Respiratory System: Ventilation and Disorders

Module III: Ventilation

• Module III focuses on ventilation of the respiratory tract.

Respiratory system anatomy

• The respiratory system includes the sphenoidal sinus, nasal cavity, pharynx, alveoli, right lung, diaphragm, frontal sinus, nasal conchae, nose, larynx, trachea, bronchus, bronchioles, and left lung.

Functions of the Airways

• The upper airway allows airflow into and out of the lungs.
• The upper airway warms, humidifies, and filters inspired air.
• The upper airway protects the lower airway from foreign matter.
• The lower airway facilitates gas exchange.
• Defence mechanisms of the lower airway include irritant reflex, mucociliary system, and secretory immunity.

Disorders of the Upper Respiratory Tract

• Allergies, cold, and sinusitis are disorders of the upper respiratory tract.

Type I Hypersensitivity Reactions

• Type I Hypersensitivity Reactions involve an IgE response to antigens (allergens).
• Antibodies travel to cells, releasing chemicals like histamine, leukotrienes, and interleukins, to produce an allergic reaction.
• Genetic mechanisms influence Type I reactions.
• Allergic rhinitis, anaphylaxis, and asthma are types of Type I Reactions.

Allergic Rhinitis

• Allergic Rhinitis is also known as "hay fever".
• Allergic rhinitis involves inflammation of the nasal mucosa after exposure to allergens.
• Signs and symptoms of allergic rhinitis include tearing eyes, sneezing, nasal congestion, postnasal drip, and itching of the throat.
• There is a high genetic predisposition to allergies.
• Symptoms of allergic rhinitis may only occur at specific times of the year.

Treatment of Allergic Rhinitis

• Preventers are used for prophylaxis and should be started at least 2 weeks prior to the start of allergy season.
• Antihistamines, intranasal corticosteroids, and mast cell stabilizers are preventers.
• Relievers provide immediate, temporary relief of acute allergy symptoms and include oral or intranasal decongestants.

Antihistamines

• First-generation antihistamine prototype: diphenhydramine
• Indicated for seasonal allergies as well as anaphylaxis, motion sickness, and insomnia.
• Second-generation antihistamine prototype: cetirizine
  • Indicated for seasonal allergies
• Antihistamines selectively block histamine from reaching H1 receptors in blood vessels, capillaries, and nerves and decreases itching, sneezing, and rhinorrhea.
• Adverse effects of antihistamines include sedation and anticholinergic side effects like dry mouth and constipation.
• Precautions for antihistamine usage include pregnancy, children/elderly, seizures, cardiac disease, urinary retention, and open-angle glaucoma.
• CNS depression, like alcohol, benzodiazepines, and opioids, can occur
• Diphenhydramine has a half-life of 6-12 hours, while cetirizine has a half-life of 24 hours.
• Antihistamines are often combined with nasal decongestants; the first generation antihistamines should be taken at night, and they are best taken with food and lots of water.

Intranasal corticosteroids- mometasone

• Intranasal corticosteroids are for seasonal allergies
• Mometasone decreases the production of inflammatory markers and reduces ALL allergic symptoms
• Applied directly to the nasal mucosa to decrease local inflammation, tissue edema and cause a mild vasoconstriction.
• Side effects include nasal irritation, epistaxis, burning in the throat and headache.
• Clear nasal passages before administration; should be taken daily not just as needed.
• Helps with all allergic symptoms and sinusitis.

Mast cell stabilizer- cromolyn

• Cromolyn serves as a mast cell stabilizer for allergies and/or asthma as it prevents the release of histamine and leukotrienes by inhibiting degranulation after contact with antigens.
• Common side effects, including burning of nasal mucosa, irritation of the throat, cough, and nasal congestion.
• Bronchospasm and anaphylaxis is a rare side effect.
• It’s administered intranasal for allergies and via a nebulizer for asthma, working by reducing all allergic symptoms, but is not as effective as ICS.
• Giving for weeks to months before it works is neccessarry not for acute treatment, and administered 4-6x/day

Pseudoephedrine & Oxymetazoline

• Pseudoephedrine is a nasal decongestant.
• Oxymetazoline treats nasal Allergies
• Pseudoephedrine is a sympathomimetic, whereas oxymetazoline activates alpha-1 receptors on blood vessels, causing vasoconstriction and decreasing inflammation..
• Side effects of Pseudoephedrine include insomnia, nervousness, etc
• Narrow angle glaucoma, uncontrolled hypertension, coronary artery disease, hyperthyroid, and benign prostatic hyperplasia are contraindications for Pseudoephedrine.
• Caution must be observed with Pseudoephedrine (OTC)
• Side effects of Oxymetazoline = rebound congestion
• Pseudoephedrine (oral) is for nasal passages in those with antihistamines, while oxymetazoline (intranasal) tapers use one nostril at a time.

Anaphylaxis

• Anaphylaxis is an acute, life-threatening, multi-system syndrome caused by a sudden release of mast cell mediators into the circulation.
• The body demonstrates an enhanced the response to an antigen.
• It is a Type I Hypersensitivity Reaction-mediated by antibody IgE.
• ALL patients with a history of anaphylaxis should wear a medical alert bracelet/necklace and always carry epinephrine with them.

Epinephrine for Anaphylaxis

• Epinephrine is used as an Emergency agent for anaphylaxis.
• Epinephrine enhances sympathomimetic activity, resulting in vasoconstriction and decreased mucosal edema in the upper airway.
• Epinephrine increases heart and contractility
• It results in bronchodilation and decreased release of mast cell mediators
• Weight-based dosing. For patients over 25kg a 0.3mg auto injector can be used
• There are no absolute contraindications for epinephrine in the setting of anaphylaxis.

Common Cold

• The common cold is a viral infection of the upper respiratory tract (URT)
• The common cold and it’s self-limiting.
• Treatments and Drug therapy is symptomatic.
• Treatment options includes:
  • Antihistamines
  • Decongestants
  • Antitussives
  • Expectorants
  • Mucolytics
• Avoid combination products.

Antitussive: Dextromethorphan

• Dextromethorphan is an Antitussive helps with a persistent, non-productive cough
• It decreases the sensitivity of cough receptors and interrupts cough impulse transmission by acting in the CNS or peripheral nervous system.
• Side Effects include Euphoria- "robo-tripping" in high doses, can be abused, Dizziness, drowsiness, Gl issues
• You evaluate patient's respiratory status and response to medication and read the LABELS!
• Opioids (codeine) can be used too

Expectorant: Guaifenesin

• Guaifenesin is an Expectorant - helps Productive cough, upper respiratory infection
• It Reduce the surface tension of secretions (decreases the stickiness), drink WATER
• Which thins mucus, making it easier to cough out of the lungs and drain out of nose and sinuses
• Side effects include : GI Upset / Drowsiness, dizziness
• Do not crush tablets, give with food !!

Mucolytic: acetylcysteine

• Acetylcysteine is a Mucolytic, for Productive cough and/or overproduction of mucus
• Directly disrupts the disulfide linkages in mucus proteins- which decreases mucus viscosity- easier for patient to expectorate
• side effects include Nausea, rhinorrhea, bronchospasms*, dizziness
• Inhalation via nebulizer, used for Patients with a history of bronchospasm, asthma or respiratory insufficiency
• Clear airways before administration / Tell patients to expectorate secretions, and smells like rotten eggs

Sinusitis

• Sinusitis Etiology includes viral, bacterial, or fungal; allergies/colds increasing the bacteria.
• Blockages of sinus /blockages of sinus (polyp, etc)
• Drug therapy with Antibiotics ONLY if absolutely necessary/ , Nal corticosteroids/ or antihistamines,
• Home therapies are better!!

Lower Respiratory System

• Etiology ASTHMA CHRONIC, OBSTRUCTIVE, PULMONARY, DISORDER, (COPD), CYSTIC, FIBROSIS PNEUMOΝΙΑ, TUBERCULOSIS
• The primary function of the Lungs allows for gas exchange
• The gas exchange with alveoli, that form alveolar walls

Ventilation

• Ventilation moves air into lungs, and distribution withing them
• Factors of infuence include lung volume/capacity, Compliance, resistance

Lung Volumes and Capacities

Term | Definition

• -- | ---
• Tidal Volume | A normal breath (~500ml) or the amount of gas entering or leaving the lung during normal breathing
• Inspiratory Reserve Volume | The amount of gas a person is to inspire above a normal breath maximal of deep breath, ~3L
• Expiratory Reserve Volume | The amount of gas expired beyond tidal volume (~1.2 L)
• Residual Volume | The volume left in the lungs at the end of a maximal expiration (~1.2L)
• Lung Capacities | Lung Capacities
• Vital Capacity | The total volume of gas that be exhaled during maximal respiration (~4.8 L)
• Inspiratory Capacity | The amount of gas -Inspired from a resting Expiration (~3.5L)
• Functional Residual Capacity | The amount of gas left during lungs/ end a normal Expiration Total Lung Capacity | The amount of gas in the lungs at maximal inspiration (~6L)

Lung Innervation

• Diameter controlled by smooth muscle and ANS system
• Broncho constriction caused by Parasympathetic stimulation
• Bronchodilation Caused by Sympathetic (B2 Receptors) to relaxes the smooth muscle

Lower Respiratory Disorders

• The lower Respiratory System has diseases such as Asthma, COPD and Asthma-COPD Overlap .
• Both are lung diseases, swelling of the airways restrict expiratory airflow!
• Asthma, COPD, ACOSWELLING airways is more
• Asthma increases over children/ adult ; boys/girls
  • Has genetics factors with Prenatal, Maternal smoking, diet use,
  • Lungs is reduced after birth; Atopic disease, active passive with increase of BMI

Asthma Pathophysiology

• There is increased Resistance that is airway obstruction cause hyper response.
• Bronchospasm, inflammation, high secretion, and inhalations
• narrow bronchial lumen can still expand in the alveoli -Exhalations
• increase pressure & "closes!"

What happens in Asthma?

Change | Signs and Symptoms

• -- | ---
• Bronchial constriction | Sudden dyspnea, wheezing, limited breath sounds
• Excessive Mucus Production | Coughing: Thick, clear, or sputum
• Hypoxemia | Rapid- Tachyypnea of accessory muscles

Asthma treatment

• Goals includes:
  • Optimize asthma
  • Risk reduction
  • Educate
  • Types of Education includes:
    • asthma + triggers/medicine
    • action plan +techniques
    • quick release medicine

Chronic Obstructive Pulmonary Disorder

• This is progressive disorder/characterized chronic and obstructed of airflow.
• With Anatomic changes- narrowing of small airways and destruction of lung
• Lung elastic is a factor
• Airflow resistant-
• The reverse of resistance
• Two types, chronic and emphysema
• cases are from cigarrette smoking

COPD Symptoms

• Cough = Chronic in characteristics
• Mucus= Hypersecretion
• Dysfunction- Cillia
• Lungs = Hyperextension, / Abnormalities
• Diagnostics test PFTs and dyspnea

2 General Types of COPD

Type | Characteristics

• -- | ---
• Blue Bloater = Chronic Bronchitis | Is a chronic excess mucus secretion into
• Pink Puffer =Emphysema | With small airways/ hyperinflation & airwayClosure

Diagnosis of COPD with PFT results

• GOLD 1: Mild (FEV1 ≥80% predicted)
• GOLD 2: Moderate (50% predicted ≤FEV1 <80% predicted)
• GOLD 3: Severe (30% predicted ≤FEV1 <50% predicted)
• GOLD 4: Very severe (FEV1 <30% predicted)

COPD Considerations

• Must be use cautious with beta blockers; because these cause bronchoconstriction
• No cure, goal is to stop progressive education and have education such as: smoking techniques with rehabilitation.
• Vaccinations are key, so must be function as well as gas exchange

Asthma VS COPD

Asthma vs. COPD | Asthma | COPD

• -- | --- | ---
• Sensitizing agent with CD4+ T Lymphocytes | Airway inflammation and Eosinophils | Noxious, CD8+ T, Lymphocytes
• Airflow Limitation reversible Airflow: Irreversible

Clinical Feature

• Symptoms = minutes > 20 hours
• Triggers at night from Allergens
• Have airflow spirometry (peak Flow)
• normal test/worsening
• Immediate bronchodilators
• Normal Radiography/Eczema

COPD

• Symptoms = > 40 hours
• Have daily dyspnea
• Records a airflow -Has heavy risk = Tabaco
• Rapid acting, doesn’t relieve Symptoms

Pharmacologic Treatment

• Inhaled mediations = enhance because is the direct site
• Device =meter- does dry powered + nebulizers

Asthma and COPD

• Medication = Beta-2 agonists bronchodilators, anti-inflammatory agents.
• Medications are broken between rescue & controllers

Prototype | Characteristics

• -- | ---
• Short Acting Beta-2 Agonists (SABA)-Albuterol + Controller is quick use | Selectivity for beta 2 = smooth lungs , cilia motility. Toxicity minimal, but Too High is deadly
• Long-Acting Beta-2 Agonist (LABA) Salmeterol =Slow of Maintenance | This is schedule and for is with chest; No coffee

Beta-2 Patient

• What you appropriately use?
• Limit, no report of difficulty
• No over-the-counter + If exercise

Anticholinergics (short/long)

• Blocks for as a Controller agent, and block for dry in peanut
• Check and rinse.

Combination therapy

• The combination of albuterol and patropium

Methylxanthimes

• Helps with Caffeine with adverse to smoking and antibiotics

Inhaled Corticosteroid (ICS): Budesonide

• It suppresses = Long term for Beta2 Agonst
• It decrease airway for Beta2 again-

Medication summary for Both Asthma and COPD

Asthma | COPD

• -- | ---
• SABA for everyone (plus or minus a SAMA)
• Inhaled corticosteroid (ICS) and LAMA or LABA
• Can not be use for a Leukotriene / asthma

Other Respiratory Disorders

Cystic Fibrosis (CF)

• It’s (Inherited)
• CFTR has thick, obstruction glands.
  • Lungs are primary
  • There the mucus and DNA Chemotherapy
  • chest
  • glucose and exercise

CFTR modifier: ivacaftor:

• Its mutations for it cellular. Skin can cause interaction

Other Notes for CF Class

• Normal is always functional to the cell
• 22% = no function at 88%
• Correction the long term, may help for the channel

Pneumonia

• Etiology= Fungal, or Bacterial, with the Inflammatory reaction in or lungs.
• Causes may have secretions and with systemic with Inhalation in the content

Types of pneumonia

•Lobnar • Interstitial, symmetrical Bronch •air bronchogram

Bacteria

• Manifestation: •Fever with Sputum
• bacterial

TB : Mycobacterium Classification

Risk factor •Long term with the HIV & tobacco • In-contact to others.

TB Presentation: •Night Fever & Cough • airway

TB and Drugs

• Must know that drugs help to treat what in body?

• Must have multiple Drugs

Drug | Side effect

• -- | ---
• Rifampin | Red urine
• Isoniazid | Peripheral neritis, disulfiram Pyrazinamide | Inc uric Ethambutol | Visual disturbances

COPD

• Reversible with medications inhalation to have long term!

Module III overview: ventilation and respiratory tract. Covers respiratory system anatomy including the nasal cavity, pharynx, larynx, trachea, and lungs. Functions of airways, defence mechanisms and allergies are also discussed.