THE RESPIRATORY SYSTEM

1. THE RESPIRATORY SYSTEM CH. 15 Goodman

2. Pulmonary or Respiratory?Overview and Definitions • Pulmonary (think of anatomical structures) • Pulmonary (from L. pulmonarius “of the lungs,”) is more inclusive - however respiration is really the end game goal of the system • Pulmonary system includes the upper airways; lower airways and alveoli • Pulmonary system allows for external respiration; but only given internal respiration – in other words, without internal respiration - external respiration is not possible. • Respiratory (think of a process or a physiological function) • Respiration - gas exchange • Ventilation - air flow that supports (allows) for respiration

3. BREAK IT DOWN….. • RESPIRATION AND VENTILATION • REMEMBER that ventilation is air in/out of lungs • AND that respiration is gas exchange • WELL… respiration can be divided into external respiration and internal respiration • EXTERNAL respiration is exchange of O2/CO2 between air and blood • INTERNAL respiration is exchange of O2/CO2 between blood and tissue (metabolic process)

4. THE PULMONARY SYSTEM Note: divided into 3 sections: Upper airways, lower airways and alveoli

5. RESPIRATION • Respiration is a flow of gases; flow is dependent on pressure gradients; therefore respiratory flows of particular gases (oxygen, carbon dioxide) are dependent on partial pressure gradients; HgB saturation of oxygen is dependent on the partial pressure of oxygen in arterial blood as determined by the oxyhemoglobin dissociation curve:

6. OXYHEMOGLOBIN DISSOCIATION CURVE Note: When PaO2 < 60 mmHg, the SpO2 or SaO2 drops below 90%

7. Oxyhemoglobin Dissociation Curve • What is the oxyhemoglobin dissociation curve and why is it important? • The Oxyhemoglobin dissociation curve describes the non-linear tendency for oxygen to bind to hemoglobin: below a SaO2 of 90%, small differences in PaO2 result in large changes in SaO2. • This is the way to describe the causal nature of the PaO2 on the SaO2

8. DEFINITIONS/ABBREVIATIONS • O2 saturation taken with pulse oximeter (estimation of SaO2) • O2 saturation in arterial blood • Partial pressure of O2 in arterial blood • NOT SYNONYMOUS! • SpO2 • SaO2 • PaO2

9. MAJOR SEQUELA of pulmonary disease or injury: • Hypoxemia is the most common condition caused by pulmonary disease or injury. • Hypoxemia is deficient oxygenation of arterial blood. • This may lead to hypoxia; prolonged hypoxia will cause tissue damage or death. • Hypoxia is a broad term meaning diminished availability of oxygen to the body tissues.

10. DEFINITIONS with associated numbers…. • Hypoxemia- low oxygen levels in the arterial blood *PaO2 is normally > 95 mm Hg • Hypercarbia - elevated carbon dioxide levels in the arterial blood (Pa CO2 > 45 mm Hg; Normally = 40mm Hg) • Respiratory Acidosis - pH < 7.4 with elevated PaCO2

11. CAUSES OF HYPOXEMIA

12. SIGNS and SYMPTOMS

13. OXYGEN TRANSPORT DEFICITS • Pathological conditions of every major organ system can have secondary effects on the pulmonary system; pulmonary secondary effects are typically the life threatening component of illnesses. • For example - pulmonary complications are the major cause of death due to just about every chronic neurological condition; and are the life threatening complications that arise following surgery • “Critical care” is typically critical due to the pulmonary needs

14. PT IMPLICATION • PT assessing signs and symptoms of pulmonary disease must consider that these (signs and symptoms) may be secondary effects and should investigate underlying etiological factors • EXAMPLE of a PT assessment: Patient demonstrates a decline in functional mobility secondary to inability to tolerate low level activities due to CHF and COPD complicated by acute exacerbation of these conditions with diagnosis of pneumonia.

15. Signs & Symptoms of Pulmonary Disease • Cough (sign) • dry vs wet • productive vs non productive (does something come up (or get swallowed) • dry can be a sign of early onset of CHF (low specificity) - specificity increases if highly repeatable with physical exertion / fatigue (i.e. if every time the patient exerts to fatigue they get a dry cough)

16. COUGH/SPUTUM (continued) • TYPES OF SPUTUM: • Purulent: containing pus; composed of WBCs, cellular debris, mucus, dead tissue…. • Can be greenish-yellow, milky white • Non-purulent: not containing pus • Hemoptysis: coughing/spitting up blood

17. DYSPNEA • Dyspnea (SOB) (symptom) • breathlessness - uncomfortable feeling with breathing • Dyspnea that occurs in recumbant position (including supine) -> orthopnea • Signs of dyspnea can include tachypnea, nasal flaring, accessory muscle use • Signs that dyspnea is due to a medical emergency include: wheezing, cyanosis, drops in BP, irregular cardiac rhythm

18. CYANOSIS • Cyanosis (sign) • bluish discoloration due to a lack of oxygen • Can be due to low oxygen in the blood (Hct and/or SpO2); or due to oxygen delivery • (blood flow) • Blood flow problems can be local (vascular issues) or systemic (low cardiac output)

19. CLUBBING • Clubbing (sign) • Thickening and widening of terminal phalanges of fingers and toes – painless • Tend to be caused by conditions of prolonged interference of tissue perfusion - common in Cystic Fibrosis, COPD, lung cancer, bronchiectasis, pulmonary fibrosis, congenital heart disease

20. ALTERED BREATHING PATTERNS • Altered breathing patterns (signs) • 1. Accessory muscle dependence • 2. Cheyne-stokes respiration - cycles of deep to shallow breathing with periods of apnea then starting the cycle over again - common with brain damage and severe heart failure • 3. Thoracic paradox - inward movement of thorax during inspiration (thoracic ms paralysis; rib fracture) • 4. Abdominal paradox - inward movement of abdomen during inspiration (diaphragm paralysis)

21. LUNG SOUNDS Sounds (signs) • Wheezes - high pitched sounds due to difficulty with airflow • Stridor – high-pitched wheeze that occurs with significant upper airway obstruction ; *medical emergency; can be heard without a stethoscope • Fine Crackles (Rales)- “static electricity” sound with inspiration associated with mucous, edema or atelectasis • Course crackles (Rhonchi) - course sound deep in lungs associated with loose mucous, lots of edema

22. AGING and the PULMONARY SYSTEM Aging and the Pulmonary • Aging results in declines in: ventilation, respiration and pulmonary defenses to infectious processes and environmental pollutants • Ventilation: *declines with age in FVC, FEV1, Peak Flow; *increases with age in RV and FRC. • These changes are mostly due to age related changes in lung tissue (reduced elasticity, less wall structure -> airways collapse and trap air); as well as in musculoskeletal changes of the thorax and breathing muscles.

23. AGING/RESPIRATORY CHANGES • Respiration: decreases in ventilation / perfusion matching (related to increases in RV and FRC); decreases in diffusion due to decreased alveolar surface area; net result: increase in Ve/VO2 and Ve/VCO2 with aging (i.e. need to ventilate more air in a minute to consume1 L of O2, or expire 1 L CO2) • Normal Ve/VO2 = 22-26; can increase to 26-28 without being diagnosed with pulmonary disease

24. AGING CHANGES….. • Pulmonary defenses: reduced because of less ventilation (impacts coughing and general mucociliary clearance); and also less specific mucociliary clearance due to less cilia activity **Most adults attain maximal lung function (as measured by FEV1) during their early twenties, but with increasing age, especially after age 55 years, there is an overall decrease in the functional ability of the lungs to move air in and out. This decline peaks by age 75 years, to about 70% of our maximum.

25. Lung Volumes *Refer to this when reviewing age related changes in the pulmonary system.

26. General Pulmonary Disease Classifications • Intra vs. Extra Pulmonary • Intra : starts with the lung tissue itself - interstitium (parenchyma) or airways • Extra : starts with non lung tissue - such as the pleura, pleural space, chest wall (ROM or • strength) • Obstructive vs. Restrictive • Restrictive : primarily (originates as) difficulty getting air INTO the lungs • Obstructive : primarily (originates as) difficulty getting air OUT OF the lungs

27. General Pulmonary Disease Classifications • Acute vs. Chronic • Acute: short term, generally reversible • Chronic: long term, generally irreversible • Can be used to describe the entire disease, or just a component • For example - Asthma is a chronic condition, long term and generally irreversible; but airway obstruction associated with asthma is acute - comes on suddenly, is short term and is generally reversible

28. Infectious and Inflammatory Diseases • A. Pneumonia (acute, intrapulmonary, restrictive): inflammation affecting the parenchyma of the lungs; caused by infection, inhalation of toxic chemicals, aspiration of food, liquid or vomitus • B. Pneumocystis Carinii Pneumonia (acute, intrapulmonary, restrictive): progressive, almost fatal pneumonia ; origin of organism is unknown • C. Pulmonary Tuberculosis (TB) (chronic, intrapulmonary, restrictive): infectious, inflammatory systemic disease that affects the lung. May disseminate to affect the lymph nodes and other organs • D. Lung abscess (acute, intrapulmonary, restrictive): localized accumulation of purulent exudate within the lung; usually develops as a complication of pneumonia

29. A closer look at pneumonia

30. Pneumonia • PT treatment can assist with DB and coughing/ pulmonary hygiene, airway clearance, early ambulation • Clinical manifestations: • Sudden and sharp pleuritic chest pain, hacking productive cough, rust colored or green purulent sputum, dyspnea, tachypnea, decreased chest excursion on affected side, cyanosis, HA, fatigue, fever and chills and generalized aches and myalgias

31. Obstructive Lung Diseases • A. Chronic Obstructive Pulmonary Disease (COPD): chronic airflow limitation that is not completely reversible • B. Chronic Bronchitis (major underlying disease of COPD): clinically defined as a condition of productive cough lasting at least 3 months per year for 2 consecutive years • C. Emphysema (major underlying disease of COPD): pathologic accumulation of air is tissue (lung tissue) such that the lungs lose their elasticity and there is “air trapping”

32. Obstructive Lung Diseases (cont.) • D. Asthma (chronic disease, acute airway obstruction): inflammation and increased smooth muscle reaction of the airways to various stimuli. It is a chronic condition with acute exacerbations. • E. Bronchiectasis (chronic, intrapulmonary, obstructive): progressive form of obstructive lung disease characterized by irreversible destruction and dilation or airways generally associated with chronic bacterial infections • F. Bronchiolitis (chronic, intrapulmonary, obstructive): refers to several morphologically distinct pathological conditions of the small airways; was once classified as a chronic pneumonia • G. Sleep-Disordered Breathing (chronic with acute airway obstruction): collection of syndromes characterized by breathing abnormalities during sleep that result in intermittently disrupted gas exchange and in sleep interruption

33. Closer Look at COPD • Patients with COPD typically have a combination of chronic bronchitis, emphysema and small airway obstruction • Airflow limitation in COPD is usually progressive and associated with an abnormal inflammatory response to noxious particles or gases • Confirmed with spirometry testing

34. COPD

35. Restrictive Lung Diseases • A. Pulmonary fibrosis • B. Systemic Sclerosis Lung Disease • C. Chest Wall Trauma or Lung Injury • **Note that pneumonia (PNA) and tuberculosis (TB) are also restrictive lung diseases. **This major category describes conditions that lead to reduced lung volume and decreased lung compliance **PFT >>decreased TLC

36. Environmental & Occupational Diseases • A. Pneumoconiosis • B. Hypersensitivity Pneumonitis • C. Noxious gases, fumes and smoke inhalation **Occupational diseases can be divided into 3 major categories: Conditions from inhalation of: 1. inorganic dusts (example from iron ore, coal) 2. organic dusts (molds, fungal spores, wood dust, coffee beans, bird feathers) 3. fumes, gases and smoke inhalation • **The pathologic characteristics are common and include: involvement of the lung parenchyma with a fibrotic response

37. Near Drowning • Surviving (24 hours or longer) the physiological effects of hypoxemia and acidosis that result from submersion in fluid

38. Congenital Disorders • A. Cystic Fibrosis (obstructive and restrictive, chronic, intrapulmonary) • **CF is an inherited disorder of the exocrine glands affecting the hepatic, digestive, male reproductive and respiratory systems • **The basic genetic defect predisposes to chronic bacterial airway infections; almost all will develop obstructive lung disease and progressive loss of lung function

39. Parenchymal Disorders • A. Atelectasis • B. Pulmonary Edema • C. Acute Respiratory Distress Syndrome • D. Post operative respiratory failure • E. Sarcoidosis • F. Lung Cancer • **Conditions affecting the lung parenchyma(lung tissue)

40. Disorders of Pulmonary Vasculature • A. Pulmonary Embolism & Infarction • B. Pulmonary Hypertension • C. Cor pulmonale • D. Collagen Vascular Disease • **Conditions that involve the lungs and the vascular system

41. Disorders of Pleural Space • A. Pneumothorax • B. Pleurisy • C. Pleural Effusion • **Conditions involving pathology in the pleural area of the lungs (pleura of the lung describes the covering of the lung and is comprised of visceral and parietal pleura with a space in between which contains fluid)

42. Lung Volumes *Use as a reference

43. Resources: Acute Care Handbook for Physical Therapists. Paz and West, 4th ed. 2014.www.dailymail.co.uk Goodman Ch. 15

44. Andrea C. Mendes PT, DPT Sean M. Collins PT, ScD