Structures and Functions of the Respiratory System

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Structures and Functions of the Respiratory System
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Gas Exchange

• Ventilation
• Diffusion (alveolar-capillary membrane)
• Perfusion
• Diffusion (capillary-cellular level)

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Ventilation Movement of Chest Wall
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Ventilation

• Depends on volume and pressure changes within
  thoracic cavity
• Diaphragm is major muscle of inspiration also
  external intercostal muscles. Contraction
  increases diameter of thoracic cavity? ?
  intrathoracic pressure ?air flows into
  respiratory system
• Expiration is passive process d/t lung
  elasticity. ? intrathoracic pressure? air flows
  out of lungs
• Accessory muscles

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Control of Ventilation

• Neural control- respiratory center in medulla
  pons
• Central chemoreceptors sensitive to pH
• Peripheral chemoreceptors- sensitive to paO2
• Patients with COPD- hypoxic drive
• WOB- amount of effort required for the
  maintenance of a given level of ventilation (as
  WOB ?s, more energy is expended for adequate
  ventilation)

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Factors Influencing Ventilation

• Airway resistance- opposition to gas flow
• Compliance- distensibility / stretchability
• - Dependent on lung elasticity elastic
  recoil
• of chest wall
• - Decreased compliance- lungs difficult to
• inflate
• - Increased compliance- destruction of
• alveolar walls loss of tissue elasticity

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DiffusionAlveolar-Capillary Membrane
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Oxyhemoglobin Curve
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Ventilation-Perfusion

• Adequate diffusion depends on balanced
  ventilation-perfusion (V/Q) ratio
• Normal lung V4L/min Q 5L/min (0.8)
• If imbalanced gas exchange interrupted
• - High V/Q wasted or dead-space
• ventilation
• - Low V/Q blood shunted past area no
• gas exchange occurs

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V/Q Matching
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Perfusion
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DiffusionBody Tissue-Blood Capillary
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COPD

• Progressive, irreversible airflow limitation
• Associated with abnormal inflammatory response of
  lungs to noxious particles or gases

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COPDEtiology

• Cigarette smoking
• Occupational chemicals and dusts
• Air pollution
• Infection
• Heredity- A1-antitrysin deficiency
• Aging

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COPDPathophysiology

• Primary process is inflammation
• Inhalation of noxious particles? inflammatory
  cells release mediators (leukotrienes,
  interleukins, TNF) ? airways become inflammed
  with increased goblet cells ? excess mucus
  production (bronchitis) structural remodeling
  to peripheral airways with ?d collagen scar
  tissue

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COPDPathophysiology

• Destruction of lung tissue caused by imbalance of
  proteinases/antiproteinases results in emphysema
  with loss of attachments peripheral airway
  collapse (Centrilobar- affects respiratory
  bronchioles/upper lobes/mild disease panlobar-
  alveolar ducts, sacs, respiratory bronchioles-
  lower lobes/AAT deficiency

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COPDPathophysiology

• Air goes into lungs easily but unable to come
  out air trapped in distal alveoli, causing
  hyperinflation overdistension
• PV thickens with ?surface area for gas exchange-
  V/Q mismatch

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COPDChronic Bronchitis vs. Emphysema
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Emphysema
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Chronic BronchitisBlue Bloater versus Pink Puffer
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COPD Behaviors

• Develop slowly around 50 years of age after
  history of smoking
• Cough, sputum production, dyspnea
• In late stages, dyspnea at rest
• Wheezing/chest tightness- may vary
• Prolonged IE, ?BS, tripod position, pursed-lip
  breathing, edema
• ? A-P diameter of chest
• Advanced- weight loss, anorexia (hypermetabolic
  state)
• Hypoxemia, possible hypercapnia
• Bluish-red color from polycythemia, cyanosis

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Increased A-P DiameterBarrel-Chest
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COPDDiagnosis

• PFTs (? RV, ?FEV1)
• CXR
• ABGs
• Sputum CS if infection suspected
• EKG- RV hypertrophy
• 6 minute oxy-walk

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COPD Classification
Spirometry Results
Stage I Mild FEV1/FVC lt 0.70 FEV1 80 predicted
Stage II Moderate FEV1/FVC lt 0.70 50 FEV1 lt 80 predicted
Stage III Severe FEV1/FVC lt 0.70 30 FEV1 lt 50 predicted
Stage IV Very Severe FEV1/FVC lt 0.70 FEV1 lt 30 predicted OR FEV1 lt 50 predicted PLUS chronic respiratory failure
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COPDComplications

• Cor pulmonale- RV hypertrophy 2º pulmonary
  hypertension (late)
• Exacerbations of COPD
• Acute respiratory failure
• Peptic ulcer and gastroesophageal reflux disease
• Depression/anxiety

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COPD- Collaborative Care

• Smoking cessation
• Medications- bronchodilators (inhaled
  step-wise), Spriva (LA anticholinergic), ICS
• Oxygen therapy
• RT- PLB, diphragmatic, cough, CPT, nebulization
  therapy
• Nutrition- Avoid over/underweight, rest 30
  before eating, 6 small meals, avoid foods that
  need a great deal of chewing, avoid exercise 1 hr
  before meal, take fluids between meals to avoid
  stomach distension

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COPDNursing Diagnoses

• Ineffective Breathing Pattern
• Impaired Gas Exchange
• Ineffective Airway Clearance
• Imbalanced Nutrition Less than Body Requirements

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Asthma

• Chronic inflammatory disorder associated with
  airway hyperresponsiveness leading to recurrent
  episodes (attacks)
• Often reversible airflow limitation
• Prevalence increasing in many countries,
  especially in children

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AsthmaPathophysiology

• Airway hyperresponsiveness as a result of
  inflammatory process
• Airflow limitation leads to hyperventilation
• Decreased perfusion ventilation of alveoli
  leads to V/Q mismatch
• Untreated inflammation can lead to LT damage that
  is irreversible
• Chronic inflammation results in airway remodeling

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AsthmaPotential Triggers

• Allergens 40
• Exercise (EIA)
• Air pollutants
• Occupational factors
• Respiratory infections viral
• Chronic sinus and nose problems
• Drugs and food additives ASA, NSAIDs,
  ß-blockers, ACEi, dye, sulfiting agents
• Gastroesophageal reflux disease (GERD)
• Psychological factors- stress

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Asthma Inflammation Effects

• Bronchospasm
• Plasma exudation
• Mucus secretion
• AHR
• Structural changes

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Asthma InflammationClinical Manifestations

• Cough
• Chest tightness
• Wheeze
• Dyspnea
• Expiration prolonged -13 or 14, due to
  bronchospasm, edema, and mucus
• Feeling of suffocation- upright or slightly bent
  forward using accessory muscles
• Behaviors of hypoxemia- restlessness, anxiety,
  ?HR BP, PP

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AsthmaDiagnosis

• History and patterns of symptoms
• Measurements of lung function
• PFTs- usually WNL between attacks ? FVC, FEV1
• PEFR- correlates with FEV
• Measurement of airway responsiveness
• CXR
• ABGs
• Allergy testing (skin, IgE)

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AsthmaTherapeutic Goals

• No (or minimal) daytime symptoms
• No limitations of activity
• No nocturnal symptoms
• No (or minimal) need for rescue medication
• Avoid adverse effects from asthma medications
• Normal lung function
• No exacerbation
• Prevent asthma mortality
• Minimal twice or less per week

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AsthmaCollaborative Management

• Suppress inflammation
• Reverse inflammation
• Treat bronchoconstriction
• Stop exposure to risk factors that sensitized the
  airway

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AsthmaMedications

• Antiinflammatory Agents
• Corticosteroids- suppress inflammatory response.
  Reduce bronchial hyperresponsiveness mucus
  production, ? B2 receptors
• Inhaled preferred route to minimize systemic
  side effects
• Teaching
• Monitor for oral candidiasis
• Systemic many systemic effects monitor blood
  glucose
• Mast cell stabilizers- NSAID inhibit release of
  mediators from mast cells suppress other
  inflammatory cells (Intal, Tilade)

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AsthmaMedications

• Antiinflammatory Agents
• Leukotriene modifiers
• Block action of leukotrienes
• Accolate, Singulair, Zyflo)
• Not for acute asthma attacks
• Monclonal Ab to IgE
• ? circulating IgE
• Prevents IgE from attaching to mast cells, thus
  preventing the release of chemical mediators
• For asthma not controlled by corticosteroids
• Xolair SQ

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AsthmaMedications

• Bronchodilators
• B-agonists- SA for acute bronchospasm to
  prevent exercised induced asthma (EIA)
  (Proventil, Alupent) LA for LT control
• Combination ICS LA B-agonist (Advair)
• Methylxanthines- Theophylline alternative
  bronchodilator if other agents ineffective.
  Narrow margin of safety high incidence of
  interaction with other medications
• Anticholinergics- block bronchoconstriction .
  Additive effect with B-agonists (Atrovent)

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AsthmaPatient Teaching- Medications

• Name/dosage/route/schedule/purpose/SE
• Majority administered by inhalation (MDI, DPI,
  nebulizers)
• Spacer MDI- for poor coordination
• Care of MDI- rinse with warm H2O 2x/week
• Potential for overuse
• Poor adherence with asthma therapy is challenge
  for LT management
• Avoid OTC medications

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AsthmaCollaborative Care

• GINA- decrease asthma morbidity/mortality
  improve the management of asthma worldwide
• Education is cornerstone
• Mild Intermittent/Persistent avoid triggers,
  premedicate before exercise, SA or LA Beta
  agonists, ICS, leukotriene blockers
• Acute episode Oxygen to keep O2Satgt90, ABGs,
  MDI B-agonist if severe- anticholinergic
  nebulized w/B agonist, systemic corticosteroids

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AsthmaNursing Diagnoses

• Ineffective Airway Clearance
• Impaired Gas Exchange
• Anxiety
• Deficient Knowledge

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Pneumonia

• HAP- pneumonia occurring 48 hours or longer after
  admission
• VAP- pneumonia occurring 48-72 hours after ET
  intubation
• HCAP- hospitalized for 2 or more days within 90
  days of infection resided in LTC facility
  received IV therapy or wound care within past 30
  days of current infection attended a hospital or
  dialysis clinic
• Aspiration pneumonia- abnormal entry of
  secretions into lower airway

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PneumoniaPathophysiology

• Congestion
• Fluid enters alveoli organisms multiply
  infection spreads
• Red hapatization
• Massive capillary vasodilation alveoli filled
  with organisms, neutrophils, RBCs, fibrin
• Gray hepatization
• Blood flow decreases leukocytes fibrin
  consolidate in affected part
• Resolution
• Resolution healing exudate processed by
  macrophages

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PneumoniaRisk Factors

• Aging
• Air pollution
• Altered LOC
• Altered oral normal flora secondary to
  antibiotics
• Prolonged immobility
• Chronic diseases
• Debilitating illness
• Immunocompromised state

• Inhalation or aspiration of noxious substances
• NG tube feedings
• Malnutrition
• Resident of Long-term care
• Smoking
• Tracheal intubation
• Upper respiratory tract infection

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Pneumonia Behaviors

• Usually sudden onset
• Fever, shaking chills, SOB, cough w/purulent
  sputum, pleuritic CP
• Elderly/debilitated- confusion or stupor

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Pneumonia- Complications

• Pleuritis
• Pleural effusion- 40 of hospitalized patients
• Atelectasis
• Bacteremia
• Lung abscess
• Empyema
• Pericarditis

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PneumoniaDiagnostic Studies

• CXR
• Sputum CS
• Blood cultures
• ABGs
• Leukocytosis

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Pleural Effusion
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Pneumonia
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PneumoniaCollaborative Care

• Prompt treatment with antibiotics
• Oxygen, analgesics, antipyretics
• Influenza vaccine
• Pneumococcal vaccine
• Nutrition
• PSI Pneumonia Patient Outcomes Research Team
  Severity Index
• Determine whether to treat at home or in hospital

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PneumoniaNursing Assessment

• Fever in any hospitalized patient
• Pain
• Tachypnea
• Use of accessory muscles
• Rapid, bounding pulse
• Relative bradycardia
• Coughing
• Purulent sputum

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PneumoniaNursing Assessment

• Consolidation
• Auscultation
• Bronchial breathing
• Bronchovesicular rhonchi
• Crackles
• Fremetis
• Egophony
• Whispered pectroloquy

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PneumoniaNursing Diagnoses

• Ineffective airway clearance RT copious
  tracheobronchial secretions
• Activity intolerance RT altered respiratory
  function
• Risk for fluid volume deficit RT fever and
  dyspnea
• Knowledge deficit about the treatment regimen and
  preventive health measures

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PneumoniaPotential Problems

• Hypotension and shock
• Respiratory failure
• Atelectasis
• Pleural effusion
• Delerium
• Superinfection

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PneumoniaNursing Goals

• Improving airway patency
• Conserving energy rest
• Maintaining proper fluid balance
• Patient understanding of treatment and prevention
• Prevention of complications

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PneumoniaNursing Interventions

• Improving airway patency
• Removing secretions coughing vs. suctioning
• Adequate hydration loosens secretions
• Air humidification to loosen secretions and
  improve ventilation
• Chest physiotherapy loosens and mobilizes
  secretions

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PneumoniaNursing Interventions

• Promoting rest and conserving energy
• Bedrest with frequent changes of position
• Energy conservation
• Sedatives to decrease work of breathing and
  energy expenditure unless contraindicated
• Promoting fluid intake
• Dehydration is possible RT insensible fluid
  losses through respiratory tract
• If not contraindicated, increase fluid intake to
  2 liters/day

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PneumoniaNursing Interventions

• Patient education and home care considerations
• Increase activities as tolerated fatigue and
  weakness may be prolonged
• Breathing exercises to clear the lungs should be
  taught
• Smoking cessation if indicated smoking destroys
  tracheobronchial ciliary action, which is the
  first line of defense for the lungs. Smoking
  also irritates the mucus cells of the bronchi and
  inhibits the function of alvolar macrophages
• Patient is encouraged to get influenza vaccine
  because influenza increases risk for secondary
  bacterial infections
• Staphylococcus
• H. influenzae
• S. pneumonae
• Encouraged to get Pneumovax against S. pneumonae

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Pneumonia- Core Measures

• Oxygenation assessment (ABGs, oximetry)
• Pneumococcal vaccine (gt65yo prior to DC)
• BC performed within 24h prior to after hospital
  arrival
• BC before first antibiotic
• Adult smoking cessation advice
• Antibiotic timing- within 4 hours of arriving to
  hospital
• Influenza vaccine