • MNT: varies • Body comp. fluctuation –