Respiratory System: Anatomy and Processes

• Primary function is gas exchange to provide oxygen to body cells and remove carbon dioxide

Components of the Respiratory System

• Upper airway includes the nose, mouth, pharynx, larynx, and trachea
  • Functions to warm, humidify, and filter air
• Lower airway includes the primary, secondary, and tertiary bronchi, bronchioles, alveolar ducts, and alveoli
  • Alveoli are the functional units for gas exchange
• Pleura are membranes that surround and cushion the lungs protecting them, the space between the layers is the pleural cavity

Exchanges

• Ventilation is the flow of air into and out of the alveoli
  • Asthma causes bronchoconstriction, which decreases ventilation
• Diffusion is the exchange of oxygen and carbon dioxide between alveoli and red blood cells in the bloodstream
  • Lung fibrosis increases alveolar thickness, impairing diffusion
• Perfusion is the exchange of oxygen and carbon dioxide between red blood cells and body tissues
  • Peripheral arterial disease restricts blood flow to the extremities, decreasing perfusion
• Arterial blood gases are used to assess acid-base balance, ventilation, and oxygenation in critically ill patients

Normal ABG Limits

• pH measures hydrogen ion concentration, normal range is 7.35-7.45
• PaCO2 measures partial pressure of carbon dioxide, normal range is 35-45 mmHg
• HCO3 measures bicarbonate, normal range is 21-28 mEq/L
• PaO2 measures partial pressure of oxygen, normal range is 80-100 mmHg
• SaO2 measures oxygen saturation, normal range is 95-100%
  • SpO2 is measured via pulse oximetry with a normal range of 95-100%
  • Patients with COPD are expected to have SpO2 and SaO2 levels in the low 90s
• Pulmonary function tests evaluate lung function, including lung volume, capacity, and rate of flow
  • Useful for diagnosing asthma and COPD

Bronchoscopy

• Bronchoscopy involves inserting a bronchoscope into the airway for visualization and specimen collection
• Pre-Op: Maintain the patient NPO for 4-8 hours and prepare them for sedation
• Post-Op: Ensure the patient's gag reflex returns before allowing them to eat or drink
  • Sore throat with blood-tinged sputum is expected
  • Pneumothorax may occur within 24 hours after the procedure

Thoracentesis

• Thoracentesis involves inserting a needle into the posterior chest to aspirate fluid or air from the pleural space
• Pre-Op: Position the patient upright with arms supported on pillows or an overbed table, educating them not to move, talk, or cough
• Post-Op: Monitor for mediastinal shift, pneumothorax, bleeding, and hypotension
  • If complications are suspected, obtain a chest X-ray, and encourage deep breaths to expand the lungs

Oxygenation

• Hypoxemia: low oxygen content in the arterial blood( less than 80 mmHg), which can lead to hypoxia, or deficient oxygen supply to the tissues
• Early S/S of Hypoxia: restlessness, irritability, abnormal breathing, tachycardia, tachypnea, hypertension, pallor
• Late S/S of Hypoxia: decreased LOC, increased lactic acid (lactic acidosis), dysrhythmias, bradycardia, bradypnea, hypotension, cyanosis
• Oxygen toxicity: exposure to above-normal O2 partial pressures leading to non-productive cough, nasal congestion, substernal pain, headache, NV, fatigue, and sore throat
• Use the lowest necessary oxygen liter flow to manage hypoxia oxygen toxicity

Oxygen Delivery Devices

• Nasal cannula delivers 1-6 L/min, use water-based lubricant to prevent drying
• Simple face mask delivers 5-8 L/min, impairs ability to eat, drink, and talk
• Partial rebreather delivers 10-15 L/min, adjust flow rate to maintain bag ⅔ full
• Non-rebreather delivers 10-15 L/min, inflate the reservoir bag before applying
• Aerosol mask/face tent delivers 6-15 L/min, good for facial traumas or burns
• Venturi devices provide the most precise O2 delivery (up to 40%) without intubation and the flow rate depends on the mask being attached

Sleep Apnea

• Breathing disruption in sleep that lasts > 10 seconds and occurs > or equal to 5 times per hour
• Obstructive sleep apnea: upper airways become blocked by overly relaxed airway muscles or by tongue/soft palate
• Central sleep apnea: the brain doesn't send signals to the muscles that control breathing
• Risk factors include obesity, large tonsils, neuromuscular or endocrine disorders
• Signs and symptoms: persistent daytime sleepiness, irritability
• Diagnosis: polysomnography, overnight sleep study
• Interventions: CPAP or BIPAP Machine

Respiratory Diseases

• Asthma: a chronic inflammatory disorder of the airway that is intermittent and reversible
  • Triggers (allergens, cold air) cause inflammation and airway hyperresponsiveness, leading to bronchoconstriction and airway obstruction
  • Signs and Symptoms: dyspnea, wheezing, chest tightness, coughing, tachypnea, use of accessory muscles, prolonged expiration, barrel chest with severe asthma
  • Labs: PFTs, ABG (decreased PaO2), SpO2 less than 92%
  • Treatment: bronchodilators, anticholinergics, anti-inflammatories, leukotriene antagonists
• Patient education to monitor asthma using a peak flow meter, perform 3 times and record the highest number and to indetify and avoid triggers
  • Exercise-induced asthma, the patient should use a bronchodilator 30 min before
  • Differentiate between short-acting and long-acting medications and proper use of MDI or DPI inhalers with Albuterol as a short-acting reliever for acute attacks, and salmeterol as long acting, taken daily
  • Complication: status asthmaticus - airway obstruction unresponsive to usual therapy and can lead to pneumothorax and cardiac/respiratory distress
    • S/S: extremely labored breathing, gasping or inability to speak, anxiety, decreased LOC, neck vein distention, pulsus paradoxus, and cyanosis
    • Interventions: bronchodilators, epinephrine, corticosteroids
    • Nursing considerations: administer oxygen, prepare for emergency intubation and mechanical ventilation

COPD

• Chronic obstructive pulmonary disease is a group of diseases (emphysema, chronic bronchitis) that causes irreversible airway obstruction
  • Emphysema causes destruction of alveoli, decreased lung elasticity, hyperinflation, and air trapping
  • Bronchitis causes inflammation of the airways and hypersecretion of mucus, leading to hypoventilation, hypoxemia, and hypercapnia
  • Risk factors include smoking, air pollution, occupational chemicals/dusts, infection
  • Common Signs and Symptoms: cough, excess sputum, dyspnea, crackles/wheezing, barrel chest, use of accessory muscles, nail clubbing, cyanosis, hyperresonance due to trapped air, rapid/shallow respirations, decreased SpO2, “tripod” position
  • Labs: ABG (increased PaCO2, decreased PaO2), polycythemia, chest X-ray, PFTs
  • Treatment: inhaled bronchodilators, anticholinergics, corticosteroids, mucolytics, systemic corticosteroids, oxygen therapy
    • Giving high concentrations of oxygen can cause a patient with COPD to lose their hypoxic drive to breathe
    • Place patient in upright position, administer oxygen as prescribed, monitor for complications (ex: R sided HF)
    • Smoking cessation, breathing techniques, effective coughing, incentive spirometer, small and frequent meals, increased fluids, high calorie/protein diet, oxygen safety

Cystic Fibrosis

• Genetic disorder that impairs lung function and causes dysfunction in other organs/tissues that make mucus or sweat
  • Autosomal recessive, causing obstruction of NaCl transport within cell membranes, resulting in thick, sticky mucus that plugs organ ducts and leads to organ failure

Cystic Fibrosis Signs and Symptoms

• Respiratory: wheezing, coughing, dyspnea, mucus plugs, cyanosis, barrel chest, clubbing, chronic respiratory infections
• GI: steatorrhea (fatty, malodorous stools) delayed growth, fat-soluble vitamin deficiency
• Skin: high NaCl content in sweat, saliva, and tears
• Labs: sweat chloride test, DNA testing, PFTs, stool analysis

Cystic Fibrosis Interventions

• Meds: bronchodilators, anticholinergics, dornase alfa, antibiotics, pancreatic enzymes
• Procedures: chest physiotherapy - uses percussion, vibration, postural drainage, and breathing exercises to loosen respiratory secretions
  • Schedule treatments before meals 1-2 hours or after meals to avoid vomiting, using a bronchodilator 30-60 minutes before treatment
  • Administer oxygen, encourage increased fluids, increased protein/calorie diet, provide supplements such as fat-soluble vitamins (ADEK)

Interstitial Lung Disease (ILD)

• A group of lung disorders that cause stiff and noncompliant lungs, which are restrictive diseases, which causes issues getting air into the lungs
• Chronic inflammation damages the drugs, replacing healthy lung tissue with fibrotic scar tissue
• Risk factors include environmental inhalants, immune disorders, sarcoidosis
  • Common Signs and Symptoms: cough, dyspnea, chest discomfort, fatigue, nail clubbing
  • Labs: X-ray, lung biopsy, PFTs
  • Treatment: Oxygen, corticosteroids, lung transplant

Pulmonary Hypertension

• High BP in the lungs
• Increased vascular resistance and narrowing of the arteries in the lungs increase pressure in the right ventricle, leading to right ventricle enlargement/failure which is Cor Pulmonale
• Causes: cardiac defects, pulmonary embolism, lung disease (ex: COPD)
• Common Signs and Symptoms: dyspnea, pallor, fatigue, chest pain on exertion, weakness, edema related to right-sided heart failure
  • Labs: cardiac catheterization, ABG, EKG, PFTs, hemodynamic monitoring
  • Treatment: diuretics, digoxin, vasodilators, oxygen therapy
  • Nursing Considerations: fluid restriction for right-sided heart failure, monitor I&Os and daily weight, and encourage frequent rest periods

Upper Respiratory Tract Infections

• Inflammation of nasal mucosa (rhinitis), sinuses (sinusitis), pharynx (pharyngitis), larynx (laryngitis), tonsils (tonsillitis)
  • -itis = inflammation
  • Viral infection, bacterial infection, or allergies can cause the release of histamine, resulting in vasodilation and edema
  • Signs and Symptoms rhinorrhea, sore throat, headache, facial pain, fever, hoarseness, difficulty swallowing
  • Labs: pharyngeal culture to rule out group A beta-hemolytic streptococcal infection, influenza, and COVID-19
  • Treatment: nasal saline irrigation, steam inhalation with Meds like mucolytics, decongestants, analgesics, antibiotics for bacterial infections

Influenza

• Highly contagious acute viral respiratory infection
  • Influenza A, B, or C virus is spread primarily through droplets from person-to-person, attaching to epithelial cells in the respiratory tract and replicates
  • Prevention: hand washing, annual vaccination, avoid close contact with infected individuals, masking
  • Common Signs and Symptoms: fever/chills, malaise, muscle aches, headache, rhinorrhea, cough, sore throat
  • Labs: rapid influenza diagnostic test using nasal/throat swab
  • Treatment: saline gargles, rest, increased fluid intake and Meds like antiviral agents, analgesics, antitussives along with droplet precautions

Pneumonia

• Excess fluid in the lungs due to inflammation
  • Infections organism causes inflammation and fluid collection in and around the alveoli, leading to impaired gas exchange
  • Common Signs and Symptoms: fever, SOB, chest pain, cough, dyspnea, confusion, crackles/wheezes
  • Labs: increased WBCs, ABG, sputum culture
    • Obtain sputum culture before starting antibiotics
    • Labs: chest X-ray
    • Treatment: antibiotics, bronchodilators, oxygen therapy
    • High Fowler's position, administer oxygen as prescribed, encourage coughing, deep breathing, use of an incentive spirometer, increased fluid intake

Tuberculosis (TB)

• Infectious disease in the lungs caused by Mycobacterium tuberculosis
  • Transmitted via aerosolization
  • Organism attaches to the alveoli, triggering an immune response, ingestion of the bacilli by macrophages, and formation of granulomas
  • Signs and Symptoms cough longer than 3 weeks, purulent and/or bloody sputum, night sweats, weight loss, lethargy
  • Labs: Blood test, Mantoux skin test, AFB culture, CXR
    • Treatment: combination of drug therapy with 6-12 months -Nursing considerations: place patient in negative airflow room wear N-95 mask in room, patient should wear surgical mask when leaving room
    • Screen family for TB while teaching patient how to do sputum samples every 2-4 weeks, only safe after 3 negative cultures

Pulmonary Embolism (PE)

• Life-threatening blockade in a lung artery via DVT
  • Embolus becomes lodged in pulmonary circulation Pulmonary vascular occlusion leads to impaired gas exchange
  • Causes: Obesity, immobility, afib, pregnancy, surgery, long bone fractures
  • Signs and Symptoms: SOB, anxiety, chest pain w/ inspiration, tachy, hypotension, petechiae, and diaphoresis
• Diagnostics: Increased d-dimer and CT angiogram for presence - Interventions: Meds & surgical intervention (thrombolectomy) -Nursing: Monitor oxygen, upright position, PT to prevent future complications(compression socks, mobility, stop smoking)

Pleural Disorders

• Patho: increase in pressure within the pleural space d/t blood, air or fluid which can lead to lung collapse.
  • Types: - Hemothorax: blood accumulation -Pneumothorax: air accumulation -Pleural effusion: fluid accumulation
• S/S: respiratory distress; reduced breath sounds, hyperresonance or fullness
• Diagnostics: Chest X-ray
• Interventions: Benzodiazepines/analgesics for pain management, chest tube
  • Chest Tube - inserted to drain & positioned upward for hemothorax & downward pneumothorax

Tension Pneumothroax

Air is trapped in the pleural cavity under positive pressure when air cant escape on expiration, which builds up in pressure that collapses the lung

Acute Respiratory Distress Syndrome (ARDS)

• Patho: Systemic Inflammatory Response causes inflammation and collapse of the lungs d/t edema or fluid -Causes: trauma, pnemonia shock, sepsis
  • Diagnostics: V/Q mismatch, inflammation and hypoxemia

Acute Respiratory Failure (ARF)

• Patho: Lack of O2, inability to extract CO2 d/t lung collapse -Causes: PE, Heart Failure -Diagnostics: Electrolytes, BUN and Creatine
• Interventions: Maintain airway, Effective positioning (good lung down & HOB 30 degrees)

Beta 2 Adrenergic Agonists

• Bronchodilator
  • Medications: Albuterol and salmeterol
  • Indications: COPD/Asthma -PT Teaching: when a glucocorticoid is prescribed, be advised to administer the Bronchodilator first and wait 5 mins.

Xanthine Derivatives

• Bronchodilator - Medication: theophylline & aminophylline -Indication: COPD and asthmatic conditions

Anticholinergics

• Bronchodilator - Medication: Ipratropium and tiotropium - Indications COPD; asthma

Leukotriene Receptor Antagonist

• Bronchodilators that alleviates astham - Medications: montelukast- relieve ashtma and zafirlukast reduce airway inflammation

Interventions against Dry Coughs

• Antitussives: Benzonatate, Codeine and Dextromethorphan
• Medications aim to suppress the cough d/t side effects: sedation/ GI upset/respiratory depression

Medication for wet coughs

• Expectorants - Guaifenesin - help the body cough up all that gunk
• Mucolytics - Acetylcysteine - pulmonary disorder remedy